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Sample records for active npc inverters

  1. Optimized Pulse Width Modulation for transformerless active-NPC inverters

    DEFF Research Database (Denmark)

    Achilladelis, Nikolaos; Koutroulis, Eftichios; Blaabjerg, Frede

    2014-01-01

    The transformerless DC/AC inverter topologies are employed in Photovoltaic systems in order to improve the power conversion efficiency, power density and cost. The Active-Neutral Point Clamped (Active-NPC) transformerless inverters have the advantage of achieving better thermal balance among thei...

  2. Optimal design of NPC and Active-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2012-01-01

    Targeting at a cost-effective deployment of grid-connected PhotoVoltaic (PV) systems, this paper presents a new methodology for the optimal design of transformerless PV inverters, which are based on the Neutral Point Clamped (NPC) and the Active-Neutral Point Clamped (ANPC) topologies. The design...... optimization results demonstrate that a different set of optimal values of the PV inverter switching frequency and output filter components are derived for the NPC and ANPC topologies, respectively, as well as for each of the PV inverter installation sites under study. The NPC and ANPC PV inverter structures......, which are derived using the proposed design optimization methodology exhibit lower Levelized Cost Of generated Electricity (LCOE) and manufacturing cost and they are simultaneously capable to inject more energy into the electric grid than the corresponding non-optimized PV inverters. Thus, the proposed...

  3. The PWM strategies of grid-connected distributed generation active NPC inverters

    DEFF Research Database (Denmark)

    Ma, Lin; Xinmin, Jin; Kerekes, Tamas

    2009-01-01

    The Neutral Point Clamped topology due to high efficiency, low leakage current and EMI, its integration is widely used in the distributed generation (DG) systems. However the main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which...... leads to an unequal distribution of temperature. By using the Active NPC topology, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper two known strategies are discussed and a new proposed PWM strategy......, namely the Adjustable Losses Distribution (ALD) PWM strategy is proposed for better losses distribution in the Active NPC (ANPC) topology. Simulations using Simulink and the PLECS toolbox have been done for evaluating efficiency of different NPC topologies and some experimental results are presented...

  4. Cascaded impedance networks for NPC inverter

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang

    2010-01-01

    they are subject to the renewable sources. To date, three distinct types of impedance networks can be summarized for implementing a hybrid source impedance network, which can in principle be combined and cascaded before connected to a NPC inverter by proposed two ways. The resulting cascaded impedance network NPC...

  5. A new Zero Voltage Switching three-level NPC inverter

    DEFF Research Database (Denmark)

    He, Ning; Chen, Yenan; Xu, Dehong

    2015-01-01

    A novel Zero Voltage Switching (ZVS) three-level NPC inverter topology using a new ZVS Space Vector Modulation (SVM) scheme is proposed. A detailed operation analysis of ZVS three-level NPC inverter is given. The ZVS condition of the proposed ZVS inverter is derived and it can be achieved of all...

  6. A New N-Level Inverter Based on Z-NPC

    Directory of Open Access Journals (Sweden)

    E. Babaei

    2017-12-01

    Full Text Available First of all, in this paper, the topology and operation of the three-phase three-level Z-source inverter based on neutral-point-clamped (Z-NPC are studied. Moreover, different combinations of permissible switching states and control signals are explained for this inverter. In this paper, the topology of the three-phase three-level Z-NPC inverter is extended for an n-level state. Also, a combination of allowed switching states with relevant mathematical equations is presented for the proposed n-level Z-NPC inverter. In comparison with multilevel voltage-source inverters (only voltage-boost capability, the proposed multilevel Z-NPC inverter is a single-stage converter and it has a buck-boost capability of voltage. On the other hand, the control of two-stage converters compared to single-stage converters can be more difficult because of existing more active and passive components. In this paper, two new PWM control methods are also proposed for various multilevel Z-NPC inverters. One advantage of the proposed PWM control methods in comparison with conventional PWM control methods is maintaining the charge balance of the dc-link capacitors in neutral point. The correct performance of the proposed multilevel Z-NPC topology and PWM control methods are verified by the obtained results of analysis and simulations performed in the PSCAD software.

  7. Analyze and Improve Lifetime in 3L-NPC Inverter from Power Cycle and Thermal Balance

    DEFF Research Database (Denmark)

    Chen, Quan; Chen, Zhe; Wang, Qunjing

    2014-01-01

    Three-level Neutral-point-clamped (3L-NPC) topology is becoming a realistic alternative to the conventional one in high-voltage and high-power application. Studies show that the power cycling mean time to failure (MTTF) of the semiconductor bond wire in 3L-NPC inverter system may be very short...... under some common conditions. Firstly, this paper shows the impact of some key parameters on power electronic system lifetime according the analysis of semiconductor failure mechanism. Secondly, a switching frequency reduction method based on the position relationship between the flowing current...... and load voltage is applied to reduce power cycle and switching losses. And then, three-level active neutral point-clamped topology is taken into account to wake the most thermo stressed device. In order to validate the improve lifetime method in this paper, a 2MW 3L-NPC converter used in wind energy has...

  8. Asymmetric power device rating selection for even temperature distribution in NPC inverter

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede

    2017-01-01

    the power rating and lifetime of the NPC inverter are limited by the most stressed devices. In this paper, an asymmetric power device rating selection method for the NPC inverter is proposed in order to balance the lifetimes of the power devices. The thermal distribution of the power devices is analyzed......A major drawback of the NPC inverter is an unequal power loss distribution among the power devices which leads to unequal temperature stress among them. Therefore, certain power devices experience higher temperature stress, which is the main cause of power device module failure and thus both...... based on 30 kW NPC inverter as a case study. Analytical power loss and thermal impedance models depending on the chip size are derived. Finally, using these models, the junction temperatures of the power devices depending on the chip size is discussed and a proper chip size for an even temperature...

  9. The Circuit-Level Decoupling Modulation Strategy for Three-Level Neutral-Point-Clamped (TL-NPC) Inverter

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2011-01-01

    In this paper, a circuit-level decoupling modulation strategy is proposed for the three-level (TL) neutral-point-clamped (NPC) inverters. With the proposed modulation scheme, the TL-NPC inverter can be decoupled into two three-level Buck converters in each defined operating section, which makes...

  10. Snubber-less NPC inverter by a novel reduction technique of parasitic inductance for magnet power supplies

    Energy Technology Data Exchange (ETDEWEB)

    Koseki, K., E-mail: kunio.koseki@kek.jp; Morita, Y.

    2014-10-11

    The effects induced by parasitic inductance were studied in a neutral point clamped (NPC) inverter. The energy stored in the parasitic inductance by the output current causes a surge voltage during the turn-off period of semiconductor switches. The effect is serious in a magnet power supply for which a large excitation current is required. It is predicted by a circuit analysis that the parasitic inductance causes an electrical breakdown of the semiconductor switches. It was found that the most promising way to mitigate the effect is to reduce the parasitic inductance. With newly developed circuitry and layout of an NPC inverter, cancelation of the induced magnetic field, which is based on Ampere's circuital law, in power devices has been accomplished. The newly developed NPC inverter has been operated successfully with both a resistive dummy load and the dipole magnets in the main ring synchrotron at the J-PARC facility.

  11. High performance fuzzy sliding mode control of DFIG supplied by seven level NPC inverter

    Directory of Open Access Journals (Sweden)

    Mohamed BENKAHLA

    2017-09-01

    Full Text Available This article presents the powers control of a variable speed wind turbine (WT based on a doubly fed induction generator (DFIG because of their advantages in terms of economy and control. The considered system consists of a double fed induction generator whose stator is connected directly to the network and its rotor is supplied by seven-level inverter with structure NPC are well used to minimize the harmonics absorbed by the DFIG. In order to control the power flowing between the stator of the DFIG and the grid. Have been studied and compared two types of controllers : Sliding Mode Control (SMC and Fuzzy SMC (FSMC. Their respective performances are compared in terms of power reference tracking, response to sudden speed variations, sensitivity to perturbations and robustness against machine parameters variations.

  12. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    OpenAIRE

    Xu, Shi-Zhou; He, Feng-You

    2016-01-01

    In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single pe...

  13. Discontinuous PWM Modulation Strategy with Circuit-Level Decoupling Concept of Three-Level Neutral-Point Clamped (NPC) Inverter

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2013-01-01

    inverters, but also reduces the switching loss of the inverter along with an inherent neutral point (NP) voltage control. Based on a circuit-level decoupling concept, the NPC inverter can be decoupled into two three-level Buck converters in every defined operating section, and thereby the controller design...... can be reduced by one third. In order to explain the operation of this topology properly, the decoupling principle including the driving signal synthesis and the NP potential variation are analyzed in detail in this paper. Finally the viability and performance of the proposed modulation scheme...

  14. New strategy for eliminating zero-sequence circulating current between parallel operating three-level NPC voltage source inverters

    DEFF Research Database (Denmark)

    Li, Kai; Dong, Zhenhua; Wang, Xiaodong

    2018-01-01

    A novel strategy based on a zero common mode voltage pulse-width modulation (ZCMV-PWM) technique and zero-sequence circulating current (ZSCC) feedback control is proposed in this study to eliminate ZSCCs between three-level neutral point clamped (NPC) voltage source inverters, with common AC and DC......, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can...

  15. Design of Neutral-Point Voltage Controller of a Three-level NPC Inverter with Small DC-Link Capacitors

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.

    2013-01-01

    A Neutral-Point-Clamped (NPC) three-level inverter with small dc-link capacitors is presented in this paper. The inverter requires zero average neutral-point current for stable neutral-point voltage. The small dc-link capacitors may not maintain capacitor voltage balance, even with zero neutral......-point voltage control on the basis of the continuous model. The design method for optimum performance is discussed. The implementation of the proposed modulation strategy and the controller is very simple. The controller is implemented in a 7.5 kW induction machine based drive with only 14 ìF dc-link capacitors...

  16. New strategy for eliminating zero-sequence circulating current between parallel operating three-level NPC voltage source inverters

    DEFF Research Database (Denmark)

    Li, Kai; Dong, Zhenhua; Wang, Xiaodong

    2018-01-01

    buses, that are operating in parallel. First, an equivalent model of ZSCC in a three-phase three-level NPC inverter paralleled system is developed. Second, on the basis of the analysis of the excitation source of ZSCCs, i.e., the difference in common mode voltages (CMVs) between paralleled inverters......, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can...... be eliminated effectively under steady and dynamic states. Moreover, the proposed strategy exhibits the advantage of not requiring carrier synchronization. It can be utilized in inverters with different types of filter....

  17. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    Directory of Open Access Journals (Sweden)

    Shi-Zhou Xu

    2016-01-01

    Full Text Available In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single period were calculated. Secondly, a thermal equilibrium dynamic control based on DPMW dual-mode modulation was proposed, which can switch the modulation dynamically according to the change of dynamic power loss to realize dynamic control of power loss and thermal equilibrium of inverter. Finally, simulation and experiment prove the effectiveness of the proposed strategy.

  18. Neutral-point voltage dynamic model of three-level NPC inverter for reactive load

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, Sergio

    2012-01-01

    A three-level neutral-point-clamped inverter needs a controller for the neutral-point voltage. Typically, the controller design is based on a dynamic model. The dynamic model of the neutral-point voltage depends on the pulse width modulation technique used for the inverter. A pulse width modulati...

  19. Optimization of SiC-based H5 and Conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    effective in terms of energy production than their non-optimized and Si-based counterparts. Reducing the market price of SiC-type power semiconductors enables to design optimized PV inverters with a lower cost of energy than that of PV inverters employing Si technology, thus maximizing the economic...... profitability of the PV system....

  20. Optimization of SiC-based H5 and conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2015-01-01

    The transformerless dc/ac inverters are critical components in the rapidly growing market of grid-connected photovoltaic (PV) applications. They are synthesized by combining available solutions in terms of the power-section topology, power-semiconductors manufacturing technology, and structure...

  1. A New PWM Strategy for Grid-Connected Half-Bridge Active NPC Converters With Losses Distribution Balancing Mechanism

    DEFF Research Database (Denmark)

    Lin, Ma; Kerekes, Tamas; Rodriguez, Pedro

    2015-01-01

    (NPC) and derived topologies offers high efficiency, low leakage current, and low EMI. However, one main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which leads to an unequal distribution of temperature that can affect lifetime...

  2. Development of a magnet power supply with sub-ppm ripple performance for J-PARC with a novel common-mode rejection method with an NPC inverter

    International Nuclear Information System (INIS)

    Koseki, K.; Kurimoto, Y.

    2014-01-01

    The mechanism that generates common-mode noise in inverter circuits, which are widely used in magnet power supplies, was evaluated by a circuit simulation. By following asymmetric operational sequences, pulsed voltage is applied to the parasitic capacitance of power cables that causes a common-mode current at each switching period of the semiconductor switches. Common-mode noise was also found to disturb the normal-mode excitation current by inducing higher frequency components in the applied voltage to the magnet. To eliminate the disturbing effect by the common-mode noise, a newly developed operational method that uses a neutral point clamped, NPC, inverter with reduced switching sequences was evaluated both by a circuit simulation and experimentally. The operational method for the NPC inverter could sufficiently reduce the common-mode noise. A high-power test operation performed using 16 bending magnets at the J-PARC facility achieved a ripple of less than 1 ppm in the excitation current

  3. Development of a magnet power supply with sub-ppm ripple performance for J-PARC with a novel common-mode rejection method with an NPC inverter

    Energy Technology Data Exchange (ETDEWEB)

    Koseki, K., E-mail: kunio.koseki@kek.jp; Kurimoto, Y.

    2014-05-21

    The mechanism that generates common-mode noise in inverter circuits, which are widely used in magnet power supplies, was evaluated by a circuit simulation. By following asymmetric operational sequences, pulsed voltage is applied to the parasitic capacitance of power cables that causes a common-mode current at each switching period of the semiconductor switches. Common-mode noise was also found to disturb the normal-mode excitation current by inducing higher frequency components in the applied voltage to the magnet. To eliminate the disturbing effect by the common-mode noise, a newly developed operational method that uses a neutral point clamped, NPC, inverter with reduced switching sequences was evaluated both by a circuit simulation and experimentally. The operational method for the NPC inverter could sufficiently reduce the common-mode noise. A high-power test operation performed using 16 bending magnets at the J-PARC facility achieved a ripple of less than 1 ppm in the excitation current.

  4. Multiple low frequency dual reference PWM control of a grid connected photovoltaic three phase NPC inverter with DC/DC boost converter

    Directory of Open Access Journals (Sweden)

    Mechouma Rabiaa

    2014-01-01

    Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.

  5. Simulation and Modeling of a Five -Level (NPC Inverter Fed by a Photovoltaic Generator and Integrated in a Hybrid Wind-PV Power System

    Directory of Open Access Journals (Sweden)

    M. Rezki,

    2017-08-01

    Full Text Available A distributed hybrid coordinated wind photovoltaic (PV power system was proposed in this paper. As oil and coal reserves are being depleted whilst at the same time the energy demand is growing, it is important to consider alternative energy generating techniques. Today, the five-level (NPC inverter represents a good alternative for several industrial applications. To take advantage of the five-level inverter topology and the benefits of renewable energy represented by a photovoltaic generator, a new scheme of these controllers is proposed in this work. This paper outlines the design of a hybrid power system consisting of a solar photovoltaic (PV and a wind power system. The system is modeled in Matlab Simulink and tested for various conditions. The model and results are discussed in this paper.

  6. Filter optimization of Si and SiC semiconductor-based H5 and Conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    Single-phase transformerless Photovoltaic (PV) inverters are synthesized by combining available solutions in terms of the power section topology, power semiconductors manufacturing technology and structure of the output filter. A design method is presented in this paper for optimizing the power......C-based PV inverters will inject more energy into the electric grid, compared to the Si-based structures and enable the reduction of the output filter size, weight and cost. Employing an LLCL-type output filter and simultaneously reducing the cost of SiC power semiconductors to the level of their Si...

  7. A new model predictive control algorithm by reducing the computing time of cost function minimization for NPC inverter in three-phase power grids.

    Science.gov (United States)

    Taheri, Asghar; Zhalebaghi, Mohammad Hadi

    2017-11-01

    This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  8. Open-switch fault detection method of an NPC converter for wind turbine systems

    DEFF Research Database (Denmark)

    Lee, June-Seok; Lee, Kyo-Beum; Blaabjerg, Frede

    2013-01-01

    In wind turbine generation (WTG) systems, the neutral-point-clamped (NPC) topology is widely used as the part of a back-to-back converter since the three-level NPC topology has more advantages than the conventional two-level inverter especially for high power. There are twelve switches in the NPC......-switch detection method of the NPC converter is different from that of the NPC inverter due to the different current paths of the NPC converter. This paper proposes the open-switch fault detection method of the NPC converter connected the permanent-magnet synchronous generator (PMSG). Moreover, the open...

  9. Acid sphingomyelinase activity is regulated by membrane lipids and facilitates cholesterol transfer by NPC2.

    Science.gov (United States)

    Oninla, Vincent O; Breiden, Bernadette; Babalola, Jonathan O; Sandhoff, Konrad

    2014-12-01

    During endocytosis, membrane components move to intraluminal vesicles of the endolysosomal compartment for digestion. At the late endosomes, cholesterol is sorted out mainly by two sterol-binding proteins, Niemann-Pick protein type C (NPC)1 and NPC2. To study the NPC2-mediated intervesicular cholesterol transfer, we developed a liposomal assay system. (Abdul-Hammed, M., B. Breiden, M. A. Adebayo, J. O. Babalola, G. Schwarzmann, and K. Sandhoff. 2010. Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion. J. Lipid Res. 51: 1747-1760.) Anionic lipids stimulate cholesterol transfer between liposomes while SM inhibits it, even in the presence of anionic bis(monoacylglycero)phosphate (BMP). Preincubation of vesicles containing SM with acid sphingomyelinase (ASM) (SM phosphodiesterase, EC 3.1.4.12) results in hydrolysis of SM to ceramide (Cer), which enhances cholesterol transfer. Besides SM, ASM also cleaves liposomal phosphatidylcholine. Anionic phospholipids derived from the plasma membrane (phosphatidylglycerol and phosphatidic acid) stimulate SM and phosphatidylcholine hydrolysis by ASM more effectively than BMP, which is generated during endocytosis. ASM-mediated hydrolysis of liposomal SM was also stimulated by incorporation of diacylglycerol (DAG), Cer, and free fatty acids into the liposomal membranes. Conversely, phosphatidylcholine hydrolysis was inhibited by incorporation of cholesterol, Cer, DAG, monoacylglycerol, and fatty acids. Our data suggest that SM degradation by ASM is required for physiological secretion of cholesterol from the late endosomal compartment, and is a key regulator of endolysosomal lipid digestion. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

  10. Niemann-Pick C1 (NPC1/NPC1-like1 Chimeras Define Sequences Critical for NPC1’s Function as a Filovirus Entry Receptor

    Directory of Open Access Journals (Sweden)

    Esther Ndungo

    2012-10-01

    Full Text Available We recently demonstrated that Niemann-Pick C1 (NPC1, a ubiquitous 13-pass cellular membrane protein involved in lysosomal cholesterol transport, is a critical entry receptor for filoviruses. Here we show that Niemann-Pick C1-like1 (NPC1L1, an NPC1 paralog and hepatitis C virus entry factor, lacks filovirus receptor activity. We exploited the structural similarity between NPC1 and NPC1L1 to construct and analyze a panel of chimeras in which NPC1L1 sequences were replaced with cognate sequences from NPC1. Only one chimera, NPC1L1 containing the second luminal domain (C of NPC1 in place of its own, bound to the viral glycoprotein, GP. This engineered protein mediated authentic filovirus infection nearly as well as wild-type NPC1, and more efficiently than did a minimal NPC1 domain C-based receptor recently described by us. A reciprocal chimera, NPC1 containing NPC1L1’s domain C, was completely inactive. Remarkably, an intra-domain NPC1L1-NPC1 chimera bearing only a ~130-amino acid N–terminal region of NPC1 domain C could confer substantial viral receptor activity on NPC1L1. Taken together, these findings account for the failure of NPC1L1 to serve as a filovirus receptor, highlight the central role of the luminal domain C of NPC1 in filovirus entry, and reveal the direct involvement of N–terminal domain C sequences in NPC1’s function as a filovirus receptor.

  11. Optimal Design of Modern Transformerless PV Inverter Topologies

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    the operational lifetime period of the PV installation, is also considered in the optimization process. According to the results of the proposed design method, different optimal values of the PV inverter design variables are derived for each PV inverter topology and installation site. The H5, H6, neutral point...... clamped, active-neutral point clamped and conergy-NPC PV inverters designed using the proposed optimization process feature lower levelized cost of generated electricity and lifetime cost, longer mean time between failures and inject more PV-generated energy into the electric grid than their nonoptimized......The design optimization of H5, H6, neutral point clamped, active-neutral point clamped, and conergy-NPC transformerless photovoltaic (PV) inverters is presented in this paper. The components reliability in terms of the corresponding malfunctions, affecting the PV inverter maintenance cost during...

  12. Optimal Design of Modern Transformerless PV Inverter Topologies

    OpenAIRE

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    The design optimization of H5, H6, neutral point clamped, active-neutral point clamped, and conergy-NPC transformerless photovoltaic (PV) inverters is presented in this paper. The components reliability in terms of the corresponding malfunctions, affecting the PV inverter maintenance cost during the operational lifetime period of the PV installation, is also considered in the optimization process. According to the results of the proposed design method, different optimal values of the PV inver...

  13. Development of modulation strategies for NPC converter addressing DC link voltage balancing and CMV reduction

    DEFF Research Database (Denmark)

    Boian, D.; Biris, C.; Teodorescu, Remus

    2012-01-01

    3L-NPC inverters are more popular due to their superior performance compared with two level inverters. One of the most optimal applications for multilevel inverter is the Adjustable Speed Drives (ASD). The industry reported numerous ASD failures due to high frequency PWM. Those failures consist i...... strategies is to reduce the Common Mode Voltage (CMV) and balance the DC Link Voltage....

  14. The NPC: A Higher Priority for Networking Policy

    Science.gov (United States)

    Kuhns, Jeff C.

    2006-01-01

    This article discusses the scope of activities of the Network Policy Council (NPC), which has been designed to provide a more direct channel of communications within EDUCAUSE and to provide policy formulation more visibility. The NPC is an advisory council to EDUCAUSE whose members are selected from those who have interest in this area and are…

  15. Open-Switch Fault Detection Method of a Back-to-Back Converter Using NPC Topology for Wind Turbine Systems

    DEFF Research Database (Denmark)

    Lee, June-Seok; Lee, Kyo_Beum; Blaabjerg, Frede

    2015-01-01

    system can break down in the worst case scenario. To improve the reliability of WTG systems, an open-switch fault detection method for back-to-back converters using the NPC topology is required. This study analyzes effects of inner and outer open-switch faults of the NPC rectifier and inverter......In wind turbine generation (WTG) systems, a back-to-back converter with a neutral-point-clamped (NPC) topology is widely used because this topology has more advantages than a conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology....... An open-switch fault in the NPC rectifier of the back-to-back converter leads to the distortion of the input current and torque vibration in the system. Additionally, an open-switch fault in the NPC inverter of the back-to-back converter causes the distortion of the output current. Furthermore, the WTG...

  16. Five-Level Z-Source Neutral Point-Clamped Inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    This paper proposes a five-level Z-source neutralpoint- clamped (NPC) inverter with two Z-source networks functioning as intermediate energy storages coupled between dc sources and NPC inverter circuitry. Analyzing the operational principles of Z-source network with partial dclink shoot......-through scheme reveals the hidden theories in the five-level Z-source NPC inverter unlike the operational principle appeared in the general two-level Z-source inverter, so that the five-level Z-source NPC inverter can be designed with the modulation of carrier-based phase disposition (PD) or alternative phase...

  17. Model predictive control for a dual active bridge inverter with a floating bridge

    OpenAIRE

    Chowdhury, Shajjad; Wheeler, Patrick W.; Gerada, C.; Patel, Chintan

    2016-01-01

    This paper presents a Model Predictive Control technique applied to a dual active bridge inverter where one of the bridges is floating. The proposed floating bridge topology eliminates the need for isolation transformer in a dual inverter system and therefore reduces the size, weight and losses in the system. To achieve multilevel output voltage waveforms the floating inverter DC link capacitor is charged to the half of the main DC link voltage. A finite-set Model Predictive Control technique...

  18. Investigation of Pseudo-Active State in Z-Source Inverter

    DEFF Research Database (Denmark)

    Schaltz, Erik; Oprea, Octavian; Larsen, Lasse

    2005-01-01

    This paper introduces a new operating state of the Z-source inverter denoted the pseudo-active state. The pseudoactive state is a state that may boost the output voltage of the Zsource inverter to a level higher than expected. The influence of the pseudo-active state is investigated and an equation...

  19. Transformer-based asymmetrical embedded Z-source neutral point clamped inverters with continuous input current and enhanced voltage boost capability

    DEFF Research Database (Denmark)

    Mo, W.; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-so......-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation....

  20. Model Predictive Control of Z-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    2011-01-01

    This paper presents Model Predictive Control (MPC) of Z-source Neutral Point Clamped (NPC) inverter. For illustration, current control of Z-source NPC grid-connected inverter is analyzed and simulated. With MPC’s advantage of easily including system constraints, load current, impedance network...... response are obtained at the same time with a formulated Z-source NPC inverter network model. Operation steady state and transient state simulation results of MPC are going to be presented, which shows good reference tracking ability of this method. It provides new control method for Z-source NPC inverter...

  1. Plant phosphatidylcholine-hydrolyzing phospholipases C NPC3 and NPC4 with roles in root development and brassinolide signaling in Arabidopsis thaliana.

    Science.gov (United States)

    Wimalasekera, Rinukshi; Pejchar, Premysl; Holk, André; Martinec, Jan; Scherer, Günther F E

    2010-05-01

    Phosphatidylcholine-hydrolyzing phospholipase C (PC-PLC) catalyzes the hydrolysis of phosphatidylcholine (PC) to generate phosphocholine and diacylglycerol (DAG). PC-PLC has a long tradition in animal signal transduction to generate DAG as a second messenger besides the classical phosphatidylinositol splitting phospholipase C (PI-PLC). Based on amino acid sequence similarity to bacterial PC-PLC, six putative PC-PLC genes (NPC1 to NPC6) were identified in the Arabidopsis genome. RT-PCR analysis revealed overlapping expression pattern of NPC genes in root, stem, leaf, flower, and silique. In auxin-treated P(NPC3):GUS and P(NPC4):GUS seedlings, strong increase of GUS activity was visible in roots, leaves, and shoots and, to a weaker extent, in brassinolide-treated (BL) seedlings. P(NPC4):GUS seedlings also responded to cytokinin with increased GUS activity in young leaves. Compared to wild-type, T-DNA insertional knockouts npc3 and npc4 showed shorter primary roots and lower lateral root density at low BL concentrations but increased lateral root densities in response to exogenous 0.05-1.0 μM BL. BL-induced expression of TCH4 and LRX2, which are involved in cell expansion, was impaired but not impaired in repression of CPD, a BL biosynthesis gene, in BL-treated npc3 and npc4. These observations suggest NPC3 and NPC4 are important in BL-mediated signaling in root growth. When treated with 0.1 μM BL, DAG accumulation was observed in tobacco BY-2 cell cultures labeled with fluorescent PC as early as 15 min after application. We hypothesize that at least one PC-PLC is a plant signaling enzyme in BL signal transduction and, as shown earlier, in elicitor signal transduction.

  2. Influence of the active layer pattern on the electrical characteristics of organic inverters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Hyun; Kwon, Jin-Hyuk; Bae, Jin-Hyuk [Kyungpook National University, Daegu (Korea, Republic of); Park, Jae-Hoon; Baang, Sung-Keun [Hallym University, Chuncheon (Korea, Republic of)

    2014-12-15

    We describe the importance of a patterned active layer for the fine driving of organic inverters. In the case of a non-patterned inverter, the capacitance as a function of the applied bias in an organic capacitor structure exhibits a slow saturation nature due to the slow movement of charge carriers. Hence, during the operation of organic inverters with non-patterned active layers, the voltage gains inevitably exhibit lower values whereas higher gains are achieved in the case of sharply-patterned pentacene layers. These results suggest that the patterning of the active layer can be a decisive factor for realizing high-performance electronic circuits based on organic semiconductors.

  3. Grid-Voltage-Feedforward Active Damping for Grid-Connected Inverter with LCL Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    For the grid-connected voltage source inverters, the feedforward scheme of grid voltage is commonly adopted to mitigate the current distortion caused by grid background voltages harmonics. This paper investigates the grid-voltage-feedforward active damping for grid connected inverter with LCL...... filter. It reveals that proportional feedforward control can not only fulfill the mitigation of grid disturbance, but also offer damping effects on the LCL filter resonance. Digital delays are intrinsic to digital controlled inverters; with these delays, the feedforward control can be equivalent...

  4. Shunt Active-Power-Filter Topology Based on Parallel Interleaved Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Asiminoaei, Lucian; Aeloiza, E.

    2008-01-01

    In this paper, an interleaved active-power-filter concept with reduced size of passive components is discussed. The topology is composed of two pulsewidth-modulation interleaved voltage-source inverters connected together on the ac line and sharing the same dc-link capacitor. The advantages......, because the power sharing allows one to use a higher switching frequency in each inverter. This paper analyzes the design of the passive components and gives a practical and low-cost solution for the minimization of the circulation currents between the inverters, by using common-mode coils. Several...

  5. LCCT-derived three-level three-phase inverters

    DEFF Research Database (Denmark)

    Shults, Tatiana; Husev, Oleksandr; Blaabjerg, Frede

    2017-01-01

    Solutions for a family of the novel three-level neutral-point-clamped (NPC) inductor-capacitor-capacitor-transformer (LCCT)-derived three-phase inverters are described and compared. Component design guidelines and steady state analysis, current and voltage waveforms are given. The authors......' simulation results confirm the theoretical predictions. It was found that an asymmetrical three-level NPC LCCT-derived inverter with a single diode in the impedance source network is the most promising solution. Experimental results for an asymmetrical three-level NPC LCCT-derived inverter with a single...

  6. Trans-Z-source Neutral Point Clamped inverter

    DEFF Research Database (Denmark)

    Mo, W.; Loh, P. C.; Li, D.

    2012-01-01

    Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...

  7. Active Damping Techniques for LCL-Filtered Inverters-Based Microgrids

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Firoozabadi, Mehdi Savaghebi; Askarian Abyaneh, Hossein

    2015-01-01

    LCL-type filters are widely used in gridconnected voltage source inverters, since it provides switching ripples reduction with lower cost and weight than the L-type counterpart. However, the inclusion of LCL-filters in voltage source inverters complicates the current control design regarding system...... the different active damping approaches for grid-connected inverters with LCL filters, which are based on high-order filters and additional feedbacks methods. These techniques are analyzed and discussed in detail....... stability issues; because an inherent resonance peak appears due to zero impedance at that resonance frequency. Moreover, in grid-interactive low-voltage microgrids, the interactions among the LCL-filtered-based parallel inverters may result in a more complex multiresonance issue which may compromise...

  8. Design and analysis of active power control strategies for distributed generation inverters under unbalanced grid faults

    NARCIS (Netherlands)

    Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

    2010-01-01

    Distributed power generation systems are expected to deliver active power into the grid and support it without interruption during unbalanced grid faults. Aiming to provide grid-interfacing inverters the flexibility to adapt to the coming change of grid requirements, an optimised active power

  9. An Active Power Filter Based on a Three-Level Inverter and 3D-SVPWM for Selective Harmonic and Reactive Compensation

    Directory of Open Access Journals (Sweden)

    José Luis Monroy-Morales

    2017-03-01

    Full Text Available Active Power Filters (APFs have been used for reducing waveform distortion and improving power quality. However, this function can be improved by means of a selective harmonic compensation. Since an APF has rating restrictions, it is convenient to have the option of selecting an individual or a set of particular harmonics in order to compensate and apply the total APF capabilities to eliminate these harmonics, in particular those with a greater impact on the Total Harmonic Distortion (THD. This paper presents the development of a new APF prototype based on a three-phase three-level Neutral Point Clamped (NPC inverter with selective harmonic compensation capabilities and reactive power compensation. The selective harmonic compensation approach uses several Synchronous Rotating Frames (SRF, to detect and control individual or a set of harmonics using d and q variables. The APF includes a Three-Dimensional Space Vector Modulator (3D-SVPWM in order to generate the compensation currents. Because of its multilevel topology, the proposed active power filter can be used in diverse power quality applications at sub-transmission and distribution voltage levels. Simulation and experimental results are shown to validate the proposed solution and assess the prototype performance in different scenarios.

  10. Electric vehicle battery charging algorithm using PMSM windings and an inverter as an active rectifier

    DEFF Research Database (Denmark)

    Zaja, Mario; Oprea, Matei-lon; Suárez, Carlos Gómez

    2014-01-01

    for battery charging. Alternatively, charging could be done using the motor windings as grid side inductors and controlling the inverter to operate as an active boost rectifier. The challenge in this approach is the unequal phase inductances which depend on the rotor position. Another problem appears when...... an integrated charger control algorithm to charge the battery through a permanent magnet synchronous machine (PMSM) windings....

  11. Advances in PV Inverters

    DEFF Research Database (Denmark)

    Anthon, Alexander

    and preferably low complexity leads to new research demands. This is especially true in the field of low cost residential PV inverters where efficiencies are used as major selling arguments. Traditional converter topologies equipped with conventional Silicon based semiconductors to date reach their limitations......, a replacement of only two switching devices per phase leg can greatly reduce the semiconductor losses. The Hybrid-NPC converter can be seen as an attractive and cost competitive alternative to the Silicon Carbide based converter, also allowing to overcome the major drawbacks with the conventional Silicon IGBT...

  12. Localization and role of NPC1L1 in cholesterol absorption in human intestine.

    Science.gov (United States)

    Sané, Alain Théophile; Sinnett, Daniel; Delvin, Edgard; Bendayan, Moise; Marcil, Valérie; Ménard, Daniel; Beaulieu, Jean-François; Levy, Emile

    2006-10-01

    Recent studies have documented the presence of Niemann-Pick C1-Like 1 (NPC1L1) in the small intestine and its capacity to transport cholesterol in mice and rats. The current investigation was undertaken to explore the localization and function of NPC1L1 in human enterocytes. Cell fractionation experiments revealed an NPC1L1 association with apical membrane of the enterocyte in human jejunum. Signal was also detected in lysosomes, endosomes, and mitochondria. Confirmation of cellular NPC1L1 distribution was obtained by immunocytochemistry. Knockdown of NPC1L1 caused a decline in the ability of Caco-2 cells to capture micellar [(14)C]free cholesterol. Furthermore, this NPC1L1 suppression resulted in increased and decreased mRNA levels and activity of HMG-CoA reductase, the rate-limiting step in cholesterol synthesis, and of ACAT, the key enzyme in cholesterol esterification, respectively. An increase was also noted in the transcriptional factor sterol-regulatory element binding protein that modulates cholesterol homeostasis. Efforts were devoted to define the impact of NPC1L1 knockdown on other mediators of cholesterol uptake. RT-PCR evidence is presented to show the significant decrease in the levels of scavenger receptor class B type I (SR-BI) with no changes in ABCA1, ABCG5, and cluster determinant 36 in NPC1L1-deficient Caco-2 cells. Together, our data suggest that NPC1L1 contributes to intestinal cholesterol homeostasis and possibly cooperates with SR-BI to mediate cholesterol absorption in humans.

  13. Reliability Evaluation of a Single-phase H-bridge Inverter with Integrated Active Power Decoupling

    DEFF Research Database (Denmark)

    Tang, Junchaojie; Wang, Haoran; Ma, Siyuan

    2016-01-01

    it with the traditional passive DC-link solution. The converter level reliability is obtained by component level electro-thermal stress modeling, lifetime model, Weibull distribution, and Reliability Block Diagram (RBD) method. The results are demonstrated by a 2 kW single-phase inverter application.......Various power decoupling methods have been proposed recently to replace the DC-link Electrolytic Capacitors (E-caps) in single-phase conversion system, in order to extend the lifetime and improve the reliability of the DC-link. However, it is still an open question whether the converter level...... reliability becomes better or not, since additional components are introduced and the loading of the existing components may be changed. This paper aims to study the converter level reliability of a single-phase full-bridge inverter with two kinds of active power decoupling module and to compare...

  14. Pulsewidth-modulated 2-source neutral-point-clamped inverter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chang; Gao, Feng

    2007-01-01

    This paper presents the careful integration of a newly proposed Z-source topological concept to the basic neutral-point-clamped (NPC) inverter topology for designing a three-level inverter with both voltage-buck and voltage-boost capabilities. The designed Z-source NPC inverter uses two unique X......-shaped inductance-capacitance (LC) impedance networks that are connected between two isolated dc input power sources and its inverter circuitry for boosting its AC output voltage. Through the design of an appropriate pulsewidth-modulation (PWM) algorithm, the two impedance networks can be short......-circuited sequentially (without shooting through the inverter full DC link) for implementing the ldquonearest-three-vectorrdquo modulation principle with minimized harmonic distortion and device commutations per half carrier cycle while performing voltage boosting. With only a slight modification to the inverter PWM...

  15. Simulation model of harmonics reduction technique using shunt active filter by cascade multilevel inverter method

    Science.gov (United States)

    Andreh, Angga Muhamad; Subiyanto, Sunardiyo, Said

    2017-01-01

    Development of non-linear loading in the application of industry and distribution system and also harmonic compensation becomes important. Harmonic pollution is an urgent problem in increasing power quality. The main contribution of the study is the modeling approach used to design a shunt active filter and the application of the cascade multilevel inverter topology to improve the power quality of electrical energy. In this study, shunt active filter was aimed to eliminate dominant harmonic component by injecting opposite currents with the harmonic component system. The active filter was designed by shunt configuration with cascaded multilevel inverter method controlled by PID controller and SPWM. With this shunt active filter, the harmonic current can be reduced so that the current wave pattern of the source is approximately sinusoidal. Design and simulation were conducted by using Power Simulator (PSIM) software. Shunt active filter performance experiment was conducted on the IEEE four bus test system. The result of shunt active filter installation on the system (IEEE four bus) could reduce THD current from 28.68% to 3.09%. With this result, the active filter can be applied as an effective method to reduce harmonics.

  16. An Active Trap Filter for Switching Harmonics Attenuation of Low-Pulse-Ratio Inverters

    DEFF Research Database (Denmark)

    Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

    2017-01-01

    method has also been proposed for the ATF to better enforce its active switching harmonic bypassing ability. Compared with conventional schemes for controlling active power filters, the proposed method is more readily implemented, since it requires neither current reference generation nor high......-bandwidth current control loop. Moreover, the use of a series LC-filter at its ac-side helps the ATF to reduce its inverter voltage and power ratings. Compensated frequency range of the ATF can hence be enlarged by using a comparably higher switching frequency and a proper step-by-step design procedure...

  17. Active control of flying capacitor currents in multilevel voltage-source inverters

    Czech Academy of Sciences Publication Activity Database

    Kokeš, Petr; Semerád, Radko

    2013-01-01

    Roč. 58, č. 4 (2013), s. 393-410 ISSN 0001-7043 Institutional support: RVO:61388998 Keywords : voltage source inverter (VSI) * multilevel inverter * flying capacitor Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  18. Stability Analysis and Active Damping for LLCL-filter-Based Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    to use either passive or active damping methods. This paper analyzes the stability of the LLCL-filter based grid-connected inverter and identifies a critical resonant frequency for the LLCL-filter when sampling and transport delays are considered. In a high resonant frequency region the active damping...... is not required but in a low resonant frequency region the active damping is necessary. The basic LLCL resonance damping properties of different feedback states based on a notch filter concept are also studied. Then an active damping method which is using the capacitor current feedback for LLCL......-filter is introduced. Based on this active damping method, a design procedure for the controller is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  19. Olfactory deficits in Niemann-Pick type C1 (NPC1 disease.

    Directory of Open Access Journals (Sweden)

    Marina Hovakimyan

    Full Text Available BACKGROUND: Niemann-Pick type C disease (NPC is a rare autosomal recessive lipid storage disease characterized by progressive neurodegeneration. As only a few studies have been conducted on the impact of NPC on sensory systems, we used a mutant mouse model (NPC1(-/- to examine the effects of this disorder to morphologically distinct regions of the olfactory system, namely the olfactory epithelium (OE and olfactory bulb (OB. METHODOLOGY/PRINCIPAL FINDINGS: For structural and functional analysis immunohistochemistry, electron microscopy, western blotting, and electrophysiology have been applied. For histochemistry and western blotting, we used antibodies against a series of neuronal and glia marker proteins, as well as macrophage markers. NPC1(-/- animals present myelin-like lysosomal deposits in virtually all types of cells of the peripheral and central olfactory system. Especially supporting cells of the OE and central glia cells are affected, resulting in pronounced astrocytosis and microgliosis in the OB and other olfactory cortices. Up-regulation of Galectin-3, Cathepsin D and GFAP in the cortical layers of the OB underlines the critical role and location of the OB as a possible entrance gate for noxious substances. Unmyelinated olfactory afferents of the lamina propria seem less affected than ensheathing cells. Supporting the structural findings, electro-olfactometry of the olfactory mucosa suggests that NPC1(-/- animals exhibit olfactory and trigeminal deficits. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a pronounced neurodegeneration and glia activation in the olfactory system of NPC1(-/-, which is accompanied by sensory deficits.

  20. A Two-Stage Robust Optimization for Centralized-Optimal Dispatch of Photovoltaic Inverters in Active Distribution Networks

    DEFF Research Database (Denmark)

    Ding, Tao; Li, Cheng; Yang, Yongheng

    2017-01-01

    Optimally dispatching Photovoltaic (PV) inverters is an efficient way to avoid overvoltage in active distribution networks, which may occur in the case of PV generation surplus load demand. Typically, the dispatching optimization objective is to identify critical PV inverters that have the most...... nature of solar PV energy may affect the selection of the critical PV inverters and also the final optimal objective value. In order to address this issue, a two-stage robust optimization model is proposed in this paper to achieve a robust optimal solution to the PV inverter dispatch, which can hedge...... against any possible realization within the uncertain PV outputs. In addition, the conic relaxation-based branch flow formulation and second-order cone programming based column-and-constraint generation algorithm are employed to deal with the proposed robust optimization model. Case studies on a 33-bus...

  1. [Active miniature inverted-repeat transposable elements transposon in plants: a review].

    Science.gov (United States)

    Hu, Bingjie; Zhou, Mingbing

    2018-02-25

    Miniature inverted-repeat transposable elements transposon is a special transposon that could transpose by "cut-paste" mechanism, which is one of characteristics of DNA transposons. Otherwise, the copy number of MITEs is very high, which is one of characteristics of RNA transposons. Many MITE families have been reported, but little about active MITEs. We summarize recent advances in studying active MITEs. Most the MITEs belong to the Tourist-like family, such as mPing, mGing, PhTourist1, Tmi1 and PhTst-3. Additionally, DTstu1 and MITE-39 belong to Stowaway-like family, and AhMITEs1 belongs to Mutator-like family. Moreover, we summarize the structure (terminal inverse repeats and target site duplications), copy number, evolution pattern and transposition characteristics of these active MITEs, to provide the foundation for the identification of other active MITEs and subsequent research on MITE transposition and amplification mechanism.

  2. Expression patterns of sterol transporters NPC1 and NPC2 in the cnidarian-dinoflagellate symbiosis.

    Science.gov (United States)

    Dani, Vincent; Priouzeau, Fabrice; Mertz, Marjolijn; Mondin, Magali; Pagnotta, Sophie; Lacas-Gervais, Sandra; Davy, Simon K; Sabourault, Cécile

    2017-10-01

    The symbiotic interaction between cnidarians (e.g., corals and sea anemones) and photosynthetic dinoflagellates of the genus Symbiodinium is triggered by both host-symbiont recognition processes and metabolic exchange between the 2 partners. The molecular communication is crucial for homeostatic regulation of the symbiosis, both under normal conditions and during stresses that further lead to symbiosis collapse. It is therefore important to identify and fully characterise the key players of this intimate interaction at the symbiotic interface. In this study, we determined the cellular and subcellular localization and expression of the sterol-trafficking Niemann-Pick type C proteins (NPC1 and NPC2) in the symbiotic sea anemones Anemonia viridis and Aiptasia sp. We first established that NPC1 is localised within vesicles in host tissues and to the symbiosome membranes in several anthozoan species. We demonstrated that the canonical NPC2-a protein is mainly expressed in the epidermis, whereas the NPC2-d protein is closely associated with symbiosome membranes. Furthermore, we showed that the expression of the NPC2-d protein is correlated with symbiont presence in healthy symbiotic specimens. As npc2-d is a cnidarian-specific duplicated gene, we hypothesised that it probably arose from a subfunctionalisation process that might result in a gain of function and symbiosis adaptation in anthozoans. Niemann-Pick type C proteins may be key players in a functional symbiosis and be useful tools to study host-symbiont interactions in the anthozoan-dinoflagellate association. © 2017 John Wiley & Sons Ltd.

  3. Improved Active-Neutral-Point-Clamped (I-ANPC) Multilevel Converter: Fundamental Circuit Topology, Innovative Modulatioin Technique, and Experimental Validation

    DEFF Research Database (Denmark)

    Dargahi, Vahid; Corzine, Keith A.; Enslin, Johan H.

    2018-01-01

    For medium-voltage (MV) high-power industrial applications including HVDC and variable-speed motor drives, multilevel converters are deemed predominant topology. One of the promising derived-topologies from neutral-point-clamped (NPC) configuration is active NPC (ANPC) inverter that offers improved......-capacitor (FC) and four switches such as the insulated-gate bipolar transistors (IGBTs). The I-ANPC converter has considerable advantages over the classic multilevel inverters that makes it a preferable topology for MV applications. The substantial reduction in the number of cells in comparison with classic...

  4. Stability analysis and active damping for LLCL-filter based grid-connected inverters

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A higher order passive power filter (LLCL-filter) for the grid-tied inverter is becoming attractive for the industrial applications due to the possibility to reduce the cost of the copper and the magnetic material. To avoid the well-known stability problems of the LLCL-filter it is requested to use...... either passive or active damping methods. This paper analyzes the stability when damping is required and when damping is not necessary considering sampling and transport delay. Basic LLCL resonance damping properties of different feedback states are also studied. Then an active damping method which...... is using the capacitor current feedback for LLCL-filter is introduced. Based on this method, a design procedure for the control method is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  5. A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    M. Pakdel

    2017-04-01

    Full Text Available This paper presents a novel neutral point clamped full-bridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies.

  6. An active damping method based on biquad digital filter for parallel grid-interfacing inverters with LCL filters

    DEFF Research Database (Denmark)

    Lu, Xiaonan; Sun, Kai; Huang, Lipei

    2014-01-01

    around the switching frequency and its multiples. Although the LCL-filters have several advantages compared to single inductance filter, its resonance problem should be noticed. Conventionally, the resonance analysis is mainly focused on the single inverter system, whereas in a renewable energy system...... to the conventional active damping approaches, the biquad filter based active damping method does not require additional sensors and control loops. Meanwhile, the multiple instable closed-loop poles of the parallel inverter system can be moved to the stable region simultaneously. Real-time simulations based on d...

  7. A Series-LC-Filtered Active Trap Filter for High Power Voltage Source Inverter

    DEFF Research Database (Denmark)

    Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

    2016-01-01

    Passive trap filters are widely used in high power Voltage Source Inverters (VSI) for the switching harmonic attenuation. The usage of the passive trap filters requires clustered and fixed switching harmonic spectrum, which is not the case for low pulse-ratio or Variable Switching Frequency (VSF...... current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output...... impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control...

  8. RNA Export through the NPC in Eukaryotes.

    Science.gov (United States)

    Okamura, Masumi; Inose, Haruko; Masuda, Seiji

    2015-03-20

    In eukaryotic cells, RNAs are transcribed in the nucleus and exported to the cytoplasm through the nuclear pore complex. The RNA molecules that are exported from the nucleus into the cytoplasm include messenger RNAs (mRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), small nuclear RNAs (snRNAs), micro RNAs (miRNAs), and viral mRNAs. Each RNA is transported by a specific nuclear export receptor. It is believed that most of the mRNAs are exported by Nxf1 (Mex67 in yeast), whereas rRNAs, snRNAs, and a certain subset of mRNAs are exported in a Crm1/Xpo1-dependent manner. tRNAs and miRNAs are exported by Xpot and Xpo5. However, multiple export receptors are involved in the export of some RNAs, such as 60S ribosomal subunit. In addition to these export receptors, some adapter proteins are required to export RNAs. The RNA export system of eukaryotic cells is also used by several types of RNA virus that depend on the machineries of the host cell in the nucleus for replication of their genome, therefore this review describes the RNA export system of two representative viruses. We also discuss the NPC anchoring-dependent mRNA export factors that directly recruit specific genes to the NPC.

  9. Active power control strategies for inverter-based distributed power generation adapted to grid-fault ride-through requirements

    NARCIS (Netherlands)

    Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

    2009-01-01

    Distributed power generation is expected to deliver power into the grid without interruption during voltage dips. To improve system ride-through capabilities, a generalized active power control strategy is proposed for grid-interfacing inverters. Specifically, a current reference generation strategy

  10. Inverting the Linear Algebra Classroom

    Science.gov (United States)

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  11. A Refined Self-Tuning Filter-Based Instantaneous Power Theory Algorithm for Indirect Current Controlled Three-Level Inverter-Based Shunt Active Power Filters under Non-sinusoidal Source Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yap Hoon

    2017-02-01

    Full Text Available In this paper, a refined reference current generation algorithm based on instantaneous power (pq theory is proposed, for operation of an indirect current controlled (ICC three-level neutral-point diode clamped (NPC inverter-based shunt active power filter (SAPF under non-sinusoidal source voltage conditions. SAPF is recognized as one of the most effective solutions to current harmonics due to its flexibility in dealing with various power system conditions. As for its controller, pq theory has widely been applied to generate the desired reference current due to its simple implementation features. However, the conventional dependency on self-tuning filter (STF in generating reference current has significantly limited mitigation performance of SAPF. Besides, the conventional STF-based pq theory algorithm is still considered to possess needless features which increase computational complexity. Furthermore, the conventional algorithm is mostly designed to suit operation of direct current controlled (DCC SAPF which is incapable of handling switching ripples problems, thereby leading to inefficient mitigation performance. Therefore, three main improvements are performed which include replacement of STF with mathematical-based fundamental real power identifier, removal of redundant features, and generation of sinusoidal reference current. To validate effectiveness and feasibility of the proposed algorithm, simulation work in MATLAB-Simulink and laboratory test utilizing a TMS320F28335 digital signal processor (DSP are performed. Both simulation and experimental findings demonstrate superiority of the proposed algorithm over the conventional algorithm.

  12. Inverted oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C [Physics Department, Anadolu University, Eskisehir (Turkey); Kilic, A [Physics Department, Anadolu University, Eskisehir (Turkey); Coruh, A [Physics Department, Sakarya University, Sakarya (Turkey)

    2006-07-15

    The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wavefunction for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete, and the energy is given as a linear function of the quantum number n.

  13. Comparative Evaluation of Pulsewidth Modulation Strategies for Z-Source Neutral-Point-Clamped Inverter

    DEFF Research Database (Denmark)

    Loh, P.C.; Blaabjerg, Frede; Wong, C.P.

    2007-01-01

    modulation (PWM) strategies for controlling the Z-source NPC inverter. While developing the PWM techniques, attention has been devoted to carefully derive them from a common generic basis for improved portability, easier implementation, and most importantly, assisting readers in understanding all concepts......Z-source neutral-point-clamped (NPC) inverter has recently been proposed as an alternative three-level buck-boost power conversion solution with an improved output waveform quality. In principle, the designed Z-source inverter functions by selectively "shooting through" its power sources, coupled...... to the inverter using two unique Z-source impedance networks, to boost the inverter three-level output waveform. Proper modulation of the new inverter would therefore require careful integration of the selective shoot-through process to the basic switching concepts to achieve maximal voltage-boost, minimal...

  14. Accurate and Less-Disturbing Active Anti-Islanding Method based on PLL for Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Agelidis, Vassilios; Teodorescu, Remus

    2008-01-01

    Islanding prediction is a necessary feature of inverter-based photovoltaic (PV) system in order to meet stringent standard requirements for interconnection with the electrical grid. Both passive and active anti-islanding methods exist. Typically, active methods modify a given parameter, which also...... extracted from the voltage at PCC moves outside of a preset threshold value. This new active anti-islanding method meets both standard requirements IEEE 929-2000, IEEE 1547.1 and VDE 0126.1.1. The disturbance used by this method is small compared to other active anti-islanding methods, such as active...

  15. Enhanced Buck-Boost Three-Level Neutral-Point-Clamped Inverters

    DEFF Research Database (Denmark)

    Tan, K. K.; Gao, F.; Chiang Loh, Poh

    2009-01-01

    In traditional three-level neutral-point-clamped (NPC) inverters, a major issue is capacitor voltage imbalance, which results in low order harmonics. The compensation of the capacitor voltages often require additional control complexity, which cannot be conveniently implemented. The "alternative...... phase opposition disposition" (APOD) modulation method used in traditional NPC topologies also has lower harmonics performance as compared to the "phase disposition" (PD) modulation method.In this paper, we introduce a new three-level NPC topology that utilises the harmonically superior PD modulation...... method, with the ability to easily adjust for capacitor voltage imbalances. To further improve the boost capability of the three-level NPC inverters, another new topology introduces 2 additional diodes,achieving higher boost performance while totally eliminating thepossibility of capacitor voltage...

  16. A Fast-Processing Modulation Strategy for Three-Phase Four-Leg Neutral-Point-Clamped Inverter Based on the Circuit-Level Decoupling Concept

    DEFF Research Database (Denmark)

    Ghoreishy, Hoda; Zhang, Zhe; Thomsen, Ole Cornelius

    2012-01-01

    In this paper, a modulation strategy based on the circuit-level decoupling concept is proposed and investigated for the three-level four-leg neutral-point-clamped (NPC) inverter,with the aim of delivering power to all sorts of loads, linear/nonlinear and balanced/unbalanced. By applying the propo......In this paper, a modulation strategy based on the circuit-level decoupling concept is proposed and investigated for the three-level four-leg neutral-point-clamped (NPC) inverter,with the aim of delivering power to all sorts of loads, linear/nonlinear and balanced/unbalanced. By applying...... the proposed modulation strategy, the four-leg NPC inverter can be decoupled into three three-level Buck converters in each defined operating section. This makes the controller design much simpler compared to the conventional four-leg NPC inverter controllers. Also, this technique can be implemented...

  17. Fabrication of Hybrid Polymer Solar Cells By Inverted Structure Based on P3HT:PCBM Active Layer

    Directory of Open Access Journals (Sweden)

    Shobih Shobih

    2017-08-01

    Full Text Available Hybrid polymer solar cell has privilege than its conventional structure, where it usually has structure of (ITO/PEDOT:PSS/Active Layer/Al. In humid environment the PEDOT:PSS will absorb water and hence can easily etch the ITO. Therefore it is necessary to use an alternative method to avoid this drawback and obtain more stable polymer solar cells, namely by using hybrid polymer solar cells structure with an inverted device architecture from the conventional, by reversing the nature of charge collection. In this paper we report the results of the fabrication of inverted bulk heterojunction polymer solar cells based on P3HT:PCBM as active layer, utilizing ZnO interlayer as buffer layer between the ITO and active layer with a stacked structure of ITO/ZnO/P3HT:PCBM/PEDOT:PSS/Ag. The ZnO interlayer is formed through short route, i.e. by dissolving ZnO nanoparticles powder in chloroform-methanol solvent blend rather than by sol-gel process. Based on the measurement results on electrical characteristics of inverted polymer solar cells under 500 W/m2 illumination and AM 1.5 direct filter at room temperature, cell with annealing process of active layer at 110 °C for 10 minutes results in higher cell performance than without annealing, with an open-circuit voltage of 0.21 volt, a short-circuit current density of 1.33 mA/cm2 , a fill factor of 43.1%, and a power conversion efficiency of 0.22%. The low cell’s performance is caused by very rough surface of ZnO interlayer.

  18. An Enhanced Droop Control Scheme for Resilient Active Power Sharing in Paralleled Two-Stage PV Inverter Systems

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

    2016-01-01

    Traditional droop-controlled systems assume that the generators are able to provide sufficient power as required. This is however not always true, especially in renewable systems, where the energy sources (e.g., photovoltaic source) may not be able to provide enough power (or even loss of power...... generation) due to the intermittency. In that case, unbalance in active power generation may occur among the paralleled systems. Additionally, most droop-controlled systems have been assumed to be a single dc-ac inverter with a fixed dc input source. The dc-dc converter as the front-end of a two...

  19. A SVPWM based on fluctuate capacitor voltage in 3L-NPC back-to-back converter applied to wind energy

    DEFF Research Database (Denmark)

    Chen, Quan; Wang, Qunjing; Chen, Zhe

    2014-01-01

    Three-level Neutral-point-clamped (3L-NPC) converters are becoming a realistic alternative to the conventional converters in high-power wind-energy applications. But the unbalance in the supported capacitors' voltage of back-to-back 3L-NPC converters, including the dynamics of the capacitors...... between the fluctuate voltage of upper and lower capacitors is extracted. Based on this error factor the duty-time of every active voltage vector is calculated. In order to validate the model and the control strategy proposed in this paper, a 2MW 3L-NPC converter used in wind energy has been simulated....

  20. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gao, F.

    2008-01-01

    -voltage oscillations to the system. Therefore, Z-source inverters are in effect safer and less complex, and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family of embedded EZ...

  1. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

    Chiang Loh, Poh; Gao, Feng; Blaabjerg, Frede

    2010-01-01

    overvoltage oscillations to the system. Therefore, Z-source inverters are, in effect, safer and less complex and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family...

  2. Acceleration control system for semi-active in-car crib with joint application of regular and inverted pendulum mechanisms

    Science.gov (United States)

    Kawashima, T.

    2016-09-01

    To reduce the risk of injury to an infant in an in-car crib (or in a child safety bed) collision shock during a car crash, it is necessary to maintain a constant force acting on the crib below a certain allowable value. To realize this objective, we propose a semi-active in-car crib system with the joint application of regular and inverted pendulum mechanisms. The arms of the proposed crib system support the crib like a pendulum while the pendulum system itself is supported like an inverted pendulum by the arms. In addition, the friction torque of each arm is controlled using a brake mechanism that enables the proposed in-car crib to decrease the acceleration of the crib gradually and maintain it around the target value. This system not only reduces the impulsive force but also transfers the force to the infant's back using a spin control system, i.e., the impulse force acts is made to act perpendicularly on the crib. The spin control system was developed in our previous work. This work focuses on the acceleration control system. A semi-active control law with acceleration feedback is introduced, and the effectiveness of the system is demonstrated using numerical simulation and model experiment.

  3. Acceleration control system for semi-active in-car crib with joint application of regular and inverted pendulum mechanisms

    International Nuclear Information System (INIS)

    Kawashima, T

    2016-01-01

    To reduce the risk of injury to an infant in an in-car crib (or in a child safety bed) collision shock during a car crash, it is necessary to maintain a constant force acting on the crib below a certain allowable value. To realize this objective, we propose a semi-active in-car crib system with the joint application of regular and inverted pendulum mechanisms. The arms of the proposed crib system support the crib like a pendulum while the pendulum system itself is supported like an inverted pendulum by the arms. In addition, the friction torque of each arm is controlled using a brake mechanism that enables the proposed in-car crib to decrease the acceleration of the crib gradually and maintain it around the target value. This system not only reduces the impulsive force but also transfers the force to the infant's back using a spin control system, i.e., the impulse force acts is made to act perpendicularly on the crib. The spin control system was developed in our previous work. This work focuses on the acceleration control system. A semi-active control law with acceleration feedback is introduced, and the effectiveness of the system is demonstrated using numerical simulation and model experiment. (paper)

  4. Nezha, a novel active miniature inverted-repeat transposable element in cyanobacteria

    International Nuclear Information System (INIS)

    Zhou Fengfeng; Tran Thao; Xu Ying

    2008-01-01

    Miniature inverted-repeat transposable elements (MITEs) were first identified in plants and exerted extensive proliferations throughout eukaryotic and archaeal genomes. But very few MITEs have been characterized in bacteria. We identified a novel MITE, called Nezha, in cyanobacteria Anabaena variabilis ATCC 29413 and Nostoc sp. PCC 7120. Nezha, like most previously known MITEs in other organisms, is small in size, non-coding, carrying TIR and DR signals, and of potential to form a stable RNA secondary structure, and it tends to insert into A+T-rich regions. Recent transpositions of Nezha were observed in A. variabilis ATCC 29413 and Nostoc sp. PCC 7120, respectively. Nezha might have proliferated recently with aid from the transposase encoded by ISNpu3-like elements. A possible horizontal transfer event of Nezha from cyanobacteria to Polaromonas JS666 is also observed

  5. Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC patients

    Directory of Open Access Journals (Sweden)

    Bouzouita Kamel

    2004-09-01

    Full Text Available Abstract Background Undifferentiated Nasopharyngeal Carcinoma (NPC patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL and tumor- infiltrating (TIL lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10 and three immunoglobulin isotypes (IgM, IgG, IgA. Methods Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA. Data were analysed using Student's t-test and probability values below 5% were considered significant. Results The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002, IL-10 (p = 0,020, IgM (p= 0,0003 and IgG (p Conclusion Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC.

  6. Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC) patients

    International Nuclear Information System (INIS)

    Fliss-Jaber, Lilia; Houissa-Kastally, Radhia; Bouzouita, Kamel; Khediri, Naceur; Khelifa, Ridha

    2004-01-01

    Undifferentiated Nasopharyngeal Carcinoma (NPC) patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV) which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL) and tumor- infiltrating (TIL) lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10) and three immunoglobulin isotypes (IgM, IgG, IgA). Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM) for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA). Data were analysed using Student's t-test and probability values below 5% were considered significant. The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002), IL-10 (p = 0,020), IgM (p= 0,0003) and IgG (p < 0,0001) than their PBL. On the other hand, patients PBL produced significantly higher levels of IL-2 (p = 0,022), IL-10 (p = 0,016) and IgM (p = 0,004) than those of controls. No significant differences for IL-6 and IgA were observed. Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC

  7. Grid-Connection Half-Bridge PV Inverter System for Power Flow Controlling and Active Power Filtering

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2012-01-01

    Full Text Available A half-bridge photovoltaic (PV system is proposed, which can not only deal with bidirectional power flowing but also improve power quality. According to varying insolation, the system conditions real power for dc and ac loads to accommodate different amounts of PV power. Furthermore, the system eliminates current harmonics and improves power factor simultaneously. As compared with conventional PV inverter, the total number of active switches and current sensors can be reduced so that its cost is lower significantly. For current command determination, a linear-approximation method (LAM is applied to avoid the complicated calculation and achieve the maximum power point tracking (MPPT feature. For current controlling, a direct-source-current-shaping (DSCS algorithm is presented to shape the waveform of line current. Simulation results and practical measurements also demonstrate the feasibility of the proposed half-bridge PV system.

  8. Development of Flexible Active Power Control Strategies for Grid-Connected Photovoltaic Inverters by Modifying MPPT Algorithms

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    As the penetration level of grid-connected PV systems increases, more advanced control functionality is demanded. In order to ensure smooth and friendly grid integration as well as enable more PV installations, the power generated by PV systems needs to be flexible and capable of: 1) limiting...... strategies for grid-connected PV inverters by modifying maximum power point tracking algorithms, where the PV power is regulated by changing the operating point of the PV system. In this way, no extra equipment is needed, being a cost-effective solution. Experiments on a 3-kW grid-connected PV system have...... the maximum feed-in power, 2) ensuring a smooth change rate, and 3) providing a power reserve. Besides, such flexible power control functionalities have to be achieved in a cost-effective way in order to ensure the competitiveness of solar energy. Therefore, this paper explores flexible active power control...

  9. Trans-Z-source and Γ-Z-source neutral-point-clamped inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    Z-source neutral-point-clamped (NPC) inverters are earlier proposed for obtaining voltage buck-boost and three-level switching simultaneously. Their performances are, however, constrained by a trade-off between their input-to-output gain and modulation ratio. This trade-off can lead to high...

  10. Single-Phase 3L PR Controlled qZS Inverter Connected to the Distorted Grid

    DEFF Research Database (Denmark)

    Makovenko, Elena; Husev, Oleksandr; Roncero-Clemente, Carlos

    2016-01-01

    This paper presents a single-phase three-level NPC qZS inverter connected to a distorted grid using PID and PR regulators. A case study system along with the control strategy are described. Tuning approaches for PID and PR regulators are addressed and validated by means of simulation results...

  11. Single-Phase LLCL-Filter-based Grid-Tied Inverter with Low-Pass Filter Based Capacitor Current Feedback Active damper

    DEFF Research Database (Denmark)

    Liu, Yuan; Wu, Weimin; Li, Yun

    2016-01-01

    The capacitor-current-feedback active damping method is attractive for high-order-filter-based high power grid-tied inverter when the grid impedance varies within a wide range. In order to improve the system control bandwidth and attenuate the high order grid background harmonics by using the quasi....... In this paper, a low pass filter is proposed to be inserted in the capacitor current feedback loop op LLCL-filter based grid-tied inverter together with a digital proportional and differential compensator. The detailed theoretical analysis is given. For verification, simulations on a 2kW/220V/10kHz LLCL...

  12. The employment of post graduates by NPC

    International Nuclear Information System (INIS)

    Furber, B.N.; Lunt, A.R.W.

    1980-01-01

    The Nuclear Power Company has the sole responsibility in Britain for the design, construction, and commissioning of nuclear power stations. The Company employs some 2400 people, mainly at its two principal administrative and laboratory sites at Risley, Cheshire and Whetstone, Leicester. In carrying out its responsibilities the Company utilises skills in design, project management, planning, quality control, research and development and many other facets of contemporary nuclear engineering. Accordingly it has well formed views on the employment and training of the engineer and scientists who must exhibit and manage such skills. These views are brought out in this paper with particular reference to the relevance of post graduate training to the Company's Research and Development Department. Staff with post graduate research experience are also employed on other engineering activities in the company. The relevance of their experience to non-research work they undertake is also discussed. (author)

  13. Fault-tolerant three-level inverter

    Science.gov (United States)

    Edwards, John; Xu, Longya; Bhargava, Brij B.

    2006-12-05

    A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

  14. A 3D-Space Vector Modulation Algorithm for Three Phase Four Wire Neutral Point Clamped Inverter Systems as Power Quality Compensator

    Directory of Open Access Journals (Sweden)

    Palanisamy Ramasamy

    2017-11-01

    Full Text Available A Unified Power Quality Conditioner (UPQC is designed using a Neutral Point Clamped (NPC multilevel inverter to improve the power quality. When designed for high/medium voltage and power applications, the voltage stress across the switches and harmonic content in the output voltage are increased. A 3-phase 4-wire NPC inverter system is developed as Power Quality Conditioner using an effectual three dimensional Space Vector Modulation (3D-SVM technique. The proposed system behaves like a UPQC with shunt and series active filter under balanced and unbalanced loading conditions. In addition to the improvement of the power quality issues, it also balances the neutral point voltage and voltage balancing across the capacitors under unbalanced condition. The hardware and simulation results of proposed system are compared with 2D-SVM and 3D-SVM. The proposed system is stimulated using MATLAB and the hardware is designed using FPGA. From the results it is evident that effectual 3D-SVM technique gives better performance compared to other control methods.

  15. Benchmark of AC and DC active power decoupling circuits for second-order harmonic mitigation in kW-scale single-phase inverters

    DEFF Research Database (Denmark)

    Qin, Zian; Tang, Yi; Loh, Poh Chiang

    2015-01-01

    studied, where the commercially available film capacitors, circuit topologies, and control strategies for active power decoupling are all taken into account. Then, an adaptive decoupling voltage control method is proposed to further improve the performance of dc decoupling in terms of efficiency...... and reliability. The feasibility and superiority of the identified solution for active power decoupling together with the proposed adaptive decoupling voltage control method are finally verified by both the experimental results obtained on a 2 kW single-phase inverter.......This paper presents the benchmark study of ac and dc active power decoupling circuits for second-order harmonic mitigation in kW-scale single-phase inverters. First of all, the best solutions of active power decoupling to achieve high efficiency and power density are identified and comprehensively...

  16. Three-Level Z-Source Inverters Using a Single LC Impedance Network

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Lim, Sok Wei; Gao, Feng

    2007-01-01

    two LC impedance networks and two isolated dc sources, which can significantly increase the overall system cost and require a more complex modulator for balancing the network inductive voltage boosting. Offering a number of less costly alternatives, this letter presents the design and control of two...... three-level Z-source inverters, whose output voltage can be stepped down or up using only a single LC impedance network connected between the dc input source and either a neutral-point-clamped (NPC) or dc-link cascaded inverter circuitry. Through careful design of their modulation scheme, both inverters...

  17. Modified Synchronous Reference Frame Based Shunt Active Power Filter with Fuzzy Logic Control Pulse Width Modulation Inverter

    Directory of Open Access Journals (Sweden)

    Suleiman Musa

    2017-05-01

    Full Text Available Harmonic distortion in power networks has greatly reduced power quality and this affects system stability. In order to mitigate this power quality issue, the shunt active power filter (SAPF has been widely applied and it is proven to be the best solution to current harmonics. This paper evaluates the performance of the modified synchronous reference frame extraction (MSRF algorithm with fuzzy logic controller (FLC based current control pulse width modulation (PWM inverter of three-phase three-wire SAPF to mitigate current harmonics. The proposed FLC is designed with a reduced amount of membership functions (MFs and rules, and thus significantly reduces the computational time and memory size. Modeling and simulations of SAPF are carried out using MATLAB/Simulink R2012a with the power system toolbox under steady-state condition, and this is followed with hardware implementation using a TMS320F28335 digital signal processor (DSP, Specrum Digital Inc., Stafford, TX, USA. The results obtained demonstrate a good and satisfactory response to mitigate the harmonics in the system. The total harmonic distortion (THD for the system has been reduced from 25.60% to 0.92% and 1.41% in the simulation study with and without FLC, respectively. Similarly for the experimental study, the SAPF can compensate for the three-phase load current by reducing THD to 5.07% and 7.4% with and without FLC, respectively.

  18. Improved Power Conversion Efficiency of Inverted Organic Solar Cells by Incorporating Au Nanorods into Active Layer.

    Science.gov (United States)

    He, Yeyuan; Liu, Chunyu; Li, Jinfeng; Zhang, Xinyuan; Li, Zhiqi; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-07-29

    This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversion efficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

  19. Transcriptome-wide effects of inverted SINEs on gene expression and their impact on RNA polymerase II activity.

    Science.gov (United States)

    Tajaddod, Mansoureh; Tanzer, Andrea; Licht, Konstantin; Wolfinger, Michael T; Badelt, Stefan; Huber, Florian; Pusch, Oliver; Schopoff, Sandy; Janisiw, Michael; Hofacker, Ivo; Jantsch, Michael F

    2016-10-25

    Short interspersed elements (SINEs) represent the most abundant group of non-long-terminal repeat transposable elements in mammalian genomes. In primates, Alu elements are the most prominent and homogenous representatives of SINEs. Due to their frequent insertion within or close to coding regions, SINEs have been suggested to play a crucial role during genome evolution. Moreover, Alu elements within mRNAs have also been reported to control gene expression at different levels. Here, we undertake a genome-wide analysis of insertion patterns of human Alus within transcribed portions of the genome. Multiple, nearby insertions of SINEs within one transcript are more abundant in tandem orientation than in inverted orientation. Indeed, analysis of transcriptome-wide expression levels of 15 ENCODE cell lines suggests a cis-repressive effect of inverted Alu elements on gene expression. Using reporter assays, we show that the negative effect of inverted SINEs on gene expression is independent of known sensors of double-stranded RNAs. Instead, transcriptional elongation seems impaired, leading to reduced mRNA levels. Our study suggests that there is a bias against multiple SINE insertions that can promote intramolecular base pairing within a transcript. Moreover, at a genome-wide level, mRNAs harboring inverted SINEs are less expressed than mRNAs harboring single or tandemly arranged SINEs. Finally, we demonstrate a novel mechanism by which inverted SINEs can impact on gene expression by interfering with RNA polymerase II.

  20. Modulation Methods for Three-level Neutral-Point-Clamped Inverter Achieving Stress Redistribution under Moderate Modulation Index

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede

    2016-01-01

    This letter investigates the loss and thermal behaviors of a three-level neutral-point-clamped (3L-NPC) inverter undergoing moderate modulation index, which is typically presented during minor voltage sags of the power grid or speed changes of the electric machines. A series of new space vector m...

  1. Kemeny commission report. Comments by NPC (Nuclear Power Company)

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Following the accident at Three Mile island in March 1979 the Nuclear Power Company (NPC) has made evaluations of the available information and carried out preliminary investigations of the implications of the accident for all UK AGR's and for the PWR design. The results are summarized. Recommendations of the President's Commission are discussed with especial reference to those under the following headings: (1) The utility and its suppliers. (2) Training of operating personnel. (3) Technical assessment. It is concluded that while many of the relevant recommendations in the report of the President's Commission are already satisfied by UK practices for nuclear safety, and are being applied by NPC in their current programmes of work on AGR's and PWR's it is realised that it is of the utmost importance that complacent attitudes to safety are not allowed to develop. The accident at TMI and report of the Commision have provided a sharp reminder of the necessity to maintain unremitting vigilance in all aspects of design, construction and operation which are involved with the safety of the public and operators.

  2. NREL Pyrheliometer Comparisons: September 26-October 7, 2016 (NPC-2016)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, Ibrahim [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dooraghi, Mike [National Renewable Energy Lab. (NREL), Golden, CO (United States); Andreas, Afshin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Habte, Aron [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-10-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements. National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners and operators, each NPC provides an opportunity to determine the unique World Radiometric Reference transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR. NPC-2016 was September 26 through October 7, 2016. Participants operated 45 absolute cavity radiometers and 27 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky, direct normal solar irradiance during this period.

  3. Psychiatric and neurological symptoms in patients with Niemann-Pick disease type C (NP-C): Findings from the International NPC Registry.

    Science.gov (United States)

    Bonnot, Olivier; Gama, Clarissa S; Mengel, Eugen; Pineda, Mercè; Vanier, Marie T; Watson, Louise; Watissée, Marie; Schwierin, Barbara; Patterson, Marc C

    2017-10-09

    Niemann-Pick disease type C (NP-C) is a rare inherited neurovisceral disease that should be recognised by psychiatrists as a possible underlying cause of psychiatric abnormalities. This study describes NP-C patients who had psychiatric manifestations at enrolment in the international NPC Registry, a unique multicentre, prospective, observational disease registry. Treating physicians' data entries describing psychiatric manifestations in NPC patients were coded and grouped by expert psychiatrists. Out of 386 NP-C patients included in the registry as of October 2015, psychiatric abnormalities were reported to be present in 34% (94/280) of those with available data. Forty-four patients were confirmed to have identifiable psychiatric manifestations, with text describing these psychiatric manifestations. In these 44 patients, the median (range) age at onset of psychiatric manifestations was 17.9 years (2.5-67.9; n = 15), while the median (range) age at NP-C diagnosis was 23.7 years (0.2-69.8; n = 34). Almost all patients (43/44; 98%) had an occurrence of ≥1 neurological manifestation at enrolment. These data show that substantial delays in diagnosis of NP-C are long among patients with psychiatric symptoms and, moreover, patients presenting with psychiatric features and at least one of cognitive impairment, neurological manifestations, and/or visceral symptoms should be screened for NP-C.

  4. In silico assessment of phosphorylation and O-β-GlcNAcylation sites in human NPC1 protein critical for Ebola virus entry.

    Science.gov (United States)

    Basharat, Zarrin; Yasmin, Azra

    2015-08-01

    Ebola is a highly pathogenic enveloped virus responsible for deadly outbreaks of severe hemorrhagic fever. It enters human cells by binding a multifunctional cholesterol transporter Niemann-Pick C1 (NPC1) protein. Post translational modification (PTM) information for NPC1 is crucial to understand Ebola virus (EBOV) entry and action due to changes in phosphorylation or glycosylation at the binding site. It is difficult and costly to experimentally assess this type of interaction, so in silico strategy was employed. Identification of phosphorylation sites, including conserved residues that could be possible targets for 21 predicted kinases was followed by interplay study between phosphorylation and O-β-GlcNAc modification of NPC1. Results revealed that only 4 out of 48 predicted phosphosites exhibited O-β-GlcNAc activity. Predicted outcomes were integrated with residue conservation and 3D structural information. Three Yin Yang sites were located in the α-helix regions and were conserved in studied vertebrate and mammalian species. Only one modification site S425 was found in β-turn region located near the N-terminus of NPC1 and was found to differ in pig, mouse, cobra and humans. The predictions suggest that Yin Yang sites may not be important for virus attachment to NPC1, whereas phosphosite 473 may be important for binding and hence entry of Ebola virus. This information could be useful in addressing further experimental studies and therapeutic strategies targeting PTM events in EBOV entry. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Single stage buck-boost DC-AC neutral point clamped inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Andrew, A.

    2012-01-01

    This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence......, it has enhanced buck-boost functionality and low output voltage distortions compared to the traditional Z-source inverter; it has continuous input current which reduces the source stress and inverter noise; it also contains two built-in capacitors which can block the DC current in the transformer...... windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation...

  6. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2016-01-01

    Inductive-capacitive-inductive (LCL)-type line filters are widely used in grid-connected voltage source inverters (VSIs), since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L......-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid...... passive (resistive) resonance damping solutions, due to their additional power losses, active damping (AD) techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF) AD has...

  7. Hepatic NPC1L1 overexpression ameliorates glucose metabolism in diabetic mice via suppression of gluconeogenesis.

    Science.gov (United States)

    Kurano, Makoto; Hara, Masumi; Satoh, Hiroaki; Tsukamoto, Kazuhisa

    2015-05-01

    Inhibition of intestinal NPC1L1 by ezetimibe has been demonstrated to improve glucose metabolism in rodent models; however, the role of hepatic NPC1L1 in glucose metabolism has not been elucidated. In this study, we analyzed the effects of hepatic NPC1L1 on glucose metabolism. We overexpressed NPC1L1 in the livers of lean wild type mice, diet-induced obesity mice and db/db mice with adenoviral gene transfer. We found that in all three mouse models, hepatic NPC1L1 overexpression lowered fasting blood glucose levels as well as blood glucose levels on ad libitum; in db/db mice, hepatic NPC1L1 overexpression improved blood glucose levels to almost the same as those found in lean wild type mice. A pyruvate tolerance test revealed that gluconeogenesis was suppressed by hepatic NPC1L1 overexpression. Further analyses revealed that hepatic NPC1L1 overexpression decreased the expression of FoxO1, resulting in the reduced expression of G6Pase and PEPCK, key enzymes in gluconeogenesis. These results indicate that hepatic NPC1L1 might have distinct properties of suppressing gluconeogenesis via inhibition of FoxO1 pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Niemann-pick type C1 (NPC1) overexpression alters cellular cholesterol homeostasis.

    Science.gov (United States)

    Millard, E E; Srivastava, K; Traub, L M; Schaffer, J E; Ory, D S

    2000-12-08

    The Niemann-Pick type C1 (NPC1) protein is a key participant in intracellular trafficking of low density lipoprotein cholesterol, but its role in regulation of sterol homeostasis is not well understood. To characterize further the function of NPC1, we generated stable Chinese hamster ovary (CHO) cell lines overexpressing the human NPC1 protein (CHO/NPC1). NPC1 overexpression increases the rate of trafficking of low density lipoprotein cholesterol to the endoplasmic reticulum and the rate of delivery of endosomal cholesterol to the plasma membrane (PM). CHO/NPC1 cells exhibit a 1.5-fold increase in total cellular cholesterol and up to a 2.9-fold increase in PM cholesterol. This increase in PM cholesterol is closely paralleled by a 3-fold increase in de novo cholesterol synthesis. Inhibition of cholesterol synthesis results in marked redistribution of PM cholesterol to intracellular sites, suggesting an unsuspected role for NPC1 in internalization of PM cholesterol. Despite elevated total cellular cholesterol, CHO/NPC1 cells exhibit increased cholesterol synthesis, which may be attributable to both resistance to oxysterol suppression of sterol-regulated gene expression and to reduced endoplasmic reticulum cholesterol levels under basal conditions. Taken together, these studies provide important new insights into the role of NPC1 in the determination of the levels and distribution of cellular cholesterol.

  9. Power density investigations for the large wind turbines' grid-side press-pack IGBT 3L-NPC-VSCs

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

    2012-01-01

    -thermal models are required to be derived, implemented, and utilized. In this study, employed as a grid-side medium voltage full-scale voltage source converters (VSCs) in a multi-MW wind turbine, press-pack IGBT three-level neutral-point-clamped VSC (3L-NPC-VSC), 3L active NPC-VSC (3L-ANPC-VSC), and 3L neutral......Power density is the important design criterion in wind turbine converter design provided that satisfactory converter performance is guaranteed. In order to assess a converter in terms of power density, which is dependent on converter electrical and thermal behaviors, converter electro......-point-piloted VSC (3L-NPP-VSC) are characterized in terms of converter operating principles, physical structure, power loss, and DC bus capacitor size for establishing the basis for converter electro-thermal modeling. Via the practical implementations of the converter electro-thermal models in a computation...

  10. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    Iman Lorzadeh

    2016-08-01

    Full Text Available Inductive-capacitive-inductive (LCL-type line filters are widely used in grid-connected voltage source inverters (VSIs, since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid passive (resistive resonance damping solutions, due to their additional power losses, active damping (AD techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF AD has attracted considerable attention due to its effective damping performance and simple implementation. This paper thus presents a state-of-the-art review of resonance and stability characteristics of CCF-based AD approaches for a digitally-controlled LCL filter-based grid-connected inverter taking into account the effect of computation and pulse width modulation (PWM delays along with a detailed analysis on proper design and implementation.

  11. Structure of N-Terminal Domain of NPC1 Reveals Distinct Subdomains for Binding and Transfer of Cholesterol

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyock Joo; Abi-Mosleh, Lina; Wang, Michael L.; Deisenhofer, Johann; Goldstein, Joseph L.; Brown, Michael S.; Infante, Rodney E.; (UTSMC)

    2010-09-21

    LDL delivers cholesterol to lysosomes by receptor-mediated endocytosis. Exit of cholesterol from lysosomes requires two proteins, membrane-bound Niemann-Pick C1 (NPC1) and soluble NPC2. NPC2 binds cholesterol with its isooctyl side chain buried and its 3{beta}-hydroxyl exposed. Here, we describe high-resolution structures of the N-terminal domain (NTD) of NPC1 and complexes with cholesterol and 25-hydroxycholesterol. NPC1(NTD) binds cholesterol in an orientation opposite to NPC2: 3{beta}-hydroxyl buried and isooctyl side chain exposed. Cholesterol transfer from NPC2 to NPC1(NTD) requires reorientation of a helical subdomain in NPC1(NTD), enlarging the opening for cholesterol entry. NPC1 with point mutations in this subdomain (distinct from the binding subdomain) cannot accept cholesterol from NPC2 and cannot restore cholesterol exit from lysosomes in NPC1-deficient cells. We propose a working model wherein after lysosomal hydrolysis of LDL-cholesteryl esters, cholesterol binds NPC2, which transfers it to NPC1(NTD), reversing its orientation and allowing insertion of its isooctyl side chain into the outer lysosomal membranes.

  12. NREL Pyrheliometer Comparisons: September 22-26, 2014 (NPC-2014)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.; Dooraghi, M.; Habte, A.

    2014-10-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements. As with all measurement systems, absolute cavity radiometers and other types of pyrheliometers are subject to performance changes over time. NREL has developed and maintained a select group of absolute cavity radiometers with direct calibration traceability to the World Radiometric Reference (WRR), and uses these reference instruments to calibrate pyrheliometers and pyranometers using the ISO 17025 accredited Broadband Outdoor Radiometer Calibration (BORCAL) process. National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners and operators, each NPC provides an opportunity to determine the unique WRR transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR. NPC-2014 was held September 22-26, 2014. Participants operated 36 absolute cavity radiometers and 22 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky direct normal solar irradiance during this period, and this report documents the findings.

  13. Inverting an Introductory Statistics Classroom

    Science.gov (United States)

    Kraut, Gertrud L.

    2015-01-01

    The inverted classroom allows more in-class time for inquiry-based learning and for working through more advanced problem-solving activities than does the traditional lecture class. The skills acquired in this learning environment offer benefits far beyond the statistics classroom. This paper discusses four ways that can make the inverted…

  14. Y-source inverter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang

    2014-01-01

    This paper introduces a new 3-phase Y-source inverter whose gain is presently not matched by classical impedance-network-based inverters operating at the same duty ratio. The proposed network uses a tightly coupled transformer with three windings. By squeezing the shoot-through range while keeping...... higher boost, the inverter can operate at a higher modulation index, thereby minimizing switching device stress and providing better output power quality. In addition, the inverter has more degrees of freedom for setting the voltage gain and modulation index than other classical impedance-source networks...

  15. Enhanced Buck–Boost Neutral-Point-Clamped Inverters With Simple Capacitive-Voltage Balancing

    DEFF Research Database (Denmark)

    Tan, Kuan Khoon; Gao, Feng; Loh, Poh Chiang

    2010-01-01

    introduced for extending the inverters’ variation range to include voltageboost operation, but they generally require the inclusion of large passive components or have not yet been optimized in terms of waveform quality. The balancing of their capacitive voltages using a simple technique has also not yet...... simultaneously, two new buck–boost NPC inverters with simple capacitive-voltage-balancing capability are proposed. Both inverters are demonstrated to exhibit a doubling of voltage gain, with one of them also shown to produce a better output waveform quality. Simulation and experimental results are provided...

  16. Kinetic imaging of NPC1L1 and sterol trafficking between plasma membrane and recycling endosomes in hepatoma cells

    DEFF Research Database (Denmark)

    Hartwig Petersen, Nicole; Færgeman, Nils J; Yu, Liqing

    2008-01-01

    fluorescent protein (NPC1L1-EGFP) and cholesterol analogues in hepatoma cells. At steady state about 42% of NPC1L1 resided in the transferrin (Tf) positive, sterol enriched endocytic recycling compartment (ERC), while time-lapse microscopy demonstrated NPC1L1 traffic between plasma membrane and ERC...... the ERC to the plasma membrane. NPC1L1-EGFP facilitated transport of fluorescent sterols from the plasma membrane to the ERC. Insulin induced translocation of vesicles containing NPC1L1 and fluorescent sterol from the ERC to the cell membrane. Upon polarization of hepatoma cells NPC1L1 resided almost...... exclusively in the canalicular membrane, where the protein is highly mobile. Our study demonstrates dynamic trafficking of NPC1L1 between cell surface and intracellular compartments and suggests that this transport is involved in NPC1L1 mediated cellular sterol uptake....

  17. Active Layer Spin Coating Speed Dependence of Inverted Organic Solar Cell Based on Eosin-Y-Coated ZnO Nanorod Arrays

    Science.gov (United States)

    Ginting, R. T.; Yap, C. C.; Yahaya, M.; Fauzia, V.; Salleh, M. M.

    2013-04-01

    The active layer spin coating speed dependence of the performance of inverted organic solar cells (OSCs) based on Eosin-Y-coated ZnOnanorods has been investigated. An active layer consisted of poly(2-methoxy-5-(2'-ethyl)-hexyloxy-p-phenylenevinylene) (MEH-PPV) as donor and phenyl-c61-butyric acid methyl ester (PCBM) as acceptor was employed, whereas ZnO nanorods were utilized as electron transporting layer. The active layer was deposited on top of Eosin-Y-coated ZnO nanorods with various spin coating speeds (1000-4000 rpm). Inverted OSCs with a structure of FTO/Eosin-Y-coated ZnO nanorods/MEH-PPV:PCBM /Ag were characterized through the current density-voltage (J-V) measurement under illumination intensity of 100 mW/cm2. Based on the investigation, the short circuit current density (Jsc) and the power conversion efficiency (PCE) enhanced significantly, where as fill factor slightly increased with spin coating speed. The two-diode equivalent model was found to fit the experimental J-V curves very well. The optimum PCE of 1.18 ± 0.07% was achieved at the highest spin coating speed of 4000 rpm, as a result of the decrement of diffusion current density (Jdiff), recombination current density (Jrec), and ideality factor, thus further confirms the strong built-in electric field in thinner photoactive layer.

  18. Benchmark of AC and DC Active Power Decoupling Circuits for Second-Order Harmonic Mitigation in Kilowatt-Scale Single-Phase Inverters

    DEFF Research Database (Denmark)

    Qin, Zian; Tang, Yi; Loh, Poh Chiang

    2016-01-01

    efficiency and high power density is identified and comprehensively studied, and the commercially available film capacitors, the circuit topologies, and the control strategies adopted for active power decoupling are all taken into account. Then, an adaptive decoupling voltage control method is proposed...... to further improve the performance of dc decoupling in terms of efficiency and reliability. The feasibility and superiority of the identified solution for active power decoupling together with the proposed adaptive decoupling voltage control method are finally verified by both the simulation and experimental......This paper presents the benchmark study of ac and dc active power decoupling circuits for second order harmonic mitigation in kW scale single-phase inverters. First of all, a brief comparison of recently reported active power decoupling circuits is given, and the best solution that can achieve high...

  19. Prognosis and histology in Stage I nasopharyngeal carcinoma (NPC)

    International Nuclear Information System (INIS)

    Saw, D.; Ho, J.H.C.; Fong, M.; Chan, C.L.; Tse, C.H.; Lau, W.H.

    1985-01-01

    During 1969-1975, 212 new patients with Stage I nasopharyngeal carcinoma (NPC) with a tumor apparently confined to the nasopharynx were treated at Queen Elizabeth Hospital, Kowloon, Hong Kong. The initial histologies of 137 patients were available for review and further studies. The primary tumors were histologically classified into two major types - squamous cell carcinoma (35 patients) and undifferentiated carcinoma (102 patients). The latter was further divided into 4 sub-types: lymphoepithelioma of the Schmincke type, lymphoepithelioma of the Regaud type, spindle cell carcinoma, and undifferentiated carcinoma of the nasopharyngeal type. Such histological typing of the initial tumor was not of value in predicting the clinical outcome, whether in terms of 5-year crude or disease-free survival rate, or the tendency of the tumor to develop recurrence at the primary site, or distance metastases after a standardized course of radiation therapy. There is not significant correlation between the extent of mononuclear infiltration nor fibrosis in the tumor stroma and the survival or tumor control rates

  20. NREL Pyrheliometer Comparison: September 16 to 27, 2013 (NPC-2013)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.; Dooraghi, M.; Habte, A.

    2013-11-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for the development and deployment of solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations traceable to an international standard is the first step in producing research-quality solar irradiance measurements. As with all measurement systems, absolute cavity radiometers and other types of pyrheliometers are subject to performance changes over time. NREL has developed and maintained a group of absolute cavity radiometers with direct calibration traceability to the World Radiometric Reference (WRR). These reference instruments are used by NREL to calibrate pyrheliometers and pyranometers using the ISO 17025 accredited Broadband Outdoor Radiometer Calibration (BORCAL) process (Reda et al. 2008). NPCs are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners/operators, e.g. NREL, NASA, NIST, NOAA, USA industry and academia, USA-DOE and other national laboratories, and national and international organizations. Each NPC provides an opportunity to determine the unique World Radiometric Reference (WRR) transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the International System of Units through WRR.

  1. Next Generation Inverter

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zilai [General Motors LLC, Detroit, MI (United States); Gough, Charles [General Motors LLC, Detroit, MI (United States)

    2016-04-22

    The goal of this Cooperative Agreement was the development of a Next Generation Inverter for General Motors’ electrified vehicles, including battery electric vehicles, range extended electric vehicles, plug-in hybrid electric vehicles and hybrid electric vehicles. The inverter is a critical electronics component that converts battery power (DC) to and from the electric power for the motor (AC).

  2. Modular inverter system

    Science.gov (United States)

    Ma, Mingyao; Hu, Haibing; Kutkut, Nasser; Batarseh, Issa; Shen, John; , Bkayrat, Raed

    2017-08-01

    A system connected to an AC power grid having an AC phase signal includes an inverter module including a first inverter coupled to a DC voltage, actuated based on the AC phase signal. The first inverter provides a first voltage signal having predetermined harmonic components. A second inverter includes second switch elements coupled to the DC voltage and actuated by a second set of control signals phase delayed with respect to the first control signals. A transformer module has first and second primary windings coupled to the first and second inverters. The transformer module further includes a secondary winding coupled to first primary winding, the second primary winding, and the AC power grid. The secondary winding is configured to provide a secondary output voltage to the AC power grid by combining the first voltage signal and the second voltage signal such that the predetermined harmonic components are substantially cancelled.

  3. A Single Residue in Ebola Virus Receptor NPC1 Influences Cellular Host Range in Reptiles

    Science.gov (United States)

    2016-09-07

    VH-2) is resistant to infection in an NPC1-36   dependent manner . We found that VH-2 cells are resistant to EBOV infection because the Rus-37...infection in a host species-dependent manner (24). Here, we demonstrate that an adjacent 89   residue, 503, highly conserved in the domain C of NPC1...Tyr sequence 194   change at residue 503 might influence EBOV GPCL–NPC1 binding in a bidirectional manner . 195   Accordingly, we expressed and

  4. A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    T. Demirdelen

    2016-10-01

    Full Text Available In recent years, shunt hybrid active power filters are being increasingly considered as a viable alternative to both passive filters and active power filters for compensating harmonics. In literature, their applications are restricted to balanced systems and low voltage applications and therefore not for industrial applications. This paper investigates the performance of a modular cascaded multilevel inverter based Shunt Hybrid Active Power Filter (SHAPF for reactive power compensation and selective harmonics elimination under distorted/unbalanced grid voltage conditions in medium voltage levels. In the proposed control method, reactive power compensation is achieved successfully with a perceptible amount and the performance results of harmonic compensation are satisfactory. Theoretical analysis and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

  5. The Use of Active Elements to Reduce the Size and Weight of Passive Components in Adjustable Speed Drives

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan

    the effectiveness of the new active damping method are presented. A Neutral-Point-Clamped (NPC) three-level inverter with small DC-link capacitors is selected as viable option for a two-level inverter in this thesis for low voltage applications. This inverter requires zero average neutral-point current for stable...... neutral-point potential. The small DC-link capacitors may not maintain the capacitor voltage balance even with zero neutral-point current due to nonlinearities present in the circuit. This requires a fast control of the neutral-point voltage. A simple carrier-based modulation strategy is proposed which......-link capacitor based drive system shows instability while it is operated with high input line inductance at the operating points with high power. This thesis presents a simple, new active damping technique that can stabilize effectively the drive system at the unstable operating points offering greatly reduced...

  6. IMPLEMENTASI KLASIFIKASI BAYESIAN UNTUK STRATEGI MENYERANG JARAK DEKAT PADA NPC (NON PLAYER CHARACTERMENGGUNAKAN UNITY 3D

    Directory of Open Access Journals (Sweden)

    Siti Asmiatun

    2016-06-01

    Full Text Available Abstract—Dalam sebuah game strategi penyerangan untuk melawan musuh harus diterapkan, sehingga lebih menarik pemain game untuk menyelesaikan permainan sampai dengan tujuan yang akan dicapai. Penelitian ini membahas tentang strategi menyerang jarak dekat untuk NPC (Non Player Character. Dalam sebuah game khususnya untuk game FPS (First Person Shooter, dibutuhkan suatu strategi NPC, dengan tujuan untuk membuat game menjadi lebih atraktif dan realistik. Strategi menyerang dalam penelitian ini adalah membagi beberapa perilaku penyerangan NPC ketika berada pada posisi paling dekat dengan musuh. Penelitian ini menerapkan algoritma bayesian untuk klasifikasi perilaku penyerangan NPC tersebut. Klasifikasi tersebut diharapkan dapat meningkatkan strategi menyerang melawan musuh. Klasifikasi  penyerangan NPC dibiagi menjadi dua perilaku penyerangan yaitu perilaku memukul dan perilaku menggigit. Sedangkan untuk variabel yang digunakan dalam klasifikasi bayesian adalah health point, attack point player dan jarak yang diperoleh dari kondisi NPC. Dari hasil pengujian metode klasifikasi bayesian menggunakan pengujian confusion matrix, dengan percobaan permainan sebanyak 10 kali, telah  menghasilkan presentasi tingkat akurasi pada confusion matrix mencapai nilai persentase sebesar 80 %. Hal ini membubktikan bahwa klasifikasi perilaku penyerangan jarak dekat dengan metode klasifikasi bayesian dapat diterapkan dengan hasil yang baik.

  7. Multilevel DC link inverter

    Science.gov (United States)

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  8. Reliable inverter systems

    Science.gov (United States)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  9. Automatic load sharing in inverter modules

    Science.gov (United States)

    Nagano, S.

    1979-01-01

    Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

  10. NREL Pyrheliometer Comparisons: September 25-October 6, 2017 (NPC-2017)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, Ibrahim M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dooraghi, Michael R. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Andreas, Afshin M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Habte, Aron M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-07

    et al. 2008). National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all ACR owners and operators, each NPC provides an opportunity to determine the unique WRR transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR.

  11. The Impact of Power Switching Devices on the Thermal Performance of a 10 MW Wind Power NPC Converter

    Directory of Open Access Journals (Sweden)

    Ke Ma

    2012-07-01

    Full Text Available Power semiconductor switching devices play an important role in the performance of high power wind energy generation systems. The state-of-the-art device choices in the wind power application as reported in the industry include IGBT modules, IGBT press-pack and IGCT press-pack. Because of significant deviation in the packaging structure, electrical characteristics, as well as thermal impedance, these available power switching devices may have various thermal cycling behaviors, which will lead to converter solutions with very different cost, size and reliability performance. As a result, this paper aimed to investigate the thermal related characteristics of some important power switching devices. Their impact on the thermal cycling of a 10 MW three-level Neutral-Point-Clamped wind power converter is then evaluated under various operating conditions; the main focus will be on the grid connected inverter. It is concluded that the thermal performances of the 3L-NPC wind power converter can be significantly changed by the power device technology as well as their parallel configurations.

  12. Real field mission profile oriented design of a SiC-based PV-inverter application

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Christian; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    This paper introduces a real field mission profile oriented design tool for the new generation of grid connected PV-inverters applications based on SiC-devices. The proposed design tool consists of a grid connected PV-inverter model, an ElectroThermal model, a converter safe operating area (SOA...... Zth_H in order to perform in a safe mode for the whole operating range. Furthermore, the proposed design tool considers the mission profile (the measured solar irradiance and ambient temperature) from the real field where the converter will operate. Thus, a realistic loading of the converter devices......) model, a mission profile model and an the evaluation block. The PV-system model involves a three level bipolar switch neutral point clamped (3L-BS NPC) inverter connected to the three phase grid through a LCL-filter. Moreover, the SOA model calculates the required converter heatsink thermal impedance...

  13. Loss and thermal redistributed modulation methods for three-level neutral-point-clamped wind power inverter undergoing Low Voltage Ride Through

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede

    2012-01-01

    The three-level neutral-point-clamped (3L-NPC) converter is a promising multilevel topology in the application of mega-watts wind power generation system. However, the growing requirements by grid codes may impose high stress and even give reliability problem to this converter topology. This paper...... modulation methods, the thermal distribution in the 3L-NPC wind power inverter undergoing LVRT becomes more equal, and the junction temperature of the most stressed devices can be also relieved. Also the control ability of DC-bus neutral point potential, which is one of the crucial considerations for the 3L...

  14. Resonant snubber inverter

    Science.gov (United States)

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  15. Investigation of the sideband effect for the LCL-type grid-connected inverter with high LCL resonance frequency

    DEFF Research Database (Denmark)

    Yang, Dongsheng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    The LCL-type grid connected inverter has been widely used as the intelligent power interface between the distributed generation unit and the power grid. To reduce the cost and volume of the filter, it is desirable to design the LCL filter with higher resonance frequency provided that the quality...... of injected grid current is not compromised. Actually, it is the typical case for the T-type or NPC three-level inverter to design its LCL resonance frequency close to half of the switching frequency. In this case, however, the sideband effect of SPWM modulation can impose a significant impact on the system...

  16. The GARP Complex Is Involved in Intracellular Cholesterol Transport via Targeting NPC2 to Lysosomes.

    Science.gov (United States)

    Wei, Jian; Zhang, Ying-Yu; Luo, Jie; Wang, Ju-Qiong; Zhou, Yu-Xia; Miao, Hong-Hua; Shi, Xiong-Jie; Qu, Yu-Xiu; Xu, Jie; Li, Bo-Liang; Song, Bao-Liang

    2017-06-27

    Proper intracellular cholesterol trafficking is critical for cellular function. Two lysosome-resident proteins, NPC1 and NPC2, mediate the egress of low-density lipoprotein-derived cholesterol from lysosomes. However, other proteins involved in this process remain largely unknown. Through amphotericin B-based selection, we isolated two cholesterol transport-defective cell lines. Subsequent whole-transcriptome-sequencing analysis revealed two cell lines bearing the same mutation in the vacuolar protein sorting 53 (Vps53) gene. Depletion of VPS53 or other subunits of the Golgi-associated retrograde protein (GARP) complex impaired NPC2 sorting to lysosomes and caused cholesterol accumulation. GARP deficiency blocked the retrieval of the cation-independent mannose 6-phosphate receptor (CI-MPR) to the trans-Golgi network. Further, Vps54 mutant mice displayed reduced cellular NPC2 protein levels and increased cholesterol accumulation, underscoring the physiological role of the GARP complex in cholesterol transport. We conclude that the GARP complex contributes to intracellular cholesterol transport by targeting NPC2 to lysosomes in a CI-MPR-dependent manner. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. SEEPAGE/INVERT INTERACTIONS

    International Nuclear Information System (INIS)

    P.S. Domski

    2000-01-01

    As directed by a written development plan (CRWMS M andO 1999a), a conceptual model for water entering the drift and reacting with the invert materials is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction, and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE), Revision 2 (NRC 1999). This AMR also seeks to: (1) Develop a logical conceptual model for physical/chemical interactions between seepage and the invert materials; (2) screen potential processes and reactions that may occur between seepage and invert to evaluate the potential consequences of the interactions; and (3) outline how seepage/invert processes may be quantified. This document provides the conceptual framework for screening out insignificant processes and for identifying and evaluating those seepage/invert interactions that have the potential to be important to subsequent PAO analyses including the Engineered Barrier System (EBS) physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. Additionally, the concepts discussed within this report may also apply to certain near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts. The seepage/invert interactions will not directly affect any principal factors

  18. Structural Insights into the Niemann-Pick C1 (NPC1)-Mediated Cholesterol Transfer and Ebola Infection.

    Science.gov (United States)

    Gong, Xin; Qian, Hongwu; Zhou, Xinhui; Wu, Jianping; Wan, Tao; Cao, Pingping; Huang, Weiyun; Zhao, Xin; Wang, Xudong; Wang, Peiyi; Shi, Yi; Gao, George F; Zhou, Qiang; Yan, Nieng

    2016-06-02

    Niemann-Pick disease type C (NPC) is associated with mutations in NPC1 and NPC2, whose gene products are key players in the endosomal/lysosomal egress of low-density lipoprotein-derived cholesterol. NPC1 is also the intracellular receptor for Ebola virus (EBOV). Here, we present a 4.4 Å structure of full-length human NPC1 and a low-resolution reconstruction of NPC1 in complex with the cleaved glycoprotein (GPcl) of EBOV, both determined by single-particle electron cryomicroscopy. NPC1 contains 13 transmembrane segments (TMs) and three distinct lumenal domains A (also designated NTD), C, and I. TMs 2-13 exhibit a typical resistance-nodulation-cell division fold, among which TMs 3-7 constitute the sterol-sensing domain conserved in several proteins involved in cholesterol metabolism and signaling. A trimeric EBOV-GPcl binds to one NPC1 monomer through the domain C. Our structural and biochemical characterizations provide an important framework for mechanistic understanding of NPC1-mediated intracellular cholesterol trafficking and Ebola virus infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Power Capability Investigation Based on Electrothermal Models of Press-pack IGBT Three-Level NPC and ANPC VSCs for Multimegawatt Wind Turbines

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

    2012-01-01

    to provide reactive power support as an ancillary service. For multimegawatt full-scale wind turbines, power capability depends on converter topology and semiconductor switch technology. As power capability limiting factors, switch current, semiconductor junction temperature, and converter output voltage...... are addressed in this study for the three-level neutral-point-clamped voltage source converter (3L-NPC-VSC) and 3L Active NPC VSC (3L-ANPC-VSC) with press-pack insulated gate bipolar transistors employed as a grid-side converter. In order to investigate these VSCs' power capabilities under various operating...... conditions with respect to these limiting factors, a power capability generation algorithm based on the converter electrothermal model is developed. Built considering the VSCs' operation principles and physical structure, the model is validated by a 2 MV·A single-phase 3L-ANPC-VSC test setup. The power...

  20. Triazoles inhibit cholesterol export from lysosomes by binding to NPC1.

    Science.gov (United States)

    Trinh, Michael N; Lu, Feiran; Li, Xiaochun; Das, Akash; Liang, Qiren; De Brabander, Jef K; Brown, Michael S; Goldstein, Joseph L

    2017-01-03

    Niemann-Pick C1 (NPC1), a membrane protein of lysosomes, is required for the export of cholesterol derived from receptor-mediated endocytosis of LDL. Lysosomal cholesterol export is reportedly inhibited by itraconazole, a triazole that is used as an antifungal drug [Xu et al. (2010) Proc Natl Acad Sci USA 107:4764-4769]. Here we show that posaconazole, another triazole, also blocks cholesterol export from lysosomes. We prepared P-X, a photoactivatable cross-linking derivative of posaconazole. P-X cross-linked to NPC1 when added to intact cells. Cross-linking was inhibited by itraconazole but not by ketoconazole, an imidazole that does not block cholesterol export. Cross-linking of P-X was also blocked by U18666A, a compound that has been shown to bind to NPC1 and inhibit cholesterol export. P-X also cross-linked to purified NPC1 that was incorporated into lipid bilayer nanodiscs. In this in vitro system, cross-linking of P-X was inhibited by itraconazole, but not by U18666A. P-X cross-linking was not prevented by deletion of the N-terminal domain of NPC1, which contains the initial binding site for cholesterol. In contrast, P-X cross-linking was reduced when NPC1 contained a point mutation (P691S) in its putative sterol-sensing domain. We hypothesize that the sterol-sensing domain has a binding site that can accommodate structurally different ligands.

  1. Challenging Ubiquitous Inverted Files

    NARCIS (Netherlands)

    de Vries, A.P.

    2000-01-01

    Stand-alone ranking systems based on highly optimized inverted file structures are generally considered ‘the’ solution for building search engines. Observing various developments in software and hardware, we argue however that IR research faces a complex engineering problem in the quest for more

  2. Energy-Saving Inverter

    Science.gov (United States)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  3. Argonne inverted sputter source

    International Nuclear Information System (INIS)

    Yntema, J.L.; Billquist, P.J.

    1983-01-01

    The emittance of the inverted sputter source with immersion lenses was measured to be about 5π mm mrad MeV/sup 1/2/ at the 75% level over a wide range of beam intensities. The use of the source in experiments with radioactive sputter targets and hydrogen loaded targets is described. Self contamination of the source is discussed

  4. Synthesis and evaluation of radioiodinated NPC 22009, a putative CRF receptor antagonist

    International Nuclear Information System (INIS)

    Balasubramanian, V.; Hiner, R.N.; Mavunkel, B.J.; Elliott, R.L.; Abreu, M.E.

    1992-01-01

    Several studies have suggested that corticotropin-releasing factor (CRF) plays a role in stress-related disorders such as anxiety, depression, anorexia nervosa and stress-induced immune suppression. Hence CRF antagonists have potential therapeutic utility. Recently the authors discovered that pyrazolones such as NPC 22009 and the corresponding disulfide behave as CRF antagonists in vitro with micromolar potency. To probe the nature of this CRF antagonism they developed a convenient synthesis of radioiodinated NPC 22009. Details of the synthesis and preliminary pharmacological studies are presented

  5. Single stage three level grid interactive MPPT inverter for PV systems

    International Nuclear Information System (INIS)

    Ozdemir, Saban; Altin, Necmi; Sefa, Ibrahim

    2014-01-01

    Highlights: • A three phase three-level NPC inverter for grid interactive PV systems is proposed. • A novel MPPT algorithm is introduced for single stage systems. • The proposed algorithm is robust with respect to parameter variations of PV system. • THD level is measured as 3.45% and it meets the international standards (<5%). • Total system efficiency is measured as 93.08%. - Abstract: In this study, three-phase, single stage neutral point clamped grid interactive inverter is designed and implemented. The reference current of the voltage source inverter is determined by maximum power point tracking sub-program in order to obtain maximum power from photovoltaic modules instantaneously. Proposed control is realized via TMS320F28335 32-bit floating point processor. The modified incremental conductance method is applied for maximum power point tracking; the PI regulator is used to control the inverter output current shape and level. Galvanic isolation is provided by a line frequency transformer that matches inverter output voltage to the grid voltage level and prevents DC current injection into the grid. Experimental results show that the designed inverter imports energy to the grid with unity power factor, total harmonic distortion level is 3.45% and this value is in the limits of the international standards. In addition, the total efficiency of the system is measured as 93.08%. The proposed system gets the maximum power from photovoltaic module and dispatches into the grid without using additional DC/DC converter

  6. Robustness analysis of active damping methods for an inverter connected to the grid with an LCL-filter

    DEFF Research Database (Denmark)

    Ricchiuto, D.; Liserre, M.; Kerekes, Tamas

    2011-01-01

    Grid-connected converters usually employ an LCL-filter to reduce PWM harmonics. To avoid the wellknown stability problems it is requested to use either passive or active damping methods. Active damping methods avoid losses and preserve the filter effectiveness but they are more sensitive...... to parameters variation. In this paper the robustness of active damping methods is investigated considering those using only the same state variable (grid-side or converter-side current) normally used for current control (filter-based) or those methods using more state-variables (multiloop). Simulation...

  7. Quasi-Y-source inverter

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    This paper introduces a new inverter topology called a “quasi-Y-source inverter”. The proposed inverter inherits all the advantages of the original Y-source inverter. In addition, the new topology draws continuous current from the source which is required for many renewable sources. It also has dc......-current-blocking capacitors, which avoids saturation in the transformer core. Simulations and experimental results have proved the validity of the proposed inverter....

  8. Inverter communications using output signal

    Science.gov (United States)

    Chapman, Patrick L.

    2017-02-07

    Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

  9. Milliwatt dc/dc Inverter

    Science.gov (United States)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  10. Resonant-inductor-voltage feedback active damping based control for grid-connected inverters with LLCL-filters

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2014-01-01

    damping method with an extra feedback provides a high rejection of the resonance so that the dynamic is improved. In this paper, taking a Proportional-Resonant (PR) together with a harmonic compensator (HC), resonant-inductor-voltage-feedback active damping is applied on an LLCL-filter based three...... of the proposed method is investigated in simulation and by experimental results....

  11. Inverted emulsion drilling fluid

    Energy Technology Data Exchange (ETDEWEB)

    Ana, I; Astanei, E; Mireanu, G; Orosz, M; Popescu, F; Vasile, I

    1979-07-28

    The subject of the invention is the method of obtaining inverted drilling fluid which is required during stripping of a productive bed and ending of a well where difficulties develop during drilling of the argillaceous rock. Example: in a reservoir with capacity 30 m/sup 3/, 10 m/sup 3/ of diesel fuel are added. A total of 1000 kg of emulsifier are added to the diesel fuel consisting of: 85 mass% of a mixture of sodium and potassium salts of fatty acids, residues of fatty acids or naphthene acids with high molecular weight taken in proportion of 10:90; 5 mass% of a mixture of polymers with hydrophilic-hydrophobic properties obtained by mixing 75 mass% of polyethylene oxide with molecular weight 10,000 and 25 mass% of propylene oxide with molecular weight 15,000, and 10 mass% of salt on alkaline earth metal (preferably calcium chloride). The mixture is mixed into complete dissolving. Then 1200 kg of filtering accelerator are added obtained from concentrated sulfuric acid serving for sulfur oxidation, asphalt substance with softening temperature 85-104/sup 0/C and fatty acids C/sub 10/-C/sub 20/ taken in a proportion of 23.70 and 7 mass% The mixture obtained in this manner is neutralized by adding calcium hydroxide and equal quantities of alumina and activated bentonite clay in a concentration of 1-10 mass%, more preferably 5 mass% in relation to the initial mixture. The obtained mass is mixed until complete dispersion, after which 200 kg of organophilic clay are added obtained from bentonite of the type montmorillonite of sodium by processing with derivate obtained from amine of the type of the quaternary base of ammonium salt, and agent of hydrophobization of the type of fatty alcohols, fatty acids, nonion surfactants of the block-polymer type. After complete dispersion of the organophilic clay, 100 kg of stabilizer of emulsion of the surfactant type was added with molecular weight of 250010,000, more preferably 5000, in concentration of 0.1-5.0 mass%, more

  12. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    International Nuclear Information System (INIS)

    Kosicek, Marko; Malnar, Martina; Goate, Alison; Hecimovic, Silva

    2010-01-01

    It has been suggested that cholesterol may modulate amyloid-β (Aβ) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD (β-amyloid precursor protein (APP), β-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/Aβ formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1 -/- cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, γ-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards Aβ occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  13. Inverter ratio failure detector

    Science.gov (United States)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  14. Genetic variation in the cholesterol transporter NPC1L1, ischaemic vascular disease, and gallstone disease

    DEFF Research Database (Denmark)

    Lauridsen, Bo Kobberø; Stender, Stefan; Frikke-Schmidt, Ruth

    2015-01-01

    developed IVD or symptomatic gallstone disease, respectively, during follow-up from 1977 to 2013. We genotyped four common NPC1L1 variants, previously associated with reduced LDL cholesterol levels, thus mimicking the effect of ezetimibe, and calculated a weighted genotype score. With increasing genotype...

  15. Multilayer control for inverters in parallel operation without signal interconnection

    DEFF Research Database (Denmark)

    Hua, Ming; Hu, Haibing; Xing, Yan

    2011-01-01

    A multilayer control is proposed for inverters with wireless parallel operation in this paper. The control is embedded in every inverter respectively and consists of three layers. The first layer is based on an improved droop method, which shares the active and reactive power in each module...

  16. Sterol transfer between cyclodextrin and membranes: similar but not identical mechanism to NPC2-mediated cholesterol transfer.

    Science.gov (United States)

    McCauliff, Leslie A; Xu, Zhi; Storch, Judith

    2011-08-30

    Niemann--Pick C disease is an inherited disorder in which cholesterol and other lipids accumulate in the late endosomal/lysosomal compartment. Recently, cyclodextrins (CD) have been shown to reduce symptoms and extend lifespan in animal models of the disease. In the present studies we examined the mechanism of sterol transport by CD using in vitro model systems and fluorescence spectroscopy and NPC2-deficient fibroblasts. We demonstrate that cholesterol transport from the lysosomal cholesterol-binding protein NPC2 to CD occurs via aqueous diffusional transfer and is very slow; the rate-limiting step appears to be dissociation of cholesterol from NPC2, suggesting that specific interactions between NPC2 and CD do not occur. In contrast, the transfer rate of the fluorescent cholesterol analogue dehydroergosterol (DHE) from CD to phospholipid membranes is very rapid and is directly proportional to the acceptor membrane concentration, as is DHE transfer from membranes to CD. Moreover, CD dramatically increases the rate of sterol transfer between membranes, with rates that can approach those mediated by NPC2. The results suggest that sterol transfer from CD to membranes occurs by a collisional transfer mechanism involving direct interaction of CD with membranes, similar to that shown previously for NPC2. For CD, however, absolute rates are slower compared to NPC2 for a given concentration, and the lysosomal phospholipid lysobisphosphatidic acid (LBPA) does not stimulate rates of sterol transfer between membranes and CD. As expected from the apparent absence of interaction between CD and NPC2, the addition of CD to NPC2-deficient fibroblasts rapidly rescued the cholesterol accumulation phenotype. Thus, the recent observations of CD efficacy in mouse models of NPC disease are likely the result of CD enhancement of cholesterol transport between membranes, with rapid sterol transfer occurring during CD--membrane interactions.

  17. Evidence that human papillomavirus causes inverted papilloma is sparse.

    Science.gov (United States)

    Justice, Jeb M; Davis, Kern M; Saenz, Daniel A; Lanza, Donald C

    2014-12-01

    Controversy exists regarding the pathogenesis of inverted papilloma as it relates to the involvement of human papillomavirus (HPV). The purpose of this report is to describe the prevalence of HPV in nondysplastic, "early inverted papilloma" and to summarize HPV detection rates in the general population and in other HPV related neoplasia. This case series report characterizes consecutive inverted papilloma patients from January 2005 to August 2012 with regard to smoking history, dysplasia, and HPV detection rates. Presence or absence of low/high risk HPV was determined by standardized in situ hybridization DNA probes. Medline literature review was performed to determine the prevalence of HPV in inverted papilloma without moderate or severe dysplasia. Thirty-six consecutive patients were identified with an average age of 63.6 (range, 40-84) years; gender: 23 men, 13 women. More than half (55%) were active or former smokers (14% active and 41% former). High/low risk HPV was present in 1 in 36 (2.7%) patients and 1 in 36 (2.7%) had mild dysplasia. In the literature review: (1) HPV was detected in 16.4% of inverted papilloma without dysplasia; (2) oral cavity HPV detection was 4.2% to 11.4% in the normal population; and (3) HPV was normally detected in 85% to 95% of HPV-related neoplasia. Given histological features of inverted papilloma and comparatively low detection rates of HPV in inverted papilloma without dysplasia (2.7%), as well as the summary of the world literature, HPV is not related to the initial pathogenesis of inverted papilloma or inverted papilloma's tendency to persist or recur. It is postulated that since inverted papilloma is more an inflammatory polyp, it is susceptible to secondary HPV infection because of its metaplasia. Tobacco and other causes of respiratory epithelium remodeling are more plausible explanations for the initial tissue transformation to inverted papilloma. © 2014 ARS-AAOA, LLC.

  18. Identification of 58 novel mutations in Niemann-Pick disease type C: correlation with biochemical phenotype and importance of PTC1-like domains in NPC1.

    Science.gov (United States)

    Park, Walter D; O'Brien, John F; Lundquist, Patrick A; Kraft, Daniel L; Vockley, Cate Walsh; Karnes, Pamela S; Patterson, Marc C; Snow, Karen

    2003-10-01

    The two known complementation groups of Niemann-Pick Type C disease, NPC1 and NPC2, result from non-allelic protein defects. Both the NPC1 and NPC2 (HE1) gene products are intimately involved in cholesterol and glycolipid trafficking and/or transport. We describe mutation analysis on samples from 143 unrelated affected NPC patients using conformation sensitive gel electrophoresis and DNA sequencing as the primary mutation screening methods for NPC1 and NPC2, respectively. These methods are robust, sensitive, and do not require any specialized laboratory equipment. Analyses identified two NPC1 mutations for 115 (80.4%) patients, one NPC1 mutation for 10 (7.0%) patients, two NPC2 mutations for five (3.5%) patients, one NPC2 mutation for one (0.7%) patient, and no mutations for 12 (8.4%) patients. Thus, mutations were identified on 251 of 286 (88%) disease alleles, including 121 different mutations (114 in NPC1 and seven in NPC2), 58 of which are previously unreported. The most common NPC1 mutation, I1061T, was detected on 18% of NPC alleles. Other NPC1 mutations were mostly private, missense mutations located throughout the gene with clustering in the cysteine-rich luminal domain. Correlation with biochemical data suggests classification of several mutations as severe and others as moderate or variable. The region between amino acids 1038 and 1253, which shares 35% identity with Patched 1, appears to be a hot spot for mutations. Additionally, a high percentage of mutations were located at amino acids identical to the NPC1 homolog, NPC1L1. Biochemical complementation analysis of cases negative for mutations revealed a high percentage of equivocal results where the complementation group appeared to be non-NPC1 and non-NPC2. This raises the possibilities of an additional NPC complementation group(s) or non-specificity of the biochemical testing for NPC. These caveats must be considered when offering mutation testing as a clinical service. Copyright 2003 Wiley-Liss, Inc.

  19. Control of Grid Connected Photovoltaic System Using Three-Level T-Type Inverter

    Science.gov (United States)

    Zorig, Abdelmalik; Belkeiri, Mohammed; Barkat, Said; Rabhi, Abdelhamid

    2016-08-01

    Three-level T-Type inverter (3LT2I) topology has numerous advantageous compared to three-level neutral-point-clamped (NPC) inverter. The main benefits of 3LT2I inverter are the efficiency, inverter cost, switching losses, and the quality of output voltage waveforms. In this paper, a photovoltaic distributed generation system based on dual-stage topology of DC-DC boost converter and 3LT2I is introduced. To that end, a decoupling control strategy of 3LT2I is proposed to control the current injected into the grid, reactive power compensation, and DC-link voltage. The resulting system is able to extract the maximum power from photovoltaic generator, to achieve sinusoidal grid currents, and to ensure reactive power compensation. The voltage-balancing control of two split DC capacitors of the 3LT2I is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The proposed system performance is investigated at different operating conditions.

  20. Generalized coupling resonance modeling, analysis, and active damping of multi-parallel inverters in microgrid operating in grid-connected mode

    DEFF Research Database (Denmark)

    Chen, Zhiyong; Chen, Yandong; Guerrero, Josep M.

    2016-01-01

    This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic...

  1. Solar Charged Stand Alone Inverter

    OpenAIRE

    M.Vasugi; Prof R.Jayaraman

    2014-01-01

    This paper deals with solar powered stand alone inverter which converts the variable dc output of a photovoltaic solar panel into ac that can be fed to loads. Stand alone inverters are used in systems where the inverter get its energy from batteries charged by photo voltaic arrays. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. This charge discharge controller is needed to prevent the battery from being overcharged o...

  2. Gas cooled traction drive inverter

    Science.gov (United States)

    Chinthavali, Madhu Sudhan

    2013-10-08

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  3. Epstein-barr virus latent membrane protein 1 (EBV-LMP1) and tumor proliferation rate as predictive factors of nasopharyngeal cancer (NPC) radiation response

    Energy Technology Data Exchange (ETDEWEB)

    Gondhowiardjo, S. [Univ. of Indonesia, Jakarta (Indonesia). Faculty of Medicine

    2000-05-01

    Irradiation is still the treatment of choice in NPC treatment as one of highest malignancy in Indonesia as well as in Southeast Asia. Up to now there is no accurate predictor on radiation response, since that the similar histo-morphological pattern, as a well-known prognostic factor can revealed a wide range of treatment outcomes. Purpose of the study is to established the influence of EBV-LMP 1 as the most important protein expressed by EBV oncogenes in cellular behavior such as proliferation rate, tumor aggressivity in NPC and to find out the role of both, proliferation rate and EBV-LMP1 expression as a predictor on NPC radiation response. One-hundred seventy-two paraffin-embedded biopsy specimens from NPC patients were analysed flow-cytometrically to obtain the S-phase fraction value as the proliferation parameter. From this group of patients, 81 fresh specimen biopsies could be collected, and the EBV-LMP 1 expression were detected by western blotting technique (mAB S12-Karolinska Institute) could be done. Several variables such as clinical stage, pathology pattern and radiation response were also collected. The radiation responses were established clinically (by nasopharyngoscopy), by CT scanning and pathologically. Sixty-five percent of our patients belong to the T3 and T4, whereby the N2-3 group consists 75% of them. Fourteen percent of the patients are Hsu type I, 48% are Hs type II and the rest belong to Hsu type III. Our study revealed that the mean SPF value was 14.62% (10.18%, which correlated (p<0.05) with the tumor and nodal sizes). The rate of positive expression of the EBV-LMP1 was 50%, and did not show a correlation with the proliferation activity as well as the radiation response. However, it showed a significant correlation with the tumor and nodal size. There was a significant correlation between this proliferation value with the radiation response calculated by both, bivariate as well as by multivariate analysis. The complete and incomplete

  4. 2015 Inverter Workshop | Photovoltaic Research | NREL

    Science.gov (United States)

    Inverter Workshop 2015 Inverter Workshop Wednesday, February 25, 2015 Chair: Jack Flicker In about inverters. This workshop represented a follow-on to the inverter workshops that Sandia National conversations between module and inverter experts. Agenda For a detailed schedule of the day's events, access

  5. Simplified High-Power Inverter

    Science.gov (United States)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  6. Electronic inverter assembly

    Science.gov (United States)

    Singh, Brij N.; Schmit, Christopher J.

    2018-05-22

    A first driver portion comprises a set of first components mounted on or associated with a first circuit board. A second circuit board is spaced apart from the first circuit board. A second driver portion comprises a set of second components mounted on or associated with the second circuit board, where the first driver portion and the second driver portion collectively are adapted to provide input signals to the control terminal of each semiconductor switch of an inverter. A first edge connector is mounted on the first circuit board. A second edge connector is mounted on the second circuit board. An interface board has mating edges that mate with the first edge connector and the second edge connector.

  7. Concerted regulation of npc2 binding to endosomal/lysosomal membranes by bis(monoacylglycero)phosphate and sphingomyelin

    DEFF Research Database (Denmark)

    Enkavi, Giray; Mikkolainen, Heikki; Güngör, Burçin

    2017-01-01

    remained elusive. Here, based on an extensive set of atomistic simulations and free energy calculations, we clarify the mechanism and energetics of npc2-membrane binding and characterize the roles of physiologically relevant key lipids associated with the binding process. Our results capture in atomistic......Niemann-Pick Protein C2 (npc2) is a small soluble protein critical for cholesterol transport within and from the lysosome and the late endosome. Intriguingly, npc2-mediated cholesterol transport has been shown to be modulated by lipids, yet the molecular mechanism of npc2-membrane interactions has......). This mode is associated with cholesterol uptake and release. On the other hand, the second mode (Supine) places the cholesterol binding pocket away from the membrane surface, but has overall higher membrane binding affinity. We determined that bis(monoacylglycero)phosphate (bmp) is specifically required...

  8. Experimental Evaluation of PV Inverter Anti-Islanding with Grid Support Functions in Multi-Inverter Island Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, Brian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chakraborty, Sudipta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bell, Frances [SolarCity, San Mateo, CA (United States); McCarty, Michael [SolarCity, San Mateo, CA (United States)

    2016-07-01

    As PV and other DER systems are connected to the grid at increased penetration levels, island detection may become more challenging for two reasons: 1.) In islands containing many DERs, active inverter-based anti-islanding methods may have more difficulty detecting islands because each individual inverter's efforts to detect the island may be interfered with by the other inverters in the island. 2.) The increasing numbers of DERs are leading to new requirements that DERs ride through grid disturbances and even actively try to regulate grid voltage and frequency back towards nominal operating conditions. These new grid support requirements may directly or indirectly interfere with anti-islanding controls. This report describes a series of tests designed to examine the impacts of both grid support functions and multi-inverter islands on anti-islanding effectiveness. Crucially, the multi-inverter anti-islanding tests described in this report examine scenarios with multiple inverters connected to multiple different points on the grid. While this so-called 'solar subdivision' scenario has been examined to some extent through simulation, this is the first known work to test it using hardware inverters. This was accomplished through the use of power hardware-in-the-loop (PHIL) simulation, which allows the hardware inverters to be connected to a real-time transient simulation of an electric power system that can be easily reconfigured to test various distribution circuit scenarios. The anti-islanding test design was a modified version of the unintentional islanding test in IEEE Standard 1547.1, which creates a balanced, resonant island with the intent of creating a highly challenging condition for island detection. Three common, commercially available single-phase PV inverters from three different manufacturers were tested. The first part of this work examined each inverter individually using a series of pure hardware resistive-inductive-capacitive (RLC

  9. Genetic variation at the NPC1L1 gene locus, plasma lipoproteins, and heart disease risk in the elderly

    Science.gov (United States)

    Niemann-Pick C1-like 1 protein (NPC1L1) plays a critical role in intestinal cholesterol absorption. Our objective was to examine whether five variants (-133A>G, -18A>C, L272L, V1296V, and U3_28650A>G) at the NPC1L1 gene have effects on lipid levels, prevalence, and incidence of coronary heart diseas...

  10. Analisis Harmonisa Inverter PWM Satu Fasa

    OpenAIRE

    Rejeki Simanjorang

    2008-01-01

    Pada tesis ini dianalisis harmonisa inverter PWM satu fasa. Inverter PWM satu fasa yang akan ditinjau adalah inverter satu fasa jembatan penuh (konvensional) dan inverter komposit. Analisis difokuskan pada penentuan pola penyaklaran yang optimum agar pembangkitan harmonisa dan switching losses inverter rendah. Untuk menentukan pola penyaklaran optimum maka dilakukan analisis yang berbasis pada rangkaian ekivalen harmonisa inverter satu fasa. Dengan menggunakan pola penyaklaran optimum, kedua ...

  11. Transformerless PV inverters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borup, U.

    2009-12-15

    Since the start of the project the market for grid connected PV inverters have developed further. When the project started three - phase inverter were only available in high power systems. The technology developed within this project will enable three phase technology also to be implemented in string inverters for system down to 10 kW. We expect this to be very attractive due to the increased demand for symmetrical feed-in to the grid. The project relevance is therefore high and the sector continues to develop very much driven by technology. Especially the inverter technology is getting a lot of focus. The inverter systems are expected to take a much larger role in supporting the electrical grid in the future. The technology platform developed within the project is prepared to be extended with these utility functionalities. The main results of the project were: 1) A new technology concept for transformer-less inverters has been demonstrated with a number of prototypes. 2) Efficiency above 97,7% has been proven. 3) Efficiency and Maximum power point tracking has been optimized to ensure that almost all energy produced of the panels is transferred to the grid. 4) The platform is developed with a very fast control board, which enables extended functionality as demanding grid supporting functions in the future. Details about cost price and details about the control loop implementation is excluded from the report due to the competitive situation for Danfoss Solar Inverters A/S. (LN)

  12. Modulation of Current Source Inverter

    Directory of Open Access Journals (Sweden)

    Golam Reza Arab Markadeh

    2011-04-01

    Full Text Available Direct torque control with Current Source Inverter (CSI instead of voltage source inverter is so appropriate because of determining the torque of induction motor with machine current and air gap flux. In addition, Space-Vector Modulation (SVM is a more proper method for CSI because of low order harmonics reduction, lower switching frequency and easier implementation. This paper introduces the SVM method for CSI and uses the proposed inverter for vector control of an induction motor. The simulation results illustrate fast dynamic response and desirable torque and speed output. Fast and accurate response to changes of speed and load torque reference completely proves the prominence of this method.

  13. Detecting and mitigating inverter aging

    International Nuclear Information System (INIS)

    Gunther, W.E.; Taylor, J.H.; Aggarwal, S.K.

    1988-01-01

    Nuclear power plants use inverters to supply power to safety-related equipment, instrumentation, and controls. They convert direct current (dc) to alternating current (ac) power, thereby making low voltage ac power available even under a station blackout condition. As part of the U.S. NRC's nuclear plant aging research (NPAR) program, the operating experience of this equipment has been analyzed to determine the dominant failure modes and causes. This paper summarizes that data, and then describes methods which can be employed to detect inverter degradation prior to failure, as well as methods to minimize the failure effects. In both cases, the mitigation of inverter aging is emphasized

  14. Stationary Frame Current Control Evaluations for Three-Phase Grid-Connected Inverters with PVR-based Active Damped LCL Filters

    DEFF Research Database (Denmark)

    Han, Yang; Shen, Pan; Guerrero, Josep M.

    2016-01-01

    Grid-connected inverters (GCIs) with LCL output filter have the ability of attenuating high-frequency (HF) switching ripples. However, by using only grid-current control, the system is prone to resonances if it is not properly damped, and the current distortion would be amplified significantly...... method is adopted. Furthermore, the grid voltage feed-forward and multiple PR controllers are integrated in the current loop to mitigate the current distortion introduced by the grid background distortion. Besides, the parameters design guidelines are presented to show the feasibility and effectiveness...

  15. Prognostic value of anti-Epstein-Barr virus antibodies in nasopharyngeal carcinoma (NPC)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Mu-Tai; Yeh, Chi-Yuan [Chang-Hua Christian Hospital, Chang-Hua (Taiwan, Province of China)

    1998-03-01

    Eighty patients with histological diagnoses of nasopharyngeal cancer (NPC) were referred to Chang-Hua Christian Hospital for curative radiotherapy from 1985 to 1995. A mean dose of 7,020 cGy in 39 fractions was delivered to the primary tumor using a telecobalt-60 unit or 6-10 MV X-ray linear accelerator. Pre- and postradiotherapy serum levels of anti-Epstein-Barr virus (EBV)/VCA IgG and IgA were determined for all patients using the indirect immunoperoxidase assay. Multivariate analysis was done to determine which factors affected the patients` treatment outcome and survival. Five patients were excluded from this study due to incomplete radiotherapy, leaving 75 patients eligible for analysis. Overall local control was 77.3%, with a mean disease-free interval of 19.7 months. Factors affecting local control included radiation dose and pretreatment anti-EBV/VCA IgG titer. The overall 5-year actuarial survival for the 75 patients was 75%, with a median survival of 129.5 months. The 5-year actuarial survival rates for stage I+II, III, and IV patients were 90%, 40%, and 45%, respectively. Prognostic factors for survival included tumor histological type and pretreatment anti-EBV/VCA IgA titer, while prognostic factors for local control included total radiation dose received and pretreatment anti-EBV/VCA IgG titer. We found that there was a significant difference in the geometric mean titer of anti-EBV/VCA IgA antibodies before and after radiotherapy. Prognostic factors affecting NPC patients` actuarial survival included tumor histology and pretreatment IgA titer, while prognostic factors for local control of NPC included total radiation dose received and pretreatment IgG titer. (K.H.)

  16. Prognostic value of anti-Epstein-Barr virus antibodies in nasopharyngeal carcinoma (NPC)

    International Nuclear Information System (INIS)

    Liu, Mu-Tai; Yeh, Chi-Yuan

    1998-01-01

    Eighty patients with histological diagnoses of nasopharyngeal cancer (NPC) were referred to Chang-Hua Christian Hospital for curative radiotherapy from 1985 to 1995. A mean dose of 7,020 cGy in 39 fractions was delivered to the primary tumor using a telecobalt-60 unit or 6-10 MV X-ray linear accelerator. Pre- and postradiotherapy serum levels of anti-Epstein-Barr virus (EBV)/VCA IgG and IgA were determined for all patients using the indirect immunoperoxidase assay. Multivariate analysis was done to determine which factors affected the patients' treatment outcome and survival. Five patients were excluded from this study due to incomplete radiotherapy, leaving 75 patients eligible for analysis. Overall local control was 77.3%, with a mean disease-free interval of 19.7 months. Factors affecting local control included radiation dose and pretreatment anti-EBV/VCA IgG titer. The overall 5-year actuarial survival for the 75 patients was 75%, with a median survival of 129.5 months. The 5-year actuarial survival rates for stage I+II, III, and IV patients were 90%, 40%, and 45%, respectively. Prognostic factors for survival included tumor histological type and pretreatment anti-EBV/VCA IgA titer, while prognostic factors for local control included total radiation dose received and pretreatment anti-EBV/VCA IgG titer. We found that there was a significant difference in the geometric mean titer of anti-EBV/VCA IgA antibodies before and after radiotherapy. Prognostic factors affecting NPC patients' actuarial survival included tumor histology and pretreatment IgA titer, while prognostic factors for local control of NPC included total radiation dose received and pretreatment IgG titer. (K.H.)

  17. Nanowire NMOS Logic Inverter Characterization.

    Science.gov (United States)

    Hashim, Yasir

    2016-06-01

    This study is the first to demonstrate characteristics optimization of nanowire N-Channel Metal Oxide Semiconductor (NW-MOS) logic inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. A computer-based model used to produce static characteristics of NW-NMOS logic inverter. In this research two circuit configuration of NW-NMOS inverter was studied, in first NW-NMOS circuit, the noise margin for (low input-high output) condition was very low. For second NMOS circuit gives excellent noise margins, and results indicate that optimization depends on applied voltage to the inverter. Increasing gate to source voltage with (2/1) nanowires ratio results better noise margins. Increasing of applied DC load transistor voltage tends to increasing in decreasing noise margins; decreasing this voltage will improve noise margins significantly.

  18. Influence of radiotherapy on CD4+ CD25high regulatory cells in peripheral blood of NPC patients

    International Nuclear Information System (INIS)

    Liu Li; Ding Qian; Song Yingqiu; Cao Rubo; Yao Junxia; Huang Shiang

    2006-01-01

    Objective: The current study was designed to investigate the changes in peripheral CD4 + CD25 high regulatory T (CD4 + CD25 high Tr) cells in patients with nasopharyngeal carcinoma (NPC) and the influence of radiotherapy on immunity function. Methods: The peripheral blood was collected from 36 patients with NPC and 30 healthy controls. By using monoclonal antibodies, the blood samples were evaluated with flow cytometry for lymphocyte subsets and Tr cells. Results: The ratio of CD4 + /CD8 + in the NPC group was not significantly less than that in the healthy controls (P>0.05), but the prevalence of the CD4 + CD25 high Tr cells was significantly higher than that of the healthy group [(2.76 ± 1.06)% versus (2.06 ± 0.98)%, P + CD25 high Tr cells was higher than before it [(4.88 ± 1.02)%, P + CD25 high Tr cells in peripheral blood of NPC patients with or without radiotherapy was significantly higher than those in healthy controls, which may be related to immunosupression and tumor progression in such patients. This finding suggests that CD4 + CD25 high Tr cells in peripheral blood of NPC patients can be a useful index for monitoring the immunity function. (authors)

  19. Γ-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....

  20. Tri-State Current Source Inverter With Improved Dynamic Performance

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Wong, Chow Pang

    2008-01-01

    Traditional dc-ac current source inverter (CSI) has a right-half-plane (RHP) zero in its control-to-output transfer function. This RHP zero causes the inverter output to fall before rising when a step increase in command reference is required (commonly known as non-minimum-phase effect). To achieve...... a better dynamic response, this paper proposes the design of a tri-state CSI using only an additional semiconductor switch for introducing unique freewheeling states to the traditional six active and three null states of a CSI. With the freewheeling states inserted appropriately within the inverter state...... sequence, the inductive boosting and discharging intervals can be decoupled, allowing the RHP zero to be eliminated with only minor circuit modifications (high level control schemes like predictive and multiloop voltage/current control remain unchanged). The designed inverter can be controlled using...

  1. Normalization of Hepatic Homeostasis in the Npc1nmf164 Mouse Model of Niemann-Pick Type C Disease Treated with the Histone Deacetylase Inhibitor Vorinostat.

    Science.gov (United States)

    Munkacsi, Andrew B; Hammond, Natalie; Schneider, Remy T; Senanayake, Dinindu S; Higaki, Katsumi; Lagutin, Kirill; Bloor, Stephen J; Ory, Daniel S; Maue, Robert A; Chen, Fannie W; Hernandez-Ono, Antonio; Dahlson, Nicole; Repa, Joyce J; Ginsberg, Henry N; Ioannou, Yiannis A; Sturley, Stephen L

    2017-03-17

    Niemann-Pick type C (NP-C) disease is a fatal genetic lipidosis for which there is no Food and Drug Administration (FDA)-approved therapy. Vorinostat, an FDA-approved inhibitor of histone deacetylases, ameliorates lysosomal lipid accumulation in cultured NP-C patient fibroblasts. To assess the therapeutic potential of histone deacetylase inhibition, we pursued these in vitro observations in two murine models of NP-C disease. Npc1 nmf164 mice, which express a missense mutation in the Npc1 gene, were treated intraperitoneally, from weaning, with the maximum tolerated dose of vorinostat (150 mg/kg, 5 days/week). Disease progression was measured via gene expression, liver function and pathology, serum and tissue lipid levels, body weight, and life span. Transcriptome analyses of treated livers indicated multiple changes consistent with reversal of liver dysfunction that typifies NP-C disease. Significant improvements in liver pathology and function were achieved by this treatment regimen; however, NPC1 protein maturation and levels, disease progression, weight loss, and animal morbidity were not detectably altered. Vorinostat concentrations were >200 μm in the plasma compartment of treated animals but were almost 100-fold lower in brain tissue. Apolipoprotein B metabolism and the expression of key components of lipid homeostasis in primary hepatocytes from null ( Npc1 -/- ) and missense ( Npc1 nmf164 ) mutant mice were altered by vorinostat treatment, consistent with a response by these cells independent of the status of the Npc1 locus. These results suggest that HDAC inhibitors have utility to treat visceral NP-C disease. However, it is clear that improved blood-brain barrier penetration will be required to alleviate the neurological symptoms of human NP-C disease. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Normalization of Hepatic Homeostasis in the Npc1nmf164 Mouse Model of Niemann-Pick Type C Disease Treated with the Histone Deacetylase Inhibitor Vorinostat*

    Science.gov (United States)

    Munkacsi, Andrew B.; Hammond, Natalie; Schneider, Remy T.; Senanayake, Dinindu S.; Higaki, Katsumi; Lagutin, Kirill; Bloor, Stephen J.; Ory, Daniel S.; Maue, Robert A.; Chen, Fannie W.; Hernandez-Ono, Antonio; Dahlson, Nicole; Repa, Joyce J.; Ginsberg, Henry N.; Ioannou, Yiannis A.; Sturley, Stephen L.

    2017-01-01

    Niemann-Pick type C (NP-C) disease is a fatal genetic lipidosis for which there is no Food and Drug Administration (FDA)-approved therapy. Vorinostat, an FDA-approved inhibitor of histone deacetylases, ameliorates lysosomal lipid accumulation in cultured NP-C patient fibroblasts. To assess the therapeutic potential of histone deacetylase inhibition, we pursued these in vitro observations in two murine models of NP-C disease. Npc1nmf164 mice, which express a missense mutation in the Npc1 gene, were treated intraperitoneally, from weaning, with the maximum tolerated dose of vorinostat (150 mg/kg, 5 days/week). Disease progression was measured via gene expression, liver function and pathology, serum and tissue lipid levels, body weight, and life span. Transcriptome analyses of treated livers indicated multiple changes consistent with reversal of liver dysfunction that typifies NP-C disease. Significant improvements in liver pathology and function were achieved by this treatment regimen; however, NPC1 protein maturation and levels, disease progression, weight loss, and animal morbidity were not detectably altered. Vorinostat concentrations were >200 μm in the plasma compartment of treated animals but were almost 100-fold lower in brain tissue. Apolipoprotein B metabolism and the expression of key components of lipid homeostasis in primary hepatocytes from null (Npc1−/−) and missense (Npc1nmf164) mutant mice were altered by vorinostat treatment, consistent with a response by these cells independent of the status of the Npc1 locus. These results suggest that HDAC inhibitors have utility to treat visceral NP-C disease. However, it is clear that improved blood-brain barrier penetration will be required to alleviate the neurological symptoms of human NP-C disease. PMID:28031458

  3. Preparation of inverted medium and processing in the inverted medium

    International Nuclear Information System (INIS)

    Zafarullah, Ijaz; Tian Minghzen; Chang Tiejun; Randall Babbitt, W.

    2007-01-01

    The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm 3+ :YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%

  4. Preparation of inverted medium and processing in the inverted medium

    Energy Technology Data Exchange (ETDEWEB)

    Zafarullah, Ijaz [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)]. E-mail: ijaz@montana.edu; Tian Minghzen [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Chang Tiejun [The Spectrum Laboratory, Montana State University, Bozeman, MT 59717 (United States); Randall Babbitt, W. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2007-11-15

    The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm{sup 3+}:YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%.

  5. Accelerating development of advanced inverters :

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C.; Gonzalez, Sigifredo; Ropp, Michael; Schutz, Dustin

    2013-11-01

    The high penetration of utility interconnected photovoltaic (PV) systems is causing heightened concern over the effect that variable renewable generation will have on the electrical power system (EPS). These concerns have initiated the need to amend the utility interconnection standard to allow advanced inverter control functionalities that provide: (1) reactive power control for voltage support, (2) real power control for frequency support and (3) better tolerance of grid disturbances. These capabilities are aimed at minimizing the negative impact distributed PV systems may have on EPS voltage and frequency. Unfortunately, these advanced control functions may interfere with island detection schemes, and further development of advanced inverter functions requires a study of the effect of advanced functions on the efficacy of antiislanding schemes employed in industry. This report summarizes the analytical, simulation and experimental work to study interactions between advanced inverter functions and anti-islanding schemes being employed in distributed PV systems.

  6. Curcumin inhibits cholesterol uptake in Caco-2 cells by down-regulation of NPC1L1 expression

    Directory of Open Access Journals (Sweden)

    Duan Rui-Dong

    2010-04-01

    Full Text Available Abstract Background Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1 protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells. Methods Caco-2 cells were cultured to confluence. The micelles composed of bile salt, monoolein, and 14C-cholesterol were prepared. We first incubated the cells with the micelles in the presence and absence of ezetimibe, the specific inhibitor of NPC1L1, to see whether the uptake of the cholesterol in the cells was mediated by NPC1L1. We then pretreated the cells with curcumin at different concentrations for 24 h followed by examination of the changes of cholesterol uptake in these curcumin-treated cells. Finally we determined whether curcumin affects the expression of NPC1L1 by both Western blot analysis and qPCR quantification. Results We found that the uptake of radioactive cholesterol in Caco-2 cells was inhibited by ezetimibe in a dose-dependent manner. The results indicate that the uptake of cholesterol in this study was mediated by NPC1L1. We then pretreated the cells with 25-100 μM curcumin for 24 h and found that such a treatment dose-dependently inhibited cholesterol uptake with 40% inhibition obtained by 100 μM curcumin. In addition, we found that the curcumin-induced inhibition of cholesterol uptake was associated with significant decrease in the levels of NPC1L1 protein and NPC1L1 mRNA, as analyzed by Western blot and qPCR, respectively. Conclusion

  7. Curcumin inhibits cholesterol uptake in Caco-2 cells by down-regulation of NPC1L1 expression.

    Science.gov (United States)

    Feng, Dan; Ohlsson, Lena; Duan, Rui-Dong

    2010-04-19

    Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1) protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells. Caco-2 cells were cultured to confluence. The micelles composed of bile salt, monoolein, and 14C-cholesterol were prepared. We first incubated the cells with the micelles in the presence and absence of ezetimibe, the specific inhibitor of NPC1L1, to see whether the uptake of the cholesterol in the cells was mediated by NPC1L1. We then pretreated the cells with curcumin at different concentrations for 24 h followed by examination of the changes of cholesterol uptake in these curcumin-treated cells. Finally we determined whether curcumin affects the expression of NPC1L1 by both Western blot analysis and qPCR quantification. We found that the uptake of radioactive cholesterol in Caco-2 cells was inhibited by ezetimibe in a dose-dependent manner. The results indicate that the uptake of cholesterol in this study was mediated by NPC1L1. We then pretreated the cells with 25-100 muM curcumin for 24 h and found that such a treatment dose-dependently inhibited cholesterol uptake with 40% inhibition obtained by 100 muM curcumin. In addition, we found that the curcumin-induced inhibition of cholesterol uptake was associated with significant decrease in the levels of NPC1L1 protein and NPC1L1 mRNA, as analyzed by Western blot and qPCR, respectively. Curcumin inhibits cholesterol uptake through suppression of NPC1L1

  8. Inverter for Interchangeable Use as Current Source Inverter and Voltage Source Inverter for Interconnecting to Grid

    Science.gov (United States)

    Teruya, Daisuke; Masukawa, Shigeo; Iida, Shoji

    We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.

  9. Inverter design for high frequency power distribution

    Science.gov (United States)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  10. Inverters for photovoltaics: quality assurance

    International Nuclear Information System (INIS)

    Graf, J.D.; Haeberlin, H.

    2000-01-01

    This project-overview published by the University of Applied Science in Burgdorf, Switzerland, looks back at the history of the university's testing laboratory for inverters for use in photovoltaic installations and discusses the work done there. After its move from Oberburg to Burgdorf in the early nineties, the laboratory was equipped to provide testing facilities for inverters up to 60 kW. Additions have been made to the infrastructure since then to facilitate the testing of various types of inverter produced in Switzerland and other countries. The measurements that can be carried out, including DC-AC conversion efficiency, harmonics, RF interference, islanding, sensitivity to tele-control signals, turn-on power and operating voltage range are described. The improvement in the quality of the inverters tested is discussed and the importance of continued testing as new manufacturers come onto the market is emphasised. The installation of further testing equipment, such as a 25 kW solar generator simulator and apparatus for the testing of maximum-power-tracking efficiency is discussed

  11. Overload protection system for power inverter

    Science.gov (United States)

    Nagano, S. (Inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  12. Membrane fusion and inverted phases

    International Nuclear Information System (INIS)

    Ellens, H.; Siegel, D.P.; Alford, D.; Yeagle, P.L.; Boni, L.; Lis, L.J.; Quinn, P.J.; Bentz, J.

    1989-01-01

    We have found a correlation between liposome fusion kinetics and lipid phase behavior for several inverted phase forming lipids. N-Methylated dioleoylphosphatidylethanolamine (DOPE-Me), or mixtures of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC), will form an inverted hexagonal phase (HII) at high temperatures (above TH), a lamellar phase (L alpha) at low temperatures, and an isotropic/inverted cubic phase at intermediate temperatures, which is defined by the appearance of narrow isotropic 31 P NMR resonances. The phase behavior has been verified by using high-sensitivity DSC, 31 P NMR, freeze-fracture electron microscopy, and X-ray diffraction. The temperature range over which the narrow isotropic resonances occur is defined as delta TI, and the range ends at TH. Extruded liposomes (approximately 0.2 microns in diameter) composed of these lipids show fusion and leakage kinetics which are strongly correlated with the temperatures of these phase transitions. At temperatures below delta TI, where the lipid phase is L alpha, there is little or no fusion, i.e., mixing of aqueous contents, or leakage. However, as the temperature reaches delta TI, there is a rapid increase in both fusion and leakage rates. At temperatures above TH, the liposomes show aggregation-dependent lysis, as the rapid formation of HII phase precursors disrupts the membranes. We show that the correspondence between the fusion and leakage kinetics and the observed phase behavior is easily rationalized in terms of a recent kinetic theory of L alpha/inverted phase transitions. In particular, it is likely that membrane fusion and the L alpha/inverted cubic phase transition proceed via a common set of intermembrane intermediates

  13. 21 CFR 184.1859 - Invert sugar.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an aqueous...

  14. NREL Evaluates Advanced Solar Inverter Performance for Hawaiian Electric

    Science.gov (United States)

    Companies | Energy Systems Integration Facility | NREL NREL Evaluates Advanced Solar Inverter Performance for Hawaiian Electric Companies NREL Evaluates Advanced Solar Inverter Performance for Hawaiian performance and impacts of today's advanced solar inverters, as well as proprietary feedback to the inverter

  15. Breaking Barriers to Low-Cost Modular Inverter Production & Use

    Energy Technology Data Exchange (ETDEWEB)

    Bogdan Borowy; Leo Casey; Jerry Foshage; Steve Nichols; Jim Perkinson

    2005-05-31

    The goal of this cost share contract is to advance key technologies to reduce size, weight and cost while enhancing performance and reliability of Modular Inverter Product for Distributed Energy Resources (DER). Efforts address technology development to meet technical needs of DER market protection, isolation, reliability, and quality. Program activities build on SatCon Technology Corporation inverter experience (e.g., AIPM, Starsine, PowerGate) for Photovoltaic, Fuel Cell, Energy Storage applications. Efforts focused four technical areas, Capacitors, Cooling, Voltage Sensing and Control of Parallel Inverters. Capacitor efforts developed a hybrid capacitor approach for conditioning SatCon's AIPM unit supply voltages by incorporating several types and sizes to store energy and filter at high, medium and low frequencies while minimizing parasitics (ESR and ESL). Cooling efforts converted the liquid cooled AIPM module to an air-cooled unit using augmented fin, impingement flow cooling. Voltage sensing efforts successfully modified the existing AIPM sensor board to allow several, application dependent configurations and enabling voltage sensor galvanic isolation. Parallel inverter control efforts realized a reliable technique to control individual inverters, connected in a parallel configuration, without a communication link. Individual inverter currents, AC and DC, were balanced in the paralleled modules by introducing a delay to the individual PWM gate pulses. The load current sharing is robust and independent of load types (i.e., linear and nonlinear, resistive and/or inductive). It is a simple yet powerful method for paralleling both individual devices dramatically improves reliability and fault tolerance of parallel inverter power systems. A patent application has been made based on this control technology.

  16. Integrated Inverter And Battery Charger

    Science.gov (United States)

    Rippel, Wally E.

    1988-01-01

    Circuit combines functions of dc-to-ac inversion (for driving ac motor in battery-powered vehicle) and ac-to-dc conversion (for charging battery from ac line when vehicle not in use). Automatically adapts to either mode. Design of integrated inverter/charger eliminates need for duplicate components, saves space, reduces weight and cost of vehicle. Advantages in other applications : load-leveling systems, standby ac power systems, and uninterruptible power supplies.

  17. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  18. Inverted annular flow experimental study

    International Nuclear Information System (INIS)

    De Jarlais, G.; Ishii, M.

    1985-04-01

    Steady-state inverted annular flow of Freon 113 in up flow was established in a transparent test section. Using a special inlet configuration consisting of long aspect-ratio liquid nozzles coaxially centered within a heated quartz tube, idealized inverted annular flow initial geometry (cylindrical liquid core surrounded by coaxial annulus of gas) could be established. Inlet liquid and gas flowrates, liquid subcooling, and gas density (using various gas species) were measured and varied systematically. The hydrodynamic behavior of the liquid core, and the subsequent downstream break-up of this core into slugs, ligaments and/or droplets of various sizes, was observed. In general, for low inlet liquid velocities it was observed that after the initial formation of roll waves on the liquid core surface, an agitated region of high surface area, with attendant high momentum and energy transfers, occurs. This agitated region appears to propagate downsteam in a quasi-periodic pattern. Increased inlet liquid flow rates, and high gas annulus flow rates tend to diminish the significance of this agitated region. Observed inverted annular flow (and subsequent downstream flow pattern) hydrodynamic behavior is reported, and comparisons are drawn to data generated by previous experimenters studying post-CHF flow

  19. Simvastatin promotes NPC1-mediated free cholesterol efflux from lysosomes through CYP7A1/LXRα signalling pathway in oxLDL-loaded macrophages.

    Science.gov (United States)

    Xu, Xiaoyang; Zhang, Aolin; Halquist, Matthew S; Yuan, Xinxu; Henderson, Scott C; Dewey, William L; Li, Pin-Lan; Li, Ningjun; Zhang, Fan

    2017-02-01

    Statins, 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors, are the first-line medications prescribed for the prevention and treatment of coronary artery diseases. The efficacy of statins has been attributed not only to their systemic cholesterol-lowering actions but also to their pleiotropic effects that are unrelated to cholesterol reduction. These pleiotropic effects have been increasingly recognized as essential in statins therapy. This study was designed to investigate the pleiotropic actions of simvastatin, one of the most commonly prescribed statins, on macrophage cholesterol homeostasis with a focus on lysosomal free cholesterol egression. With simultaneous nile red and filipin staining, analysis of confocal/multi-photon imaging demonstrated that simvastatin markedly attenuated unesterified (free) cholesterol buildup in macrophages loaded with oxidized low-density lipoprotein but had little effect in reducing the sizes of cholesteryl ester-containing lipid droplets; the reduction in free cholesterol was mainly attributed to decreases in lysosome-compartmentalized cholesterol. Functionally, the egression of free cholesterol from lysosomes attenuated pro-inflammatory cytokine secretion. It was determined that the reduction of lysosomal free cholesterol buildup by simvastatin was due to the up-regulation of Niemann-Pick C1 (NPC1), a lysosomal residing cholesterol transporter. Moreover, the enhanced enzymatic production of 7-hydroxycholesterol by cytochrome P450 7A1 and the subsequent activation of liver X receptor α underscored the up-regulation of NPC1. These findings reveal a novel pleiotropic effect of simvastatin in affecting lysosomal cholesterol efflux in macrophages and the associated significance in the treatment of atherosclerosis. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  20. An improved modulation strategy for the three-phase Z-source inverters (ZSIs)

    DEFF Research Database (Denmark)

    Abdelhakim, Ahmed; Davari, Pooya; Blaabjerg, Frede

    2017-01-01

    Z-source inverters (ZSIs), compared to the two-stage architecture, i.e. boost-converter (BC)-fed voltage source inverter (VSI), embrace some interesting features, like the reduced size and complexity of the entire conversion system. Several research activities have been established to improve...

  1. Harmonic currents Compensator Grid-Connected Inverter at the Microgrid

    DEFF Research Database (Denmark)

    Asuhaimi Mohd Zin, A.; Naderipour, A.; Habibuddin, M.H.

    2016-01-01

    The main challenge associated with the grid-connected inverter in distributed generation (DG) systems is to maintain the harmonic contents in output current below the specified values and compensates for unbalanced loads even when the grid is subject to disturbances such as harmonic distortion...... and unbalanced loads. To overcome these challenges, a current control strategy for a three-phase grid-connected inverter under unbalanced and nonlinear load conditions is presented. It enables grid-connected inverter by the proposed control method to inject balanced clean currents to the grid even when the local...... loads are unbalanced and/or nonlinear and also compensate of the harmonic currents and control the active and reactive power. The main advantage and objective of this method is to effectively compensate for the harmonic currents content of the grid current and microgrid without using any compensation...

  2. Multilayer Control for Inverters in Parallel Operation without Intercommunications

    DEFF Research Database (Denmark)

    Hua, Ming; Hu, Haibing; Xing, Yan

    2012-01-01

    In this paper, a multilayer control is proposed for inverters able to operate in parallel without intercommunications. The first control layer is an improved droop method that introduces power proportional terms into the conventional droop scheme, letting both active and reactive power to be shared...

  3. Control electronic platform based on floating-point DSP and FPGA for a NPC multilevel back-to-back converter

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Francisco J.; Cobreces, Santiago; Bueno, Emilio J.; Hernandez, Alvaro; Mateos, Raul; Espinosa, Felipe [Department of Electronics, University of Alcala, Alcala de Henares, Madrid (Spain)

    2008-09-15

    Modern energy concepts as Distributed Power Generation are changing the appearance of electric distribution and transmission and challenging power electronics researchers, which try to develop new solutions of electronic controllers. The aim is to enable the implementation of new and more complex control algorithms to verify the last standards related to the grid energy quality for new power converters, and, also, for equipments which nowadays are operating. This paper presents the design, implementation and test of a novel real-time controller for a Neutral Point Clamped (NPC) (three-level) multilevel converter based on a floating-point Digital Signal Processor (DSP) and on a Field-Programmable Gate Array (FPGA), by operating in a cooperative way. Although the proposed system can be readily applied to any power electronic application, in this work, it is focused on the next system: a 150 kVA back-to-back three-level NPC Voltage Source Converter (VSC) for wind power applications. (author)

  4. EVALUATION PROGRAM SEVEN A SIDE FOOTBALL COACHING NATIONAL PARALIMPIC COMMITTEE (NPC) OF INDONESIA AT ASEAN PARAGAMES 2015 IN SINGAPORE

    OpenAIRE

    Asmawi, Moch.

    2017-01-01

    The purpose of the study was to evaluate program seven a side football National Paralimpic Committee (NPC) of Indonesia at ASEAN Paragames 2015 in Singapore. The research is qualitative research approach to evaluation using the model Context, Input, Process, and Product (CIPP). Triangulation method of collecting data using questionnaires, interviews, document study and observation. Research result that: 1) Evaluation of Context: have a legal basis and strong government policy, vision mission ...

  5. A hierarchical model predictive voltage control for NPC/H-bridge converters with a reduced computational burden

    DEFF Research Database (Denmark)

    Gong, Zheng; Dai, Peng; Wu, Xiaojie

    2017-01-01

    In recent years, voltage source multilevel converters are very popular in medium/high-voltage industrial applications, among which the NPC/H-Bridge converter is a popular solution to the medium/high-voltage drive systems. The conventional finite control set model predictive control (FCS-MPC) stra......In recent years, voltage source multilevel converters are very popular in medium/high-voltage industrial applications, among which the NPC/H-Bridge converter is a popular solution to the medium/high-voltage drive systems. The conventional finite control set model predictive control (FCS......-MPC) strategy is not practical for multilevel converters due to their substantial calculation requirements, especially under high number of voltage levels. To solve this problem, a hierarchical model predictive voltage control (HMPVC) strategy with referring to the implementation of g-h coordinate space vector...... and experiments with a down-scaled NPC/H-Bridge converter prototype under various conditions, which validate the proposed HMPVC strategy....

  6. Multilevel Inverter by Cascading Industrial VSI

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Pedersen, John Kim

    2002-01-01

    In this paper the modularity concept applied to medium-voltage adjustable speed drives is addressed. First, the single-phase cascaded voltage-source inverter that uses series connection of IGBT H-bridge modules with isolated dc-buses is presented. Next, a novel three-phase cascaded voltage......-source inverter that uses three IGBT triphase inverter modules along with an output transformer to obtain a 3 p.u. multilevel output voltage is introduced. The system yields in high-quality multistep voltage with up to 4 levels and low dv/dt, balanced operation of the inverter modules, each supplying a third...... of the motor rated kVA. The concept of using cascaded inverters is further extended to a new modular motor-modular inverter system where the motor winding connections are reconnected into several three-phase groups, either six-lead or 12-lead connection according to the voltage level, each powered...

  7. The Inverted Discoid Meniscus Segment: Clinical, Radiographic, and Arthroscopic Description of a Hidden Tear Pattern.

    Science.gov (United States)

    LaMont, Lauren; Ellis, Henry; Wise, Kelsey; Wilson, Philip

    2016-06-01

    A flipped, or inverted, meniscus segment is easily visualized in the normal meniscus. However, an inverted discoid meniscus segment may be difficult to appreciate because the tear occurs more centrally and leaves more meniscal rim; thus, it may be undertreated if not addressed during arthroscopy. To describe findings on clinical history, radiographs, MRI, and arthroscopy of a lateral discoid meniscus with an inverted segment and compare them with characteristics of a lateral discoid meniscus without an inverted segment. Case-control study; Level of evidence, 3. Between 2009 and 2012, a retrospective series of 121 consecutive knee arthroscopies for symptomatic lateral discoid meniscus were reviewed for the presence of an inverted fragment. Chart review of clinical presentation, operative reports, radiographic images, and arthroscopic images was performed. Comparative analysis of the clinical presentation between lateral discoid menisci with an inverted segment and noninverted lateral discoid menisci was performed by use of Fisher exact test and Mann-Whitney test. Nineteen patients with an inverted discoid meniscus segment (14 males, 5 females; average age, 15.0 years; range, 9.5-17.0 years) were compared with 102 patients with a noninverted discoid meniscus (53 males, 49 females; average age, 12.3 years; range, 5-17.0 years) (P = .011 for sex and P meniscus patients with an inverted segment had activity-related knee pain. Only 4 patients (21.0%) reported mechanical symptoms. Patients with an inverted discoid segment, compared with patients with discoid menisci without inverted segments, were more likely to have instability and effusion (P = .012 and P meniscus patients with an inverted segment (94.7%) had an injury, while only 41.2% of patients with noninverted symptomatic discoid menisci had an injury (P meniscus. During arthroscopy, the inverted discoid segment appeared normal, without a tear; upon probing, however, the inverted segment could be exposed. An

  8. Three-Phase Cascaded Multilevel Inverter Using Power Cells With Two Inverter Legs in Series

    NARCIS (Netherlands)

    Waltrich, G.; Barbi, I.

    2010-01-01

    In this paper, a modular three-phase multilevel inverter specially suited for electrical drive applications is proposed. Unlike the cascaded H-bridge inverter, this topology is based on power cells connected in cascade using two inverter legs in series. A detailed analysis of the structure and the

  9. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    Science.gov (United States)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  10. Three-level grid-connected photovoltaic inverter with maximum power point tracking

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2013-01-01

    Highlight: ► This paper reports a novel 3-level grid connected photovoltaic inverter. ► The inverter features maximum power point tracking and grid current shaping. ► The inverter can be acted as an active filter and a renewable power source. - Abstract: This paper presents a systematic way of designing control scheme for a grid-connected photovoltaic (PV) inverter featuring maximum power point tracking (MPPT) and grid current shaping. Unlike conventional design, only four power switches are required to achieve three output levels and it is not necessary to use any phase-locked-loop circuitry. For the proposed scheme, a simple integral controller has been designed for the tracking of the maximum power point of a PV array based on an improved extremum seeking control method. For the grid-connected inverter, a current loop controller and a voltage loop controller have been designed. The current loop controller is designed to shape the inverter output current while the voltage loop controller can maintain the capacitor voltage at a certain level and provide a reference inverter output current for the PV inverter without affecting the maximum power point of the PV array. Experimental results are included to demonstrate the effectiveness of the tracking and control scheme.

  11. Invert Effective Thermal Conductivity Calculation

    International Nuclear Information System (INIS)

    M.J. Anderson; H.M. Wade; T.L. Mitchell

    2000-01-01

    The objective of this calculation is to evaluate the temperature-dependent effective thermal conductivities of a repository-emplaced invert steel set and surrounding ballast material. The scope of this calculation analyzes a ballast-material thermal conductivity range of 0.10 to 0.70 W/m · K, a transverse beam spacing range of 0.75 to 1.50 meters, and beam compositions of A 516 carbon steel and plain carbon steel. Results from this calculation are intended to support calculations that identify waste package and repository thermal characteristics for Site Recommendation (SR). This calculation was developed by Waste Package Department (WPD) under Office of Civilian Radioactive Waste Management (OCRWM) procedure AP-3.12Q, Revision 1, ICN 0, Calculations

  12. Electrical design of the BUSSARD inverter system for ASDEX upgrade saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Teschke, Markus, E-mail: teschke@ipp.mpg.de; Arden, Nils; Eixenberger, Horst; Rott, Michael; Suttrop, Wolfgang

    2015-10-15

    Highlights: • A cost effective inverter topology for AUG's 16 in-vessel saddle coils has been found. • Use of commercially available power modules is possible. • A NPC-like topology of the power stage is realized in a modular way. • The high-speed controllers and PWM engines are realized on Linux-based systems. • First experimental results of AUG plasma shots are presented. - Abstract: A set of 16 in-vessel saddle coils is installed in the ASDEX Upgrade (AUG) nuclear fusion experiment for mitigation of edge localized modes (ELM) and feedback control of resistive wall modes (RWM). The coils were driven by DC current only during previous campaigns. Now, a new inverter system “BUSSARD” (German abbr. for “Bayerischer Umrichter, schnell schaltend für AUGs rasche Drehfelder”, translated: “bavarian fast switching inverter for AUG's fast rotating fields”) is built for the experiment. A four-phase system has been assembled to simultaneously operate up to 4 groups of coils consisting of up to 4 serial-connected coils each. The maximum current is 1.3 kA with a ripple in the range of 7% and the frequency is variable between DC and approx. 100 Hz. The switching frequency is variable between approximately 3 and 10 kHz. As a first application, rotating fields are generated. The system can be enhanced in two stages to 16-phase operation with a bandwidth of 500 Hz and a 24 phase system with a bandwidth of up to 3 kHz.

  13. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios

    2017-05-11

    Inverted base pavements involve a well-compacted granular aggregate base built between a thin asphalt concrete layer and a cement-treated base. Inverted base pavements can be constructed using conventional equipment and procedures but require proper quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost. Inverted base pavements rely on the complementary interaction between layers. The cement-treated base provides a stiff foundation for efficient compaction and constrains the deformation of the stress-sensitive granular aggregate base. The thin asphalt surface layer deforms as a membrane and develops low tensile stress. Additional large-scale field tests should be conducted to assess the performance of inverted base pavement designs in a wide range of conditions relevant to the USA.

  14. On Invertible Sampling and Adaptive Security

    DEFF Research Database (Denmark)

    Ishai, Yuval; Kumarasubramanian, Abishek; Orlandi, Claudio

    2011-01-01

    functionalities was left open. We provide the first convincing evidence that the answer to this question is negative, namely that some (randomized) functionalities cannot be realized with adaptive security. We obtain this result by studying the following related invertible sampling problem: given an efficient...... sampling algorithm A, obtain another sampling algorithm B such that the output of B is computationally indistinguishable from the output of A, but B can be efficiently inverted (even if A cannot). This invertible sampling problem is independently motivated by other cryptographic applications. We show......, under strong but well studied assumptions, that there exist efficient sampling algorithms A for which invertible sampling as above is impossible. At the same time, we show that a general feasibility result for adaptively secure MPC implies that invertible sampling is possible for every A, thereby...

  15. Detecting and mitigating battery charger and inverter aging

    International Nuclear Information System (INIS)

    Gunther, W.E.; Lewis, R.; Subudhi, M.

    1988-08-01

    This report constitutes the second of the two-phase approach for assessing the safety and operational aspects of battery charger and inverter aging in nuclear power plants. This work, conducted by Brookhaven National Laboratory (BNL) under the auspices of the US NRC Nuclear Plant Aging Research (NPAR) Program, evaluated operating experience data, nuclear power plant maintenance practices, and plant design information to determine the impact of battery charger and inverter aging on safety, and the methods which should be used to detect aging degradation and mitigate its effects. A naturally aged inverter and battery charger were tested at BNL to evaluate the naturally aged condition, the effectiveness of condition monitoring techniques, and the practicality of implementing selected maintenance and monitoring recommendations. Temperature monitoring, component parameter measurements, and the periodic observation of critical circuit waveforms are viable methods for monitoring aging degradation. A maintenance program for battery chargers and inverters is recommended. As described in this report, the maintenance program incorporates inspection, monitoring, testing and repair activities which should be performed to detect and mitigate aging effects, and thereby assure the operational readiness of this important equipment throughout the plant's operating life. 32 refs., 43 figs., 19 tabs

  16. Highly efficient fully transparent inverted OLEDs

    Science.gov (United States)

    Meyer, J.; Winkler, T.; Hamwi, S.; Schmale, S.; Kröger, M.; Görrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

    2007-09-01

    One of the unique selling propositions of OLEDs is their potential to realize highly transparent devices over the visible spectrum. This is because organic semiconductors provide a large Stokes-Shift and low intrinsic absorption losses. Hence, new areas of applications for displays and ambient lighting become accessible, for instance, the integration of OLEDs into the windshield or the ceiling of automobiles. The main challenge in the realization of fully transparent devices is the deposition of the top electrode. ITO is commonly used as transparent bottom anode in a conventional OLED. To obtain uniform light emission over the entire viewing angle and a low series resistance, a TCO such as ITO is desirable as top contact as well. However, sputter deposition of ITO on top of organic layers causes damage induced by high energetic particles and UV radiation. We have found an efficient process to protect the organic layers against the ITO rf magnetron deposition process of ITO for an inverted OLED (IOLED). The inverted structure allows the integration of OLEDs in more powerful n-channel transistors used in active matrix backplanes. Employing the green electrophosphorescent material Ir(ppy) 3 lead to IOLED with a current efficiency of 50 cd/A and power efficiency of 24 lm/W at 100 cd/m2. The average transmittance exceeds 80 % in the visible region. The on-set voltage for light emission is lower than 3 V. In addition, by vertical stacking we achieved a very high current efficiency of more than 70 cd/A for transparent IOLED.

  17. Leakage current analysis of a single-phase transformer-less PV inverter connected to the grid

    DEFF Research Database (Denmark)

    Ma, Lin; Tang, F.; Zhou, F.

    2009-01-01

    Due to the large surface of the PV generator, its stray capacity with respect to the ground reaches values that can be quite high. When no transformer is used in a grid-connected PV system, common-mode current, which caused by the common mode voltage, can flow through the stray capacitance between...... the PV array and the ground. It is quite harmful to the body safety and PV system. In order to avoid leakage current, different inverter topologies that generate no varying common-mode voltages, such as bipolar pulse-width modulation (PWM) full-bridge topology, NPC topology have been proposed. From...... the safety and energy saving viewpoint, it is necessary to develop a higher efficiency topology. In this paper, the generation mechanism of common mode current is discussed. Then different methods used to eliminate the leakage current are compared. Finally, the full-bridge which generates no varying common...

  18. Clinical observation in nasopharyngeal carcinoma (NPC) treated with the anti-EGFR monoclonal antibody followed by helical tomotherapy

    International Nuclear Information System (INIS)

    Hou Jun; Feng Linchun; Cai Boning; Lu Na; Du Lei; Ma Lin; Xu Shouping; Xie Chuanbin

    2011-01-01

    Objective: To evaluate the clinical outcome and the acute toxicity in nasopharyngeal carcinoma (NPC) treated with tomotherapy followed by the anti-EGFR monoclonal antibody. Methods: Between March 2008 and November 2009, 34 newly diagnosed NPC patients were treated with helical tomotherapy combined with nimotuzumab or cetuximab. All the patients underwent tomotherapy at the dose of 70 Gy/33F for the gross tumor volume (pGTV ns ) and positive lymphnodes (GTV nd ), and 60 Gy/33F for the high risk clinical target volume (PTV 1 ), and 56 Gy/33 F for the low risk clinical target volume (PTV 2 ), respectively. 17 patients in group N were given weekly injection of 200 mg for 6-7 times and 17 patients in group C were given initial dosage 400 mg/m 2 followed by subsequent weekly dosage of 250 mg/m 2 for 6-7 times. Acute lesions were evaluated with the RTOG/EORTC criteria. Result: The median follow-up time was 22 months. The effective rates (CR + PR) in 3, 6 and 12 months were 14/17, 12/17, 12/17 in group N and 15/17, 14/17, 14/17 in group C. The 1 year survival rate was 15/17 in group Nand 17/17 in group C. Nimotuzumab had less acute mucositis reaction (u=2.25, P< 0.05), weight loss (t=2.56, P=0.02) and rash (u=4.36, P<0.01) compared with cetuximab. Conclusions: Helical tomotherapy combined with nimotuzumab or cetuximab was effective and made no difference in the short-term efficacy and 1 year survival rate for the patients with NPC. Nimotuzumab has less acute reaction than cetuximab. More studies should be done to prove long-term effects. (authors)

  19. The Nurse Professional Competence (NPC) Scale: Self-reported competence among nursing students on the point of graduation.

    Science.gov (United States)

    Gardulf, Ann; Nilsson, Jan; Florin, Jan; Leksell, Janeth; Lepp, Margret; Lindholm, Christina; Nordström, Gun; Theander, Kersti; Wilde-Larsson, Bodil; Carlsson, Marianne; Johansson, Eva

    2016-01-01

    International organisations, e.g. WHO, stress the importance of competent registered nurses (RN) for the safety and quality of healthcare systems. Low competence among RNs has been shown to increase the morbidity and mortality of inpatients. To investigate self-reported competence among nursing students on the point of graduation (NSPGs), using the Nurse Professional Competence (NPC) Scale, and to relate the findings to background factors. The NPC Scale consists of 88 items within eight competence areas (CAs) and two overarching themes. Questions about socio-economic background and perceived overall quality of the degree programme were added. In total, 1086 NSPGs (mean age, 28.1 [20-56]years, 87.3% women) from 11 universities/university colleges participated. NSPGs reported significantly higher scores for Theme I "Patient-Related Nursing" than for Theme II "Organisation and Development of Nursing Care". Younger NSPGs (20-27years) reported significantly higher scores for the CAs "Medical and Technical Care" and "Documentation and Information Technology". Female NSPGs scored significantly higher for "Value-Based Nursing". Those who had taken the nursing care programme at upper secondary school before the Bachelor of Science in Nursing (BSN) programme scored significantly higher on "Nursing Care", "Medical and Technical Care", "Teaching/Learning and Support", "Legislation in Nursing and Safety Planning" and on Theme I. Working extra paid hours in healthcare alongside the BSN programme contributed to significantly higher self-reported scores for four CAs and both themes. Clinical courses within the BSN programme contributed to perceived competence to a significantly higher degree than theoretical courses (93.2% vs 87.5% of NSPGs). Mean scores reported by NSPGs were highest for the four CAs connected with patient-related nursing and lowest for CAs relating to organisation and development of nursing care. We conclude that the NPC Scale can be used to identify and measure

  20. Industry Perspectives on Advanced Inverters for U.S. Solar Photovoltaic Systems. Grid Benefits, Deployment Challenges, and Emerging Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Reiter, Emerson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ardani, Kristen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Edge, Ryan [Solar Electric Power Association (SEPA), Washington, DC (United States)

    2015-09-01

    To clarify current utility strategies and other considerations related to advanced inverter deployment, we interviewed 20 representatives from 11 leading organizations closely involved with advanced inverter pilot testing, protocols, and implementation. Included were representatives from seven utilities, a regional transmission operator, an inverter manufacturer, a leading solar developer, and a consortium for grid codes and standards. Interview data represent geographically the advanced inverter activities identified in SEPA's prior survey results--most interviewed utilities serve California, Arizona, and Hawaii, though we also interviewed others from the Northeast, Mid-Atlantic, and Southeast.

  1. Leakage current measurement in transformerless PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

    2012-01-01

    Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

  2. Switching Characteristics of Ferroelectric Transistor Inverters

    Science.gov (United States)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  3. Static Characteristics of the Ferroelectric Transistor Inverter

    Science.gov (United States)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  4. Inverted CERN School of Computing

    CERN Multimedia

    IT Department

    2011-01-01

      The 5th edition of the Inverted CERN School of Computing (iCSC, “Where students turn into teachers”) will take place next Thursday and Friday (3 and 4 of March) at CERN, Building 31 - IT Amphitheatre - Third Floor. Attendance is free and open to everyone. The programme is designed so that you can attend the lectures that interest you. This year highlights: Cloud Computing, Software Engineering, Cryptography Registration is not mandatory, but will allow you to obtain a copy of the full booklet (first registered, first served). Programme overview: Thursday 3 March 2011 10:00 - 10:15 Introduction School opening 10:15 - 11:10 Lecture 1 Virtualization: what it is, how it works – Luigi Gallerani 11:20 - 12:15 Lecture 2 Server Virtualization at work – Carlos Garcia Fernandez 14:00 - 14:55 Lecture 3 Unweaving Clouds: Principles and Practice – Belmiro Moreira 15:30 - 16:25 Lecture 4 Understanding Cryptography: From Caesar to Public-Key – Nicola...

  5. Hardware Development of a Laboratory-Scale Microgrid Phase 1--Single Inverter in Island Mode Operation: Base Year Report, December 2000 -- November 2001

    Energy Technology Data Exchange (ETDEWEB)

    Venkataramanan, G.; Illindala, M. S.; Houle, C.; Lasseter, R. H.

    2002-11-01

    This report summarizes the activities of the first year of a three-year project to develop control software for micro-source distributed generation systems. The focus of this phase was on internal energy storage requirements, the modification of an off-the-shelf motor drive system inverter to supply utility-grade ac power, and a single inverter system operating in island mode. The report provides a methodology for determining battery energy storage requirements, a method for converting a motor drive inverter into a utility-grade inverter, and typical characteristics and test results of using such an inverter in a complex load environment.

  6. Large-Signal Lyapunov-Based Stability Analysis of DC/AC Inverters and Inverter-Based Microgrids

    Science.gov (United States)

    Kabalan, Mahmoud

    study. This will enable future studies to save computational effort and produce the most accurate results according to the needs of the study being performed. Moreover, the effect of grid (line) impedance on the accuracy of droop control is explored using the 5th order model. Simulation results show that traditional droop control is valid up to R/X line impedance value of 2. Furthermore, the 3rd order nonlinear model improves the currently available inverter-infinite bus models by accounting for grid impedance, active power-frequency droop and reactive power-voltage droop. Results show the 3rd order model's ability to account for voltage and reactive power changes during a transient event. Finally, the large-signal Lyapunov-based stability analysis is completed for a 3 bus microgrid system (made up of 2 inverters and 1 linear load). The thesis provides a systematic state space large-signal nonlinear mathematical modeling method of inverter-based microgrids. The inverters include the dc-side dynamics associated with dc sources. The mathematical model is then used to estimate the domain of asymptotic stability of the 3 bus microgrid. The three bus microgrid system was used as a case study to highlight the design and optimization capability of a large-signal-based approach. The study explores the effect of system component sizing, load transient and generation variations on the asymptotic stability of the microgrid. Essentially, this advancement gives microgrid designers and engineers the ability to manipulate the domain of asymptotic stability depending on performance requirements. Especially important, this research was able to couple the domain of asymptotic stability of the ac microgrid with that of the dc side voltage source. Time domain simulations were used to demonstrate the mathematical nonlinear analysis results.

  7. Fully patterned and low temperature transparent ZnO-based inverters

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Heredia, G. [Centro de Investigación en Materiales Avanzados, Unidad Monterrey, México (Mexico); Department of Materials Science and Engineering, University of Texas at Dallas (United States); Mejia, I.; Rivas-Aguilar, M.E.; Hernandez-Como, N. [Department of Materials Science and Engineering, University of Texas at Dallas (United States); Martinez-Landeros, V.H. [Centro de Investigación en Materiales Avanzados, Unidad Monterrey, México (Mexico); Department of Materials Science and Engineering, University of Texas at Dallas (United States); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Unidad Monterrey, México (Mexico); Quevedo-Lopez, M.A., E-mail: mquevedo@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas (United States)

    2013-10-31

    The fabrication and characterization of transparent logic inverters based on zinc oxide (ZnO) thin film transistors (TFTs) is reported. The inverters are fabricated using standard photolithographic techniques on glass substrates, and the entire fabrication process temperature is maintained < 100 °C, which render the devices suitable for flexible and transparent electronics applications. Pulsed laser deposition is used to deposit aluminum-doped zinc oxide and ZnO as electrode and active semiconductor materials, respectively. Electrical characterization for individual TFTs demonstrate mobilities of ∼ 10 cm{sup 2}/V-s, threshold voltages of 6 V, sub-threshold slopes of 630 mV/decade and I{sub ON}/I{sub OFF} ratios of 5 × 10{sup 6}. Films characterized by UV-Vis showed optical transmission > 80% in the visible spectrum. The inverters are analyzed with AC input signals at frequencies of 100 and 500 Hz. The AC response shows an average rise and fall time transitions of 0.65 and 0.44 ms, respectively. Measured inverters delay is in the order of 0.21 ms. - Highlights: • Logic inverters based on zinc oxide thin film transistors. • Inverters fabricated using temperatures below 100 °C and standard photolithography. • Transparent aluminum-doped zinc oxide as gate, drain and source electrodes. • Devices with total transmittance in the visible range above 80%. • AC inverter response up to 500 Hz.

  8. Fully patterned and low temperature transparent ZnO-based inverters

    International Nuclear Information System (INIS)

    Gutierrez-Heredia, G.; Mejia, I.; Rivas-Aguilar, M.E.; Hernandez-Como, N.; Martinez-Landeros, V.H.; Aguirre-Tostado, F.S.; Quevedo-Lopez, M.A.

    2013-01-01

    The fabrication and characterization of transparent logic inverters based on zinc oxide (ZnO) thin film transistors (TFTs) is reported. The inverters are fabricated using standard photolithographic techniques on glass substrates, and the entire fabrication process temperature is maintained < 100 °C, which render the devices suitable for flexible and transparent electronics applications. Pulsed laser deposition is used to deposit aluminum-doped zinc oxide and ZnO as electrode and active semiconductor materials, respectively. Electrical characterization for individual TFTs demonstrate mobilities of ∼ 10 cm 2 /V-s, threshold voltages of 6 V, sub-threshold slopes of 630 mV/decade and I ON /I OFF ratios of 5 × 10 6 . Films characterized by UV-Vis showed optical transmission > 80% in the visible spectrum. The inverters are analyzed with AC input signals at frequencies of 100 and 500 Hz. The AC response shows an average rise and fall time transitions of 0.65 and 0.44 ms, respectively. Measured inverters delay is in the order of 0.21 ms. - Highlights: • Logic inverters based on zinc oxide thin film transistors. • Inverters fabricated using temperatures below 100 °C and standard photolithography. • Transparent aluminum-doped zinc oxide as gate, drain and source electrodes. • Devices with total transmittance in the visible range above 80%. • AC inverter response up to 500 Hz

  9. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... optimization. The proposed method is used to calculate the voltage bands and droop settings of PV inverters at each node by the supervisory controller. The local controller of each PV inverter implements the volt/var control and if necessary, the active power curtailment as per the received settings and based...... on measured local voltages. The advantage of the proposed method is that the calculated reactive power and active power droop settings enable fair contribution of the PV inverters at each node to the voltage regulation. Simulation studies are conducted using DigSilent Power factory software on a simplified...

  10. Development of inverter for elevator door control

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.K.; Choi, U.D.; Jung, M.K.; Choi, S.K. [HHI R and D Center (Korea, Republic of); Yun, J.H.; Han, S.B. [HELCO R and D Center (Korea, Republic of)

    1995-07-01

    Most of the elevator door controllers have been controlled by DC Motors as an actuator. Recently, The control system using AC induction motor and general purpose inverter has been applied to control of elevator door. But there are some difficulties in making use of this system, such as adjustment of door speed pattern, door open-close time, and security of passenger safety. In order to solve these problems, a special inverter has been developed with an encoder feedback. From the result of field-test, we proved that a special inverter with encoder feedback device has come to considerable effect. Until now about 1,200 sets of these inverters are operated in Korea and about 100 sets are operated in South-east Asia. (author). 3 refs., 10 figs., 3 tabs.

  11. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios; Santamarina, Carlos

    2017-01-01

    quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost

  12. Integrated Inverter For Driving Multiple Electric Machines

    Science.gov (United States)

    Su, Gui-Jia [Knoxville, TN; Hsu, John S [Oak Ridge, TN

    2006-04-04

    An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1-S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

  13. Performance analysis of new type grid-tied inverter-Aalborg Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Wang, Zhen; Ji, Junhao

    2014-01-01

    Aalborg Inverter is a grid-tied DC/AC inverter. In order to optimize the design, its power losses are analyzed in detail, combined with a description of the single-phase operating principle and the modulation strategy. A 2 kW / 220 V experimental prototype is constructed to verify the theoretical...... analysis. It is concluded that a minimize inductance in the power loop does help the inverter to achieve the high efficiency with the good dynamic performance....

  14. Work Station For Inverting Solar Cells

    Science.gov (United States)

    Feder, H.; Frasch, W.

    1982-01-01

    Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

  15. The CMOS Integration of a Power Inverter

    OpenAIRE

    Mannarino, Eric Francis

    2016-01-01

    Due to their falling costs, the use of renewable energy systems is expanding around the world. These systems require the conversion of DC power into grid-synchronous AC power. Currently, the inverters that carry out this task are built using discrete transistors. TowerJazz Semiconductor Corp. has created a commercial CMOS process that allows for blocking voltages of up to 700 V, effectively removing the barrier to integrating power inverters onto a single chip. This thesis explores this proce...

  16. Base drive for paralleled inverter systems

    Science.gov (United States)

    Nagano, S. (Inventor)

    1980-01-01

    In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

  17. Improved Layout of Inverter for EMC Analysis

    OpenAIRE

    Yade , Ousseynou; Martin , Christian; Vollaire , Christian; Bréard , Arnaud; Ali , Marwan; Meuret , Régis; Hervé , Morel

    2017-01-01

    International audience; This paper details EMC (electromagnetic compatibility) analysis on an inverter application. The work deals with the whole power chain (±270Vdc input voltage to 3-phase 115 Vac output voltage). This inverter is composed by modular parts (power module and EMC filters) that supply motors in more electrical aircraft. Through our analysis an approach is defined to design a detailed lumped circuit model of the power module layout by using Q3D extractor and SABER software. Fr...

  18. On Stability of Voltage Source Inverters in Weak Grids

    DEFF Research Database (Denmark)

    Adib, Aswad; Mirafza, Behrooz; Wang, Xiongfei

    2018-01-01

    As the number of inverters increases in the power grid, the stability of grid-tied inverters becomes an important concern for the power industry. In particular, a weak grid can lead to voltage fluctuations at the inverter terminals and consequently cause inverter instability. In this paper, impac...

  19. Hardness of deriving invertible sequences from finite state machines

    DEFF Research Database (Denmark)

    Hierons, Robert M.; Mousavi, Mohammad Reza; Thomsen, Michael Kirkedal

    2017-01-01

    invertible sequences; these allow one to construct additional UIOs once a UIO has been found. We consider three optimisation problems associated with invertible sequences: deciding whether there is a (proper) invertible sequence of length at least K; deciding whether there is a set of invertible sequences...

  20. Current control loop of 3-phase grid-connected inverter

    International Nuclear Information System (INIS)

    Jabbar, A F; Mansor, M

    2013-01-01

    This paper presents a comparative study of current control loop in 3-phase inverter which is used to control the active and reactive output power. Generally, current control loop, power control loop and phase lock-loop are the conventional parameters that can be found in an inverter system controlled by the conventional linear control type, for instance proportional (P), integral (I) and derivative (D). If the grid remains stable throughout the day, PID control can be use. However variation of magnitude, frequency, voltage dips, transient, and other related power quality issues occur in a 3-phase grid often affects the control loop. This paper aims to provide an overall review on the available current control techniques used in grid connected system.

  1. A Hybrid, Current-Source/Voltage-Source Power Inverter Circuit

    DEFF Research Database (Denmark)

    Trzynadlowski, Andrzej M.; Patriciu, Niculina; Blaabjerg, Frede

    2001-01-01

    A combination of a large current-source inverter and a small voltage-source inverter circuits is analyzed. The resultant hybrid inverter inherits certain operating advantages from both the constituent converters. In comparison with the popular voltage-source inverter, these advantages include...... reduced switching losses, improved quality of output current waveforms, and faster dynamic response to current control commands. Description of operating principles and characteristics of the hybrid inverter is illustrated with results of experimental investigation of a laboratory model....

  2. Single DV-DXCCII Based Voltage Controlled First Order All-pass Filter with Inverting and Non-inverting responses

    Directory of Open Access Journals (Sweden)

    B Chaturvedi

    2015-12-01

    Full Text Available In this paper, a new voltage controlled first order all-pass filter is presented. The proposed circuit employs a single differential voltage dual-X second generation current conveyor (DV-DXCCII and a grounded capacitor only. The proposed all-pass filter provides both inverting and non inverting voltage-mode outputs from the same configuration simultaneously without any matching condition. Non-ideal analysis along with sensitivity analysis is also investigated. The proposed circuit has low active and passive sensitivities. As an application the proposed all-pass filter is connected in cascade to get higher order filter. The theoretical results are validated thorough PSPICE simulations using TSMC 0.18µm CMOS process parameters.

  3. Towards Efficient Positional Inverted Index †

    Directory of Open Access Journals (Sweden)

    Petr Procházka

    2017-02-01

    Full Text Available We address the problem of positional indexing in the natural language domain. The positional inverted index contains the information of the word positions. Thus, it is able to recover the original text file, which implies that it is not necessary to store the original file. Our Positional Inverted Self-Index (PISI stores the word position gaps encoded by variable byte code. Inverted lists of single terms are combined into one inverted list that represents the backbone of the text file since it stores the sequence of the indexed words of the original file. The inverted list is synchronized with a presentation layer that stores separators, stop words, as well as variants of the indexed words. The Huffman coding is used to encode the presentation layer. The space complexity of the PISI inverted list is O ( ( N − n ⌈ log 2 b N ⌉ + ( ⌊ N − n α ⌋ + n × ( ⌈ log 2 b n ⌉ + 1 where N is a number of stems, n is a number of unique stems, α is a step/period of the back pointers in the inverted list and b is the size of the word of computer memory given in bits. The space complexity of the presentation layer is O ( − ∑ i = 1 N ⌈ log 2 p i n ( i ⌉ − ∑ j = 1 N ′ ⌈ log 2 p j ′ ⌉ + N with respect to p i n ( i as a probability of a stem variant at position i, p j ′ as the probability of separator or stop word at position j and N ′ as the number of separators and stop words.

  4. Impact of Reactive Power Injection Outside Feed-In Hours on the Reliability of Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    , the analysis enables the translation from long-term mission profiles to device thermal loading, considering the operation at night. An analytical lifetime model is then used for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter......Current energy paradigm of mixed renewables seems to urgently require reactive power provision at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection point even outside active power feed......-in operation, especially at night. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, a detailed analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and also the reliability is performed...

  5. Pre-symptomatic activation of antioxidant responses and alterations in glucose and pyruvate metabolism in Niemann-Pick Type C1-deficient murine brain.

    Directory of Open Access Journals (Sweden)

    Barry E Kennedy

    Full Text Available Niemann-Pick Type C (NPC disease is an autosomal recessive neurodegenerative disorder caused in most cases by mutations in the NPC1 gene. NPC1-deficiency is characterized by late endosomal accumulation of cholesterol, impaired cholesterol homeostasis, and a broad range of other cellular abnormalities. Although neuronal abnormalities and glial activation are observed in nearly all areas of the brain, the most severe consequence of NPC1-deficiency is a near complete loss of Purkinje neurons in the cerebellum. The link between cholesterol trafficking and NPC pathogenesis is not yet clear; however, increased oxidative stress in symptomatic NPC disease, increases in mitochondrial cholesterol, and alterations in autophagy/mitophagy suggest that mitochondria play a role in NPC disease pathology. Alterations in mitochondrial function affect energy and neurotransmitter metabolism, and are particularly harmful to the central nervous system. To investigate early metabolic alterations that could affect NPC disease progression, we performed metabolomics analyses of different brain regions from age-matched wildtype and Npc1 (-/- mice at pre-symptomatic, early symptomatic and late stage disease by (1H-NMR spectroscopy. Metabolic profiling revealed markedly increased lactate and decreased acetate/acetyl-CoA levels in Npc1 (-/- cerebellum and cerebral cortex at all ages. Protein and gene expression analyses indicated a pre-symptomatic deficiency in the oxidative decarboxylation of pyruvate to acetyl-CoA, and an upregulation of glycolytic gene expression at the early symptomatic stage. We also observed a pre-symptomatic increase in several indicators of oxidative stress and antioxidant response systems in Npc1 (-/- cerebellum. Our findings suggest that energy metabolism and oxidative stress may present additional therapeutic targets in NPC disease, especially if intervention can be started at an early stage of the disease.

  6. A grid-connected single-phase photovoltaic micro inverter

    Science.gov (United States)

    Wen, X. Y.; Lin, P. J.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.

    2017-11-01

    In this paper, the topology of a single-phase grid-connected photovoltaic (PV) micro-inverter is proposed. The PV micro-inverter consists of DC-DC stage with high voltage gain boost and DC-AC conversion stage. In the first stage, we apply the active clamp circuit and two voltage multipliers to achieve soft switching technology and high voltage gain. In addition, the flower pollination algorithm (FPA) is employed for the maximum power point tracking (MPPT) in the PV module in this stage. The second stage cascades a H-bridge inverter and LCL filter. To feed high quality sinusoidal power into the grid, the software phase lock, outer voltage loop and inner current loop control method are adopted as the control strategy. The performance of the proposed topology is tested by Matlab/Simulink. A PV module with maximum power 300W and maximum power point voltage 40V is applied as the input source. The simulation results indicate that the proposed topology and the control strategy are feasible.

  7. Berberine suppresses tumorigenicity and growth of nasopharyngeal carcinoma cells by inhibiting STAT3 activation induced by tumor associated fibroblasts

    International Nuclear Information System (INIS)

    Tsang, Chi Man; Cheung, Yuk Chun; Lui, Vivian Wai-Yan; Yip, Yim Ling; Zhang, Guitao; Lin, Victor Weitao; Cheung, Kenneth Chat-Pan; Feng, Yibin; Tsao, Sai Wah

    2013-01-01

    Cortidis rhizoma (Huanglian) and its major therapeutic component, berberine, have drawn extensive attention in recent years for their anti-cancer properties. Growth inhibitory effects of berberine on multiple types of human cancer cells have been reported. Berberine inhibits invasion, induces cell cycle arrest and apoptosis in human cancer cells. The anti-inflammatory property of berberine, involving inhibition of Signal Transducer and Activator of Transcription 3 (STAT3) activation, has also been documented. In this study, we have examined the effects of berberine on tumorigenicity and growth of nasopharyngeal carcinoma (NPC) cells and their relationship to STAT3 signaling using both in vivo and in vitro models. Berberine effectively inhibited the tumorigenicity and growth of an EBV-positive NPC cell line (C666-1) in athymic nude mice. Inhibition of tumorigenic growth of NPC cells in vivo was correlated with effective inhibition of STAT3 activation in NPC cells inside the tumor xenografts grown in nude mice. In vitro, berberine inhibited both constitutive and IL-6-induced STAT3 activation in NPC cells. Inhibition of STAT3 activation by berberine induced growth inhibition and apoptotic response in NPC cells. Tumor-associated fibroblasts were found to secret IL-6 and the conditioned medium harvested from the fibroblasts also induced STAT3 activation in NPC cells. Furthermore, STAT3 activation by conditioned medium of tumor-associated fibroblasts could be blocked by berberine or antibodies against IL-6 and IL-6R. Our observation that berberine effectively inhibited activation of STAT3 induced by tumor-associated fibroblasts suggests a role of berberine in modulating the effects of tumor stroma on the growth of NPC cells. The effective inhibition of STAT3 activation in NPC cells by berberine supports its potential use in the treatment of NPC

  8. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification.

    Directory of Open Access Journals (Sweden)

    Bonita J Brewer

    2015-12-01

    Full Text Available DNA replication errors are a major driver of evolution--from single nucleotide polymorphisms to large-scale copy number variations (CNVs. Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model--Origin-Dependent Inverted-Repeat Amplification (ODIRA-proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error-the ligation of leading and lagging nascent strands to create "closed" forks-can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent--a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins

  9. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification.

    Science.gov (United States)

    Brewer, Bonita J; Payen, Celia; Di Rienzi, Sara C; Higgins, Megan M; Ong, Giang; Dunham, Maitreya J; Raghuraman, M K

    2015-12-01

    DNA replication errors are a major driver of evolution--from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model--Origin-Dependent Inverted-Repeat Amplification (ODIRA)-proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error-the ligation of leading and lagging nascent strands to create "closed" forks-can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent--a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of interstitial

  10. Addressable inverter matrix for process and device characterization

    Science.gov (United States)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold vltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  11. Niemann-Pick C1 like 1 gene expression is down-regulated by LXR activators in the intestine

    International Nuclear Information System (INIS)

    Duval, Caroline; Touche, Veronique; Tailleux, Anne; Fruchart, Jean-Charles; Fievet, Catherine; Clavey, Veronique; Staels, Bart; Lestavel, Sophie

    2006-01-01

    Niemann-Pick C1 like 1 (NPC1L1) is a protein critical for intestinal cholesterol absorption. The nuclear receptors peroxisome proliferator-activated receptor alpha (PPARα) and liver X receptors (LXRα and LXRβ) are major regulators of cholesterol homeostasis and their activation results in a reduced absorption of intestinal cholesterol. The goal of this study was to define the role of PPARα and LXR nuclear receptors in the regulation of NPC1L1 gene expression. We show that LXR activators down-regulate NPC1L1 mRNA levels in the human enterocyte cell line Caco-2/TC7, whereas PPARα ligands have no effect. Furthermore, NPC1L1 mRNA levels are decreased in vivo, in duodenum of mice treated with the LXR agonist T0901317. In conclusion, the present study identifies NPC1L1 as a novel LXR target gene further supporting a crucial role of LXR in intestinal cholesterol homeostasis

  12. Power inverter implementing phase skipping control

    Science.gov (United States)

    Somani, Utsav; Amirahmadi, Ahmadreza; Jourdan, Charles; Batarseh, Issa

    2016-10-18

    A power inverter includes a DC/AC inverter having first, second and third phase circuitry coupled to receive power from a power source. A controller is coupled to a driver for each of the first, second and third phase circuitry (control input drivers). The controller includes an associated memory storing a phase skipping control algorithm, wherein the controller is coupled to receive updating information including a power level generated by the power source. The drivers are coupled to control inputs of the first, second and third phase circuitry, where the drivers are configured for receiving phase skipping control signals from the controller and outputting mode selection signals configured to dynamically select an operating mode for the DC/AC inverter from a Normal Control operation and a Phase Skipping Control operation which have different power injection patterns through the first, second and third phase circuitry depending upon the power level.

  13. An SCR inverter for electric vehicles

    Science.gov (United States)

    Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.

    1980-01-01

    An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

  14. Demonstration of the serum antibody to Epstein-Barr virus specific DNA polymerased (EBV-DP) from patients with nasopharyngeal carcinoma (NPC)

    Energy Technology Data Exchange (ETDEWEB)

    Tan, R.S.; Li, J.S.; Grill, S.; Nutter, L.M.; Cheng, Y.C.

    1986-03-05

    Raji cells, an EBV genome carrying and nonproducer cell line, treated with tetradecanoyl-phorbol-13-acetate (TPA) and n-butyrate could induce a special DNA polymerase which has properties that are similar to the EBV-DP induced by TPA in P/sub 3/HR-I cells, an EBV producer cell line. Since EBV was found to have a strong association with NPC, and antibodies against EBV proteins or enzymes were found in high levels in sera from these patients, the possible presence of serum antibody against EBV-DP was examined. The serum titer of antibody to EBV-DP was found to have 190 +/- 84 units/ml serum (mean +/- S.D.) in 48 sera from patients with NPC. The titer in 52 healthy donors was 31.4 +/- 28 unit/ml serum (p < 0.01). The antibody was found to be associated with the IgG but not the IgA fraction. The antibody titers against EBV-DP were not correlated with the titer against EBV-DNase or VCA-IgA. Whether the antibody observed is against an EBV-DP core protein or its stimulating protein, as demonstrated by this laboratory previously, is still being investigated. This study demonstrated the high frequency and high titer of antibody against EBV-DP in serum from patients with NPC, and suggested the potential of utilizing this antibody titer to compliment other methods for the early diagnosis or prognosis of NPC.

  15. Improved Reliability of Single-Phase PV Inverters by Limiting the Maximum Feed-in Power

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level...... devices, allowing a quantitative prediction of the power device lifetime. A study case on a 3 kW single-phase PV inverter has demonstrated the advantages of the CPG control in terms of improved reliability.......Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level....... The CPG control strategy is activated only when the DC input power from PV panels exceeds a specific power limit. It enables to limit the maximum feed-in power to the electric grids and also to improve the utilization of PV inverters. As a further study, this paper investigates the reliability performance...

  16. Voltage resonant inverter as a power source

    OpenAIRE

    Lupenko, Anatoliy; Stakhiv, Petro

    2014-01-01

    The operation mode of a voltage resonant inverter as a power source with variable load is analyzed. In order to reduce load power variations, an approach to development of the inverter’s load power response based on providing similar positive and negative power deviations from its nominal value has been proposed. The design procedure for resonant inverter with open loop structure as a power source has been elaborated. For a high pressure sodium lamp as a load, the power deviation of about 4% ...

  17. Live Imaging of Shoot Meristems on an Inverted Confocal Microscope Using an Objective Lens Inverter Attachment

    Science.gov (United States)

    Nimchuk, Zachary L.; Perdue, Tony D.

    2017-01-01

    Live imaging of above ground meristems can lead to new insights in plant development not possible from static imaging of fixed tissue. The use of an upright confocal microscope offers several technical and biological advantages for live imaging floral or shoot meristems. However, many departments and core facilities possess only inverted confocal microscopes and lack the funding for an additional upright confocal microscope. Here we show that imaging of living apical meristems can be performed on existing inverted confocal microscopes with the use of an affordable and detachable InverterScope accessory. PMID:28579995

  18. Live Imaging of Shoot Meristems on an Inverted Confocal Microscope Using an Objective Lens Inverter Attachment.

    Science.gov (United States)

    Nimchuk, Zachary L; Perdue, Tony D

    2017-01-01

    Live imaging of above ground meristems can lead to new insights in plant development not possible from static imaging of fixed tissue. The use of an upright confocal microscope offers several technical and biological advantages for live imaging floral or shoot meristems. However, many departments and core facilities possess only inverted confocal microscopes and lack the funding for an additional upright confocal microscope. Here we show that imaging of living apical meristems can be performed on existing inverted confocal microscopes with the use of an affordable and detachable InverterScope accessory.

  19. High voltage series resonant inverter ion engine screen supply. [SCR series resonant inverter for space applications

    Science.gov (United States)

    Biess, J. J.; Inouye, L. Y.; Shank, J. H.

    1974-01-01

    A high-voltage, high-power LC series resonant inverter using SCRs has been developed for an Ion Engine Power Processor. The inverter operates within 200-400Vdc with a maximum output power of 2.5kW. The inverter control logic, the screen supply electrical and mechanical characteristics, the efficiency and losses in power components, regulation on the dual feedback principle, the SCR waveforms and the component weight are analyzed. Efficiency of 90.5% and weight density of 4.1kg/kW are obtained.

  20. Modeling the frequency response of photovoltaic inverters

    NARCIS (Netherlands)

    Ernauli Christine Aprilia, A.; Cuk, V.; Cobben, J.F.G.; Ribeiro, P.F.; Kling, W.L.

    2012-01-01

    The increased presence of photovoltaic (PV) systems inevitably affects the power quality in the grid. This new reality demands grid power quality studies involving PV inverters. This paper proposes several frequency response models in the form of equivalent circuits. Models are based on laboratory

  1. The Internet and the Inverted Classroom.

    Science.gov (United States)

    Lage, Maureen J.; Platt, Glenn

    2000-01-01

    Describes a Web site that is for an undergraduate principles of microeconomics course and a main component of "The Inverted Classroom" in which lectures take place outside of class. Explains that the Web site is divided into four sections: (1) the classroom; (2) the desk; (3) the coffee shop; and (4) the library. (CMK)

  2. An Inverted Curriculum for CS1

    DEFF Research Database (Denmark)

    Caspersen, Michael Edelgaard

    2003-01-01

    present and discuss the inverted curriculum for our introductory object-oriented programming course, and our experiences from teaching this course for four years. We identify four levels for the systematic construction of programs, and the structure of our programming course is based on these four levels......: the modeling level, the design level, the class level, and the algorithmic level....

  3. Smart Inverters for Utility and Industry Applications

    DEFF Research Database (Denmark)

    Xue, Yaosuo; Guerrero, Josep M.

    2015-01-01

    Smart inverters are emerging with increasing renewable energy and smart grid development. While the recent work reviewed mostly focuses on defining standardized control functionalities and smart grid communication protocols, we take a holistic approach in this paper and propose a holon-type smart...

  4. Two-Stage Series-Resonant Inverter

    Science.gov (United States)

    Stuart, Thomas A.

    1994-01-01

    Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

  5. Inverter Matrix for the Clementine Mission

    Science.gov (United States)

    Buehler, M. G.; Blaes, B. R.; Tardio, G.; Soli, G. A.

    1994-01-01

    An inverter matrix test circuit was designed for the Clementine space mission and is built into the RRELAX (Radiation and Reliability Assurance Experiment). The objective is to develop a circuit that will allow the evaluation of the CMOS FETs using a lean data set in the noisy spacecraft environment.

  6. Solar Power Station Output Inverter Control Design

    Directory of Open Access Journals (Sweden)

    J. Bauer

    2011-04-01

    Full Text Available The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system can be used as a generator and it shall deliver energy to the supply network. Each type of the application has different requirements on the converter and its control algorithm. But for all of them the one thing is common – the maximal efficiency. The paper focuses on design and simulation of the low power inverter that acts as output part of the whole converter. In the paper the design of the control algorithm of the inverter for both types of inverter application – for islanding mode and for operation on the supply grid – is discussed. Attention is also paid to the design of the output filter that should reduce negative side effects of the converter on the supply network.

  7. Pulse width modulation inverter with battery charger

    Science.gov (United States)

    Slicker, James M.

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  8. Analysis of Droop Controlled Parallel Inverters in Islanded Microgrids

    DEFF Research Database (Denmark)

    Mariani, Valerio; Vasca, Francesco; Guerrero, Josep M.

    2014-01-01

    Three-phase droop controlled inverters are widely used in islanded microgrids to interface distributed energy resources and to provide for the loads active and reactive powers demand. The assessment of microgrids stability, affected by the control and line parameters, is a stringent issue....... This paper shows a systematic approach to derive a closed loop model of the microgrid and then to perform an eigenvalues analysis that highlights how the system’s parameters affect the stability of the network. It is also shown that by means of a singular perturbation approach the resulting reduced order...

  9. Possibilities and problems connected with the use of inverters

    Energy Technology Data Exchange (ETDEWEB)

    Brandolini, A

    1968-01-01

    The problem, which is not new, of dc electrical nets, feeding ac users, was investigated. An analytical treatment was carried out for studying a system formed by a dc line feeding a load through an inverter, with the result of keeping, for the expressions of the active and apparent power, forms which are similar to those of the simple sinusoidal case. It resulted that in the operation of dc ac mixed nets the problems involving the exchange of nonactive power are not more difficult than those which occur in common ac nets.

  10. Robust Droop Control of Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Elkayam, Moria; Kuperman, Alon; Guerrero, Josep M.

    2016-01-01

    The use of distributed generation in microgrid systems is becoming a popular way to provide a reliable source of electricity to critical loads. Droop control techniques are used in power systems for the synchronization of grid-connected inverters by local measurements of active and reactive powers....... Despite the benefits of distributed generation, the drawback is that large grid-side impedance steps can cause a system to become unstable. A robust control method based on disturbance observer is proposed in this paper. When the proposed robust controller is utilized, closed loop performance remains...

  11. Inverter-based successive approximation capacitance-to-digital converter

    KAUST Repository

    Omran, Hesham; Alhoshany, Abdulaziz; Salama, Khaled N.

    2017-01-01

    offset voltage will result in signal-dependent and parasitic-dependent conversion errors, which necessitates an op-amp-based implementation. The inverter-based SAR CDC contemplated herein provides robust, energy-efficient, and fast operation. The inverter

  12. FPGA Based Compensation Method for Correcting Distortion in Voltage Inverters

    National Research Council Canada - National Science Library

    Williamson, Kenya D

    2007-01-01

    ...) voltage source inverters. Blanking time distortion is caused by the delay inserted to prevent the short circuit that would occur if the two transistors in the same inverter leg are both on at the same time...

  13. Online Variable Topology-Type Photovoltaic Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Wu, Fengjiang; Sun, Bo; Duan, Jiandong

    2015-01-01

    In photovoltaic (PV) grid-connected generation system, the key focus is how to expand the generation range of the PV array and enhance the total efficiency of the system. This paper originally derived expressions of the total loss and grid current total harmonics distortions of cascaded inverter...... and H-bridge inverter under the conditions of variable output voltage and power of the PV array. It is proved that, compared with the H-bridge inverter, the operation range of the cascaded inverter is wider, whereas the total loss is larger. Furthermore, a novel online variable topology-type grid......-connected inverter is proposed. A bidirectional power switch is introduced into the conventional cascaded inverter to connect the negative terminals of the PV arrays. When the output voltages of the PV arrays are lower, the proposed inverter works under cascaded inverter mode to obtain wider generation range. When...

  14. Status and Needs of Power Electronics for Photovoltaic Inverters

    Science.gov (United States)

    Qin, Y. C.; Mohan, N.; West, R.; Bonn, R.

    2002-06-01

    Photovoltaics is the utility connected distributed energy resource (DER) that is in widespread use today. It has one element, the inverter, which is common with all DER sources except rotating generators. The inverter is required to transfer dc energy to ac energy. With all the DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. Today, the PV inverter is a costly and complex component of PV systems that produce ac power. Inverter MTFF (mean time to first failure) is currently unacceptable. Low inverter reliability contributes to unreliable fielded systems and a loss of confidence in renewable technology. The low volume of PV inverters produced restricts the manufacturing to small suppliers without sophisticated research and reliability programs or manufacturing methods. Thus, the present approach to PV inverter supply has low probability of meeting DOE reliability goals.

  15. Lower-Temperature Invert Design For Diffusion Barrier

    International Nuclear Information System (INIS)

    Bruce Stanley

    2001-01-01

    The objective of this analysis is to advance the state of the subsurface facilities design to primarily support the ''Yucca Mountain Science and Engineering Report'' (DOE 2001) and to also support the preparation and revision of System Description Document's Section 2 system descriptions (CRWMS M and O 2001, pp. 9 and 11). The results may also eventually support the License Application (CRWMS M and O 2001, p. 3). The Performance Assessment Department will be the primary user of the information generated and will be used in abstraction modeling for the lower-temperature scenario (CRWMS M and O 200 1, p. 27). This analysis will evaluate the invert relative to the lower- and higher-temperature conditions in accordance with the primary tasks below. Invert design is a major factor in allowing water entering the drift to pass freely and enter the drift floor without surface ponding and in limiting diffusive transport into the host rock. Specific cost effective designs will be conceptualized under the new lower-temperature conditions in this analysis. Interfacing activities and all aspects of Integrated Safety Management and Nuclear Culture principles are included in this work scope by adhering to the respective principles during this design activity and by incorporating safety into the design analysis (CRWMS M and O 2001, p. 8). Primary tasks of this analysis include identifying available design information from existing sources on the invert as a diffusive barrier, developing concepts that reduce the amount steel, and developing other design features that accommodate both lower- and higher-temperature operating modes (CRWMS M and O 2001, p.16)

  16. Oncogenic S1P signalling in EBV-associated nasopharyngeal carcinoma activates AKT and promotes cell migration through S1P receptor 3.

    Science.gov (United States)

    Lee, Hui Min; Lo, Kwok-Wai; Wei, Wenbin; Tsao, Sai Wah; Chung, Grace Tin Yun; Ibrahim, Maha Hafez; Dawson, Christopher W; Murray, Paul G; Paterson, Ian C; Yap, Lee Fah

    2017-05-01

    Undifferentiated nasopharyngeal carcinoma (NPC) is a cancer with high metastatic potential that is consistently associated with Epstein-Barr virus (EBV) infection. In this study, we have investigated the functional contribution of sphingosine-1-phosphate (S1P) signalling to the pathogenesis of NPC. We show that EBV infection or ectopic expression of the EBV-encoded latent genes (EBNA1, LMP1, and LMP2A) can up-regulate sphingosine kinase 1 (SPHK1), the key enzyme that produces S1P, in NPC cell lines. Exogenous addition of S1P promotes the migration of NPC cells through the activation of AKT; shRNA knockdown of SPHK1 resulted in a reduction in the levels of activated AKT and inhibition of cell migration. We also show that S1P receptor 3 (S1PR3) mRNA is overexpressed in EBV-positive NPC patient-derived xenografts and a subset of primary NPC tissues, and that knockdown of S1PR3 suppressed the activation of AKT and the S1P-induced migration of NPC cells. Taken together, our data point to a central role for EBV in mediating the oncogenic effects of S1P in NPC and identify S1P signalling as a potential therapeutic target in this disease. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  17. Diode-Assisted Buck-Boost Current Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Cai, Liang; Loh, P.C.

    2007-01-01

    This paper presents a couple of novel current source inverters (CSIs) with the enhanced current buckboost capability. With the unique diode-inductor network added between current source inverter circuitry and current boost elements, the proposed buck-boost current source inverters demonstrate...... uninfluenced. Lastly, all theoretical findings were verified experimentally using constructed laboratory prototypes....

  18. Mobile Inverted Constructivism: Education of Interaction Technology in Social Media

    Science.gov (United States)

    Chai, Jia-Xiang; Fan, Kuo-Kuang

    2016-01-01

    The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…

  19. Advanced Power Electronics and Smart Inverters | Grid Modernization | NREL

    Science.gov (United States)

    Advanced Power Electronics and Smart Inverters Advanced Power Electronics and Smart Inverters , into the electric distribution system requires advanced power electronics, or smart inverters, that . Contact Sudipta Chakraborty Power Electronics Team Lead sudipta.chakraborty@nrel.gov | 303-384-7093

  20. Advanced Energy Validated Photovoltaic Inverter Technology at NREL | Energy

    Science.gov (United States)

    Inverter Technology at NREL Advanced Energy Industries-NREL's first partner at the Energy Systems Integration Facility (ESIF)-validated its advanced photovoltaic (PV) inverter technology using the ESIF's computer screen in a laboratory, with power inverter hardware in the background Photo by Dennis Schroeder

  1. Efficient/reliable dc-to-dc inverter circuit

    Science.gov (United States)

    Pasciutti, E. R.

    1970-01-01

    Feedback loop, which contains an inductor in series with a saturable reactor, is added to a standard inverter circuit to permit the inverter power transistors to be switched in a controlled and efficient manner. This inverter is applicable where the power source has either high or low impedance properties.

  2. Designing a Smaller Power Inverter: the Google Littlebox Challenge - Text

    Science.gov (United States)

    Version | Energy Systems Integration Facility | NREL Designing a Smaller Power Inverter: the Google Littlebox Challenge - Text Version er Power Inverter: the Google Littlebox Challenge - Text Version Below is the text version for the Designing a Smaller Power Inverter: the Google Littlebox

  3. DC-to-AC inverter ratio failure detector

    Science.gov (United States)

    Ebersole, T. J.; Andrews, R. E.

    1975-01-01

    Failure detection technique is based upon input-output ratios, which is independent of inverter loading. Since inverter has fixed relationship between V-in/V-out and I-in/I-out, failure detection criteria are based on this ratio, which is simply inverter transformer turns ratio, K, equal to primary turns divided by secondary turns.

  4. Mission Profile Based Sizing of IGBT Chip Area for PV Inverter Applications

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Yang, Yongheng

    2016-01-01

    Maximizing the total energy generation is of importance for Photovoltaic (PV) plants. This paper proposes a method to optimize the IGBT chip area for PV inverters to minimize the annual energy loss of the active switches based on long-term operation conditions (i.e., mission profile). The design...... yearly mission profile. Simulation results are given to verify the thermal characteristics. Furthermore, a Monte Carlo based lifetime evaluation is presented to check the IGBT reliability. The proposed design method enables a reliability-oriented energy optimized sizing of active switches for PV inverter...

  5. Reactive power and voltage control strategy based on dynamic and adaptive segment for DG inverter

    Science.gov (United States)

    Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun

    2018-03-01

    The inverter of distributed generation (DG) can support reactive power to help solve the problem of out-of-limit voltage in active distribution network (ADN). Therefore, a reactive voltage control strategy based on dynamic and adaptive segment for DG inverter is put forward to actively control voltage in this paper. The proposed strategy adjusts the segmented voltage threshold of Q(U) droop curve dynamically and adaptively according to the voltage of grid-connected point and the power direction of adjacent downstream line. And then the reactive power reference of DG inverter can be got through modified Q(U) control strategy. The reactive power of inverter is controlled to trace the reference value. The proposed control strategy can not only control the local voltage of grid-connected point but also help to maintain voltage within qualified range considering the terminal voltage of distribution feeder and the reactive support for adjacent downstream DG. The scheme using the proposed strategy is compared with the scheme without the reactive support of DG inverter and the scheme using the Q(U) control strategy with constant segmented voltage threshold. The simulation results suggest that the proposed method has a significant improvement on solving the problem of out-of-limit voltage, restraining voltage variation and improving voltage quality.

  6. Stochastic p -Bits for Invertible Logic

    Science.gov (United States)

    Camsari, Kerem Yunus; Faria, Rafatul; Sutton, Brian M.; Datta, Supriyo

    2017-07-01

    Conventional semiconductor-based logic and nanomagnet-based memory devices are built out of stable, deterministic units such as standard metal-oxide semiconductor transistors, or nanomagnets with energy barriers in excess of ≈40 - 60 kT . In this paper, we show that unstable, stochastic units, which we call "p -bits," can be interconnected to create robust correlations that implement precise Boolean functions with impressive accuracy, comparable to standard digital circuits. At the same time, they are invertible, a unique property that is absent in standard digital circuits. When operated in the direct mode, the input is clamped, and the network provides the correct output. In the inverted mode, the output is clamped, and the network fluctuates among all possible inputs that are consistent with that output. First, we present a detailed implementation of an invertible gate to bring out the key role of a single three-terminal transistorlike building block to enable the construction of correlated p -bit networks. The results for this specific, CMOS-assisted nanomagnet-based hardware implementation agree well with those from a universal model for p -bits, showing that p -bits need not be magnet based: any three-terminal tunable random bit generator should be suitable. We present a general algorithm for designing a Boltzmann machine (BM) with a symmetric connection matrix [J ] (Ji j=Jj i) that implements a given truth table with p -bits. The [J ] matrices are relatively sparse with a few unique weights for convenient hardware implementation. We then show how BM full adders can be interconnected in a partially directed manner (Ji j≠Jj i) to implement large logic operations such as 32-bit binary addition. Hundreds of stochastic p -bits get precisely correlated such that the correct answer out of 233 (≈8 ×1 09) possibilities can be extracted by looking at the statistical mode or majority vote of a number of time samples. With perfect directivity (Jj i=0 ) a small

  7. Topological Design and Modulation Strategy for Buck-Boost Three-Level Inverters

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus

    2009-01-01

    To date, designed topologies for dc-ac inversion with both voltage buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable...... can perform distinct five-level line voltage and three-level phase voltage switching by simply controlling the active switches located in the designed voltage boost section of the circuits. As a cost saving option, one active switch can further be removed from the voltage boost section of the circuits...... buck-boost threelevel inverters that can also support bidirectional power conversion. The proposed front-end circuitry is developed from the C´ ukderived buck-boost two-level inverter, and by using the "alternative phase opposition disposition" modulation scheme, the buck-boost three-level inverters...

  8. Existence of Inverted Profile in Chemically Responsive Molecular Pathways in the Zebrafish Liver

    Science.gov (United States)

    Zhang, Xun; Li, Hu; Ma, Jing; Zhang, Louxin; Li, Baowen; Gong, Zhiyuan

    2011-01-01

    How a living organism maintains its healthy equilibrium in response to endless exposure of potentially harmful chemicals is an important question in current biology. By transcriptomic analysis of zebrafish livers treated by various chemicals, we defined hubs as molecular pathways that are frequently perturbed by chemicals and have high degree of functional connectivity to other pathways. Our network analysis revealed that these hubs were organized into two groups showing inverted functionality with each other. Intriguingly, the inverted activity profiles in these two groups of hubs were observed to associate only with toxicopathological states but not with physiological changes. Furthermore, these inverted profiles were also present in rat, mouse, and human under certain toxicopathological conditions. Thus, toxicopathological-associated anti-correlated profiles in hubs not only indicate their potential use in diagnosis but also development of systems-based therapeutics to modulate gene expression by chemical approach in order to rewire the deregulated activities of hubs back to normal physiology. PMID:22140468

  9. Damping Methods for Resonances Caused by LCL-Filter-Based Current-Controlled Grid-Tied Power Inverters

    DEFF Research Database (Denmark)

    Wu, Weimin; Liu, Yuan; He, Yuanbin

    2017-01-01

    Grid-tied voltage source inverters using LCL filter have been widely adopted in distributed power generation systems (DPGSs). As high-order LCL filters contain multiple resonant frequencies, switching harmonics generated by the inverter and current harmonics generated by the active/passive loads...... innovative damping methods have been proposed. A comprehensive overview on those contributions and their classification on the inverter- and grid-side damping measures are presented. Based on the concept of the impedance-based stability analysis, all damping methods can ensure the system stability...

  10. Modeling and design of a multivariable control system for multi-paralleled grid-connected inverters with LCL filter

    DEFF Research Database (Denmark)

    Akhavan, Ali; Mohammadi, Hamid Reza; Guerrero, Josep M.

    2018-01-01

    The quality of injected current in multi-paralleled grid-connected inverters is a matter of concern. The current controlled grid-connected inverters with LCL filter are widely used in the distributed generation (DG) systems due to their fast dynamic response and better power features. However...... with resonances in the system, damping methods such as passive or active damping is necessary. Secondly and perhaps more importantly, paralleled grid-connected inverters in a microgrid are coupled due to grid impedance. Generally, the coupling effect is not taken into account when designing the control systems...

  11. Component-Minimized Buck-Boost Voltage Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    This paper presents the design of buck-boost B4 inverters that can be derived from either Ćuk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion...... between capacitors. Modulation wise, the proposed buck-boost B4 inverters can be controlled using a carefully designed carrier-based pulse-width modulation (PWM) scheme that will always ensure balanced threephase outputs as desired, while simultaneously achieving minimal voltage stress across...

  12. Five-level Z-source diode-clamped inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, Poh Chiang; Blaabjerg, Frede

    2010-01-01

    This study proposes a five-level Z-source diode-clamped inverter designed with two intermediate Z-source networks connected between the dc input sources and rear-end inverter circuitry. By partially shorting the Z-source networks, new operating states not previously reported for two-level Z......-source inverter are introduced here for operating the proposed inverter with voltage buck–boost energy conversion ability and five-level phase voltage switching. These characteristic features are in fact always ensured at the inverter terminal output by simply adopting a properly designed carrier modulation...

  13. Magnetically coupled impedance-source inverters

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Blaabjerg, Frede

    2012-01-01

    input-to-output gain, and the presence of an impedance network. The former means a high dc-link voltage, which can stress the semiconductor switches unnecessarily. The latter leads to increases in cost and size, which similarly are undesirable. To lessen these concerns, an interesting approach is to use...... magnetically coupled transformers or inductors to raise the gain and modulation ratio simultaneously, while reducing the number of passive components needed. A study of the approach is now presented to show how various existing magnetically coupled inverters can be derived by applying a generic methodology....... The same methodology is then applied to develop more magnetically coupled Z-source inverters with advantages that have not been identified in the literature. These findings have already been proven in experiments....

  14. Design And Implementation Of Cost Effective Inverter

    Directory of Open Access Journals (Sweden)

    Niaz Morshedul Haque

    2017-10-01

    Full Text Available This paper deals with the design and construct of a 100 Watt 220 Volt and 50 Hz Inverter. The system is designed without any microcontroller and it has a cost-effective design architecture. The elementary purpose of this device is to transmute 12 V DC to 220 V AC. Snubber technology is used to diminish the reverse potential transients and excessive heat of transformer winding and transistor switches. Switching pulse generated by NE 555 timer circuit and comparator circuit was used to take signal strength input from its rear as well as from both sides for triggering the MOSFET switches. Another switch is used to invert pulse between two switching circuitries. A 5 volts regulator IC 7805 was used to supply fixed 5V for biasing the switching and amplifying circuitry.

  15. Electronic Document Management Using Inverted Files System

    Science.gov (United States)

    Suhartono, Derwin; Setiawan, Erwin; Irwanto, Djon

    2014-03-01

    The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  16. Electronic Document Management Using Inverted Files System

    Directory of Open Access Journals (Sweden)

    Suhartono Derwin

    2014-03-01

    Full Text Available The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  17. The CMOS integration of a power inverter

    Science.gov (United States)

    Mannarino, Eric Francis

    Due to their falling costs, the use of renewable energy systems is expanding around the world. These systems require the conversion of DC power into grid-synchronous AC power. Currently, the inverters that carry out this task are built using discrete transistors. TowerJazz Semiconductor Corp. has created a commercial CMOS process that allows for blocking voltages of up to 700 V, effectively removing the barrier to integrating power inverters onto a single chip. This thesis explores this process using two topologies. The first is a cell-based switched-capacitor topology first presented by Ke Zou. The second is a novel topology that explores the advantage of using a bused input-output system, as in digital electronics. Simulations run on both topologies confirm the high-efficiency demonstrated in Zou’s process as well as the advantage the bus-based system has in output voltage levels.

  18. Design of High Efficient MPPT Solar Inverter

    Directory of Open Access Journals (Sweden)

    Sunitha K. A.

    2017-01-01

    Full Text Available This work aims to design a High Efficient Maximum Power Point Tracking (MPPT Solar Inverter. A boost converter is designed in the system to boost the power from the photovoltaic panel. By this experimental setup a room consisting of 500 Watts load (eight fluorescent tubes is completely controlled. It is aimed to decrease the maintenance cost. A microcontroller is introduced for tracking the P&O (Perturb and Observe algorithm used for tracking the maximum power point. The duty cycle for the operation of the boost convertor is optimally adjusted by using MPPT controller. There is a MPPT charge controller to charge the battery as well as fed to inverter which runs the load. Both the P&O scheme with the fixed variation for the reference current and the intelligent MPPT algorithm were able to identify the global Maximum power point, however the performance of the MPPT algorithm was better.

  19. Advanced Control of Wheeled Inverted Pendulum Systems

    CERN Document Server

    Li, Zhijun; Fan, Liping

    2013-01-01

    Advanced Control of Wheeled Inverted Pendulum Systems is an orderly presentation of recent ideas for overcoming the complications inherent in the control of wheeled inverted pendulum (WIP) systems, in the presence of uncertain dynamics, nonholonomic kinematic constraints as well as underactuated configurations. The text leads the reader in a theoretical exploration of problems in kinematics,dynamics modeling, advanced control design techniques,and trajectory generation for WIPs. An important concern is how to deal with various uncertainties associated with the nominal model, WIPs being characterized by unstable balance and unmodelled dynamics and being subject to time-varying external disturbances for which accurate models are hard to come by.   The book is self-contained, supplying the reader with everything from mathematical preliminaries and the basic Lagrange-Euler-based derivation of dynamics equations to various advanced motion control and force control approaches as well as trajectory generation met...

  20. Inverted radiative hierarchy of quark masses

    International Nuclear Information System (INIS)

    Berezhiani, Z.G.; Rattazzi, R.

    1992-01-01

    Inverted radiative hierarchy of quark masses is investigated. The authors suggest that the mass hierarchy is first generated in a sector of heavy isosinglet fermions due to radiative effects and then projected in the inverted way to the usual quarks by means of a universal seesaw. The simple left-right symmetric gauge model is presented with the P- and CP-parities and the exact isotopical symmetry which are softly (or spontaneously) broken in the Higgs potential. This approach naturally explains the observed pattern of quark masses and mixing, providing the quantitatively correct formula for the Cabibbo angle. Top quark is predicted to be in the 90-150 GeV range

  1. Micro-inverter solar panel mounting

    Science.gov (United States)

    Morris, John; Gilchrist, Phillip Charles

    2016-02-02

    Processes, systems, devices, and articles of manufacture are provided. Each may include adapting micro-inverters initially configured for frame-mounting to mounting on a frameless solar panel. This securement may include using an adaptive clamp or several adaptive clamps secured to a micro-inverter or its components, and using compressive forces applied directly to the solar panel to secure the adaptive clamp and the components to the solar panel. The clamps can also include compressive spacers and safeties for managing the compressive forces exerted on the solar panels. Friction zones may also be used for managing slipping between the clamp and the solar panel during or after installation. Adjustments to the clamps may be carried out through various means and by changing the physical size of the clamps themselves.

  2. Distributed Storage Inverter and Legacy Generator Integration Plus Renewables Solution for Microgrids

    Science.gov (United States)

    2015-07-01

    inverter (advantage of short term storage) and enables microgrid upgrade of legacy generator assets (integration of inverter and generator controllers ...today. The storage inverter controls and hardware are also leveraged to provide an islanding inverter ( microgrid compatibility) for renewable...transiently rated inverters, integration with legacy generator controls , and microgrid compatible inverters for PV. Key system design drivers are lowering

  3. Inverted temperature sequences: role of deformation partitioning

    Science.gov (United States)

    Grujic, D.; Ashley, K. T.; Coble, M. A.; Coutand, I.; Kellett, D.; Whynot, N.

    2015-12-01

    The inverted metamorphism associated with the Main Central thrust zone in the Himalaya has been historically attributed to a number of tectonic processes. Here we show that there is actually a composite peak and deformation temperature sequence that formed in succession via different tectonic processes. The deformation partitioning seems to the have played a key role, and the magnitude of each process has varied along strike of the orogen. To explain the formation of the inverted metamorphic sequence across the Lesser Himalayan Sequence (LHS) in eastern Bhutan, we used Raman spectroscopy of carbonaceous material (RSCM) to determine the peak metamorphic temperatures and Ti-in-quartz thermobarometry to determine the deformation temperatures combined with thermochronology including published apatite and zircon U-Th/He and fission-track data and new 40Ar/39Ar dating of muscovite. The dataset was inverted using 3D-thermal-kinematic modeling to constrain the ranges of geological parameters such as fault geometry and slip rates, location and rates of localized basal accretion, and thermal properties of the crust. RSCM results indicate that there are two peak temperature sequences separated by a major thrust within the LHS. The internal temperature sequence shows an inverted peak temperature gradient of 12 °C/km; in the external (southern) sequence, the peak temperatures are constant across the structural sequence. Thermo-kinematic modeling suggest that the thermochronologic and thermobarometric data are compatible with a two-stage scenario: an Early-Middle Miocene phase of fast overthrusting of a hot hanging wall over a downgoing footwall and inversion of the synkinematic isotherms, followed by the formation of the external duplex developed by dominant underthrusting and basal accretion. To reconcile our observations with the experimental data, we suggest that pervasive ductile deformation within the upper LHS and along the Main Central thrust zone at its top stopped at

  4. Genetic variations of the NPC1L1 gene associated with hepatitis C virus (HCV) infection and biochemical characteristics of HCV patients in China.

    Science.gov (United States)

    Zhang, A-Mei; Zhang, Cheng-Lin; Song, Yuzhu; Zhao, Ping; Feng, Yue; Wang, Binghui; Li, Zheng; Liu, Li; Xia, Xueshan

    2016-12-01

    About 2% of the world population is infected with hepatitis C virus (HCV), a leading cause of hepatic cirrhosis and hepatocellular carcinoma. The Niemann-Pick C1-like 1 cholesterol absorption receptor (NPC1L1) was recently identified to be an important factor for HCV entry into host cells. Whether genetic variations of the NPC1L1 gene are associated with HCV infection is unknown. In this study, five single nucleotide polymorphisms (SNPs) of the NPC1L1 gene were analyzed in 261 HCV-infected individuals and 265 general controls from Yunnan Province, China. No significant differences were identified in genotypes or alleles of the SNPs between the two groups. After constructing haplotypes based on the five SNPs, a significant difference between HCV-infected individuals and general controls was shown for two haplotypes. Haplotype GCCTT appeared to be a protective factor and haplotype GCCCT was a risk factor for HCV-infected individuals. Genotypes of four SNPs correlated with biochemical characteristics of HCV-infected persons. Genotypes of SNPs rs799444 and rs2070607 were correlated with total bilirubin. Genotype TT of rs917098 was a risk factor for the gamma-glutamyltransferase level. Furthermore, HCV-infected individuals carrying genotype GG of rs41279633 showed statistically higher gamma-glutamyltransferase levels than HCV-infected persons with GT and TT. The results of this study identified the association between genetic susceptibility of the NPC1L1 gene and HCV infection, as well as biochemical characteristics of HCV-infected persons in Yunnan, China. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  5. Tetrandrine Induces Apoptosis in Human Nasopharyngeal Carcinoma NPC-TW 039 Cells by Endoplasmic Reticulum Stress and Ca2+/Calpain Pathways.

    Science.gov (United States)

    Liu, Kuo-Ching; Lin, Ya-Jing; Hsiao, Yung-Ting; Lin, Meng-Liang; Yang, Jiun-Long; Huang, Yi-Ping; Chu, Yung-Lin; Chung, Jing-Gung

    2017-11-01

    Tetrandrine is an alkaloid extracted from a traditional China medicine plant, and is considered part of food therapy as well. In addition, it has been widely reported to induce apoptotic cell death in many human cancer cells. However, the mechanism of Tetrandrine on human nasopharyngeal carcinoma cells (NPC) is still questioned. In our study, we examined whether Tetrandrine can induce apoptosis of NPC-TW 039 cells. We found that cell morphology was changed after treatment with different concentrations of Tetrandrine. Further, we indicated that the NPC-TW 039 cells viability decreased in a Tetrandrine dose-dependent manner. We also found that tetrandrine induced cell cycle arrest in G 0 /G 1 phase. Tetrandrine induced DNA condensation by DAPI staining as well. In addition, we found that Tetrandrine induced Ca 2+ release in the cytosol. At the same time, endoplasmic reticulum (ER) stress occurred. Then we used western blotting to examine the protein expression which is associated with mitochondria-mediated apoptotic pathways and caspase-dependent pathways. To further examine whether Ca 2+ was released or not with Tetrandrine induced-apoptosis, we used the chelator of Ca 2+ and showed that cell viability increased. At the same time, caspase-3 expression was decreased. Furthermore, confocal microscopy examination revealed that Tetrandrine induced expression of ER stress-related proteins GADD153 and GRP78. Our results indicate that Tetrandrine induces apoptosis through calcium-mediated ER stress and caspase pathway in NPC-TW 039 cells. In conclusion, Tetrandrine may could be used for treatment of human nasopharyngeal carcinoma in future. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  6. High-speed elevators controlled by inverters

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Yoshio; Takahashi, Hideaki; Nakamura, Kiyoshi; Kinoshita, Hiroshi

    1988-10-25

    The super-high-speed elevator with superiority to 300m/min of speed, requires both the large capacity power and wide range speed controls. Therefore, in order to materialize the smooth and quiet operation characteristics, by applying the inverter control, the low torque ripple control in the low frequency range and high frequency large capacity inverting for lowering the motor in noise are necessary with their being assured of reliability. To satisfy the above necessary items, together with the development of a sine wave pulse width and frequency modulation (PWM/PFM) control system, to more precisely enable the sine wave electric current control, and 3kHz switching power converter, using a 800A power transistor module, a supervoltage control circuit under the extraordinary condition was designed. As a result of commercializing a 360m/min super-high speed inverter elevator, the power source unit, due to the effect of high power factor, could be reduced by 30% in capacity and also the higher harmonic wave including ratio could be considerably lowered to the inferiority to 5%. 2 references, 7 figures, 1 table.

  7. Bibliographic review on sinonasal inverted papilloma

    International Nuclear Information System (INIS)

    Benavides Vilchez, Juan Vicente

    2014-01-01

    Surgical management recommendations, the index of recurrence and malignancy of the sinonasal inverted papilloma were identified through a bibliographic review of publications from 2002 to 2012. In the literature reviewed several aspects were determined: the risk of recurrences and the possibility of malignization of the inverted papilloma is diminished by complete surgical resection. The actual extent of the injury must be determined in an appropriate manner. The open approaches are recommended for a better visualization of the tumor, allowing the complete resection of the lesion. Endoscopic resection is considered a posterior surgical option, to evaluate the extension of the lesion without requiring incisions in the skin, it is recommended for the treatment of lesions in early stages and as a therapeutic option for some lesions in advanced stages. The recurrence rate is lower through endoscopy in relation to traditional approaches. The unilateral nasal obstruction and the presence of a mass in the nasal cavity are clinical manifestations of the inverted papilloma, whose highest incidence occurs in men and women, between 50 and 70 years of age. By means of clinical, radiological and biopsy suspicion this pathology is confirmed. The recurrence rate is 22% in a period of time from eight to 48 months after the initial surgery. The rate of malignization is 10%, which usually occurs between six and 60 months from the diagnosis of papilloma until the appearance of carcinoma [es

  8. FET commutated current-FED inverter

    Science.gov (United States)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1983-01-01

    A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

  9. High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

    Science.gov (United States)

    Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

    2017-08-01

    Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

  10. Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection at Night Considering Mission Profiles

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    loading, considering the operation outside active feed-in hours. An analytical lifetime model is then employed for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter under different mission profiles with reactive power injection......The widespread adoption of mixed renewables urgently require reactive power exchange at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection points even outside active power feed-in operation......, especially at night when there is no solar irradiance. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, an analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and the reliability has...

  11. Control of a Multi-Functional Inverter for Grid Integration of PV and Battery Energy Storage System

    DEFF Research Database (Denmark)

    Mousazadeh, Seyyed Yousef; Firoozabadi, Mehdi Savaghebi; Beirami, A.

    2015-01-01

    This paper presents a multi-functional control of a DC/AC inverter for Power Quality compensation of nonlinear and unequal local loads and grid integration of hybrid photovoltaic (PV) and battery energy storage systems. Multi-layer neural network estimator and a DC/DC converter are used for maximum...... is used for delivering desire power to the grid. For compensation aim, instantaneous active and reactive power theory (p-q) is used. Via the algorithm, the DC/AC inverter not only can be controlled to inject the power of battery and PV, but also it is used as shunt active filter for compensating unequal...... power point tracking (MPPT) of PV array. The power system is 3-phase 4-wires and the DC/AC inverter is chosen 4-leg three phase inverter which has good performance in presence of zero sequence components. Battery energy storage is connected to PV system in common DC bus and a power management strategy...

  12. Development and validation of a new tool measuring nurses self-reported professional competence--the nurse professional competence (NPC) Scale.

    Science.gov (United States)

    Nilsson, Jan; Johansson, Eva; Egmar, Ann-Charlotte; Florin, Jan; Leksell, Janeth; Lepp, Margret; Lindholm, Christina; Nordström, Gun; Theander, Kersti; Wilde-Larsson, Bodil; Carlsson, Marianne; Gardulf, Ann

    2014-04-01

    To develop and validate a new tool intended for measuring self-reported professional competence among both nurse students prior to graduation and among practicing nurses. The new tool is based on formal competence requirements from the Swedish Board of Health and Welfare, which in turn are based on WHO guidelines. A methodological study including construction of a new scale and evaluation of its psychometric properties. 1086 newly graduated nurse students from 11 universities/university colleges. The analyses resulted in a scale named the NPC (Nurse Professional Competence) Scale, consisting of 88 items and covering eight factors: "Nursing care", "Value-based nursing care", "Medical/technical care", "Teaching/learning and support", "Documentation and information technology", "Legislation in nursing and safety planning", "Leadership in and development of nursing care" and "Education and supervision of staff/students". All factors achieved Cronbach's alpha values greater than 0.70. A second-order exploratory analysis resulted in two main themes: "Patient-related nursing" and "Nursing care organisation and development". In addition, evidence of known-group validity for the NPC Scale was obtained. The NPC Scale, which is based on national and international professional competence requirements for nurses, was comprehensively tested and showed satisfactory psychometrical properties. It can e.g. be used to evaluate the outcomes of nursing education programmes, to assess nurses' professional competences in relation to the needs in healthcare organisations, and to tailor introduction programmes for newly employed nurses. © 2013.

  13. NPC Based Design Optimization for a Net Zero Office Building in Hot Climates with PV Panels as Shading Device

    Directory of Open Access Journals (Sweden)

    Muhammad Zubair

    2018-05-01

    Full Text Available Hot areas of the world receive a high amount of solar radiation. As a result, buildings in those areas consume more energy to maintain a comfortable climate for their inhabitants. In an effort to design net-zero energy building in hot climates, PV possesses the unique advantage of generating electrical energy while protecting the building from solar irradiance. In this work, to form a net-zero energy building (NZEB, renewable resources such as solar and wind available onsite for an existing building have been analyzed in a hot climate location. PV and wind turbines in various configurations are studied to form a NZEB, where PV-only systems offer better performance than Hybrid PV Wind systems, based on net present cost (NPC. The self-shading losses in PV placed on rooftop areas are analyzed by placing parallel arrays of PV modules at various distances in between them. The effect on building cooling load by rooftop PV panels as shading devices is investigated. Furthermore, self-shading losses of PV are compared by the savings in cooling loads using PV as shading. In the case study, 12.3% saving in the cooling load of the building is observed when the building rooftop is completed shaded by PV panels; annual cooling load decreased from 3.417 GWh to 2.996 GWh, while only 1.04% shaded losses are observed for fully shaded (FS buildings compared to those with no shading (NS, as PV generation decreases from 594.39 kWh/m2 to 588.21 kWh/m2. The net present cost of the project has been decreased from US$4.77 million to US$4.41 million by simply covering the rooftop completely with PV panels, for a net-zero energy building.

  14. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    to enhance the LVRT capability based on the Malaysian standards and modern grid codes connection requirements. The proposed control overcomes the problems of dc-link over-voltage and ac over-current that may cause disconnection or damage to the inverter. For this purpose, dc-chopper brake controller...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  15. Control Architecture for Parallel-Connected Inverters in Uninterruptible Power Systems

    DEFF Research Database (Denmark)

    Zhang, Chi; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    bus. The proposed control scheme comprises two layers: (i) a local layer that contains a “reactive power-to-phase droop” in order to synchronize the phase angle of each inverter and a virtual resistance loop that guarantees equal power sharing among inverters; and (ii) a central controller...... that guarantees synchronization with an external real/fictitious utility, and critical bus voltage amplitude restoration. Improved transient and steady-state frequency, active, reactive and harmonic power sharing, and global phase-locked loop resynchronization capability are achieved. Detailed system topology...

  16. Controlled alpha-sexithiophene nanostructure formation in standard and inverted configuration organic solar cells

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Goszczak, Arkadiusz Jaroslaw; Fernandes Cauduro, André Luis

    -type domains in the active organic layer. The molecular packing in these is of same importance, as it strongly affects the carrier transport in the cells. In this work, we present the study of alpha-sexithiophene (α 6T) temperature dependent growth for standard, on gold anodes, and inverted, on electron...... accepting C60 layers, solar cell configurations. Furthermore, a comparative study of the correlation between the α-6T morphology and device performance parameters for standard and inverted solar cell configurations is presented. The morphology of the α 6T layer is controlled by means of the substrate...

  17. Shunt PWM advanced var compensators based on voltage source inverters for Facts applications

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Pedro G; Misaka, Isamu; Watanabe, Edson H [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

    1994-12-31

    Increased attention has been given to improving power system operation. This paper presents modeling, analysis and design of reactive shunt power compensators based on PWM-Voltage Source Inverters (Pulse Width Modulation -Voltage Source Inverters). (Pulse Width Modulation - Voltage Source Inverters). The control algorithm is based on new concepts of instantaneous active and reactive power theory. The objective is to show that with a small capacitor in the side of a 3-phase PWM-VSI it is possible to synthesize a variable reactive (capacitive or inductive) device. Design procedures and experimental results are presented. The feasibility of this method was verified by digital simulations and measurements on a small scale model. (author) 9 refs., 12 figs.

  18. Quantum-classical correspondence for the inverted oscillator

    Science.gov (United States)

    Maamache, Mustapha; Ryeol Choi, Jeong

    2017-11-01

    While quantum-classical correspondence for a system is a very fundamental problem in modern physics, the understanding of its mechanism is often elusive, so the methods used and the results of detailed theoretical analysis have been accompanied by active debate. In this study, the differences and similarities between quantum and classical behavior for an inverted oscillator have been analyzed based on the description of a complete generalized Airy function-type quantum wave solution. The inverted oscillator model plays an important role in several branches of cosmology and particle physics. The quantum wave packet of the system is composed of many sub-packets that are localized at different positions with regular intervals between them. It is shown from illustrations of the probability density that, although the quantum trajectory of the wave propagation is somewhat different from the corresponding classical one, the difference becomes relatively small when the classical excitation is sufficiently high. We have confirmed that a quantum wave packet moving along a positive or negative direction accelerates over time like a classical wave. From these main interpretations and others in the text, we conclude that our theory exquisitely illustrates quantum and classical correspondence for the system, which is a crucial concept in quantum mechanics. Supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1A09919503)

  19. Harmonic Analysis and Mitigation of Low- Frequency Switching Voltage Source Inverter with Auxiliary VSI

    DEFF Research Database (Denmark)

    Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

    2018-01-01

    The output currents of high-power Voltage Source Inverters (VSIs) are distorted by the switching harmonics and the background harmonics in the grid voltage. This paper presents an active harmonic filtering scheme for high-power, low-frequency switching VSIs with an additional auxiliary VSI. In th...

  20. The impact of inverted text on visual word processing: An fMRI study.

    Science.gov (United States)

    Sussman, Bethany L; Reddigari, Samir; Newman, Sharlene D

    2018-06-01

    Visual word recognition has been studied for decades. One question that has received limited attention is how different text presentation orientations disrupt word recognition. By examining how word recognition processes may be disrupted by different text orientations it is hoped that new insights can be gained concerning the process. Here, we examined the impact of rotating and inverting text on the neural network responsible for visual word recognition focusing primarily on a region of the occipto-temporal cortex referred to as the visual word form area (VWFA). A lexical decision task was employed in which words and pseudowords were presented in one of three orientations (upright, rotated or inverted). The results demonstrate that inversion caused the greatest disruption of visual word recognition processes. Both rotated and inverted text elicited increased activation in spatial attention regions within the right parietal cortex. However, inverted text recruited phonological and articulatory processing regions within the left inferior frontal and left inferior parietal cortices. Finally, the VWFA was found to not behave similarly to the fusiform face area in that unusual text orientations resulted in increased activation and not decreased activation. It is hypothesized here that the VWFA activation is modulated by feedback from linguistic processes. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. High-Performance Control of Paralleled Three-Phase Inverters for Residential Microgrid Architectures Based on Online Uninterruptable Power Systems

    DEFF Research Database (Denmark)

    Zhang, Chi; Guerrero, Josep M.; Vasquez, Juan Carlos

    2015-01-01

    In this paper, a control strategy for the parallel operation of three-phase inverters forming an online uninterruptible power system (UPS) is presented. The UPS system consists of a cluster of paralleled inverters with LC filters directly connected to an AC critical bus and an AC/DC forming a DC...... bus. The proposed control scheme is performed on two layers: (i) a local layer that contains a “reactive power vs phase” in order to synchronize the phase angle of each inverter and a virtual resistance loop that guarantees equal power sharing among inverters; (ii) a central controller that guarantees...... synchronization with an external real/fictitious utility, and critical bus voltage restoration. Constant transient and steady-state frequency, active, reactive and harmonic power sharing, and global phase-locked loop resynchronization capability are achieved. Detailed system topology and control architecture...

  2. Design of inverters for the PHOTONERGY project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-08-01

    The PHOTONERGY project (the former SolcelleInverter project) was initiated on the 1st of September 2001, with a state-of-the-art analysis, which concluded into specifications. Based on this 23 topologies were analyzed in for efficiencies. The results from this analysis was five candidates which all showed a somewhat good efficiency. These five topologies were in further investigated by means of an initial design-iteration and simulations. Two different solutions were picked up in due to their high efficiency and low cost. 1. The standard full-bridge phase shifted DC/DC converter together with a standard DC/AC inverter, 2. A modified version of the novel Shimizu topology. A patent is pending on this modified version. These two inverters are in this document developed and made ready for prototyping. This includes design and selection of reactive- and switching-components, e.g. filter- and bulk-capacitors, low- and high-frequency inductors, high frequency transformers, MOSFETs and diodes. The design of auxiliary circuits is also included, e.g. gate drivers for the MOSFETs, measuring circuits for the grid-current and -voltage, PV-module-current and voltage, protection circuits, hardware near controllers and finally a switch mode power supply. However, the design of the various controllers, except the hardware near PV-current controller for the full bridge phase shifted converter, is not documented in this report but will come later on. This includes all controllers, e.g. maximum power point tracking for the PV-module, utility grid current controller, DC-link voltage controller, phase locked loops, and detection of islanding operation. All of these control loops are to be implemented in a micro-controller. (au)

  3. The mirror map for invertible LG models

    OpenAIRE

    Kreuzer, M

    1994-01-01

    Calculating the (a,c) ring of the maximal phase orbifold for `invertible' Landau--Ginzburg models, we show that the Berglund--H"ubsch construction works for all potentials of the relevant type. The map that sends a monomial in the original model to a twisted state in the orbifold representation of the mirror is constructed explicitly. Via this map, the OP selection rules of the chiral ring exactly correspond to the twist selection rules for the orbifold. This shows that we indeed arrive at th...

  4. MPPT algorithm for voltage controlled PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco

    2008-01-01

    This paper presents a novel concept for an MPPT that can be used in case of a voltage controlled grid connected PV inverters. In case of single-phase systems, the 100 Hz ripple in the AC power is also present on the DC side. Depending on the DC link capacitor, this power fluctuation can be used t...... to track the MPP of the PV array, using the information that at MPP the power oscillations are very small. In this way the algorithm can detect the fact that the current working point is at the MPP, for the current atmospheric conditions....

  5. High efficiency inverter and ballast circuits

    International Nuclear Information System (INIS)

    Nilssen, O.K.

    1984-01-01

    A high efficiency push-pull inverter circuit employing a pair of relatively high power switching transistors is described. The switching on and off of the transistors is precisely controlled to minimize power losses due to common-mode conduction or due to transient conditions that occur in the process of turning a transistor on or off. Two current feed-back transformers are employed in the transistor base drives; one being saturable for providing a positive feedback, and the other being non-saturable for providing a subtractive feedback

  6. On the invertibility of elementary operators

    OpenAIRE

    Boudi, Nadia; Bračič, Janko

    2013-01-01

    Let $\\mathscr{X}$ be a complex Banach space and $\\mathcal{L}(\\mathscr{X})$ be the algebra of all bounded linear operators on $\\mathscr{X}$. For a given elementary operator $\\Phi$ of length $2$ on $\\mathcal{L}(\\mathscr{X})$, we determine necessary and sufficient conditions for the existence of a solution of the equation ${\\rm X} \\Phi=0$ in the algebra of all elementary operators on $\\mathcal{L}(\\mathscr{X})$. Our approach allows us to characterize some invertible elementary operators of length...

  7. Design and Implementation of nine level multilevel Inverter

    Science.gov (United States)

    Dhineshkumar, K.; Subramani, C.

    2018-04-01

    In this paper the solar based boost converter integrated Nine level multilevel inverter presented. It uses 7 switches to produce nine level output stepped waveform. The aim of the work to produce 9 level wave form using solar and boost converter. The conventional inverter has multiple sources and has 16 switches are required and also more number of voltage sources required. The proposed inverter required single solar panel and reduced number of switches and integrated boost converter which increase the input voltage of the inverter. The proposed inverter simulated and compared with R load using Mat lab and prototype model experimentally verified. The proposed inverter can be used in n number of solar applications.

  8. Hawaiian Electric Advanced Inverter Test Plan - Result Summary

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson; Nelson, Austin; Prabakar, Kumaraguru; Nagarajan, Adarsh

    2016-10-14

    This presentation is intended to share the results of lab testing of five PV inverters with the Hawaiian Electric Companies and other stakeholders and interested parties. The tests included baseline testing of advanced inverter grid support functions, as well as distribution circuit-level tests to examine the impact of the PV inverters on simulated distribution feeders using power hardware-in-the-loop (PHIL) techniques. hardware-in-the-loop (PHIL) techniques.

  9. Finishing report for the 'SolcelleInverter' project

    Energy Technology Data Exchange (ETDEWEB)

    Boekhoej Kjaer, S.

    2005-03-01

    The main objective for this research project was to develop an inverter for the AC module, where one PV module is equipped with its own dedicated inverter, and connected to the grid. A topology, among many different candidates, has been selected, based on analysis's. The inverter has been optimized in respect to cost, reliability, and efficiency, and a prototype has been build. (au)

  10. Voltage Balancing Control of Diode-Clamped Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    ŞCHIOP Adrian

    2013-10-01

    Full Text Available In this paper is developed a control scheme for mono-phase diode clamped inverter to achieve balancing voltages on inverter capacitors. First, it develops a control scheme without taking into account the need to balance voltage on two capacitors. It examines the effects on the output voltage inverter, and then it realizes two control schemes that will balance the voltages. The simulations of control schemes were performed in OrCAD Pspice.

  11. Electrical and mechanical adaptation of commercially available power inverter modules for BUSSARD – The power supply of ASDEX Upgrade in vessel saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Rott, Michael, E-mail: Michael.Rott@ipp.mpg.de [Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching (Germany); Arden, Nils; Eixenberger, Horst [Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching (Germany); Klädtke, Kevin [Technical University Munich, Arcisstraße 21, D-80333 München (Germany); Teschke, Markus; Suttrop, Wolfgang [Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2015-10-15

    Highlights: • Mechanical design of inverters for restricted space and good mountability. • Supply of DC link possible with thyristor converter. • Plant safety by independent overcurrent protections and a commercially arc detection system. • Ground fault detection by fast differential current measurement. • Possibilities of changing the inductance of a two windings iron core choke. - Abstract: To supply the ASDEX Upgrade's B-coils with AC current up to 1.3 kA{sub p} at 500 Hz with arbitrary waveforms, a set of 16 inverters has been designed and partially built. To keep cost and development time low, commercially available power modules are used and existing current converters feed the DC links. Three power modules are mounted in one cubicle for realizing a three level neutral point clamped (NPC) topology with lowest possible inductivity and making the most of the limited space available. The paper presents the effort and steps required to adapt standard power blocks towards the needs of the ASDEX Upgrade power supply as well as the mechanical optimizations for good mountability, flexibility and scalability. Besides, solutions for mandatory personnel safety and plant safety are presented.

  12. Electrical and mechanical adaptation of commercially available power inverter modules for BUSSARD – The power supply of ASDEX Upgrade in vessel saddle coils

    International Nuclear Information System (INIS)

    Rott, Michael; Arden, Nils; Eixenberger, Horst; Klädtke, Kevin; Teschke, Markus; Suttrop, Wolfgang

    2015-01-01

    Highlights: • Mechanical design of inverters for restricted space and good mountability. • Supply of DC link possible with thyristor converter. • Plant safety by independent overcurrent protections and a commercially arc detection system. • Ground fault detection by fast differential current measurement. • Possibilities of changing the inductance of a two windings iron core choke. - Abstract: To supply the ASDEX Upgrade's B-coils with AC current up to 1.3 kA_p at 500 Hz with arbitrary waveforms, a set of 16 inverters has been designed and partially built. To keep cost and development time low, commercially available power modules are used and existing current converters feed the DC links. Three power modules are mounted in one cubicle for realizing a three level neutral point clamped (NPC) topology with lowest possible inductivity and making the most of the limited space available. The paper presents the effort and steps required to adapt standard power blocks towards the needs of the ASDEX Upgrade power supply as well as the mechanical optimizations for good mountability, flexibility and scalability. Besides, solutions for mandatory personnel safety and plant safety are presented.

  13. Integral inverter/battery charger for use in electric vehicles

    Science.gov (United States)

    Thimmesch, D.

    1983-01-01

    The design and test results of a thyristor based inverter/charger are discussed. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25 kWh propulsion battery in 8 hours from a 220 volt ac line. The integral charger employs the inverter commutation components at a resonant ac/dc isolated converter rated at 3.6 kW. Charger efficiency and power factor at an output power of 3.6 kW are 86% and 95% respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132 volt propulsion battery, can provide a peak shaft power of 34 kW (45 ph) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. Inverter efficiency during motoring operation at motor shaft speeds above 450 rad/sec (4300 rpm) is 92-94% for output power levels above 11 KW (15 hp). The combined ac inverter/charger package weighs 47 kg (103 lbs).

  14. Advanced DC/AC inverters applications in renewable energy

    CERN Document Server

    Luo, Fang Lin

    2013-01-01

    DC/AC inversion technology is of vital importance for industrial applications, including electrical vehicles and renewable energy systems, which require a large number of inverters. In recent years, inversion technology has developed rapidly, with new topologies improving the power factor and increasing power efficiency. Proposing many novel approaches, Advanced DC/AC Inverters: Applications in Renewable Energy describes advanced DC/AC inverters that can be used for renewable energy systems. The book introduces more than 100 topologies of advanced inverters originally developed by the authors,

  15. INVERTING ORTHOTOPIC ILEOCYSTOPLASTY FOR SHORT MESENTERY

    Directory of Open Access Journals (Sweden)

    V. A. Perepechay

    2010-01-01

    Full Text Available During orthotopic ileocystoplasty, the short mesentery causes an increase in the risk of incompetence of anastomosis of the reservoir with the urethra. Inverting orthotopic ileocystoplasty ensures a free reservoir pull-through into the small pelvis and eliminates tissue tension in the anastomosis. The proposed procedure differs from the Studer operation in that the reservoir is sutured lengthwise, after which it is inverted between the mesenteric leaves. The posterior reservoir wall is anteverted and freely brought out into the small pelvis. This reduces the distance to the urethral stump by 3-4 cm. This procedure was used in 19 patients to be operated on. There were no cases of reservoir or reservoir-urethral anastomotic incompetence. The mean neocystic capacity was 110, 350, and 490 ml 0, 3, and 12 months, respectively, after urethral catheter removal. The maximum reservoir pressure does not exceed 40 (mean 30 cm H2O. Daytime urinary retention was 94.7%; nocturnal urinary retention during forced nocturnal miction was 79%. The obtained functional results compare well with those achieved during the similar procedures.

  16. INVERTING ORTHOTOPIC ILEOCYSTOPLASTY FOR SHORT MESENTERY

    Directory of Open Access Journals (Sweden)

    V. A. Perepechay

    2014-07-01

    Full Text Available During orthotopic ileocystoplasty, the short mesentery causes an increase in the risk of incompetence of anastomosis of the reservoir with the urethra. Inverting orthotopic ileocystoplasty ensures a free reservoir pull-through into the small pelvis and eliminates tissue tension in the anastomosis. The proposed procedure differs from the Studer operation in that the reservoir is sutured lengthwise, after which it is inverted between the mesenteric leaves. The posterior reservoir wall is anteverted and freely brought out into the small pelvis. This reduces the distance to the urethral stump by 3-4 cm. This procedure was used in 19 patients to be operated on. There were no cases of reservoir or reservoir-urethral anastomotic incompetence. The mean neocystic capacity was 110, 350, and 490 ml 0, 3, and 12 months, respectively, after urethral catheter removal. The maximum reservoir pressure does not exceed 40 (mean 30 cm H2O. Daytime urinary retention was 94.7%; nocturnal urinary retention during forced nocturnal miction was 79%. The obtained functional results compare well with those achieved during the similar procedures.

  17. Robotic system construction with mechatronic components inverted pendulum: humanoid robot

    Science.gov (United States)

    Sandru, Lucian Alexandru; Crainic, Marius Florin; Savu, Diana; Moldovan, Cristian; Dolga, Valer; Preitl, Stefan

    2017-03-01

    Mechatronics is a new methodology used to achieve an optimal design of an electromechanical product. This methodology is collection of practices, procedures and rules used by those who work in particular branch of knowledge or discipline. Education in mechatronics at the Polytechnic University Timisoara is organized on three levels: bachelor, master and PhD studies. These activities refer and to design the mechatronics systems. In this context the design, implementation and experimental study of a family of mechatronic demonstrator occupy an important place. In this paper, a variant for a mechatronic demonstrator based on the combination of the electrical and mechanical components is proposed. The demonstrator, named humanoid robot, is equivalent with an inverted pendulum. Is presented the analyze of components for associated functions of the humanoid robot. This type of development the mechatronic systems by the combination of hardware and software, offers the opportunity to build the optimal solutions.

  18. A Transformer-less Single Phase Inverter For photovoltaic Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Alizadeh, Ebrahim; Qu, Ying

    2017-01-01

    A single phase transformer-less inverter is introduced in this paper. The negative polarities of the input voltage and output terminal have common ground. Therefore, the leakage current problem that is common in PV systems is eliminated naturally. In addition, the proposed inverter has fewer comp...

  19. Sine-wave three phase resonance inverter for operation of ...

    African Journals Online (AJOL)

    naeema

    conventional and simple solution to this requirement are in the following [8]. Using conventional H-bridge inverter beside of a step-up transformer. Using a renewable energy source with sufficiently large output voltage, which may be realized by a string of series connected modules followed by an H-bridge inverter [12], [13].

  20. Fast Grid Frequency Support from Distributed Inverter-Based Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-05-04

    This presentation summarizes power hardware-in-the-loop testing performed to evaluate the ability of distributed inverter-coupled generation to support grid frequency on the fastest time scales. The research found that distributed PV inverters and other DERs can effectively support the grid on sub-second time scales.

  1. Power system services provided by inverter connected distributed energy resources

    DEFF Research Database (Denmark)

    For the last few years there has been a significant increase of DER units in Denmark, of those units more and more are connected to the power system using inverters. These inverter connected units have the potential to support the electrical power system with various power system services. One...

  2. Solar-Based Boost Differential Single Phase Inverter | Eya | Nigerian ...

    African Journals Online (AJOL)

    Solar-Based Boost Differential Single Phase Inverter. ... Solar-based boost differential inverter is reduced down to 22.37% in closed loop system with the aid of Proportional –integral-Differential (PID) ... The dc power source is photovoltaic cell.

  3. Inverted hierarchy and asymptotic freedom in grand unified supersymmetric theories

    International Nuclear Information System (INIS)

    Aratyn, H.

    1983-01-01

    The interrelation between an inverted hierarchy mechanism and asymptotic freedom in supersymmetric theories is analyzed in two models for which we performed a detailed analysis of the effective potentials and effective couplings. We find it difficult to accommodate an inverted hierarchy together with asymptotic freedom for the matter-Yukawa couplings. (orig.)

  4. Analytical modeling of inverted annular film boiling

    International Nuclear Information System (INIS)

    Analytis, G.T.; Yadigaroglu, G.

    1987-01-01

    By employing a two-fluid formulation similar to the one used in the most recent LWR accident analysis codes, a model for the Inverted Annular Film Boiling region is developed. The conservation equations, together with appropriate closure relations are solved numerically. Successful comparisons are made between model predictions and heat transfer coefficient distributions measured in a series of single-tube reflooding experiments. Generally, the model predicts correctly the dependence of the heat transfer coefficient on liquid subcooling and flow rate; for some cases, however, heat transfer is still under-predicted, and an enhancement of the heat exchange from the liquid-vapour interface to the bulk of the liquid is required. The importance of the initial conditions at the quench front is also discussed. (orig.)

  5. Analytical modeling of inverted annular film boiling

    International Nuclear Information System (INIS)

    Analytis, G.T.; Yadigaroglu, G.

    1985-01-01

    By employing a two-fluid formulation similar to the one used in the most recent LWR accident analysis codes, a model for the Inverted Annular Film Boiling region is developed. The conservation equations, together with appropriate constitutive relations are solved numerically and successful comparisons are made between model predictions and heat transfer coefficient distributions measured in a series of single-tube reflooding experiments. The model predicts generally correctly the dependence of the heat transfer coefficient on liquid subcooling and flow rate, through, for some cases, heat transfer is still under-predicted, and an enhancement of the heat exchange from the liquid-vapour interface to the bulk of the liquid is required

  6. Scalar field cosmologies with inverted potentials

    Energy Technology Data Exchange (ETDEWEB)

    Boisseau, B.; Giacomini, H. [Université de Tours, Laboratoire de Mathématiques et Physique Théorique, CNRS/UMR 7350, 37200 Tours (France); Polarski, D., E-mail: bruno.boisseau@lmpt.univ-tours.fr, E-mail: hector.giacomini@lmpt.univ-tours.fr, E-mail: david.polarski@umontpellier.fr [Université Montpellier and CNRS, Laboratoire Charles Coulomb, UMR 5221, F-34095 Montpellier (France)

    2015-10-01

    Regular bouncing solutions in the framework of a scalar-tensor gravity model were found in a recent work. We reconsider the problem in the Einstein frame (EF) in the present work. Singularities arising at the limit of physical viability of the model in the Jordan frame (JF) are either of the Big Bang or of the Big Crunch type in the EF. As a result we obtain integrable scalar field cosmological models in general relativity (GR) with inverted double-well potentials unbounded from below which possess solutions regular in the future, tending to a de Sitter space, and starting with a Big Bang. The existence of the two fixed points for the field dynamics at late times found earlier in the JF becomes transparent in the EF.

  7. Improving generalized inverted index lock wait times

    Science.gov (United States)

    Borodin, A.; Mirvoda, S.; Porshnev, S.; Ponomareva, O.

    2018-01-01

    Concurrent operations on tree like data structures is a cornerstone of any database system. Concurrent operations intended for improving read\\write performance and usually implemented via some way of locking. Deadlock-free methods of concurrency control are known as tree locking protocols. These protocols provide basic operations(verbs) and algorithm (ways of operation invocations) for applying it to any tree-like data structure. These algorithms operate on data, managed by storage engine which are very different among RDBMS implementations. In this paper, we discuss tree locking protocol implementation for General inverted index (Gin) applied to multiversion concurrency control (MVCC) storage engine inside PostgreSQL RDBMS. After that we introduce improvements to locking protocol and provide usage statistics about evaluation of our improvement in very high load environment in one of the world’s largest IT company.

  8. Motion Analysis Based on Invertible Rapid Transform

    Directory of Open Access Journals (Sweden)

    J. Turan

    1999-06-01

    Full Text Available This paper presents the results of a study on the use of invertible rapid transform (IRT for the motion estimation in a sequence of images. Motion estimation algorithms based on the analysis of the matrix of states (produced in the IRT calculation are described. The new method was used experimentally to estimate crowd and traffic motion from the image data sequences captured at railway stations and at high ways in large cities. The motion vectors may be used to devise a polar plot (showing velocity magnitude and direction for moving objects where the dominant motion tendency can be seen. The experimental results of comparison of the new motion estimation methods with other well known block matching methods (full search, 2D-log, method based on conventional (cross correlation (CC function or phase correlation (PC function for application of crowd motion estimation are also presented.

  9. Scalar field cosmologies with inverted potentials

    International Nuclear Information System (INIS)

    Boisseau, B.; Giacomini, H.; Polarski, D.

    2015-01-01

    Regular bouncing solutions in the framework of a scalar-tensor gravity model were found in a recent work. We reconsider the problem in the Einstein frame (EF) in the present work. Singularities arising at the limit of physical viability of the model in the Jordan frame (JF) are either of the Big Bang or of the Big Crunch type in the EF. As a result we obtain integrable scalar field cosmological models in general relativity (GR) with inverted double-well potentials unbounded from below which possess solutions regular in the future, tending to a de Sitter space, and starting with a Big Bang. The existence of the two fixed points for the field dynamics at late times found earlier in the JF becomes transparent in the EF

  10. Modifications to Battery chargers and inverters Units

    International Nuclear Information System (INIS)

    Raison, Florent

    2015-01-01

    Over-exceeding the seismic specifications of the nuclear industry has always been the top priority of AEG Power Solutions. Since the Forsmark event, and especially since the Fukushima Daichi accident, utilities have reviewed their specifications. As a consequence, safety related battery chargers and inverters have to withstand higher acceleration levels. Simulation, design and test procedures are key drivers of the battery charger and inverter industry. Forces analysis through simulation is the first step of the product design process. The CAD drawings of our equipment, including the mechanical frame of the cabinet and the internal components, are used for the simulation of vibration. In the frame of 10 Hz, most new specifications show higher values, with higher constraints on our equipment. Our nuclear product range has been adapted to these new requirements. PCBs (Printed Circuit Boards), as key components in charge of the regulation and monitoring of the load, are first separately tested during the design phase, as a specific component. They are subjected to the following tests: Critical load analysis, Thermal imaging, Climatic test, Vibration and shock test. Then the complete equipment will follow a complete test program, including: Type test, EMC test, Seismic test, Aging test. Technology is key in achieving goals in terms of robustness and reliability of battery chargers and inverters. AEG Power Solutions renewed its entire range of products in 2011-2013 and made relevant choices. By updating its complete range of nuclear products, AEG Power Solutions is now offering a new range of solutions to the nuclear industry which minimize the risk of component obsolescence, in case of product replacement on existing nuclear power plants, or of new construction. In order to increase the product reliability and to facilitate the qualification programs of the products, the decision was made to offer 100% analogue technology (Software free). The different regulation and

  11. Transistorized PWM inverter-induction motor drive system

    Science.gov (United States)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  12. Simulation of Fuzzy Adaptive PI Controlled Grid Interactive Inverter

    Directory of Open Access Journals (Sweden)

    Necmi ALTIN

    2009-03-01

    Full Text Available In this study, a voltage source grid interactive inverter is modeled and simulated in MATLAB/Simulink. Inverter is designed as current controlled and a fuzzy-PI current controller used for the generation of switching pattern to shape the inverter output current. The grid interactive inverter consists of a line frequency transformer and a LC type filter. Galvanic isolation between the grid and renewable energy source is obtained by the line frequency transformer and LC filter is employed to filter the high frequency harmonic components in current waveform due to PWM switching and to reduce the output current THD. Results of the MATLAB/Simulink simulation show that inverter output current is in sinusoidal waveform and in phase with line voltage, and current harmonics are in the limits of international standards (

  13. 27-Level DC–AC inverter with single energy source

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2012-01-01

    Highlights: ► This paper reports a novel 27-level DC–AC inverter using only single renewable energy source. ► The efficiency of the inverter is very high. The output waveform is almost sinusoidal. ► The cost is low as the number of power switches required is only 12. - Abstract: A novel design of multilevel DC–AC inverter using only single renewable energy source is presented in this paper. The proposed approach enables multilevel output to be realised by a few cascaded H-bridges and a single energy source. As an illustration, a 27-level inverter has been implemented based on three cascaded H-bridges with a single energy source and two capacitors. Using the proposed novel switching strategy, 27 levels can be realized and the two virtual energy sources can be well regulated. Experimental results are included to demonstrate the effectiveness of the proposed inverter.

  14. A unified grid current control for grid-interactive DG inverters in microgrids

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    This paper proposes a unified grid current control for grid-interactive distributed generation inverters. In the approach, the grid-side current, instead of inverter-side current, is controlled as an inner loop, while the filter capacitor voltage is indirectly regulated through a virtual admittan...... locus analyses in the discrete z-domain are performed for elaborating the controller design. Simulations and experimental results demonstrate the performances of the proposed approach.......This paper proposes a unified grid current control for grid-interactive distributed generation inverters. In the approach, the grid-side current, instead of inverter-side current, is controlled as an inner loop, while the filter capacitor voltage is indirectly regulated through a virtual admittance...... in the outer loop. It, therefore, provides several superior features over traditional control schemes: 1) high-quality grid current in the grid-connected mode, 2) inherent derivative-less virtual output impedance control, and 3) the unified active damping for both grid-connected and islanded operations. Root...

  15. Modeling Single-Phase Inverter and Its Decentralized Coordinated Control by Using Feedback Linearization

    Directory of Open Access Journals (Sweden)

    Renke Han

    2014-01-01

    Full Text Available It is a very crucial problem to make a microgrid operated reasonably and stably. Considering the nonlinear mathematics model of inverter established in this paper, the input-output feedback linearization method is used to transform the nonlinear mathematics model of inverters to a linear tracking synchronization and consensus regulation control problem. Based on the linear mathematics model and multiagent consensus algorithm, a decentralized coordinated controller is proposed to make amplitudes and angles of voltages from inverters be consensus and active and reactive power shared in the desired ratio. The proposed control is totally distributed because each inverter only requires local and one neighbor’s information with sparse communication structure based on multiagent system. The hybrid consensus algorithm is used to keep the amplitude of the output voltages following the leader and the angles of output voltage as consensus. Then the microgrid can be operated more efficiently and the circulating current between DGs can be effectively suppressed. The effectiveness of the proposed method is proved through simulation results of a typical microgrid system.

  16. Inverted 'V' osteotomy excision arthroplasty for bony ankylosed elbows

    Directory of Open Access Journals (Sweden)

    Rex Chadrabose

    2011-12-01

    Full Text Available Abstract Background Bony ankylosis of elbow is challenging and difficult problem to treat. The options are excision arthroplasty and total elbow replacement. We report our midterm results on nine patients, who underwent inverted 'V' osteotomy excision arthroplasty in our hospital with good functional results. Materials Our case series includes 9 patients (seven males and two females with the mean age of 34 years (13-56 years. Five patients had trauma, two had pyogenic arthritis, one had tuberculous arthritis, and one had pyogenic arthritis following surgical fixation. Results The average duration of follow up is 65 months (45 months-80 months. The mean Mayo's elbow performance score (MEPS preoperatively was 48 (35-70. The MEPS at final follow up was 80 (60-95. With no movement at elbow and fixed in various degrees of either flexion or extension preoperatively, the mean preoperative position of elbow was 64°(30°to 100°. The mean post operative range of motion at final follow up was 27°of extension (20-500, 116°of flexion (1100-1300, and the arc of motion was 88°(800-1000. One patient had ulnar nerve neuropraxia and another patient developed median nerve neuropraxia, and both recovered completely in six weeks. No patient had symptomatic instability of the elbow. All patients were asymptomatic except one patient, who had pain mainly on heavy activities. Conclusion We conclude that inverted 'V' osteotomy excision arthroplasty is a viable option in the treatment of bony ankylosis of the elbow in young patients.

  17. Thin type inverter for machine-room-less elevator; Machine roomless elevator yo usugata inverter

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-01-10

    In the elevator industry, a machine-room-less elevator, which does not necessitate a machine room usually installed on the roof, has come into the spotlight in the domain of low and intermediate speed elevators. The lack of a machine room, however, will necessarily limit the space for the installation of the traction motor and control panel. Fuji Electric Co., Ltd., in order to properly cope with the situation, has developed in cooperation with Fujitec Co., Ltd., a very thin type inverter installable on an elevator hall floor. The inverter, based on Fuji Electric's high-performance vector control inverter FRENIC5000VG5, is as thin as 100mm, and is available in three series up to 11kW. For the embodiment of such a thin structure, a cooling structure of Fuji Electric's own is employed, and prudence is exercised as required at many locations so that maintainability will not be impaired throughout the very thin control panel design. (translated by NEDO)

  18. An Optimal Current Controller Design for a Grid Connected Inverter to Improve Power Quality and Test Commercial PV Inverters.

    Science.gov (United States)

    Algaddafi, Ali; Altuwayjiri, Saud A; Ahmed, Oday A; Daho, Ibrahim

    2017-01-01

    Grid connected inverters play a crucial role in generating energy to be fed to the grid. A filter is commonly used to suppress the switching frequency harmonics produced by the inverter, this being passive, and either an L- or LCL-filter. The latter is smaller in size compared to the L-filter. But choosing the optimal values of the LCL-filter is challenging due to resonance, which can affect stability. This paper presents a simple inverter controller design with an L-filter. The control topology is simple and applied easily using traditional control theory. Fast Fourier Transform analysis is used to compare different grid connected inverter control topologies. The modelled grid connected inverter with the proposed controller complies with the IEEE-1547 standard, and total harmonic distortion of the output current of the modelled inverter has been just 0.25% with an improved output waveform. Experimental work on a commercial PV inverter is then presented, including the effect of strong and weak grid connection. Inverter effects on the resistive load connected at the point of common coupling are presented. Results show that the voltage and current of resistive load, when the grid is interrupted, are increased, which may cause failure or damage for connecting appliances.

  19. Reducing GBA2 Activity Ameliorates Neuropathology in Niemann-Pick Type C Mice.

    Directory of Open Access Journals (Sweden)

    André R A Marques

    Full Text Available The enzyme glucocerebrosidase (GBA hydrolyses glucosylceramide (GlcCer in lysosomes. Markedly reduced GBA activity is associated with severe manifestations of Gaucher disease including neurological involvement. Mutations in the GBA gene have recently also been identified as major genetic risk factor for Parkinsonism. Disturbed metabolism of GlcCer may therefore play a role in neuropathology. Besides lysosomal GBA, cells also contain a non-lysosomal glucosylceramidase (GBA2. Given that the two β-glucosidases share substrates, we speculated that over-activity of GBA2 during severe GBA impairment might influence neuropathology. This hypothesis was studied in Niemann-Pick type C (Npc1-/- mice showing secondary deficiency in GBA in various tissues. Here we report that GBA2 activity is indeed increased in the brain of Npc1-/- mice. We found that GBA2 is particularly abundant in Purkinje cells (PCs, one of the most affected neuronal populations in NPC disease. Inhibiting GBA2 in Npc1-/- mice with a brain-permeable low nanomolar inhibitor significantly improved motor coordination and extended lifespan in the absence of correction in cholesterol and ganglioside abnormalities. This trend was recapitulated, although not to full extent, by introducing a genetic loss of GBA2 in Npc1-/- mice. Our findings point to GBA2 activity as therapeutic target in NPC.

  20. Harmonic mitigation in islanded microgrids by inverter-interfaced distributed energy resource

    Energy Technology Data Exchange (ETDEWEB)

    Xiongfei Wang

    2012-10-15

    An exciting growth of microgrids market has been witnessed around the world, driven on one hand by the increasing deployment of Distributed Energy Resource (DER) and on the other hand by the ongoing transformations of electric power systems towards more decentralized, intelligent, and resilient networks. The ability of dynamic islanding furnishes microgrids a prominent feature, which not only contributes to a more reliable electricity supply but also provides a systematic way to maximize the benefits of DER units for both customers and utilities. However, during islanded operations, microgrids are more sensitive to power quality disturbances, owing to the low short circuit ratio and limited capacity of DER units. As a consequence, harmonic distortion caused by the proliferation of nonlinear electronic equipment becomes more apparent. The recently released IEEE 1547 series standards have outlined the acceptable harmonic voltage and current distortion limits for islanded operations of microgrids. This thesis concentrates on developing advanced control algorithms for DER inverters in order to provide active harmonic conditioning services, including harmonic voltage reduction, harmonic current filtering and resonance damping in islanded microgrids. The research work is composed of two main parts. The first part is concerned with building a stable islanded microgrid, where the reduction of circulating current in the parallel DER inverters is studied. The second part addresses the harmonic distortion resulting from nonlinear loads and shunt-connected capacitors via the different control algorithms of DER inverters. Furthermore, to establish the basic control aspects for the islanded microgrid built in this project, a wide variety of control schemes for DER inverters within an islanded microgrid environment are evaluated. The merits and demerits of the different control methods are discussed. In light of this, the hierarchical control system is adopted, including the

  1. Novel T-Z source inverter with high voltage gain and reduced transformer turn ratio

    DEFF Research Database (Denmark)

    Mostaan, Ali; Sharifi Malfejani, Saeed; Soltani, Mohsen

    2015-01-01

    Novel voltage source inverter based on the Z source inverter structure is introduced in this paper. In this new inverter, two inductors of the impedance network in conventional Z source inverter are replaced with two transformers or coupled inductors, but unlike the T-Z source inverter that it......'s voltage gain is raised with increasing the transformers turn ratio, the voltage gain in the proposed inverter is raised with lowering the transformer turn ratio. Therefore, transformers with lower turn ratio are required in the proposed inverter in compare with T- Z source inverter that can lead to lower...

  2. Pulse width modulated buck-boost five-level current source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.

    2008-01-01

    , resulting in the natural balance of input current. For maintaining the normalized volt-sec average unchanged, the alternative phase opposition disposition (APOD) modulation scheme with typical gating signal mapping technique from voltage source inverter (VSI) to CSI can be assumed to control the five......This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches......-level buck-boost CSIs. Next by observing the hidden current charging path during inductive charging interval under APOD modulation, it is noted that the buck-boost five-level CSI can then be further modified with lesser active component without degrading output performance. To verify the theoretical findings...

  3. Transition from direct to inverted charge transport Marcus regions in molecular junctions via molecular orbital gating

    Science.gov (United States)

    Yuan, Li; Wang, Lejia; Garrigues, Alvar R.; Jiang, Li; Annadata, Harshini Venkata; Anguera Antonana, Marta; Barco, Enrique; Nijhuis, Christian A.

    2018-04-01

    Solid-state molecular tunnel junctions are often assumed to operate in the Landauer regime, which describes essentially activationless coherent tunnelling processes. In solution, on the other hand, charge transfer is described by Marcus theory, which accounts for thermally activated processes. In practice, however, thermally activated transport phenomena are frequently observed also in solid-state molecular junctions but remain poorly understood. Here, we show experimentally the transition from the Marcus to the inverted Marcus region in a solid-state molecular tunnel junction by means of intra-molecular orbital gating that can be tuned via the chemical structure of the molecule and applied bias. In the inverted Marcus region, charge transport is incoherent, yet virtually independent of temperature. Our experimental results fit well to a theoretical model that combines Landauer and Marcus theories and may have implications for the interpretation of temperature-dependent charge transport measurements in molecular junctions.

  4. A hybrid damping method for LLCL-filter based grid-tied inverter with a digital filter and an RC parallel passive damper

    DEFF Research Database (Denmark)

    Wu, Weimin; Lin, Zhe; Sun, Yunjie

    2013-01-01

    Grid-tied inverters have been widely used to inject the renewable energies into the distributed power generation systems. However, a large variation of the grid impedance challenges the stability of the high-order power filter based grid-tied inverter. Many passive and active damping methods have...... been proposed to overcome this issue. Recently, a composite passive damping method for a high-order power filter based grid-tied inverter with an RC parallel damper and an RL series damper was presented to eliminate this problem, but at the cost of more material and power losses. In this paper...

  5. Power Inverter Topologies for Photovoltaic Modules - A Review

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj; Pedersen, John Kim; Blaabjerg, Frede

    2002-01-01

    This review-paper focuses on the latest development of inverters for photovoltaic AC-Modules. The power range for these inverters is usually within 90 Watt to 500 Watt, which covers the most commercial photovoltaic-modules. Self-commutated inverters have replaced the grid-commutated ones. The same...... is true for the bulky low-frequency transformers versus the high-frequency transformers, which are used to adapt the voltage level. The AC-Module provides a modular design and a flexible behaviour in various grid conditions. It hereby opens the market for photovoltaic-power for everyone at a low cost due...

  6. Acute proptosis: Unusual initial presentation of sinonasal inverted papilloma

    Institute of Scientific and Technical Information of China (English)

    Norihan Ibrahim; Baharuddin Abdullah; Regunath Kandasamy; Nor Hayati Othman; Mohtar Ibrahim; Adil Hussein

    2017-01-01

    Inverted papilloma is an uncommon histopathological finding of maxillary sinus tumor. We reported here a rare case of inverted papilloma of maxillary sinus presented initially with ipsilateral proptosis. A middle-aged lady with history of having allergic rhinitis presented with progressive left eye proptosis. Assessment revealed presence of orbital mass arising from paranasal sinus, in which the histopathological examination was initially inconclusive, and later it turned up to be inverted papilloma, partly with malignant transformation. High index of suspicion is necessary especially in those patients with recurrent non-specific sinonasal symptoms, which may need repeated biopsy and histopathological examination. Ocular manifestation signifies a more advance disease.

  7. Vacuum arc switched inverter tests at 2.5 MVA

    International Nuclear Information System (INIS)

    Miller, R.N.; Gilmour, A.S. Jr.

    1979-01-01

    A mathematical analysis of the unloaded vacuum arc switch (VAS) inverter is undertaken; a key element in this analysis is the assumption of a constant voltage drop of 50 volts across each VAS while it is conducting. From this analysis a constant VAS-voltage model is developed to explain the VAS inverter operation. A comparison of data obtained from laboratory tests of the inverter is made with data obtained from this model, and agreement is found to be within 10% for up to 15 alternations

  8. Electric machine and current source inverter drive system

    Science.gov (United States)

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  9. Six transformer based asymmetrical embedded Z-source inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Poh Chiang, Loh; Chi, Jin

    2013-01-01

    Embedded/Asymmetrical embedded Z-source inverters were proposed to maintain smooth input current/voltage across the dc source and within the impedance network, remain the shoot-through feature used to boost up the dc-link voltage without adding bulky filter at input side. This paper introduces a ...... a class of transformer based asymmetrical embedded Z-source inverters which keep the smooth input current and voltage while achieving enhanced voltage boost capability. The presented inverters are verified by laboratory prototypes experimentally....

  10. Robustness analysis of the efficiency in PV inverters

    DEFF Research Database (Denmark)

    Pigazo, Alberto; Liserre, Marco; Blaabjerg, Frede

    2013-01-01

    topology and control strategy but also on the characteristics of the employed components. The aim of this paper is evaluate the effect of physical variations associated to the main components on the overall efficiency of PV inverters. It is concluded that a statistical evaluation of the power converter......During last years an increasing attention has been paid to the efficiency of grid-connected PV inverters. They are manufactured from a number of discrete components and by using a certain topology and control strategy. Hence, the performance of a certain PV inverter not only depends on the selected...

  11. Asymmetrical and symmetrical embedded Z-source inverters

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Li, D.

    2011-01-01

    ends, which indirectly translates to a lowering of overall system cost. These noted advantages are indeed appropriate for applications like photovoltaic and fuel cell energy harnessing, and have already been confirmed in simulation and experimentally using a laboratory-implemented inverter prototype.......This study presents two types of embedded Z-source inverters with each type further divided into asymmetrical and symmetrical realisations. Being different from their traditional counterparts, the presented inverters have their dc sources inserted within their X-shaped impedance networks so...

  12. An iterative method to invert the LTSn matrix

    Energy Technology Data Exchange (ETDEWEB)

    Cardona, A.V.; Vilhena, M.T. de [UFRGS, Porto Alegre (Brazil)

    1996-12-31

    Recently Vilhena and Barichello proposed the LTSn method to solve, analytically, the Discrete Ordinates Problem (Sn problem) in transport theory. The main feature of this method consist in the application of the Laplace transform to the set of Sn equations and solve the resulting algebraic system for the transport flux. Barichello solve the linear system containing the parameter s applying the definition of matrix invertion exploiting the structure of the LTSn matrix. In this work, it is proposed a new scheme to invert the LTSn matrix, decomposing it in blocks and recursively inverting this blocks.

  13. Inverted Lymphoglandular Polyp in Descending Colon

    Directory of Open Access Journals (Sweden)

    Shengmei Zhou

    2015-01-01

    Full Text Available A 47-year-old male with a history of left colon cancer, status post left colon resection for 12 years, presented with rectal bleeding. Colonoscopic examination revealed an 8 mm sessile polyp in the proximal descending colon. Microscopic examination showed that the surface of this polyp was covered with a layer of normal colonic mucosa with focal surface erosion. In the submucosal layer, an intimate admixture of multiple cystically dilated glands and prominent lymphoid aggregates with germinal centers was seen. The glands were lined by columnar epithelium. Immunohistochemical staining showed the glands were positive for CK20 and CDX2 and negative for CK7, with a low proliferative index, mostly consistent with reactive colonic glands. The patient remained asymptomatic after one-year follow-up. A review of the literature shows very rare descriptions of similar lesions, but none fits exactly this pattern. We would designate this inverted lymphoglandular polyp and present this case to raise the awareness of recognizing this unusual histological entity.

  14. Balance control strategy of two-amplitude actively clamped resonant DC-Link inverter clamping voltage%双幅有源箝位谐振直流环节逆变器箝位电压平衡控制策略

    Institute of Scientific and Technical Information of China (English)

    陈沁野; 张德华; 侯尧杰

    2012-01-01

    Aiming at the big loss of the traditional clamping voltage balance control strategies, in two-amplitude actively clamped resonant DC-LINK inverter, the work process of DC link was analyzed. In order to keep the clamp capacitor voltage balance the value set in DC-link work, no short-circuit control was proposed.The DC-link of inverter was calculated by Mathcad. The loss of two modes of short-circuit control and no short-circuit control were compared.Under the no short-circuit control and voltage ripple is not be greater than twenty percent, the parameters of the clamp capacitor were calculated. The results indicate that, the micro-power ACRDCLI clamping voltage balance use no short-circuit control,that can reduce the loss of the DC link and can use thin-film capacitor as a clamp capacitor to achieve the micro-power ACRDCLI low loss and iong life requirements.%针对微型功率双幅有源箝位谐振直流环节逆变器在正常工作过程中,传统箝位电压平衡母线短路控制策略带来损耗大的问题,开展了直流环节工作过程的分析,针对直流环节正常工作的情况下,箝位电容电压必须能平衡在设定值,提出了箝位电压平衡母线无短路控制策略,根据给出的损耗估算方法,通过Mathcad计算,对比了母线短路控制和无短路控制两种方式下的损耗,同时计算出了母线无短路控制箝位电容电压纹波不大于20%下的箝位电容参数.研究结果表明:微型功率ACRDCLI箝位电压平衡采用母线无短线控制,不但可以减少双幅有源箝位谐振直流环节逆变器的损耗,并且可以使用薄膜电容作为箝位电容,以达到微型功率ACRDCLI损耗低、寿命长的要求.

  15. Intracellular trafficking of the free cholesterol derived from LDL cholesteryl ester is defective in vivo in Niemann-Pick C disease: insights on normal metabolism of HDL and LDL gained from the NP-C mutation.

    Science.gov (United States)

    Shamburek, R D; Pentchev, P G; Zech, L A; Blanchette-Mackie, J; Carstea, E D; VandenBroek, J M; Cooper, P S; Neufeld, E B; Phair, R D; Brewer, H B; Brady, R O; Schwartz, C C

    1997-12-01

    Niemann-Pick C disease (NP-C) is a rare inborn error of metabolism with hepatic involvement and neurological sequelae that usually manifest in childhood. Although in vitro studies have shown that the lysosomal distribution of LDL-derived cholesterol is defective in cultured cells of NP-C subjects, no unusual characteristics mark the plasma lipoprotein profiles. We set out to determine whether anomalies exist in vivo in the cellular distribution of newly synthesized, HDL-derived or LDL-derived cholesterol under physiologic conditions in NP-C subjects. Three affected and three normal male subjects were administered [14C]mevalonate as a tracer of newly synthesized cholesterol and [3H]cholesteryl linoleate in either HDL or LDL to trace the distribution of lipoprotein-derived free cholesterol. The rate of appearance of free [14C]- and free [3H]cholesterol in the plasma membrane was detected indirectly by monitoring their appearance in plasma and bile. The plasma disappearance of [3H]cholesteryl linoleate was slightly faster in NP-C subjects regardless of its lipoprotein origin. Appearance of free [14C] cholesterol ill the plasma (and in bile) was essentially identical in normal and affected individuals as was the initial appearance of free [3H]cholesterol derived from HDL, observed before extensive exchange occurred of the [3H]cholesteryl linoleate among lipoproteins. In contrast, the rate of appearance of LDL-derived free [3H]cholesterol in the plasma membrane of NP-C subjects, as detected in plasma and bile, was retarded to a similar extent that LDL cholesterol metabolism was defective in cultured fibroblasts of these affected subjects. These findings show that intracellular distribution of both newly synthesized and HDL-derived cholesterol are essentially unperturbed by the NP-C mutation, and therefore occur by lysosomal-independent paths. In contrast, in NP-C there is defective trafficking of LDL-derived cholesterol to the plasma membrane in vivo as well as in vitro

  16. Design consideration of resonance inverters with electro-technological application

    Science.gov (United States)

    Hinov, Nikolay

    2017-12-01

    This study presents design consideration of resonance inverters with electro-technological application. The presented methodology was achieved as a result of investigations and analyses of different types and working regimes of resonance inverters, made by the author. Are considered schemes of resonant inverters without inverse diodes. The first harmonic method is used in the analysis and design. This method for the case of inverters with electro-technological application gives very good accuracy. This does not require the use of a complex and heavy mathematical apparatus. The proposed methodology is easy to use and is suitable for use in training students in power electronics. Authenticity of achieved results is confirmed by simulating and physical prototypes research work.

  17. Reliability Assessment of Transformerless PV Inverters considering Mission Profiles

    Directory of Open Access Journals (Sweden)

    Yongheng Yang

    2015-01-01

    Full Text Available Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved by either modifying the modulation schemes or adding extra power switching devices, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redistributed and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature. The mission profile is translated to device thermal loading, which is used for lifetime prediction. Comparison results reveal the lifetime mismatches among the power switching devices operating under the same condition, which offers new thoughts for a robust design and a reliable operation of grid-connected transformerless PV inverters with high efficiency.

  18. Closed-loop waveform control of boost inverter

    DEFF Research Database (Denmark)

    Zhu, Guo Rong; Xiao, Cheng Yuan; Wang, Haoran

    2016-01-01

    The input current of single-phase inverter typically has an AC ripple component at twice the output frequency, which causes a reduction in both the operating lifetime of its DC source and the efficiency of the system. In this paper, the closed-loop performance of a proposed waveform control method...... to eliminate such a ripple current in boost inverter is investigated. The small-signal stability and the dynamic characteristic of the inverter system for input voltage or wide range load variations under the closed-loop waveform control method are studied. It is validated that with the closedloop waveform...... control, not only was stability achieved, the reference voltage of the boost inverter capacitors can be instantaneously adjusted to match the new load, thereby achieving improved ripple mitigation for a wide load range. Furthermore, with the control and feedback mechanism, there is minimal level of ripple...

  19. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

  20. Energy-efficient adjustable speed double inverter-fed woundrotor ...

    African Journals Online (AJOL)

    Energy-efficient adjustable speed double inverter-fed woundrotor induction motor ... at speeds up to double rated without the magnetic flux reducing is presented. ... Keywords: power, double-fed wound-rotor induction motor drive, steel and ...

  1. Diode-Assisted Buck-Boost Voltage-Source Inverters

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus

    2009-01-01

    , a number of diode-assisted inverter variants can be designed with each having its own operational principle and voltage gain expression. For controlling them, a generic modulation scheme that can be used for controlling all diode-assisted variants with minimized harmonic distortion and component stress......This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques....... Using the diode-assisted network, the proposed inverters can naturally configure themselves to perform capacitive charging in parallel and discharging in series to give a higher voltage multiplication factor without compromising waveform quality. In addition, by adopting different front-end circuitries...

  2. Multilevel inverter switching controller using a field programmable ...

    African Journals Online (AJOL)

    Conducted simulation and measurement results verified and validated the switching controller design functionality and requirement. Keywords: multilevel inverter, switching controller; FPGA, general purpose processor (GPP);digital signal processing (DSP); IGBT; Verilog, power consumption; harmonic elimination (SHE).

  3. High Radiation Resistance Inverted Metamorphic Solar Cell, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation in this SBIR Phase II project is the development of a unique triple junction inverted metamorphic technology (IMM), which will enable the...

  4. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    International Nuclear Information System (INIS)

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Gilgenbach, R. M.; Hoff, B. W.

    2015-01-01

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions

  5. Triple inverter pierce oscillator circuit suitable for CMOS

    Science.gov (United States)

    Wessendorf,; Kurt, O [Albuquerque, NM

    2007-02-27

    An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

  6. An inverter/controller subsystem optimized for photovoltaic applications

    Science.gov (United States)

    Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

  7. Design optimization of grid-connected PV inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    The DC/AC inverters are the key elements in grid-connected PV energy production systems. In this paper, new design optimization techniques focused on transformerless (very high efficiency) PV inverters are proposed. They have been developed based on an analysis of the deficiencies of the current......, state-of-the-art PV inverters design technology, which limits the amount of PV energy supplied into the electric grid. The influences of the electric grid regulations and standards and the PV array operational characteristics on the design of grid-connected PV inverters have also been considered....... The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid by the optimized PV installation....

  8. Study of Inverted Pendulum Robot Using Fuzzy Servo Control Method

    Directory of Open Access Journals (Sweden)

    Dazhong Wang

    2012-09-01

    Full Text Available The inverted pendulum robot is a classical problem in controls. The inherit instabilities in the setup make it a natural target for a control system. Inverted pendulum robot is suitable to use for investigation and verification of various control methods for dynamic systems. Maintaining an equilibrium position of the pendulum pointing up is a challenge as this equilibrium position is unstable. As the inverted pendulum robot system is nonlinear it is well-suited to be controlled by fuzzy logic. In this paper, Lagrange method has been applied to develop the mathematical model of the system. The objective of the simulation to be shown using the fuzzy control method can stabilize the nonlinear system of inverted pendulum robot.

  9. Inverted base pavements : new field test and design catalogue.

    Science.gov (United States)

    2014-01-01

    The current economic situation has severely affected the US road infrastructure and funding has become : inadequate for either maintenance or future growth. : The inverted base pavement structure is a promising alternative to achieve high quality roa...

  10. Efficient Color-Stable Inverted White Organic Light-Emitting Diodes with Outcoupling-Enhanced ZnO Layer.

    Science.gov (United States)

    Zhao, Xin-Dong; Li, Yan-Qing; Xiang, Heng-Yang; Zhang, Yi-Bo; Chen, Jing-De; Xu, Lu-Hai; Tang, Jian-Xin

    2017-01-25

    Inverted organic light-emitting diode (OLED) has attracted extensive attention due to the demand in active-matrix OLED display panels as its geometry enables the direct connection with n-channel transistor backplane on the substrate. One key challenge of high-performance inverted OLED is an efficient electron-injection layer with superior electrical and optical properties to match the indium tin oxide cathode on substrate. We here propose a synergistic electron-injection architecture using surface modification of ZnO layer to simultaneously promote electron injection into organic emitter and enhance out-coupling of waveguided light. An efficient inverted white OLED is realized by introducing the nanoimprinted aperiodic nanostructure of ZnO for broadband and angle-independent light out-coupling and inserting an n-type doped interlayer for energy level tuning and injection barrier lowering. As a result, the optimized inverted white OLEDs have an external quantum efficiency of 42.4% and a power efficiency of 85.4 lm W 1- , which are accompanied by the superiority of angular color stability over the visible wavelength range. Our results may inspire a promising approach to fabricate high-efficiency inverted OLEDs for large-scale display panels.

  11. Electro-thermal Modeling for Junction Temperature Cycling-Based Lifetime Prediction of a Press-Pack IGBT 3L-NPC-VSC Applied to Large Wind Turbines

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Munk-Nielsen, Stig; Teodorescu, Remus

    2011-01-01

    Reliability is a critical criterion for multi-MW wind turbines, which are being employed with increasing numbers in wind power plants, since they operate under harsh conditions and have high maintenance cost due to their remote locations. In this study, the wind turbine grid-side converter...... reliability is investigated regarding IGBT lifetime based on junction temperature cycling for the grid-side press-pack IGBT 3L-NPC-VSC, which is a state-of-the art high reliability solution. In order to acquire IGBT junction temperatures for given wind power profiles and to use them in IGBT lifetime...... prediction, the converter electro-thermal model including electrical, power loss, and dynamical thermal models is developed with the main focus on the thermal modeling regarding converter topology, switch technology, and physical structure. Moreover, these models are simplified for their practical...

  12. Resistance Spot Welding with Middelfrequency-Inverter Weling Gun

    DEFF Research Database (Denmark)

    Rasmussen, Mogens H.

    The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun......The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun...

  13. Discontinuous interleaving of parallel inverters for efficiency improvement

    DEFF Research Database (Denmark)

    Rannestad, Bjørn; Munk-Nielsen, Stig; Gadgaard, Kristian

    2017-01-01

    Interleaved switching of parallel inverters has previously been proposed for efficiency/size improvements of grid connected three-phase inverters. This paper proposes a novel interleaving method which practically eliminates insulated gate bipolar transistor (IGBT) turn-on losses and drastically...... overall power module losses are reduced. The modulation strategy is suited for converters with doubly fed induction generators (DFIG) for wind turbines, but are not limited hereto. Improvement of switching performance are measured and operational efficiency improvements are calculated and verified...

  14. A case report of inverted papilloma of the posterior urethra

    OpenAIRE

    徳光, 正行; 井内, 裕満; 森川, 満; 八竹, 直

    1992-01-01

    A case of inverted papilloma of the posterior urethra is reported. A 59-year-old male was admitted with the chief complaint of hematuria. Urethrogram revealed a small defect in the neck of the bladder. Endoscopic examination revealed a polypoid tumor on the stalk arising from prostatic urethra, and transurethral resection was performed. The patient has been subsequently followed up and there has been no evidence of recurrence. Although 141 cases of inverted papilloma have been reported in man...

  15. A case report of inverted papilloma of the posterior urethra

    OpenAIRE

    長谷川, 総一郎; 絹川, 常郎; 松浦, 治; 竹内, 宜久; 服部, 良平; 小野, 佳成; 大島, 伸一; 村上, 榮

    1987-01-01

    Sixty-seven cases of inverted papilloma have been reported in many anatomical sites of urinary tract but only 9 cases involving the posterior urethra have been described in Japan. We report the 10th case of inverted papilloma of the posterior urethra in a 27-year-old male who complained of macroscopic hematuria. The lesion was diagnosed cystoscopically and treated by transurethral resection.

  16. Tensor product of left n-invertible operators

    Czech Academy of Sciences Publication Activity Database

    Duggal, B.P.; Müller, Vladimír

    2013-01-01

    Roč. 215, č. 2 (2013), s. 113-125 ISSN 0039-3223 R&D Projects: GA ČR GA201/09/0473 Institutional support: RVO:67985840 Keywords : Banach space * essentially left n- invertible operator * left n-invertible operator Subject RIV: BA - General Mathematics Impact factor: 0.630, year: 2013 http://journals.impan.pl/cgi-bin/doi?sm215-2-2

  17. Control Strategy for Microgrid Inverter under Unbalanced Grid Voltage Conditions

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, Wenzhao; Zhang, X.

    2014-01-01

    This paper presents the theoretical analysis of the inherent reason of current harmonic and power oscillation phenomena in case of operating the microgrid inverter under unbalanced grid voltage conditions. In order to flexibly control the current harmonic and power oscillation, a new stationary...... inverter. Finally, the performance evaluation tests are carried out under unbalanced grid voltage conditions. Results verify the effectiveness of the propose method....

  18. Host-Primed Ebola Virus GP Exposes a Hydrophobic NPC1 Receptor-Binding Pocket, Revealing a Target for Broadly Neutralizing Antibodies.

    Science.gov (United States)

    Bornholdt, Zachary A; Ndungo, Esther; Fusco, Marnie L; Bale, Shridhar; Flyak, Andrew I; Crowe, James E; Chandran, Kartik; Saphire, Erica Ollmann

    2016-02-23

    The filovirus surface glycoprotein (GP) mediates viral entry into host cells. Following viral internalization into endosomes, GP is cleaved by host cysteine proteases to expose a receptor-binding site (RBS) that is otherwise hidden from immune surveillance. Here, we present the crystal structure of proteolytically cleaved Ebola virus GP to a resolution of 3.3 Å. We use this structure in conjunction with functional analysis of a large panel of pseudotyped viruses bearing mutant GP proteins to map the Ebola virus GP endosomal RBS at molecular resolution. Our studies indicate that binding of GP to its endosomal receptor Niemann-Pick C1 occurs in two distinct stages: the initial electrostatic interactions are followed by specific interactions with a hydrophobic trough that is exposed on the endosomally cleaved GP1 subunit. Finally, we demonstrate that monoclonal antibodies targeting the filovirus RBS neutralize all known filovirus GPs, making this conserved pocket a promising target for the development of panfilovirus therapeutics. Ebola virus uses its glycoprotein (GP) to enter new host cells. During entry, GP must be cleaved by human enzymes in order for receptor binding to occur. Here, we provide the crystal structure of the cleaved form of Ebola virus GP. We demonstrate that cleavage exposes a site at the top of GP and that this site binds the critical domain C of the receptor, termed Niemann-Pick C1 (NPC1). We perform mutagenesis to find parts of the site essential for binding NPC1 and map distinct roles for an upper, charged crest and lower, hydrophobic trough in cleaved GP. We find that this 3-dimensional site is conserved across the filovirus family and that antibody directed against this site is able to bind cleaved GP from every filovirus tested and neutralize viruses bearing those GPs. Copyright © 2016 Bornholdt et al.

  19. Distortion and regulation characterization of a Mapham inverter

    Science.gov (United States)

    Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

    1989-01-01

    Output voltage Total Harmonic Distortion (THD) of a 20kHz, 6kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f sub s/f sub r, using the EASY5 engineering analysis system. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f sub s/f sub r ratio is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different than the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

  20. Photovoltaic power generating system; Sanso zetsuengata taiyoko inverter

    Energy Technology Data Exchange (ETDEWEB)

    Nojima, T; Nakashima, T; Muta, Y; Takase, K; Hirayama, K [Nishimu Electronics Industries Co. Ltd., Saga (Japan)

    1996-10-27

    Nishimu Electronics Industries Co., Ltd. has developed a new series of inverters of three phase photovoltaic power generating system with the output ranging from 10 kVA to 50 kVA. For these inverters, the inverter and the system interconnection protector were integrated to make them smaller, lighter and cheaper. Stand-alone operation function was also added. The DC input voltage ranges were between 240 and 400 V for the crystalline solar cell, and between 170 and 400 V for the amorphous one. From the viewpoint of control of inverters, the inverters are generally controlled by the voltage-type current control method during the interconnection operation, while they must be controlled by the voltage-type voltage control method during the stand-alone operation which is the same as the UPS usually operated alone. For the present inverters, two control circuits for the interconnection operation and for the stand-alone operation were prepared. The control circuits for interconnection and stand-alone operations were switched using a cam-operation switch for change-over of operation. The results of the system interconnection verification tests satisfied the criteria of Japan`s Electronic Products Test Center. 3 refs., 4 figs., 2 tabs.

  1. Distributed Storage Inverter and Legacy Generator Integration Plus Renewable Solution for Microgrids

    Science.gov (United States)

    2015-07-01

    Observation ................. 5 2.1.5 PV Inverter with Microgrid Controls .......................................................... 5 2.2 TECHNOLOGY... CONTROL OF PV POWER RAMP RATE FOR GENERATOR STABILITY ..................... 27 6.11 DEMONSTRATION 11: MICROGRID VOLTAGE SUPPORT FROM PV INVERTER...power delivery optimized storage, transiently rated inverters, integration with legacy generator controls , and microgrid compatible inverters for PV

  2. Self-Oscillating Resonant Gate Drive for Resonant Inverters and Rectifiers Composed Solely of Passive Components

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Pedersen, Jeppe Arnsdorf; Knott, Arnold

    2014-01-01

    to improve the performance of the gate drive and how the gate drive can be implemented in a class E inverter, a class DE inverter and in class E inverter with a synchronous class E rectifier. The paper shows practical implementations of all the proposed inverters and converters operating in the Very High...

  3. Small-Signal Modeling, Analysis and Testing of Parallel Three-Phase-Inverters with A Novel Autonomous Current Sharing Controller

    DEFF Research Database (Denmark)

    Guan, Yajuan; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2015-01-01

    A novel simple and effective autonomous currentsharing controller for parallel three-phase inverters is employed in this paper. The novel controller is able to endow to the system high speed response and precision in contrast to the conventional droop control as it does not require calculating any...... active or reactive power, instead it uses a virtual impedance loop and a SFR phase-locked loop. The small-signal model of the system was developed for the autonomous operation of inverter-based microgrid with the proposed controller. The developed model shows large stability margin and fast transient...

  4. Applying the min-projection strategy to improve the transient performance of the three-phase grid-connected inverter.

    Science.gov (United States)

    Baygi, Mahdi Oloumi; Ghazi, Reza; Monfared, Mohammad

    2014-07-01

    Applying the min-projection strategy (MPS) to a three-phase grid-connected inverter to improve its transient performance is the main objective of this paper. For this purpose, the inverter is first modeled as a switched linear system. Then, the feasibility of the MPS technique is investigated and the stability criterion is derived. Hereafter, the fundamental equations of the MPS for the control of the inverter are obtained. The proposed scheme is simulated in PSCAD/EMTDC environment. The validity of the MPS approach is confirmed by comparing the obtained results with those of VOC method. The results demonstrate that the proposed method despite its simplicity provides an excellent transient performance, fully decoupled control of active and reactive powers, acceptable THD level and a reasonable switching frequency. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  5. A Riding-through Technique for Seamless Transition between Islanded and Grid-Connected Modes of Droop-Controlled Inverters

    DEFF Research Database (Denmark)

    Hu, Shang-hung; Lee, Tzung-Lin; Kuo, Chun-Yi

    2016-01-01

    This paper presents a seamless transition method for a droop-controlled inverter. The droop control is suitable to make the inverter work as a voltage source in both islanded and grid-connected modes, however, the transfer between theses modes can result in a big inrush current that may damage...... a smooth transition between them, requiring neither synchronization signals nor grid-side information. The control algorithm and design procedure are presented. Experimental results from a laboratory prototype validate the effectiveness of the proposed method....... the system. The proposed method allows the droop-controlled inverter to improve the transient response when transferring between modes, by detecting the inrush current, activating a current control loop during transients, and then transferring back to droop-controlled mode smoothly by using a virtual...

  6. Aalborg Inverter - A new type of “Buck in Buck, Boost in Boost” Grid-tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Blaabjerg, Frede

    2013-01-01

    This paper presents a new family of high efficiency DC/AC grid-tied inverter with a wide variation of input DC voltage. It is a kind of “Boost in Boost, Buck in Buck” inverter, meaning that only one power stage works at the high frequency to achieve the minimum switching loss. Furthermore......, the minimum filtering inductance in the power loop is achieved to reduce the conduction power loss whether in “Boost” or “Buck” mode. In theory, it can achieve higher efficiency than other inverters under the same condition of input DC voltage. The principle of operation is fully illustrated through...... the analysis on the equivalent circuits of a “three-level” single-phase inverter. Simulations show it has good control performance....

  7. New Power Sharing Control for Inverter-Dominated Microgrid Based on Impedance Match Concept

    Science.gov (United States)

    Gu, Herong; Wang, Deyu; Shen, Hong; Zhao, Wei; Guo, Xiaoqiang

    2013-01-01

    Power flow control is one of the most important issues for operating the inverter-dominated autonomous microgrid. A technical challenge is how to achieve the accurate active/reactive power sharing of inverters. P-F and Q-V droop control schemes have been widely used for power sharing in the past decades. But they suffer from the poor power sharing in the presence of unequal line impedance. In order to solve the problem, a comprehensive analysis of the power droop control is presented, and a new droop control based on the impedance match concept is proposed in this paper. In addition, the design guidelines of control coefficients and virtual impedance are provided. Finally, the performance evaluation is carried out, and the evaluation results verify the effectiveness of the proposed method. PMID:24453910

  8. New power sharing control for inverter-dominated microgrid based on impedance match concept.

    Science.gov (United States)

    Gu, Herong; Wang, Deyu; Shen, Hong; Zhao, Wei; Guo, Xiaoqiang

    2013-01-01

    Power flow control is one of the most important issues for operating the inverter-dominated autonomous microgrid. A technical challenge is how to achieve the accurate active/reactive power sharing of inverters. P-F and Q-V droop control schemes have been widely used for power sharing in the past decades. But they suffer from the poor power sharing in the presence of unequal line impedance. In order to solve the problem, a comprehensive analysis of the power droop control is presented, and a new droop control based on the impedance match concept is proposed in this paper. In addition, the design guidelines of control coefficients and virtual impedance are provided. Finally, the performance evaluation is carried out, and the evaluation results verify the effectiveness of the proposed method.

  9. Comprehensive Loss Evaluation of Neutral-Point-Clamped (NPC) and T-Type Three-Level Invertersbased on a Circuit Level Decoupling Modulation

    DEFF Research Database (Denmark)

    Zhang, Zhe; Anthon, Alexander; Andersen, Michael A. E.

    2014-01-01

    frequencyincreases due to high switching loss of the equipped high voltagepower switches. In order to reduce switching loss and herebyenhance efficiency, a newly proposed circuit-level decouplingmodulation (CLDM) scheme is applied for these two widely usedthree-phase three-level inverters, as well...

  10. Analysis of Magnetically-Coupled Impedance Source Three-Phase Four-Switch Inverters

    DEFF Research Database (Denmark)

    Li, Kerui; Abdelhakim, Ahmed; Yang, Yongheng

    2017-01-01

    In this paper, magnetically-coupled impedance source (MCIS) three-phase four-switch inverters are introduced for renewable energy applications. This inverter utilizes two single-phase MCIS inverters to obtain a three-phase output, where less component-count is achieved in order to reduce the inve......In this paper, magnetically-coupled impedance source (MCIS) three-phase four-switch inverters are introduced for renewable energy applications. This inverter utilizes two single-phase MCIS inverters to obtain a three-phase output, where less component-count is achieved in order to reduce...... the inverter volume. On the other hand, as a result of the reduced number of switches, the proposed inverter suffers from higher voltage stresses. The MCIS inverters are first reviewed. Then, the modulation and operation principle of the MCIS three-phase inverter topology are introduced before sizing...

  11. Blade-coated sol-gel indium-gallium-zinc-oxide for inverted polymer solar cell

    Directory of Open Access Journals (Sweden)

    Yan-Huei Lee

    2016-11-01

    Full Text Available The inverted organic solar cell was fabricated by using sol-gel indium-gallium-zinc-oxide (IGZO as the electron-transport layer. The IGZO precursor solution was deposited by blade coating with simultaneous substrate heating at 120 °C from the bottom and hot wind from above. Uniform IGZO film of around 30 nm was formed after annealing at 400 °C. Using the blend of low band-gap polymer poly[(4,8-bis-(2-ethylhexyloxy-benzo(1,2-b:4,5-b’dithiophene-2,6-diyl-alt- (4-(2-ethylhexanoyl-thieno [3,4-b]thiophene--2-6-diyl] (PBDTTT-C-T and [6,6]-Phenyl C71 butyric acid methyl ester ([70]PCBM as the active layer for the inverted organic solar cell, an efficiency of 6.2% was achieved with a blade speed of 180 mm/s for the IGZO. The efficiency of the inverted organic solar cells was found to depend on the coating speed of the IGZO films, which was attributed to the change in the concentration of surface OH groups. Compared to organic solar cells of conventional structure using PBDTTT-C-T: [70]PCBM as active layer, the inverted organic solar cells showed significant improvement in thermal stability. In addition, the chemical composition, as well as the work function of the IGZO film at the surface and inside can be tuned by the blade speed, which may find applications in other areas like thin-film transistors.

  12. The overview of damping methods for three-phase grid-tied inverter with LLCL-filter

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    Compared with LCL filter, an LLCL-filter is characterized with smaller size and lower cost for grid-connected inverters. But this high order filter may also have resonant problem which will affect the system stability. Many methods can be used to alleviate the resonant problem including active da...... and shows the advantages as well as disadvantages of these methods....

  13. Power Loss Analysis and Comparision of DC and AC Side Decoupling Module in a H-bridge Inverter

    DEFF Research Database (Denmark)

    Ma, Siyuan; Wang, Haoran; Zhu, Guorong

    2016-01-01

    perspective. The analytical power loss models are derived based on the operation principles of the active power decoupling methods. A comparative study is performed based on a 500 W single-phase H-bridge inverter study case with 400 V DC-link voltage level. The results provide a guideline to justify whether...

  14. A transformerless single-phase symmetrical Z-source HERIC inverter with reduced leakage currents for PV systems

    DEFF Research Database (Denmark)

    Li, Kerui; Shen, Yanfeng; Yang, Yongheng

    2018-01-01

    and thus low leakage currents in PV applications. The symmetric Z-source HERIC inverter requires two extra active switches. Nevertheless, the operation frequency of the two switches is the line frequency, leading to negligible losses. More importantly, the performance in terms of low leakage currents...... and harmonics is improved. Experimental tests are performed to validate the analysis and performance of the proposed system....

  15. Interfacial thermal degradation in inverted organic solar cells

    International Nuclear Information System (INIS)

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain

    2015-01-01

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO 3 and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism

  16. Interfacial thermal degradation in inverted organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain, E-mail: sylvain.chambon@ims-bordeaux.fr [University of Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, F-33405 Talence (France)

    2015-12-28

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO{sub 3} and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism.

  17. A single-phase multi-level D-STATCOM inverter using modular multi-level converter (MMC) topology for renewable energy sources

    Science.gov (United States)

    Sotoodeh, Pedram

    This dissertation presents the design of a novel multi-level inverter with FACTS capability for small to mid-size (10-20kW) permanent-magnet wind installations using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with D-STATCOM option to provide utilities with more control on active and reactive power transfer of distribution lines. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to fix the power factor of the grid at a target value, regardless of wind speed, by regulating active and reactive power required by the grid. The inverter is capable of controlling active and reactive power by controlling the phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without additional cost. Simulations of the proposed inverter, with 5 and 11 levels, have been conducted in MATLAB/Simulink for two systems including 20 kW/kVAR and 250 W/VAR. To validate the simulation results, a scaled version (250 kW/kVAR) of the proposed inverter with 5 and 11 levels has been built and tested in the laboratory. Experimental results show that the reduced-scale 5- and 11-level inverter is able to fix PF of the grid as well as being compatible with IEEE standards. Furthermore, total cost of the prototype models, which is one of the major objectives of this research, is comparable with market prices.

  18. CT and MR findings of the inverted papilloma

    International Nuclear Information System (INIS)

    Lim, Seong Youb; Kim, Hak Jin; Lee, Jun Woo; Park, Jae Yeong; Lee, Sung Gap; Kim, Byung Soo; Roh, Hwan Jung; Baik, Seung Kook

    1997-01-01

    The purpose of this study is to describe the CT and MR findings of inverted papilloma and to determine the specific differential finding between inverted papilloma with and without coexisting malignancy. Twenty-two histopathologically proven inverted papillomas were included in this study ; in six patients there was coexisting malignancy. Twenty-two CT images and eight MR images were retrospectively reviewed. On CT images, the inverted papillomas were seen as unilateral sinonasal masses with bone remodeling (n=15) rather than bone destruction (n=1) and showed iso- or slightly high attenuation. Three of the six malignant cases showed aggressive bone destruction and widespread extension into the orbit, intracranial and buccal spaces, and pterygopalatine fossa. On MR images, the inverted papillomas (n=3) were iso- (n=2) or slightly high (n=1) in signal intensity in relation to muscle on T1-weighted images, and high (n=3) on T2-weighted images. Gadolinium enhanced images showed heterogenous moderate enhancement. In the cases of coexisting malignancy (n=5), the masses were iso- (n=5) on T1-weighted images, high (n=5) on T2-weighted images and also showed heterogenous moderate enhancement. Inverted papilloma should be considered in the differential diagnosis of a bulky unilateral nasal mass extending into the adjacent paranasal sinuses, especially in an elderly patient with chronic nasal obstruction. Although there were no specific differential findings in signal intensity and enhancement pattern on CT and MR images between benign and malignant inverted papilloma, aggressive bone destruction and widespread extension beyond the sinonasal cavity are findings which are highly suggestive of coexisting malignancy

  19. THE DETERMINATION OF DIFFUSION COEFFICIENT OF INVERT MATERIALS

    International Nuclear Information System (INIS)

    P. Heller and J. Wright

    2000-01-01

    The Engineered Barrier System (EBS) Testing Department is performing tests in the Department of Energy's Atlas Facility to evaluate the performance of various means for increasing the time for breakthrough of radionuclides from the waste package to the base of the invert. This includes testing various barriers in the invert as a means of increasing breakthrough time through the process of diffusion. A diffusion barrier may serve as an invert material for the emplacement drifts. The invert material may consist of crushed tuff from the repository excavation at Yucca Mountain or silica sand. The objective of this report is to determine the diffusion coefficient of the crushed tuff and silica sand invert materials specified by the EBS Testing Department. The laboratory derived information from the testing was used in the Nernst-Einstein equation (Jurinak et al. 1987, p. 626) to determine the diffusion coefficient of the invert material. This report transmits the results and describes the methodology and interpretation. The scope of this report is to determine the diffusion coefficients of the invert materials mentioned above using the centrifuge at UFA Ventures. Standard laboratory procedures, described in Section 2 of this report, were used. The diffusion coefficients are to be determined over a range of moisture contents. The report contains the diffusion coefficients calculated by the Nernst-Einstein equation (Jurinak et al. 1987, p. 626) that become a part of the Technical Database. Raw data is also included in the report, however this data does not become part of the Technical Database as per Section 3.23 of AP-SIII.3Q ''Submittal and Incorporation of Data to the Technical Data Management System''. A sieve analysis of the samples was not conducted as part of this report, but sieve analysis may be accomplished as part of other reports. Two samples of crushed tuff and two samples of silica sand were tested

  20. Analysis, Design and Implementation of a Quasi-Proportional-Resonant Controller for a Multifunctional Capacitive-Coupling Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Ye, Tao; Dai, Ning-Yi; Lam, Chi-Seng

    2016-01-01

    to compensate reactive power and transfer active power simultaneously. It is a promising solution for micro-grid and building-integrated distributed generator systems. A quasiproportional- resonant (quasi-PR) controller is applied to reduce steady-state current tracking errors of the CGCI in this paper......The capacitive-coupling grid-connected inverter (CGCI) is coupled to the point of common coupling via a second-order LC branch. Its operational voltage is much lower than that of a conventional inductive-coupling grid-connected inverter (IGCI) when it serves as a multifunctional inverter...... tracking errors are greatly reduced when the quasi-PR controller rather than the proportional-integration controller is applied. Experimental results are also provided to validate the CGCI as a multifunctional grid-connected inverter....

  1. Inverter Circuits Using ZnO Nanoparticle Based Thin-Film Transistors for Flexible Electronic Applications.

    Science.gov (United States)

    Vidor, Fábio F; Meyers, Thorsten; Hilleringmann, Ulrich

    2016-08-23

    Innovative systems exploring the flexibility and the transparency of modern semiconducting materials are being widely researched by the scientific community and by several companies. For a low-cost production and large surface area applications, thin-film transistors (TFTs) are the key elements driving the system currents. In order to maintain a cost efficient integration process, solution based materials are used as they show an outstanding tradeoff between cost and system complexity. In this paper, we discuss the integration process of ZnO nanoparticle TFTs using a high- k resin as gate dielectric. The performance in dependence on the transistor structure has been investigated, and inverted staggered setups depict an improved performance over the coplanar device increasing both the field-effect mobility and the I ON / I OFF ratio. Aiming at the evaluation of the TFT characteristics for digital circuit applications, inverter circuits using a load TFT in the pull-up network and an active TFT in the pull-down network were integrated. The inverters show reasonable switching characteristics and V / V gains. Conjointly, the influence of the geometry ratio and the supply voltage on the devices have been analyzed. Moreover, as all integration steps are suitable to polymeric templates, the fabrication process is fully compatible to flexible substrates.

  2. Inverter Circuits Using ZnO Nanoparticle Based Thin-Film Transistors for Flexible Electronic Applications

    Directory of Open Access Journals (Sweden)

    Fábio F. Vidor

    2016-08-01

    Full Text Available Innovative systems exploring the flexibility and the transparency of modern semiconducting materials are being widely researched by the scientific community and by several companies. For a low-cost production and large surface area applications, thin-film transistors (TFTs are the key elements driving the system currents. In order to maintain a cost efficient integration process, solution based materials are used as they show an outstanding tradeoff between cost and system complexity. In this paper, we discuss the integration process of ZnO nanoparticle TFTs using a high-k resin as gate dielectric. The performance in dependence on the transistor structure has been investigated, and inverted staggered setups depict an improved performance over the coplanar device increasing both the field-effect mobility and the ION/IOFF ratio. Aiming at the evaluation of the TFT characteristics for digital circuit applications, inverter circuits using a load TFT in the pull-up network and an active TFT in the pull-down network were integrated. The inverters show reasonable switching characteristics and V/V gains. Conjointly, the influence of the geometry ratio and the supply voltage on the devices have been analyzed. Moreover, as all integration steps are suitable to polymeric templates, the fabrication process is fully compatible to flexible substrates.

  3. Toxicity of invert drilling muds composted with wood/bark chips

    Energy Technology Data Exchange (ETDEWEB)

    Bessie, K. [EBA Engineering Consultants Ltd., Calgary, AB (Canada)

    2006-07-01

    Since the early to mid 1990s, many companies have composted invert (diesel) drilling muds with wood chips/bark chips in the green (forestry) zone as a method of drilling mud treatment. This presentation addressed the toxicity of invert drilling muds composted with wood/bark chips and provided some background on composted invert drilling mud (CIDM). EBA Engineering monitored 22 third-party sites in 2002, some of which were biopiles, and others land treatment areas (LTAs). Active treatment started between 1995 and 1999 and some LTAs were seeded with varying degrees of success. Composted materials had hydrocarbon odour and staining and were very moist. Materials exceeded Alberta Environment guidelines for petroleum hydrocarbons (PHCs) and sometimes barium. Most sites were within areas that had forestry production/wildlife as end land use. Receptors included plants, soil invertebrates by soil contact, and wildlife by ingestion. Stakeholder meetings were held for their input and an ecotoxicity study was developed. Material tested, tests and species used as well as results of the ecotoxicity study were presented. A comparison of results to other EBA composting studies was also given. It was concluded that CIDM affects the reproduction of earthworms and springtails, and plant growth; wood/barks chips themselves can be ecotoxic; and, other compost studies with finely ground sawdust and no bark chips had less ecotoxicity. tabs., figs.

  4. Inverting adherent cells for visualizing ECM interactions at the basal cell side

    Energy Technology Data Exchange (ETDEWEB)

    Gudzenko, Tetyana [DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1a, 76131 Karlsruhe (Germany); Franz, Clemens M., E-mail: clemens.franz@kit.edu [DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1a, 76131 Karlsruhe (Germany)

    2013-05-15

    Interactions with the extracellular matrix (ECM) govern a wide range of cellular functions, including survival, migration and invasion. However, in adherent cells these interactions occur primarily on the basal cell side, making them inaccessible to high-resolution, surface-scanning imaging techniques such as atomic force microscopy (AFM) or scanning electron microscopy (SEM). Here we describe a fast and reliable method for inverting adherent cells, exposing the basal cell membrane for direct analysis by AFM or SEM in combination with fluorescence microscopy. Cells including their matrix adhesion sites remain intact during the inversion process and are transferred together with the complete array of basally associated ECM proteins. Molecular features of ECM proteins, such as the characteristic 67 nm collagen D-periodicity, are well preserved after inversion. To demonstrate the versatility of the method, we compared basal interactions of fibroblasts with fibrillar collagen I and fibronectin matrices. While fibroblasts remodel the fibronectin layer exclusively from above, they actively invade even thin collagen layers by contacting individual collagen nanofibrils both basally and apically through a network of cellular extensions. Cell–matrix entanglement coincides with enhanced cell spreading and flattening, indicating that nanoscale ECM interactions govern macroscopic changes in cell morphology. The presented cell inversion technique can thus provide novel insight into nanoscale cell–matrix interactions at the basal cell side. - Highlights: ► We present a novel method for inverting adherent cells to expose the basal cell side. ► Basal cell sides can be imaged at high resolution by AFM and SEM. ► Cells can be inverted together with the underlying extracellular matrix. ► AFM images of inverted cells provide a nanoscale look at basal cell–ECM interactions.

  5. Transnasal endoscopic medial maxillectomy in recurrent maxillary sinus inverted papilloma.

    Science.gov (United States)

    Kamel, Reda H; Abdel Fattah, Ahmed F; Awad, Ayman G

    2014-12-01

    Maxillary sinus inverted papilloma entails medial maxillectomy and is associated with high incidence of recurrence. To study the impact of prior surgery on recurrence rate after transnasal endoscopic medial maxillectomy. Eighteen patients with primary and 33 with recurrent maxillary sinus inverted papilloma underwent transnasal endoscopic medial maxillectomy. Caldwell-Luc operation was the primary surgery in 12 patients, transnasal endoscopic resection in 20, and midfacial degloving technique in one. The follow-up period ranged between 2 to 19.5 years with an average of 8.8 years. Recurrence was detected in 8/51 maxillary sinus inverted papilloma patients (15.7 %), 1/18 of primary cases (5.5 %), 7/33 of recurrent cases (21.2 %); 3/20 of the transnasal endoscopic resection group (15%) and 4/12 of the Caldwell-Luc group (33.3%). Redo transnasal endoscopic medial maxillectomy was followed by a single recurrence in the Caldwell-Luc group (25%), and no recurrence in the other groups. Recurrence is more common in recurrent maxillary sinus inverted papilloma than primary lesions. Recurrent maxillary sinus inverted papilloma after Caldwell-Luc operation has higher incidence of recurrence than after transnasal endoscopic resection.

  6. Simulation of push-pull inverter using wide bandgap devices

    Science.gov (United States)

    Al-badri, Mustafa; Matin, Mohammed A.

    2016-09-01

    This paper discusses the use of wide bandgap devices (SiC-MOSFET) in the design of a push-pull inverter which provides inexpensive low power dc-ac inverters. The parameters used were 1200V SiC MOSFET(C2M0040120D) made by power company ROHM. This modeling was created using parameters that were provided from a device datasheet. The spice model is provided by this company to study the effect of adding this component on push-pull inverter ordinary circuit and compared results between SiC MOSFET and silicon MOSFET (IRFP260M). The results focused on Vout and Vmos stability as well as on output power and MOSFET power loss because it is a very crucial aspect on DC-AC inverter design. These results are done using the National Instrument simulation program (Multisim 14). It was found that power loss is better in the 12 and 15 vdc inverter. The Vout in the SIC MOSFET circuit shows more stability in the high current low resistance load in comparison to the Silicon MOSFET circuit and this will improve the overall performance of the circuit.

  7. Analysis and Design of Solar Photo voltaic Grid Connected Inverter

    Directory of Open Access Journals (Sweden)

    Muddasani Satyanarayana

    2015-08-01

    Full Text Available This paper presents common mode voltage analysis of single phase grid connected photovoltaic inverter. Many researchers proposed different grid tie inverters for applications like domestic powering, street lighting, water pumping, cooling and heating applications, however traditional grid tie PV inverter uses either a line frequency or a high frequency transformer between the inverter and grid but losses will increase in the network leading to reduced efficiency of the system. In order to increase the efficiency, with reduced size and cost of the system, the effective solution is to remove the isolation transformer. But common mode (CM ground leakage current due to parasitic capacitance between the PV panels and the ground making the system unreliable. The common mode current reduces the efficiency of power conversion stage, affects the quality of grid current, deteriorate the electric magnetic compatibility and give rise to the safety threats. In order to eliminate the common mode leakage current in Transformerless PV systm two control algorithms of multi-carrier pwm are implemented and compared for performance analysis.The shoot-through issue that is encountered by traditional voltage source inverter is analyzed for enhanced system reliability. These control algorithms are compared for common mode voltage and THD comparisons. The proposed system is designed using MATLAB/SIMULINK software for analysis.

  8. Development and Evaluation of a 2KVA Inverter

    Directory of Open Access Journals (Sweden)

    Ajayi Adedayo

    2013-09-01

    Full Text Available A 2KV inverter was designed, developed and tested for household applications. It consists of a heavy duty (24 V, 80 AH, oscillator unit, PWM (Pulse-width modulation controller unit, driver unit, amplifier unit, center-tap step up transformer and battery charger unit. The battery powered the circuitry and the oscillator section generates the drive signal that is amplified and set up the transformer to produce 240 V supply at the secondary winding connected to the output socket of inverter. The feedback control circuit uses discrete components such as: full wave rectifier, pulse width modulator (IC, diodes and other components to sense the output voltage (or load current. When the feedback senses that the load on the inverter output has increased, the inverter control circuitry acts by increasing the width of the switching pulse in the oscillator section which turn on the MOSFETS. MOSFETS turns on for longer time each cycle, automatically correcting the R.M.S value of the output to compensate for any drop in peak-peak output voltage as well as continuous charging of battery, consequently, maintaining a steady output voltage level in inverter irrespective of the load characteristics. The outputs of the tests carried on the unit shows that that instrument performs satisfactory well.

  9. Active Snubber Circuit for High Power Inverter Leg

    DEFF Research Database (Denmark)

    Rasmussen, Tonny Wederberg; Johansen, Morten Holst

    2009-01-01

    Abstract— High power converters in the conventional 6 pulse configuration with 6 switching elements IGBTs (Insulated Gate Bipolar Transistor) are pushed to the limit of power. Especially the switching loss is high. This reduces the switching frequency due to cooling problems. Passive snubber circ...

  10. Rayleigh instability of the inverted one-cell amphibian embryo

    International Nuclear Information System (INIS)

    Nouri, Comron; Gordon, Richard; Luppes, Roel; Veldman, Arthur E P; Tuszynski, Jack A

    2008-01-01

    The one-cell amphibian embryo is modeled as a rigid spherical shell containing equal volumes of two immiscible fluids with different densities and viscosities and a surface tension between them. The fluids represent denser yolk in the bottom hemisphere and clearer cytoplasm and the germinal vesicle in the top hemisphere. The unstable equilibrium configuration of the inverted system (the heavier fluid on top) depends on the value of the contact angle. The theoretically calculated normal modes of perturbation and the instability of each mode are in agreement with the results from ComFlo computational fluid dynamic simulations of the same system. The two dominant types of modes of perturbation give rise to axisymmetric and asymmetric sloshing of the cytoplasm of the inverted embryos, respectively. This work quantifies our hypothesis that the axisymmetric mode corresponds to failure of development, and the asymmetric sloshing mode corresponds to development proceeding normally, but with reversed pigmentation, for inverted embryos

  11. Reliability Assessment of Transformerless PV Inverters Considering Mission Profiles

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2015-01-01

    reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature). The mission profile is translated to device thermal loading, which is used for lifetime prediction. Compar¬ison results reveal the lifetime mismatches among the power switching......Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved either by modifying the modulation schemes or adding extra power switching devices......, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redis-tributed, and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device...

  12. Transformerless photovoltaic inverters with leakage current and pulsating power elimination

    DEFF Research Database (Denmark)

    Tang, Yi; Yao, Wenli; Wang, H.

    2015-01-01

    This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV......-to-ground parasitic capacitance can be bypassed by introducing a common mode (CM) conducting path to the inverter. The resulting ground leakage current is therefore well controlled to be below the regulation limit. Moreover, the proposed inverter can also eliminate the well-known double line frequency pulsating power....... The mechanism of leakage current suppression and the closed-loop control of pulsating power decoupling are discussed in the paper in details. A 500 W prototype was also built and tested in the laboratory, and both simulation and experimental results are finally presented to show the excellent performance...

  13. A solution process for inverted tandem solar cells

    DEFF Research Database (Denmark)

    Larsen-Olsen, Thue Trofod; Bundgaard, Eva; Sylvester-Hvid, Kristian O.

    2011-01-01

    Tandem solar cells with normal and inverted device geometries were prepared by a solution process. Both device types were based on the use of zinc(II)oxide as the electron transporting layer (ETL). The hole transporting layer (HTL) was either PEDOT:PSS for normal geometry tandem solar cells...... or vanadium(V)oxide in the case of inverted tandem cells. It was found that the inverted tandem solar cells performed comparable or better than the normal geometry devices, showing that the connection structure of vanadium(V)oxide, Ag nanoparticles and zinc(II)oxide functions both as a good recombination...... layer, ensuring serial connection, and as a solvent barrier, protecting the first photoactive layer from processing of the second layer. This successfully demonstrates a tandem solar cell fabrication process fully compatible with state-of-the-art solution based automated production procedures....

  14. Inverted Steam Generators for Sodium Cooled Fast Reactors

    International Nuclear Information System (INIS)

    Matal, Oldřich; Šimo, Tomáš; Matal, Oldřich Jr.

    2013-01-01

    Conclusions: Two inverted steam generators of the Czech industry provenience have still been in successful operation with no water into sodium leaks at BOR 60 (RIAR Dimitrovgrad, Russian Federation). Micromodular inverted steam generator (MMISG) since 1981 and modular inverted steam generator (MISG) since 1991. In the framework of the CP ESFR project predesign studies of 100 MW (thermal) ISG modules were performed with the consideration of MMISG and MISG design, operational and safety benefits and experience. Development of material and technology for sodium heated steam generators components reflecting contemporary domestic industrial conditions in the Czech Republic was restarted in the years 2003 to 2004 and supported in the years 2008 to 2011 by the European CP ESFR project and by the Ministry of Industry and Trade of the Czech Republic

  15. Multilevel inverter with optimal THD through the firefly algorithm

    Directory of Open Access Journals (Sweden)

    El Mehdi Belkacem Riadh

    2017-03-01

    Full Text Available Reduction of the Total Harmonic Distortion (THD in multilevel inverters requires resolution of complex nonlinear transcendental equations; in this paper we propose a combination of one of the best existing optimized hardware structures with the recent firefly algorithm, which was used to optimize the THD, through finding the best switching angles and guaranteeing the minimization of harmonics within a user defined bandwidth. The obtained THD through the simulation of the thirteen-level symmetric inverter has been reduced down to 5% (FFT of 60 harmonics. In order to validate the simulation results, a thirteen-level symmetric inverter prototype has been made, and practically experimented and tested with different loads. Consequently, the measured THD with resistive load was 4.7% on a bandwidth of 3 kHz. The main advantage of the achieved work is the reduction of the THD.

  16. Behandling af invert papillom med endonasal endoskopisk sinuskirurgi

    DEFF Research Database (Denmark)

    Andersen, Pia Juul; Kjeldsen, Anette Drøhse; Pedersen, Arne Toft

    2002-01-01

    INTRODUCTION: Inverted papilloma is a benign sinonasal tumour and has a marked tendency to recur after surgical excision. The tumour may be associated with malignancy and during growth it may destroy surrounding tissue. The treatment is either lateral rhinotomy or endoscopic sinus surgery. The aim...... of the study was to describe the course of all patients treated with endoscopic sinus surgery at the ENT Department at Vejle County Hospital during the period 1 January to 31 December 1999. MATERIAL AND METHODS: Twenty-eight journals of patients diagnosed with inverted nasal papillomas were reviewed...... with carcinoma. We did not see any serious side effects to the treatment. DISCUSSION: Endoscopic sinus surgery in combination with Caldwell-Luc can be recommended as an alternative treatment to lateral rhinotomy in patients with inverted papillomas. Preoperative staging with CT or MR-scanning, experienced...

  17. Analysis of Voltage Forming Methods for Multiphase Inverters

    Directory of Open Access Journals (Sweden)

    Tadas Lipinskis

    2013-05-01

    Full Text Available The article discusses advantages of the multiphase AC induction motor over three or less phase motors. It presents possible stator winding configurations for a multiphase induction motor. Various fault control strategies were reviewed for phases feeding the motor. The authors propose a method for quality evaluation of voltage forming algorithm in the inverter. Simulation of a six-phase voltage source inverter, voltage in which is formed using a simple SPWM control algorithm, was performed in Matlab Simulink. Simulation results were evaluated using the proposed method. Inverter’s power stage was powered by 400 V DC source. The spectrum of output currents was analysed and the magnitude of the main frequency component was at least 12 times greater than the next biggest-magnitude component. The value of rectified inverter voltage was 373 V.Article in Lithuanian

  18. Improvements in EMC performance of inverter-fed motor drives

    International Nuclear Information System (INIS)

    Zhong, E.; Lipo, T.A.

    1995-01-01

    An experimental investigation of conducted radio-noise emission from a conventional pulse width modulated (PWM) inverter of medium power feeding an induction motor is described. It is determined that the inverter system generates considerable impulse currents through the power leads feeding the system resulting in serious conducted electromagnetic interference (EMI) problems and significant voltage waveform distortion in the power system. The dominant emission sources in the system are identified. A proposed model of the drive system for the purpose of evaluation of EMI are developed. Several low-cost strategies for improvement in EMC performance of the PWM inverter are then proposed. Experimental results demonstrate that disturbance from the modified system can be dramatically reduced and that the EMC performance of the system has come very close to meeting the IEC CISPR and FCC limits on conducted emissions for digital devices

  19. Hydrodynamic stability of inverted annular flow in an adiabatic simulation

    International Nuclear Information System (INIS)

    De Jarlais, G.; Ishii, M.; Linehan, J.

    1986-01-01

    Inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from large aspect ratio nozzles, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, breakup mode, and dispersed core droplet sizes were recorded at approximately 750 data points. Inverted annular flow destabilization led to inverted slug flow at low relative velocities, and to dispersed droplet flow, core breakup length correlations were developed by extending work on free liquid jets to include this coaxial, jet disintegration phenomenon. The results show length dependence upon D/sub J/, Re/sub J/, We/sub J/, α, and We/sub G/,rel. Correlations for core shape, breakup mechanisms, and dispersed core droplet size were also developed, by extending the results of free jet stability, roll wave entrainment, and churn turbulent droplet stability studies

  20. Factorization method and new potentials from the inverted oscillator

    International Nuclear Information System (INIS)

    Bermudez, David; Fernández C, David J.

    2013-01-01

    In this article we will apply the first- and second-order supersymmetric quantum mechanics to obtain new exactly-solvable real potentials departing from the inverted oscillator potential. This system has some special properties; in particular, only very specific second-order transformations produce non-singular real potentials. It will be shown that these transformations turn out to be the so-called complex ones. Moreover, we will study the factorization method applied to the inverted oscillator and the algebraic structure of the new Hamiltonians. -- Highlights: •We apply supersymmetric quantum mechanics to the inverted oscillator potential. •The complex second-order transformations allow us to build new non-singular potentials. •The algebraic structure of the initial and final potentials is analyzed. •The initial potential is described by a complex-deformed Heisenberg–Weyl algebra. •The final potentials are described by polynomial Heisenberg algebras

  1. Arduino Mega 2560 Microcontroller Built 3-Phase Seven Level Inverter

    Directory of Open Access Journals (Sweden)

    PAVANKUMAR Shriram Mehtre

    2017-10-01

    Full Text Available n this paper, the implementation of 3-phase seven level cascaded H-bridge inverter is discussed with Arduino microcontroller and harmonic analysis is performed using Fourier series. The multilevel inverters (MLI give several benefits as reduced switching voltage stresses and the capability to operate in higher level voltage applications. A new and simple architecture Arduino Mega 2560 microcontroller is employed to produce the control signals for the seven level cascaded H-bridge MLI switches. The computer simulation is carried out in PSIM environment and prototype experimental model is developed with TLP 250 driver ICs and power MOSFET switches to validate the simulation results. The THDs present in different voltage level inverters are mathematically analysed using Fourier series.

  2. Aalborg Inverter - A New Type of “Buck in Buck, Boost in Boost” Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Ji, Junhao; Blaabjerg, Frede

    2015-01-01

    This paper presents a new family of high efficiency dc/ac grid-tied inverter with a wide variation of input dc voltage. It is a “boost in boost, buck in buck” inverter, meaning that only one power stage works at high frequency in order to achieve minimum switching loss. The minimum voltage drop...... of the filtering inductor in the power loop is achieved to reduce the conduction power loss in both “boost” and “buck” mode. The principle of operation is demonstrated through the analysis on the equivalent circuits of a “half-bridge” single-phase inverter. The theoretical analysis shows that when input dc voltage...... is larger than the magnitude of the ac voltage, it is a voltage-source inverter, and on the contrary it is current-source inverter in the other mode. A 220 V/50 Hz/ 2000 W prototype has been constructed. Simulations and experiments show that it has a good control and system performance....

  3. An extended dual input dual output three level Z source inverter with improved switch loss reduction technique

    Directory of Open Access Journals (Sweden)

    N.B. Deshmukh

    2016-12-01

    Full Text Available Multilevel inverter (MLI is a proven technology used for industrial applications due to low output total harmonic distortion (THD, high power handling capability and low active device rating. Dual output inverter is a recent trend associated with inverter topologies for specialized applications. This paper deals with three phase three level dual input dual output inverter topology with minimum active device count. Reduction in switch count leads to reduction in losses and improves reliability. Both the input sources share power equally as neutral point current ripple is maintained low. For further reduction in switching losses at higher switching frequencies, the concept of “no switching zone” or discontinuous pulse width modulation (DPWM has been put forth recently. This paper proposes modification in the placement of “no switching zone” in order to optimize switching losses and output THD (output filtering requirements for low power factor load. This study also proposes novel graphical approach to analyze the loss reduction along with its effect on output THD. The sinusoidal PWM (SPWM is used which gives satisfactory switching loss reduction without complex calculations. Moreover, the proposed topology is generalized to provide dual output at higher voltage levels. It is seen that the components reduction phenomenon becomes more pronounced as number of levels goes on increasing. The proposed converter is simulated in MATLAB software environment and results are obtained.

  4. Enhancement of Performance and Mechanism Studies of All-Solution Processed Small-Molecule based Solar Cells with an Inverted Structure.

    Science.gov (United States)

    Long, Guankui; Wu, Bo; Yang, Xuan; Kan, Bin; Zhou, Ye-Cheng; Chen, Li-Chuan; Wan, Xiangjian; Zhang, Hao-Li; Sum, Tze Chien; Chen, Yongsheng

    2015-09-30

    Both solution-processed polymers and small molecule based solar cells have achieved PCEs over 9% with the conventional device structure. However, for the practical applications of photovoltaic technology, further enhancement of both device performance and stability are urgently required, particularly for the inverted structure devices, since this architecture will probably be most promising for the possible coming commercialization. In this work, we have fabricated both conventional and inverted structure devices using the same small molecular donor/acceptor materials and compared the performance of both device structures, and found that the inverted structure based device gave significantly improved performance, the highest PCE so far for inverted structure based device using small molecules as the donor. Furthermore, the inverted device shows a remarkable stability with almost no obvious degradation after three months. Systematic device physics and charge generation dynamics studies, including optical simulation, light-intensity-dependent current-voltage experiments, photocurrent density-effective voltage analyses, transient absorption measurements, and electrical simulations, indicate that the significantly enhanced performance using inverted device is ascribed to the increasing of Jsc compared to the conventional device, which in turn is mainly attributed to the increased absorption of photons in the active layers, rather than the reduced nongeminate recombination.

  5. Invertible chaotic fragile watermarking for robust image authentication

    International Nuclear Information System (INIS)

    Sidiropoulos, Panagiotis; Nikolaidis, Nikos; Pitas, Ioannis

    2009-01-01

    Fragile watermarking is a popular method for image authentication. In such schemes, a fragile signal that is sensitive to manipulations is embedded in the image, so that it becomes undetectable after any modification of the original work. Most algorithms focus either on the ability to retrieve the original work after watermark detection (invertibility) or on detecting which image parts have been altered (localization). Furthermore, the majority of fragile watermarking schemes suffer from robustness flaws. We propose a new technique that combines localization and invertibility. Moreover, watermark dependency on the original image and the non-linear watermark embedding procedure guarantees that no malicious attacks will manage to create information leaks.

  6. Extended topologies of tapped-inductor Z-source inverters

    DEFF Research Database (Denmark)

    Zhu, Miao; Li, Ding; Gao, Feng

    2011-01-01

    In this paper, two distinct types of tapped-inductor Z-source impedance networks are proposed for implementing high performance voltage-type inverters topologies with strong voltage boost inversion abilities and less components' stresses. All proposed topologies can in principle be unified...... into a generic network entity, which is termed hybrid-source tapped-inductor impedance network. The resulting novel Z-source inverters would have a higher output voltage gain and other unique advantages that currently have not yet been investigated. Theoretical analysis for explaining these operating features...

  7. Inverted opal luminescent Ce-doped silica glasses

    Directory of Open Access Journals (Sweden)

    R. Scotti

    2006-01-01

    Full Text Available Inverted opal Ce-doped silica glasses (Ce : Si molar ratio 1 ⋅ 10−3 were prepared by a sol-gel method using opals of latex microspheres as templates. The rare earth is homogeneously dispersed in silica host matrix, as evidenced by the absence of segregated CeO2, instead present in monolithic Ce-doped SG with the same cerium content. This suggests that the nanometric dimensions of bridges and junctions of the host matrix in the inverted opal structures favor the RE distribution avoiding the possible segregation of CeO2.

  8. Grid-connected inverter for wind power generation system

    Institute of Scientific and Technical Information of China (English)

    YANG Yong; RUAN Yi; SHEN Huan-qing; TANG Yan-yan; YANG Ying

    2009-01-01

    In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation (SVPWM) is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on PI-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response.

  9. Dead-Time Generation in Six-Phase Frequency Inverter

    Directory of Open Access Journals (Sweden)

    Aurelijus Pitrėnas

    2016-06-01

    Full Text Available In this paper control of multi-phase induction drives is discussed. Structure of six-phase frequency inverter is examined. The article deals with dead-time generation circuits in six-phase frequency inverter for transistor control signals. Computer models of dead-time circuits is created using LTspice software package. Simulation results are compared with experimental results of the tested dead-time circuits. Parameters obtained in simulation results are close to the parameters obtained in experimental results.

  10. Control of Single-Stage Single-Phase PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter....

  11. SiC MOSFETs based split output half bridge inverter

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig; Beczkowski, Szymon

    2014-01-01

    output. The double pulse test shows the devices' current during commutation process and the reduced switching losses of SiC MOSFETs compared to that of the traditional half bridge. The efficiency comparison is presented with experimental results of half bridge power inverter with split output...... and traditional half bridge inverter, from switching frequency 10 kHz to 100 kHz. The experimental results comparison shows that the half bridge with split output has an efficiency improvement of more than 0.5% at 100 kHz switching frequency....

  12. Electronic inverter assembly with an integral snubber capacitor

    Science.gov (United States)

    Singh, Brij N.; Schmit, Christopher J.

    2017-08-01

    A coaxial bus connector has a first end and a second end opposite the first end. The first end has a first positive terminal and a first negative terminal coupled to a primary direct current bus of a primary inverter. The second end has a second positive terminal and a second negative terminal coupled to the secondary direct current bus of a secondary inverter, wherein the coaxial bus connector comprises a dielectric material between a center conductor and a coaxial sleeve to form a snubber capacitor to absorb electrical energy or to absorb voltage spikes.

  13. Addressable Inverter Matrix Tests Integrated-Circuit Wafer

    Science.gov (United States)

    Buehler, Martin G.

    1988-01-01

    Addressing elements indirectly through shift register reduces number of test probes. With aid of new technique, complex test structure on silicon wafer tested with relatively small number of test probes. Conserves silicon area by reduction of area devoted to pads. Allows thorough evaluation of test structure characteristics and of manufacturing process parameters. Test structure consists of shift register and matrix of inverter/transmission-gate cells connected to two-by-ten array of probe pads. Entire pattern contained in square area having only 1.6-millimeter sides. Shift register is conventional static CMOS device using inverters and transmission gates in master/slave D flip-flop configuration.

  14. Inverter power module with distributed support for direct substrate cooling

    Science.gov (United States)

    Miller, David Harold [San Pedro, CA; Korich, Mark D [Chino Hills, CA; Ward, Terence G [Redondo Beach, CA; Mann, Brooks S [Redondo Beach, CA

    2012-08-21

    Systems and/or methods are provided for an inverter power module with distributed support for direct substrate cooling. An inverter module comprises a power electronic substrate. A first support frame is adapted to house the power electronic substrate and has a first region adapted to allow direct cooling of the power electronic substrate. A gasket is interposed between the power electronic substrate and the first support frame. The gasket is configured to provide a seal between the first region and the power electronic substrate. A second support frame is adapted to house the power electronic substrate and joined to the first support frame to form the seal.

  15. Magneto-optical tweezers built around an inverted microscope

    International Nuclear Information System (INIS)

    Claudet, Cyril; Bednar, Jan

    2005-01-01

    We present a simple experimental setup of magneto-optical tweezers built around an inverted microscope. Two pairs of coils placed around the focal point of the objective generate a planar-rotating magnetic field that is perpendicular to the stretching direction. This configuration allows us to control the rotary movement of a paramagnetic bead trapped in the optical tweezers. The mechanical design is universal and can be simply adapted to any inverted microscope and objective. The mechanical configuration permits the use of a rather large experimental cell and the simple assembly and disassembly of the magnetic attachment

  16. Performance analysis of samarium cobalt P.M. synchronous motor fed from PWM inverters

    International Nuclear Information System (INIS)

    Rahman, M.A.; Choudhury, M.A.

    1985-01-01

    This paper presents an analysis and performance of samarium cobalt permanent magnet (P.M.) synchronous motors fed from two types of voltage source pulse width modulated (PWM) inverters. The analysis and test results on the steady state performance of a P.M. motor fed from PWM inverters are presented. PWM inverters are used in variable voltage variable frequency applications to avoid a double conversion process of ordinary inverters. In drives, they are used for voltage and speed regulation of motors. Use of modulation technique in inverters also allow to eliminate or minimize selected harmonics from the inverter output voltage

  17. Transparency in a Pediatric Quality Improvement Collaborative: A Passionate Journey by NPC-QIC Clinicians and Parents.

    Science.gov (United States)

    Lihn, Stacey L; Kugler, John D; Peterson, Laura E; Lannon, Carole M; Pickles, Diane; Beekman, Robert H

    2015-01-01

    Transparency-sharing data or information about outcomes, processes, protocols, and practices-may be the most powerful driver of health care improvement. In this special article, the development and growth of transparency within the National Pediatric Cardiology Quality Improvement Collaborative is described. The National Pediatric Cardiology Quality Improvement Collaborative transparency journey is guided by equal numbers of clinicians and parents of children with congenital heart disease working together in a Transparency Work Group. Activities are organized around four interrelated levels of transparency (individual, organizational, collaborative, and system), each with a specified purpose and aim. A number of Transparency Work Group recommendations have been operationalized. Aggregate collaborative performance is now reported on the public-facing web site. Specific information that the Transparency Work Group recommends centers provide to parents has been developed and published. Almost half of National Pediatric Cardiology Quality Improvement Collaborative centers participated in a pilot of transparently sharing their outcomes achieved with one another. Individual centers have also begun successfully implementing recommended transparency activities. Despite progress, barriers to full transparency persist, including health care organization concerns about potential negative effects of disclosure on reputation and finances, and lack of reliable definitions, data, and reporting standards for fair comparisons of centers. The National Pediatric Cardiology Quality Improvement Collaborative's transparency efforts have been a journey that continues, not a single goal or destination. Balanced participation of clinicians and parents has been a critical element of the collaborative's success on this issue. Plans are in place to guide implementation of additional transparency recommendations across all four levels, including extension of the activities beyond the

  18. Mitigation of Grid Current Distortion for LCL-Filtered Voltage Source Inverter with Inverter Current Feedback Control

    DEFF Research Database (Denmark)

    Xin, Zhen; Mattavelli, Paolo; Yao, WenLi

    2018-01-01

    LCL filters feature low inductance; thus, the injected grid current from an LCL-filtered Voltage Source Inverter (VSI) can be easily distorted by grid voltage harmonics. This problem is especially tough for the control system with Inverter-side Current Feedback (ICF), since the grid current...... harmonics can freely flow into the filter capacitor. In this case, because of the loss of harmonic information, traditional harmonic controllers fail to mitigate the grid current distortion. Although this problem may be avoided using the grid voltage feedforward scheme, the required differentiators may...

  19. Supervision and control of grid connected PV-Storage systems with the five level diode clamped inverter

    International Nuclear Information System (INIS)

    Himour, Kamal; Ghedamsi, Kaci; Berkouk, El Madjid

    2014-01-01

    Highlights: • Use of battery bank in grid connection photovoltaic system to ensure the energetic autonomy of the system. • Improve the quality of energy by the use of five-level inverter in a grid connection PV generation system. • Control of inverter by fast and simplified space vector pulse width modulation. • Control and supervision of active and reactive power in the grid. - Abstract: This paper aimed to evaluate the use of photovoltaic-battery storage systems to supply electric power in the distribution grid through a multilevel inverter. The proposed system is composed by four PV generators with MPPT (P and O) control, four battery storage systems connected to each capacitor of the DC link and a five level diode clamped inverter connected to the grid by a traditional three phase transformer. The proposed control has a hierarchical structure with both a grid side control level to regulate the power and the current injected to the grid and four input side regulation units. The system operator controls the power production of the four PV generators by sending out reference power signals to each input side regulation unit, the input side regulation units regulate the voltage of each capacitor of the DC link, regulate the voltage and the state of charge of each battery storage system

  20. Power control based on particle swarm optimization of grid-connected inverter for hybrid renewable energy system

    International Nuclear Information System (INIS)

    García-Triviño, Pablo; Gil-Mena, Antonio José; Llorens-Iborra, Francisco; García-Vázquez, Carlos Andrés; Fernández-Ramírez, Luis M.; Jurado, Francisco

    2015-01-01

    Highlights: • Three PSO-based PI controllers for a grid-connected inverter were presented. • Two online PSO-based PI controllers were compared with an offline PSO-tuned PI. • The HRES and the inverter were evaluated under power changes and grid voltage sags. • Online ITAE-based PSO reduced ITAE (current THD) by 15.24% (5.32%) versus offline one. - Abstract: This paper is focused on the study of particle swarm optimization (PSO)-based PI controllers for the power control of a grid-connected inverter supplied from a hybrid renewable energy system. It is composed of two renewable energy sources (wind turbine and photovoltaic – PV – solar panels) and two energy storage systems (battery and hydrogen system, integrated by fuel cell and electrolyzer). Three PSO-based PI controllers are implemented: (1) conventional PI controller with offline tuning by PSO algorithm based on the integral time absolute error (ITAE) index; (2) PI controllers with online self-tuning by PSO algorithm based on the error; and (3) PI controllers with online self-tuning by PSO algorithm based on the ITAE index. To evaluate and compare the three controllers, the hybrid renewable energy system and the grid-connected inverter are simulated under changes in the active and reactive power values, as well as under a grid voltage sag. The results show that the online PSO-based PI controllers that optimize the ITAE index achieves the best response

  1. Current-type flipped-Γ-source inverters

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Li, Ding; Blaabjerg, Frede

    2012-01-01

    are of interest since they use lesser components. Their winding turns might however become too excessive for higher demanded gains. Avoiding this usual trend, a new family of current-type flipped-Γ-source inverters are proposed, whose common gain is raised by lowering, and not increasing, the winding turns...

  2. Efficient cascade multiple heterojunction organic solar cells with inverted structure

    Science.gov (United States)

    Guo, Tingting; Li, Mingtao; Qiao, Zhenfang; Yu, Leiming; Zhao, Jianhong; Feng, Nianjun; Shi, Peiguang; Wang, Xiaoyan; Pu, Xiaoyun; Wang, Hai

    2018-05-01

    In this work, we demonstrate an efficient cascade multiple heterojunction organic solar cell with inverted structure. By using two donor materials, poly(3-hexylthiosphene) (P3HT) and titanyl phthalocyanine (TiOPc), as well as two acceptor materials, [6,6]-phenyl C61 butyric acid methyl ester (PCBM) and C60, the cascade multiple heterojunctions of P3HT:PCBM/TiOPc:C60/C60 have been constructed. Applying the optimized inverted configuration of FTO/Zinc Tin Oxide (ZTO)/C60 (30 nm)/TiOPc:C60 (1:1.5, 25 nm)/P3HT:PCBM (1:0.8, 100 nm)/MoO3 (4 nm)/Ag, the considerably enhanced open circuit voltage (VOC) and short circuit current (JSC) can be harvested together, and the power conversion efficiency (PCE) is three times higher than that of the control cell with conventional structure. The significant improvements of the inverted cell are mostly due to the broadened spectral absorption and high efficient multi-interface exciton dissociation in the cascade multiple heterojunctions, indicating that the optimized cascade heterojunctions match the inverted structure well.

  3. Smart Inverter Control and Operation for Distributed Energy Resources

    Science.gov (United States)

    Tazay, Ahmad F.

    The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart inverter will be investigated in this work based on the connection modes: microgrid at grid-tied mode and autonomous mode. In grid-tied connection, the smart inverter and VSC are used to integrate DER such as Photovoltaic (PV) and battery to provide suitable power to the system by controlling the supplied real and reactive power. The role of a smart inverter at autonomous mode includes supplying a sufficient voltage and frequency, mitigate abnormal condition of the load as well as equally sharing the total load's power. However, the operational control of the microgrid still has a major issue on the operation of the microgrid. The dissertation is divided into two main sections which are: 1. Low-level control of a single smart Inverter. 2. High-level control of the microgrid. The first part investigates a comprehensive research for a smart inverter and VSC technology at the two major connections of the microgrid. This involves controlling and modeling single smart inverter and VSC to solve specific issues of microgrid as well as improve the operation of the system. The research provides developed features for smart inverter comparing with a conventional voltage sourced converter (VSC). The two main connections for a microgrid have been deeply investigated to analyze a better way to develop and improve the operational procedure of

  4. A review of module inverter topologies suitable for photovoltaic system

    DEFF Research Database (Denmark)

    Variath, Reshmi C; Andersen, Michael A. E.; Nielsen, Ole Neis

    2010-01-01

    This paper evaluates eight module inverter topologies and provides an overview of the merits and demerits of each on the basis of circuit level Pspice simulation. The complete system is modeled in Pspice and the model is made as realistic as possible by including the parasitic elements. Only...

  5. Localized chaoticity in two linearly coupled inverted double-well ...

    African Journals Online (AJOL)

    Two linearly coupled inverted double-well oscillators for a fixed energy and varying coupling strength were studied. The dynamics yielded a chaotic system in which the Poincare surface was characterised by two non-mixing regions, one of regular motion and the other region that became chaotic as the coupling increased.

  6. Feed-Forward Control in Resonant DC Link Inverter

    OpenAIRE

    Apinan Aurasopon; Worawat Sa-ngiavibool

    2008-01-01

    This paper proposes a feed-forward control in resonant dc link inverter. The feed-forward control configuration is based on synchronous sigma-delta modulation. The simulation results showing the proposed technique can reject non-ideal dc bus improving the total harmonic distortion.

  7. Sine-wave three phase resonance inverter for operation of ...

    African Journals Online (AJOL)

    This paper proposes a high performance single-stage three phase inverter topology for the autonomous operation of renewable energy systems. The proposed configuration can boost the low voltage of renewable energy systems such as photo voltaic systems, fuel cells, and etc can also convert the output dc power, into ...

  8. inverted papilloma of the nasal cavity and paranasal sinuses

    African Journals Online (AJOL)

    1971-05-08

    May 8, 1971 ... Although the inverted papilloma of the nasal cavity has been studied for over 100 years, the clinical approach to this lesion remains ill-defined and wide recognition of the problems involved is still not evident. This may be attributed to the infrequency of the condition, the ease with which it may be mistaken ...

  9. Resonance analysis in parallel voltage-controlled Distributed Generation inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2013-01-01

    Thanks to the fast responses of the inner voltage and current control loops, the dynamic behaviors of parallel voltage-controlled Distributed Generation (DG) inverters not only relies on the stability of load sharing among them, but subjects to the interactions between the voltage control loops...

  10. Hybrid Modulation Scheme for Cascaded H-Bridge Inverter Cells ...

    African Journals Online (AJOL)

    This work proposes a switching technique for cascaded H-Bridge (CHB) cells. Single carrier Sinusoidal PWM (SCSPWM) scheme is employed in the generation of the gating signals. A sequential switching and base PWM circulation schemes are presented for this fundamental cascaded multilevel inverter topology.

  11. Charging capacitors of multilevel inverter from dc intermediate circuit

    Czech Academy of Sciences Publication Activity Database

    Bejvl, Martin

    2011-01-01

    Roč. 56, č. 2 (2011), s. 159-170 ISSN 0001-7043 R&D Projects: GA MPO FT-TA4/077 Institutional research plan: CEZ:AV0Z20570509 Keywords : electric drive * multilevel inverter * modulation and demodulation Subject RIV: JA - Electronics ; Optoelectronics, Electric al Engineering

  12. Barium titanate inverted opals-synthesis, characterization, and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Soten, I.; Miguez, H.; Yang, S.M.; Petrov, S.; Coombs, N.; Tetreault, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Dept. of Chemistry; Matsuura, N.; Ruda, H.E. [Toronto Univ., ON (Canada). Dept. of Metallurgy and Materials Science

    2002-01-01

    The engineering of cubic or tetragonal polymorphs of nanocrystalline barium titanate inverted opals has been achieved by thermally induced transformations. Optical characterization demonstrated photonic crystal behavior of the opals. The tuning of the ferroelectric-paraelectric transition around the Curie temperature is shown in this paper. (orig.)

  13. Resonant inverter supplied Interior Permanent Magnet (IPM) motor ...

    African Journals Online (AJOL)

    In this paper, rotor position in relation to the resonant frequency component current in the stator winding of DC-voltage link resonant inverter supplied Interior Permanent Magnet (IPM) motor has been developed. Six reference frames are used to relate the rotor position angle to the resonant frequency component current ...

  14. 6 5KVA POWER INVERTER DESIGN AND SIMULATION BASED ...

    African Journals Online (AJOL)

    DR. AMINU

    increasing and conventional energy resources are diminishing and even threatened to be depleted. With the increasing popularity of alternative power sources, such as solar and wind, the need for static inverters to convert dc energy stored in batteries to conventional ac form has increased substantially. This conversion.

  15. Impedance estimation of photovoltaic modules for inverter start-up ...

    Indian Academy of Sciences (India)

    Pallavi Bharadwaj

    The analysis of this paper can be used to estimate the expected peak inrush current in PV inverters. ..... scenario a mechanical switch makes and breaks the contact, .... Therefore even though the ratio of the peak to the steady current is lower ...

  16. Power inverter design for ASDEX Upgrade saddle coils

    Energy Technology Data Exchange (ETDEWEB)

    Teschke, M., E-mail: teschke@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Suttrop, W.; Rott, M. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-10-15

    Highlights: ► A cost effective inverter topology for AUG's 16 in-vessel saddle coils has been found. ► Use of commercially available power modules is possible. ► Exchange of reactive power between multiple inverters is possible. ► Influence of electromagnetic noise to AUG's diagnostics was measured. ► Gas insulation of electric feed through significantly depends on magnetic fields. It is protected by fast turn-off circuit. -- Abstract: A set of 16 in-vessel saddle coils has been installed in the ASDEX Upgrade (AUG) experiment since the end of 2011 [1]. To achieve full performance, it is necessary to operate them with alternating current (AC) of arbitrary waveforms. To generate spatially resolved magnetic fields, it is required to allocate separate power inverters to every single coil. Therefore, different topologies are analyzed and compared. Studies of the commutation behavior of power stages, different pulse width modulation (PWM) schemes and single-phase-to-earth fault detection are executed. Experiments to evaluate the electromagnetic interference (EMI) of possible inverter topologies on the AUG diagnostics are done as well. A special focus is put on the feasibility of analyzed topologies using industrially available and fully assembled “power modules” to minimize development effort and costs.

  17. Regenerative Snubber For GTO-Commutated SCR Inverter

    Science.gov (United States)

    Rippel, Wally E.; Edwards, Dean B.

    1992-01-01

    Proposed regenerative snubbing circuit substituted for dissipative snubbing circuit in inverter based on silicon controlled rectifiers (SCR's) commutated by gate-turn-off thyristor (GTO). Intended to reduce loss of power that occurs in dissipative snubber. Principal criteria in design: low cost, simplicity, and reliability.

  18. Adaptive decoupled power control method for inverter connected DG

    DEFF Research Database (Denmark)

    Sun, Xiaofeng; Tian, Yanjun; Chen, Zhe

    2014-01-01

    an adaptive droop control method based on online evaluation of power decouple matrix for inverter connected distributed generations in distribution system. Traditional decoupled power control is simply based on line impedance parameter, but the load characteristics also cause the power coupling, and alter...

  19. Grid-Connected Inverter for Distributed Generation in Microgrid

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Miveh, Mohammad Reza; Guerrero, Josep M.

    for power generation. DGS units can operate in parallel to the main grid or in a Microgrid (MG) mode. An MG is a discrete energy system consisting of DGSs and loads capable of operating in parallel with, or independently from, the main grid. Meanwhile, Grid-Connected Inverters (GCIs) are typically used...

  20. Multilevel inverter based class D audio amplifier for capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    The reduced semiconductor voltage stress makes the multilevel inverters especially interesting, when driving capacitive transducers for audio applications. A ± 300 V flying capacitor class D audio amplifier driving a 100 nF load in the midrange region of 0.1-3.5 kHz with Total Harmonic Distortion...

  1. Electron-nuclear magnetic resonance in the inverted state

    International Nuclear Information System (INIS)

    Ignatchenko, V.A.; Tsifrinovich, V.I.

    1975-01-01

    The paper considers the susceptibility of the electron-nucleus system of a ferromagnet when nuclear magnetization is inverted with respect to the hyperfine field direction. The inverted state is a situation in which nuclear magnetization is turned through π relative to its equilibrium orientation, whereas electron magnetization is in an equilibrium state with respect to an external magnetic field. The consideration is carried out for a thin plate magnetized in its plane. Amplification of a weak radiofrequency signal can be attained under the fulfilment of an additional inequality relating the interaction frequency with electron and nuclear relaxation parameters. The gain may exceed the gain for an inverted nuclear system in magnetically disordered substances. In the range of strong interaction between the frequencies of ferromagnetic (FMR) and nuclear magnetic (NMR) resonances the electron-nuclear magnetic resonance (ENMR) spectrum possesses a fine structure which is inverse to that obtained for the ENMR spectrum in a normal state. The inverted state ENMR line shape is analysed in detail for the case of so weak HF fields that the relaxation conditions may be regarded as stationary. The initial (linear) stages of a forced transient process arising in an electron-nuclear system under the effect of a strong HF field are briefly analysed

  2. Power losses in bilayer inverted small molecule organic solar cells

    KAUST Repository

    Trinh, Cong; Bakke, Jonathan R.; Brennan, Thomas P.; Bent, Stacey F.; Navarro, Francisco; Bartynski, Andrew; Thompson, Mark E.

    2012-01-01

    Inverted bilayer organic solar cells using copper phthalocyanine (CuPc) as a donor and C60 as an acceptor with the structure: glass/indium tin oxide (ITO)/ZnO/C60/CuPc/MoO3/Al, in which the zinc oxide (ZnO) was deposited by atomic layer deposition

  3. A New Green Power Inverter for Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Gert Karmisholt; Klumpner, Christian; Kjær, Søren Bækhøj

    2002-01-01

    This paper presents a new grid connected inverter for fuel cells. It consists of a two stage power conversion topology. Since the fuel cell operates with a low voltage in a wide voltage range (25 V-45 V) this volt- age must be transformed to around 350-400 V in order to invert this dc power into ac...... power to the grid. The proposed converter consists of an isolated dc-dc converter cascaded with a single phase H-bridge inverter. The dc-dc converter is a current-fed push-pull converter. A new dedicated voltage mode startup procedure has been developed in order to limit the inrush current during...... startup. The inverter is controlled as a power factor controller with resistor emulation.Experimental results of converter efficiency, grid performance and fuel cell response are shown for a 1 kW prototype. The proposed converter exhibits a high efficiency in a wide power range (higher than 92...

  4. Optimization of Nanowire-Resistance Load Logic Inverter.

    Science.gov (United States)

    Hashim, Yasir; Sidek, Othman

    2015-09-01

    This study is the first to demonstrate characteristics optimization of nanowire resistance load inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on resistance value. Increasing of load resistor tends to increasing in noise margins until saturation point, increasing load resistor after this point will not improve noise margins significantly.

  5. Dual voltage source inverter topology extending machine operating range

    NARCIS (Netherlands)

    Gerrits, T.; Wijnands, C.G.E.; Paulides, J.J.H.; Duarte, J.L.

    2012-01-01

    Field weakening operation of an electrical machine is a conventional method to extend the angular velocity range of a system above the peak output voltage of the inverter. A downside, however, is that an increased reactive current is required that creates losses but no output torque. A dual voltage

  6. Controlling An Inverter-Driven Three-Phase Motor

    Science.gov (United States)

    Dolland, C.

    1984-01-01

    Control system for three-phase permanent-magnet motor driven by linecommutated inverter uses signals generated by integrating back emf of each phase of motor. High-pass filter network eliminates low-frequency components from control loop while maintaining desired power factor.

  7. Monolithically Integrated Flexible Black Phosphorus Complementary Inverter Circuits.

    Science.gov (United States)

    Liu, Yuanda; Ang, Kah-Wee

    2017-07-25

    Two-dimensional (2D) inverters are a fundamental building block for flexible logic circuits which have previously been realized by heterogeneously wiring transistors with two discrete channel materials. Here, we demonstrate a monolithically integrated complementary inverter made using a homogeneous black phosphorus (BP) nanosheet on flexible substrates. The digital logic inverter circuit is demonstrated via effective threshold voltage tuning within a single BP material, which offers both electron and hole dominated conducting channels with nearly symmetric pinch-off and current saturation. Controllable electron concentration is achieved by accurately modulating the aluminum (Al) donor doping, which realizes BP n-FET with a room-temperature on/off ratio >10 3 . Simultaneously, work function engineering is employed to obtain a low Schottky barrier contact electrode that facilities hole injection, thus enhancing the current density of the BP p-FET by 9.4 times. The flexible inverter circuit shows a clear digital logic voltage inversion operation along with a larger-than-unity direct current voltage gain, while exhibits alternating current dynamic signal switching at a record high frequency up to 100 kHz and remarkable electrical stability upon mechanical bending with a radii as small as 4 mm. Our study demonstrates a practical monolithic integration strategy for achieving functional logic circuits on one material platform, paving the way for future high-density flexible electronic applications.

  8. Review of PV Inverter Technology Cost and Performance Projections

    Energy Technology Data Exchange (ETDEWEB)

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  9. Study of a centrifugal pump, asynchronous motor and inverter, using ...

    African Journals Online (AJOL)

    The signals generated by the micro controller have been used to program the parallel port of a computer. By reading the recorded bits of the parallel port in LabVIEW software, the signals from the micro controller have been restored and made available to the simulation model of the three-phase inverter, asynchronous ...

  10. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    operation the PV inverter operates in voltage-controlled mode to maintain a constant amplitude and frequency of the voltage ..... 10W i.e. less than 8% of the maximum power, a step size of k2 is ...... ply/demand side management system.

  11. Quenching mechanism of exciplex fluorescence by inverted micelles

    International Nuclear Information System (INIS)

    Sato, Chika; Kikuchi, Koichi

    1992-01-01

    Using an emission-absorption laser photolysis method, the quenching mechanism of the pyrene-N,N-dimethylaniline exciplex fluorscence by inverted micelles is studied. The rate of enhanced intersystem crossing depends upon water pool size and is reduced by external magnetic fields. 15 refs., 3 figs., 2 tabs

  12. Modified impedance source inverter for power conditioning system

    Indian Academy of Sciences (India)

    DC link voltage boost, reduced total harmonic distortion of output current and voltage, better voltage gain and wide range of output voltage controlcan be achieved easily with improved power quality. Experimental set-up of the modified impedance source inverter with Field Programmable Gate Array (FPGA) controller has ...

  13. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ...

  14. Power losses in bilayer inverted small molecule organic solar cells

    KAUST Repository

    Trinh, Cong

    2012-01-01

    Inverted bilayer organic solar cells using copper phthalocyanine (CuPc) as a donor and C60 as an acceptor with the structure: glass/indium tin oxide (ITO)/ZnO/C60/CuPc/MoO3/Al, in which the zinc oxide (ZnO) was deposited by atomic layer deposition, are compared with a conventional device: glass/ITO/CuPc/C60/bathocuproine/Al. These inverted and conventional devices give short circuit currents of 3.7 and 4.8 mA/cm 2, respectively. However, the inverted device gives a reduced photoresponse from the CuPc donor compared to that of the conventional device. Optical field models show that the arrangement of organic layers in the inverted devices leads to lower absorption of long wavelengths by the CuPc donor; the low energy portion of the spectrum is concentrated near the metal oxide electrode in both devices. © 2012 American Institute of Physics.

  15. Analysis of Extended Z-source Inverter for Photovoltaic System

    Science.gov (United States)

    Prakash, G.; Subramani, C.; Dhineshkumar, K.; Rayavel, P.

    2018-04-01

    The Z-source inverter has picked up prominence as a solitary stage buck-support inverter topology among numerous specialists. Notwithstanding, its boosting capacity could be constrained, and in this manner, it may not be reasonable for a few applications requiring high lift request of falling other dc-dc help converters. The Z-source inverter is a recent converter topology that exhibits both voltage-buck and voltage-boost capability This could lose the effectiveness and request all the more detecting for controlling the additional new stages. This paper is proposing another group of broadened help semi Z - source inverter (ZSI) to fill the exploration hole left in the improvement of ZSI. These new topologies can be worked with same regulation strategies that were produced for unique ZSI. Likewise, they have a similar number of dynamic switches as unique ZSI saving the single-organize nature of ZSI. Proposed topologies are dissected in the enduring state and their exhibitions are approved utilizing recreated comes about acquired in MATLAB/Simulink. Besides, they are tentatively approved with comes about acquired from a model created in the research facility. The trend of fast increase of the PV energy use is related to the increasing efficiency of solar cells as well as the improvements of manufacturing technology of solar panels.

  16. EGCG Inhibits Proliferation, Invasiveness and Tumor Growth by Up-Regulation of Adhesion Molecules, Suppression of Gelatinases Activity, and Induction of Apoptosis in Nasopharyngeal Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Chih-Yeu Fang

    2015-01-01

    Full Text Available (−-Epigallocatechin-3-gallate (EGCG, a major green tea polyphenol, has been shown to inhibit the proliferation of a variety of tumor cells. Epidemiological studies have shown that drinking green tea can reduce the incidence of nasopharyngeal carcinoma (NPC, yet the underlying mechanism is not well understood. In this study, the inhibitory effect of EGCG was tested on a set of Epstein Barr virus-negative and -positive NPC cell lines. Treatment with EGCG inhibited the proliferation of NPC cells but did not affect the growth of a non-malignant nasopharyngeal cell line, NP460hTert. Moreover, EGCG treated cells had reduced migration and invasive properties. The expression of the cell adhesion molecules E-cadherin and β-catenin was found to be up-regulated by EGCG treatment, while the down-regulation of matrix metalloproteinases (MMP-2 and MMP-9 were found to be mediated by suppression of extracellular signal-regulated kinase (ERK phosphorylation and AP-1 and Sp1 transactivation. Spheroid formation by NPC cells in suspension was significantly inhibited by EGCG. Oral administration of EGCG was capable of suppressing tumor growth in xenografted mice bearing NPC tumors. Treatment with EGCG was found to elevate the expression of p53 and p21, and eventually led to apoptosis of NPC cells via caspase 3 activation. The nuclear translocation of NF-κB and β-catenin was also suppressed by EGCG treatment. These results indicate that EGCG can inhibit the proliferation and invasiveness, and induce apoptosis, of NPC cells, making it a promising agent for chemoprevention or adjuvant therapy of NPC.

  17. Grid Voltage Modulated Control of Grid-Connected Voltage Source Inverters under Unbalanced Grid Conditions

    DEFF Research Database (Denmark)

    Li, Mingshen; Gui, Yonghao; Quintero, Juan Carlos Vasquez

    2017-01-01

    In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected voltage inverters when the grid voltage is unbalanced. The objective of the proposed control is to remove the power ripple and to improve current quality. Three power compensation...... objectives are selected to eliminate the negative sequence components of currents. The modified GVM method is designed to obtain two separate second-order systems for not only the fast convergence rate of the instantaneous active and reactive powers but also the robust performance. In addition, this method...

  18. Wind turbine inverter robust loop-shaping control subject to grid interaction effects

    DEFF Research Database (Denmark)

    Gryning, Mikkel Peter Sidoroff; Wu, Qiuwei; Blanke, Mogens

    2015-01-01

    the grid and the number of wind turbines connected. Power converter based turbines inject harmonic currents, which are attenuated by passive filters. A robust high order active filter controller is proposed to complement the passive filtering. The H∞ design of the control loop enables desired tracking......An H∞ robust control of wind turbine inverters employing an LCL filter is proposed in this paper. The controller dynamics are designed for selective harmonic filtering in an offshore transmission network subject to parameter perturbations. Parameter uncertainty in the network originates from...

  19. Control Method of Single-phase Inverter Based Grounding System in Distribution Networks

    DEFF Research Database (Denmark)

    Wang, Wen; Yan, L.; Zeng, X.

    2016-01-01

    of neutral-to-ground voltage is critical for the safety of distribution networks. An active grounding system based on single-phase inverter is proposed to achieve this objective. Relationship between output current of the system and neutral-to-ground voltage is derived to explain the principle of neutral......The asymmetry of the inherent distributed capacitances causes the rise of neutral-to-ground voltage in ungrounded system or high resistance grounded system. Overvoltage may occur in resonant grounded system if Petersen coil is resonant with the distributed capacitances. Thus, the restraint...

  20. Mathematical model of thyristor inverter including a series-parallel resonant circuit

    OpenAIRE

    Luft, M.; Szychta, E.

    2008-01-01

    The article presents a mathematical model of thyristor inverter including a series-parallel resonant circuit with the aid of state variable method. Maple procedures are used to compute current and voltage waveforms in the inverter.