WorldWideScience

Sample records for source inverters csi

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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

  6. 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...

  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. Generalized space vector control for current source inverters and rectifiers

    Directory of Open Access Journals (Sweden)

    Roseline J. Anitha

    2016-06-01

    Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

  9. 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...

  10. 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...

  11. Operation and Modulation of H7 Current Source Inverter with Hybrid SiC and Si Semiconductor Switches

    DEFF Research Database (Denmark)

    Wang, Weiqi; Gao, Feng; Yang, Yongheng

    2018-01-01

    This paper proposes an H7 current source inverter (CSI) consisting of a single parallel-connected silicon carbide (SiC) switch and a traditional silicon (Si) H6 CSI. The proposed H7 CSI takes the advantages of the SiC switch to maintain high efficiency, while significantly increasing the switching...... as an all-SiC-switch converter in terms of high performance and high efficiency with reduced DC inductance. It provides a cost-effective solution to addressing the efficiency issue of conventional CSI systems. Simulations and experiments are performed to validate the effectiveness of the proposed H7 CSI...

  12. Inverted magnetron ion source

    International Nuclear Information System (INIS)

    Singh, B.; Boyarsky, D.

    1985-01-01

    The present invention provides, in a preferred embodiment, a cylindrical stainless steel cathode with end pieces thereon to form a cathode chamber within. In addition, in a preferred embodiment, there is a stainless steel rod which passes axially through the cathode chamber and which is electrically insulated therefrom at the end pieces. The stainless steel cathode has first and second apertures formed therein with the first to be connected to a source of ionizable gas and the second to act as the opening through which there passes a stream of ions to an ion beam target. A magnetic flux source is coupled to the cathode chamber to pass magnetic flux therethrough and a voltage source is connected between the anode and the cathode to provide an electrostatic field therebetween whereby when ionizable gas is fed into the cathode chamber, it is ionized and a stream of ions emanates from the second aperture. In a preferred embodiment there is further provided an electrostatic ion focusing means to focus the ion stream emanating from the second aperture

  13. 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....

  14. 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...

  15. 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....

  16. Performance analyses of Z-source and quasi Z-source inverter for photovoltaic applications

    Science.gov (United States)

    Himabind, S.; Priya, T. Hari; Manjeera, Ch.

    2018-04-01

    This paper presents the comparative analysis of Z-source and Quasi Z-source converter for renewable energy applications. Due to the dependency of renewable energy sources on external weather conditions the output voltage, current changes accordingly which effects the performance of traditional voltage source and current source inverters connected across it. To overcome the drawbacks of VSI and CSI, Z-source and Quasi Z-source inverter (QZSI) are used, which can perform multiple tasks like ac-to-dc, dc-to-ac, ac-to-ac, dc-to-dc conversion. They can be used for both buck and boost operations, by utilizing the shoot-through zero state. The QZSI is derived from the ZSI topology, with a slight change in the impedance network and it overcomes the drawbacks of ZSI. The QZSI draws a constant current from the source when compared to ZSI. A comparative analysis is performed between Z-source and Quasi Z-source inverter, simulation is performed in MATLAB/Simulink environment.

  17. 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% ...

  18. 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....

  19. 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....

  20. 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...

  1. 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...

  2. Contrast source inversion (CSI) method to cross-hole radio-imaging (RIM) data - Part 2: A complex synthetic example and a case study

    Science.gov (United States)

    Li, Yongxing; Smith, Richard S.

    2018-03-01

    We present two examples of using the contrast source inversion (CSI) method to invert synthetic radio-imaging (RIM) data and field data. The synthetic model has two isolated conductors (one perfect conductor and one moderate conductor) embedded in a layered background. After inversion, we can identify the two conductors on the inverted image. The shape of the perfect conductor is better resolved than the shape of the moderate conductor. The inverted conductivity values of the two conductors are approximately the same, which demonstrates that the conductivity values cannot be correctly interpreted from the CSI results. The boundaries and the tilts of the upper and the lower conductive layers on the background can also be inferred from the results, but the centre parts of conductive layers in the inversion results are more conductive than the parts close to the boreholes. We used the straight-ray tomographic imaging method and the CSI method to invert the RIM field data collected using the FARA system between two boreholes in a mining area in Sudbury, Canada. The RIM data include the amplitude and the phase data collected using three frequencies: 312.5 kHz, 625 kHz and 1250 kHz. The data close to the ground surface have high amplitude values and complicated phase fluctuations, which are inferred to be contaminated by the reflected or refracted electromagnetic (EM) fields from the ground surface, and are removed for all frequencies. Higher-frequency EM waves attenuate more quickly in the subsurface environment, and the locations where the measurements are dominated by noise are also removed. When the data are interpreted with the straight-ray method, the images differ substantially for different frequencies. In addition, there are some unexpected features in the images, which are difficult to interpret. Compared with the straight-ray imaging results, the inversion results with the CSI method are more consistent for different frequencies. On the basis of what we learnt

  3. On Line Stator Resistance Tuning of DTC Control CSI Fed IM Drives

    OpenAIRE

    PANNEER SELVAM

    2012-01-01

    Current source inverter (CSI) fed drives are employed in high power applications. The conventional CSI drives suffer from drawbacks such as harmonic resonance, unstable operation at low speed ranges, and torque pulsation. CSI fed drives with Direct Torque Control (DTC) has drawn the attention of the motor drives designers because its implementation requires no position sensor. Crucial to the success of this scheme is the estimation of electromagnetic torque and stator flux linkages using the ...

  4. 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...

  5. 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.

  6. 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....

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  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. 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.

  14. Extended SVM algorithms for multilevel trans-Z-source inverter

    Directory of Open Access Journals (Sweden)

    Aida Baghbany Oskouei

    2016-03-01

    Full Text Available This paper suggests extended algorithms for multilevel trans-Z-source inverter. These algorithms are based on space vector modulation (SVM, which works with high switching frequency and does not generate the mean value of the desired load voltage in every switching interval. In this topology the output voltage is not limited to dc voltage source similar to traditional cascaded multilevel inverter and can be increased with trans-Z-network shoot-through state control. Besides, it is more reliable against short circuit, and due to several number of dc sources in each phase of this topology, it is possible to use it in hybrid renewable energy. Proposed SVM algorithms include the following: Combined modulation algorithm (SVPWM and shoot-through implementation in dwell times of voltage vectors algorithm. These algorithms are compared from viewpoint of simplicity, accuracy, number of switching, and THD. Simulation and experimental results are presented to demonstrate the expected representations.

  15. 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...

  16. 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...

  17. Operational analysis and comparative evaluation of embedded Z-Source inverters

    DEFF Research Database (Denmark)

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

    2008-01-01

    ) circuitry connected instead of the generic voltage source inverter (VSI) circuitry. Further proceeding on to the topological variation, parallel embedded Z-source inverters are presented with the detailed analysis of topological configuration and operational principles showing that they are the superior......This paper presents various embedded Z-source (EZ-source) inverters broadly classified as shunt or parallel embedded Z-source inverter. Being different from the traditional Z-source inverter, EZ-source inverters are constructed by inserting dc sources into the X-shaped impedance network so...... that the dc input current flows smoothly during the whole switching period unlike the traditional Z-source inverter. This feature is interesting when PV panels or fuel cells are assumed to power load since the continuous input current flow reduces control complexity of dc source and system design burden...

  18. 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

  19. 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...

  20. Comparison of three-phase three-level voltage source inverter with intermediate dc–dc boost converter and quasi-Z-source inverter

    DEFF Research Database (Denmark)

    Panfilov, Dmitry; Husev, Oleksandr; Blaabjerg, Frede

    2016-01-01

    This study compares a three-phase three-level voltage source inverter with an intermediate dc-dc boost converter and a quasi-Z-source inverter in terms of passive elements values and dimensions, semiconductor stresses, and overall efficiency. A comparative analysis was conducted with relative...

  1. Grid-connected to/from off-grid transference for micro-grid inverters

    OpenAIRE

    Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

    2013-01-01

    This paper compares two methods for controlling the on-line transference from connected to stand-alone mode and vice versa in converters for micro-grids. The first proposes a method where the converter changes from CSI (Current Source Inverter) in grid-connected mode to VSI (Voltage Source Inverter) in off-grid. In the second method, the inverter always works as a non-ideal voltage source, acting as VSI, using AC droop control strategy.

  2. 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...

  3. 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...

  4. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    DEFF Research Database (Denmark)

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

    2007-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...

  5. 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...

  6. Fault Ride-Through of a Grid-connected Photovoltaic System with Quasi Z Source Inverter

    DEFF Research Database (Denmark)

    Al-Durra, Ahmed; Fayyad, Yara; Muyeen, S.M.

    2016-01-01

    This article presents fault ride-through schemes for a three-phase quasi Z source single-stage photovoltaic (PV) inverter that is connected to the grid after the distribution network. The quasi Z source inverter employs a unique LC network to couple the inverter main circuit to the input of the PV...... the grid side so that the grid fault ride-through requirements can be fulfilled. Scheme A involves control modification in the system; Schemes B and C involve hardware modification in the circuit topology by adding a chopper circuit across the DC link in Scheme B and across the quasi Z source inverter...

  7. 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...

  8. 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...

  9. 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...

  10. Novel, Four-Switch, Z-Source Three-Phase Inverter

    DEFF Research Database (Denmark)

    Antal, Robert; Muntean, Nicolae; Boldea, Ion

    2010-01-01

    This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology......, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher......) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F...

  11. Evaluation of Resonant Damping Techniques for Z-Source Current-Type Inverter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gajanayake, C.J.

    2008-01-01

    For the renewable energy sources whose outputs vary continuously, a Z-source current-type inverter has been proposed as a possible buck-boost alternative for grid-interfacing. With a unique X-shaped LC network connected between its dc power source and inverter topology, Z-source current......-type inverter is however expected to suffer from compounded resonant complications in addition to those associated with its second-order output filter. To improve its damping performance, this paper proposes the careful integration of Posicast or three-step compensators before the inverter pulse-width modulator...... for damping triggered resonant oscillations. In total, two compensators are needed for wave-shaping the inverter boost factor and modulation ratio, and they can conveniently be implemented using first-in first-out stacks and embedded timers of modern digital signal processors widely used in motion control...

  12. CLOSED LOOP CONTROL OF EMBEDDED Z-SOURCE INVERTER WITH FUZZY CONTROLLER FOR SOLAR PV APPLICATIONS

    OpenAIRE

    Midde Mahesh*, K. Leleedhar Rao

    2017-01-01

    This paper proposes the use of Embedded Z –source inverter system with fuzzy controller for Solar Photo Voltaic (PV) applications with adjustable speed drives. Closed loop operation FUZZY control strategies of EZSI system are proposed. EZSI produces the same voltage gain as Z-source inverter (ZSI) but due to the DC sources embedded within the X- shaped impedance network, it has the added advantage of inherent source filtering capability and also reduced capacitor sizing. This can be achiev...

  13. Z-Source Inverter Based Power Quality Compensator with Enhanced Ride-Through Capability

    DEFF Research Database (Denmark)

    Gajanayake, C.J.; Vilathgamuwa, D.M.; Loh, P.C.

    2007-01-01

    Distributed generation has been gaining acceptance over the years and it has the potential to provide reliable power to sensitive loads. However, distributed networks are prone to unbalanced faults conditions. This makes single inverter DG systems unsuitable as UPS systems. This paper proposes...... a Zsource inverter based power quality compensator and a control structure that supplies high quality voltage to the connected sensitive load in the presence of other non linear loads. The proposed topology consists of combination of shunt and series inverters connected to a common Z-source impedance...... network. The shunt inverter is controlled to maintain a quality voltage waveform at the load bus. Whereas the series inverter enhances the ride-through capability during grid faults, protects the shunt inverter by limiting the current and also controls the power delivered to the grid. The performance...

  14. Six-Phase Vehicular Drive with Renewable DC Sources and Hybrid PWM Control of Four Inverters

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Ermuratskii, Vladimir; Blaabjerg, Frede

    2015-01-01

    The paper presents results of research of quad-inverter-based automotive system with combined scheme of PWM control of inverters, supplied by two renewable dc sources (by fuel cells and by battery). It has been shown, that hybrid switching techniques can be used successfully for control of vehicle...

  15. A single-phase embedded Z-source DC-AC inverter.

    Science.gov (United States)

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively.

  16. 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...

  17. CSI : Alaska

    International Nuclear Information System (INIS)

    Letwin, S.

    2005-01-01

    This presentation emphasized the need for northern gas supply at a time when conventional natural gas supplies are decreasing and demand is growing. It highlighted the unique qualifications of Enbridge Inc. in creating an infrastructure to move the supply to where it is in most demand. Enbridge has substantial northern experience and has a unique approach for the construction of the Alaskan Gas Pipeline which entails cooperation, stability and innovation (CSI). Enbridge's role in the joint venture with AltaGas and Inuvialuit Petroleum was discussed along with its role in the construction of the first Canadian pipeline in 1985. The 540 mile pipeline was buried in permafrost. A large percentage of Enbridge employees are of indigenous descent. Enbridge recognizes that the amount of capital investment and the associated risk needed for the Alaska Gas Pipeline will necessitate a partnership of producers, pipeline companies, Native organizations, the State of Alaska, market participants and other interested parties. 9 figs

  18. 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...

  19. 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

  20. Effect of state feedback coupling on the transient performance of voltage source inverters with LC filter

    DEFF Research Database (Denmark)

    Federico, de Bosio; Pastorelli, Michele; Antonio DeSouza Ribeiro, Luiz

    2016-01-01

    State feedback coupling between the capacitor voltage and inductor current deteriorates notably the performance during transients of voltage and current regulators in stand-alone systems based on voltage source inverters. A decoupling technique is proposed, considering the limitations introduced...

  1. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor Failure Conditions

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, P.C.; Vilathgamuwa, D.M.

    2007-01-01

    reconfigure the gating signals in order to tolerate the failed semiconductor devices without significantly decreasing the ac output quality and amplitude by properly using the inherent boost characteristic of Z-source network. In addition, the Z-source dual inverters can maintain the zero common mode voltage...... under semiconductor failure conditions, which is the unique characteristic attained by the dual inverters only. Lastly, all theoretical findings are verified in PLECS simulations....

  2. Simulation and Study of Multilevel Inverter System Fed By Photovoltaic Source

    Directory of Open Access Journals (Sweden)

    Ali Abdulrazzak Jasim

    2018-01-01

    Full Text Available This paper proposes a simulation of Photovoltaic energy used to supply an induction motor with acomparison of two types of inverters.In general, the greater number of motorswhich"are used incommercial and industrial applicationsare"induction motors. To use PV source to run the induction motor, an interface circuits are used which are a dc-dc"converter and an inverter, the PV cell has nonlinear behavior,"adc-dc converter is used along with Maximum Power Point Tracker controllerto improve theefficiency by boosting the output voltage of the PV module and to match the load demand."The dc output voltage of PV modulethen"converted to AC, two types of inverter are presented, A conventional Voltage Source Inverter system and multilevel inverter system which employselective harmonic eliminationmethod fed three phase induction motor, these two types of inverters are simulated using Matlab/Simulink and their results are presented. The FFT spectrum is presented of the output currents to analyze the harmonics reduction, which shows that the"multilevel inverter is better than VSI system"according to harmonics reduction and increment in output voltage and power.

  3. Comparative Study of Modulation Techniques for Two-Level Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2016-06-01

    Full Text Available A detailed comparative study of modulation techniques for single and three phase dc-ac inverters is presented.  Sinusoidal Pulse Width Modulation, Triplen Sinusoidal Pulse Width Modulation, Space Vector Modulation, Selective Harmonic Elimination and Wavelet Modulation are assessed and compared in terms of maximum fundamental output, harmonic performance, switching losses and operational mode.  The presented modulation techniques are applied to single and three phase voltage source inverters and are simulated using SIMULINK.  The simulation results clarify the inverter performance achieved using the different modulations techniques.

  4. A Comparison Study of Sinusoidal PWM and Space Vector PWM Techniques for Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Ömer Türksoy

    2017-06-01

    Full Text Available In this paper, the methods used to control voltage source inverters which have been intensively investigated in recent years are compared. Although the most efficient result is obtained with the least number of switching elements in the inverter topologies, the method used in the switching is at least as effective as the topology. Besides, the selected switching method to control the inverter will play an effective role in suppressing harmonic components while producing the ideal output voltage. There are many derivatives of pulse width modulation techniques that are commonly used to control voltage source inverters. Some of widespread methods are sinusoidal pulse width modulation and space vector pulse width modulation techniques. These modulation techniques used for generating variable frequency and amplitude output voltage in voltage source inverters, have been simulated by using MATLAB/SIMULINK. And, the total harmonic distortions of the output voltages are compared. As a result of simulation studies, sinusoidal pulse width modulation has been found to have more total harmonic distortion in output voltages of voltage source inverters in the simulation. Space vector pulse width modulation has been shown to produce a more efficient output voltage with less total harmonic distortion.

  5. A New Configuration for Power Sharing of Two Z-Source Inverters

    Directory of Open Access Journals (Sweden)

    M. Ghani varzaneh

    2017-09-01

    Full Text Available This paper presents a new structure to provide the ability for power sharing of two Z-source inverters. According to the operation principles of Z-source inverters, only one input source supplies the circuit, which is a limitation particularly for the stand alone systems feeded by limited output power such as photovoltaics and feul cells. Furthermore; if one source fails to supply,  the load can't be supplied. This paper covers those via interconnection of impedance network of two Z-source inverters. The operating principles of the proposed topology for the stand-alone and power sharing conditions are described and the relations are derived. The topology is simulated, which the results verify the theoretical analysis and well performance of the system. 

  6. New Switched-Dual-Source Multilevel Inverter for Symmetrical and Asymmetrical Operation

    Directory of Open Access Journals (Sweden)

    Kennedy Adinbo Aganah

    2018-04-01

    Full Text Available The increasing integration of large solar PV and wind farms into the power grid has fueled, over the past two decades, growing demands for high-power, high-voltage, utility-scale inverters. Multilevel inverters have emerged as the industry’s choice for megawatt-range inverters because of their reduced voltage stress, capability for generating an almost-sinusoidal voltage, built-in redundancy and other benefits. This paper presents a novel switched-source multilevel inverter (SS MLI architecture. This new inverter shows superior capabilities when compared to existing topologies. It has reduced voltage stress on the semiconductor, uses fewer switches (i.e., reduced size/weight/cost and exhibits increased efficiency. The proposed SS MLI is comprised of two voltage sources ( V 1 , V 2 and six switches. It is capable of generating five-level output voltage in symmetric mode (i.e., V 1 = V 2 and seven-level output voltage in asymmetric mode (i.e., V 1 ≠ V 2 . We present simulations results (using MATLAB®/Simulink® for five- and seven-level output voltages, and they strongly support the validity of the proposed inverter. These positive results are further supported experimentally using a laboratory prototype.

  7. Selective harmonic elimination strategy in eleven level inverter for PV system with unbalanced DC sources

    Science.gov (United States)

    Ghoudelbourk, Sihem.; Dib, D.; Meghni, B.; Zouli, M.

    2017-02-01

    The paper deals with the multilevel converters control strategy for photovoltaic system integrated in distribution grids. The objective of the proposed work is to design multilevel inverters for solar energy applications so as to reduce the Total Harmonic Distortion (THD) and to improve the power quality. The multilevel inverter power structure plays a vital role in every aspect of the power system. It is easier to produce a high-power, high-voltage inverter with the multilevel structure. The topologies of multilevel inverter have several advantages such as high output voltage, lower total harmonic distortion (THD) and reduction of voltage ratings of the power semiconductor switching devices. The proposed control strategy ensures an implementation of selective harmonic elimination (SHE) modulation for eleven levels. SHE is a very important and efficient strategy of eliminating selected harmonics by judicious selection of the firing angles of the inverter. Harmonics elimination technique eliminates the need of the expensive low pass filters in the system. Previous research considered that constant and equal DC sources with invariant behavior; however, this research extends earlier work to include variant DC sources, which are typical of lead-acid batteries when used in system PV. This Study also investigates methods to minimize the total harmonic distortion of the synthesized multilevel waveform and to help balance the battery voltage. The harmonic elimination method was used to eliminate selected lower dominant harmonics resulting from the inverter switching action.

  8. A modified two-level three-phase quasi-soft-switching inverter

    DEFF Research Database (Denmark)

    Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede

    2014-01-01

    A traditional Voltage Source Inverter (VSI) has higher efficiency than a Current Voltage Source (CSI) due to the less conduction power loss. However, the reverse recovery of the free-wheeling diode limits the efficiency improvement for the silicon devices based hard-switching VSI. The traditional...... quasi-soft-switching inverter can alternate between VSI and CSI by using a proper control scheme and thereby reduce the power losses caused by the reverse recovery of the free-wheeling diode. Nevertheless, slightly extra conduction power loss of the auxiliary switch is also introduced. In order...... to reduce the extra conduction power loss and the voltage stress across the DC-link capacitor, a modified two-level three-phase quasi-soft-switching inverter is proposed by using a SiC MOSFET instead of an IGBT. The principle of the modified two-level three-phase quasi-soft-switching inverter is analyzed...

  9. A Modified Droop Control Method for Parallel-Connected Current Source Inverters

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    In this paper, a novel control method was proposed for current source inverters under the grid-connected working mode. The control scheme is based on a modified droop control method, with an additional current reference signal that will be generated instead of the voltage reference. Hence......, there is only a current control loop with droop control in the whole control scheme without voltage control loop. So it is very suitable for grid-connected current source inverter which will simplify the design of the control scheme and combine the advantage of droop control. The parallel configuration...... is widely used to acquire high power demand, but the circulating current problem is a key issue that should be considered. In this paper, a simulation based on parallel current source inverters using the proposed control scheme is provided. Simulation results showed that a good circulating current...

  10. 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.

  11. 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....

  12. Z-Source-Inverter-Based Flexible Distributed Generation System Solution for Grid Power Quality Improvement

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Vilathgamuwa, D. M.; Loh, Poh Chiang

    2009-01-01

    Distributed generation (DG) systems are usually connected to the grid using power electronic converters. Power delivered from such DG sources depends on factors like energy availability and load demand. The converters used in power conversion do not operate with their full capacity all the time......-stage buck-boost inverter, recently proposed Z-source inverter (ZSI) is a good candidate for future DG systems. This paper presents a controller design for a ZSI-based DG system to improve power quality of distribution systems. The proposed control method is tested with simulation results obtained using...

  13. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor-Failure Conditions

    DEFF Research Database (Denmark)

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

    2009-01-01

    This paper evaluates and proposes various compensation methods for three-level Z-source inverters under semiconductor-failure conditions. Unlike the fault-tolerant techniques used in traditional three-level inverters, where either an extra phase-leg or collective switching states are used......, the proposed methods for three-level Z-source inverters simply reconfigure their relevant gating signals so as to ride-through the failed semiconductor conditions smoothly without any significant decrease in their ac-output quality and amplitude. These features are partly attributed to the inherent boost...... under semiconductor-failure conditions. For verifying these described performance features, PLECS simulation and experimental testing were performed with some results captured and shown in a later section for visual confirmation....

  14. CONTAIN code calculations of the effects on the source term of CsI to I/sub 2/ conversion due to severe hydrogen burns

    International Nuclear Information System (INIS)

    Valdez, G.D.; Williams, D.C.

    1986-01-01

    In experiments conducted at Sandia National Laboratories large amounts of elemental iodine were produced when CsI-Al 2 O 3 aerosol was exposed to hydrogen/air combustion. To evaluate some of the implications of the iodide conversion (observed to occur with up to 75% efficiency) for the severe accident source term, computational simulations of representative accident sequences were conducted with the CONTAIN code. The following conclusions can be drawn from this preliminary source term assessment: (1) If the containment sprays are inoperative during the accident, or failed by the hydrogen burn, the late-time source term is almost tripled when the iodide is converted to I 2 . (2) With the sprays active, the amount released without conversion of the CsI aerosol is 63% higher than for the case when conversion occurs. (3) For the case where CsI is converted to I 2 continued operation of the sprays reduces the release by a factor of 40, relative to the case in which the sprays fail at the time of the hydrogen burn. When there is no conversion, the reduction factor for continued spray operation is about a factor of 9, relative to the failed spray case

  15. 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...

  16. Generalized Multi-Cell Switched-Inductor and Switched-Capacitor Z-source Inverters

    DEFF Research Database (Denmark)

    Li, Ding; Chiang Loh, Poh; Zhu, Miao

    2013-01-01

    . Their boosting gains are, therefore, limited in practice. To overcome these shortcomings, the generalized switched-inductor and switched-capacitor Z-source inverters are proposed, whose extra boosting abilities and other advantages have already been verified in simulation and experiment....

  17. Inverter for interfacing advanced energy sources to a utility grid

    Science.gov (United States)

    Steigerwald, Robert L.

    1984-01-01

    A transistor is operated in the PWM mode such that a hlaf sine wave of current is delivered first to one-half of a distribution transformer and then the other as determined by steering thyristors operated at the fundamental sinusoidal frequency. Power to the transistor is supplied by a dc source such as a solar array and the power is converted such that a sinusoidal current is injected into a utility at near unity power factor.

  18. Modulation Schemes of Multi-phase Three-Level Z-Source Inverters

    DEFF Research Database (Denmark)

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

    2007-01-01

    different modulation requirement and output performance. For clearly illustrating the detailed modulation process, time domain analysis instead of the traditional multi-dimensional space vector demonstration is assumed which reveals the right way to insert shoot-through durations in the switching sequence...... with minimal commutation count. Lastly, the theoretical findings are verified in Matlab/PLECS simulation and experimentally using constructed laboratory prototypes.......This paper investigates the modulation schemes of three-level multiphase Z-source inverters with either two Z-source networks or single Z-source network connected between the dc sources and inverter circuitry. With the proper offset added for achieving both desired four-leg operation and optimized...

  19. Prototype inverted sputter source for negative heavy ions

    International Nuclear Information System (INIS)

    Minehara, Eisuke; Kobayashi, Chiaki; Kikuchi, Shiroh

    1977-10-01

    A sputter source from which negative heavy ion beam is extracted through a tungsten wire and disc ionizer was built and tested. An alkali metal surface ionization gun with the ionizer is described, and also performance of the surface ionization gun and of the sputter source for negative heavy ions using the gun is reported. The gun was tested for three alkali metals, i.e. sodium, potassium and cesium. Total potassium beam current of 1-2mA was obtained at entrance aperture of the magnet. Sputtering materials and gases for producing negative heavy ions are carbon, copper, aluminium, molybdenum, oxygen and air. With carbon and leakage air, the beam intensities analyzed are: 2-5μA (at Faraday cup) and 4.6-11μA (at exit slit) for C - , 3-5μA (at Faraday cup) and 6.8-11μA (at exit slit) for 2C - , and 11-15μA (at Faraday cup) and 25-34μA (at exit slit) for O - . Total beam current at the entrance aperture was 200-400μA. (auth.)

  20. Mapping thunder sources by inverting acoustic and electromagnetic observations

    Science.gov (United States)

    Anderson, J. F.; Johnson, J. B.; Arechiga, R. O.; Thomas, R. J.

    2014-12-01

    We present a new method of locating current flow in lightning strikes by inversion of thunder recordings constrained by Lightning Mapping Array observations. First, radio frequency (RF) pulses are connected to reconstruct conductive channels created by leaders. Then, acoustic signals that would be produced by current flow through each channel are forward modeled. The recorded thunder is considered to consist of a weighted superposition of these acoustic signals. We calculate the posterior distribution of acoustic source energy for each channel with a Markov Chain Monte Carlo inversion that fits power envelopes of modeled and recorded thunder; these results show which parts of the flash carry current and produce thunder. We examine the effects of RF pulse location imprecision and atmospheric winds on quality of results and apply this method to several lightning flashes over the Magdalena Mountains in New Mexico, USA. This method will enable more detailed study of lightning phenomena by allowing researchers to map current flow in addition to leader propagation.

  1. A Fuzzy Logic Based Three phase Inverter with Single DC Source for Grid Connected PV System Employing Three Phase Transformer

    OpenAIRE

    Mani, venkatesan; Ramachandran, Rajeswari; N, Deverajan

    2016-01-01

    A fuzzy based three phase inverter with single DC source for grid connected photo voltaic (PV) system employing three phase transformer is presented in this paper. Space Vector Pulse Width Modulation (SVPWM) control scheme is effectively used to generate the appropriate switching sequences to the inverter switches. The intend of the fuzzy logic approach is to meet high quality output, fast response and high robustness. Finally Total Harmonics Distortion (THD) generated by the inverter is comp...

  2. A new PWM algorithm for battery-source three-phase inverters

    Energy Technology Data Exchange (ETDEWEB)

    Chan, C.C. (Dept. of Electrical and Electronic Engineering, Univ. of Hong Kong, Pokfulam Road (HK)); Chau, K.T. (Dept. of Electrical Engineering, Hong Kong Polytechnic, Hung Hom (HK))

    1991-01-01

    A new PWM algorithm for battery-source three-phase inverters is described in this paper. The concept of the algorithm is to determine the pulsewidths by equating the areas of the segments of the sinusodial reference with the related output pulse areas. The algorithm is particularly suitable to handle a non-constant voltage source with good harmonic suppression. Since the pulsewidths are computable in real time with minimal storage requirement as well as compact hardware and software, it is especially suitable for single-chip microcomputer implementation. Experimental results show that the single-chip microcomputer Intel 8095-based battery-source inverter can control a 3 kW synchronous motor drive satisfactorily over a frequency range of 2 to 100Hz.

  3. Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter

    DEFF Research Database (Denmark)

    Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede

    2016-01-01

    This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver......This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....

  4. Modified Grid-Connected CSI for Hybrid PV/Wind Power Generation System

    Directory of Open Access Journals (Sweden)

    D. Amorndechaphon

    2012-01-01

    Full Text Available The principle of a power conditioning unit for hybrid PV/wind power generation system is proposed. The proposed power conditioner is based on the current source inverter (CSI topology. All energy sources are connected in parallel with a DC-bus through the modified wave-shaping circuits. To achieve the unity power factor at the utility grid, the DC-link current can be controlled via the wave-shaping circuits with the sinusoidal PWM scheme. In this work, the carrier-based PWM scheme is also proposed to minimize the utility current THD. The power rating of the proposed system can be increased by connecting more PV/wind modules through their wave-shaping circuits in parallel with the other modules. The details of the operating principles, the system configurations, and the design considerations are described. The effectiveness of the proposed CSI is demonstrated by simulation results.

  5. Surface chemical analysis and ab initio investigations of CsI coated C fiber cathodes for high power microwave sources

    Science.gov (United States)

    Vlahos, Vasilios; Morgan, Dane; LaCour, Matthew; Golby, Ken; Shiffler, Don; Booske, John H.

    2010-02-01

    CsI coated C fiber cathodes are promising electron emitters utilized in field emission applications. Ab initio calculations, in conjunction with experimental investigations on CsI-spray coated C fiber cathodes, were performed in order to better understand the origin of the low turn-on E-field obtained, as compared to uncoated C fibers. One possible mechanism for lowering the turn-on E-field is surface dipole layers reducing the work function. Ab initio modeling revealed that surface monolayers of Cs, CsI, Cs2O, and CsO are all capable of producing low work function C fiber cathodes (1 eV<Φ<1.5 eV), yielding a reduction in the turn-on E-field by as much as ten times, when compared to the bare fiber. Although a CsI-containing aqueous solution is spray deposited on the C fiber surface, energy dispersive x-ray spectroscopy and scanning auger microscopy measurements show coabsorption of Cs and I into the fiber interior and Cs and O on the fiber surface, with no surface I. It is therefore proposed that a cesium oxide (CsxOy) surface coating is responsible, at least in part, for the low turn E-field and superior emission characteristics of this type of fiber cathode. This CsxOy layer could be formed during preconditioning heating. CsxOy surface layers cannot only lower the fiber work function by the formation of surface dipoles (if they are thin enough) but may also enhance surface emission through their ability to emit secondary electrons due to a process of grazing electron impact. These multiple electron emission processes may explain the reported 10-100 fold reduction in the turn-on E-field of coated C fibers.

  6. Elimination of harmonics in multilevel inverters with non-equal dc sources using PSO

    International Nuclear Information System (INIS)

    Al-Othman, A.K.; Abdelhamid, Tamer H.

    2009-01-01

    Multilevel inverters supplied from equal and constant dc sources almost do not exist in practical applications. The variation of the dc sources affects the values of the switching angles required for each specific harmonic profile, as well as increases the difficulty of the harmonic elimination's equations. This paper presents an extremely fast optimal solution of harmonic elimination of multilevel inverters with non-equal dc sources using a novel Particle Swarm Optimization (PSO) algorithm. The overall system is suitable for large variable speed drives, UPS systems, and on-line utility applications such as static var compensation. A set of mathematical equations describing the general output waveform of the multilevel inverter with non-equal dc sources is formulated. PSO is then employed to compute the optimal solution set of switching angles, if it exists, for each required harmonic profile. Theoretical studies for different case studies regarding the number of levels and harmonic profile are carried out to show the effectiveness and robustness of the proposed technique, and validated through both simulations and laboratory experimentation

  7. Shootthrough fault protection system for bipolar transistors in a voltage source transistor inverter

    International Nuclear Information System (INIS)

    Wirth, W.F.

    1982-01-01

    Faulted bipolar transistors in a voltage source transistor inverter are protected against shootthrough fault current, from the filter capacitor of the d-c voltage source which drives the inverter over the d-c bus, by interposing a small choke in series with the filter capacitor to limit the rate of rise of that fault current while at the same time causing the d-c bus voltage to instantly drop to essentially zero volts at the beginning of a shootthrough fault. In this way, the load lines of the faulted transistors are effectively shaped so that they do not enter the second breakdown area, thereby preventing second breakdown destruction of the transistors

  8. Removal of Direct Current Link Harmonic Ripple in Single Phase Voltage Source Inverter Systems Using Supercapacitors

    Science.gov (United States)

    2016-09-01

    Khaligh, “Optimization of sizing and battery cycle life in battery/ultracapacitor hybrid energy storage systems for electric vehicle applications...depth cycling operation in photovoltaic system ,” in 22nd International Conference “Mixed Design of Integrated Circuits and Systems ,” Toruń, Poland...CURRENT LINK HARMONIC RIPPLE IN SINGLE-PHASE VOLTAGE SOURCE INVERTER SYSTEMS USING SUPERCAPACITORS by Gabriel D. Hernandez September 2016

  9. Mitigation of Flicker using STATCOM with Three-Level 12-pulse Voltage Source Inverter

    OpenAIRE

    Ali Z a'fari

    2011-01-01

    Voltage flicker is a disturbance in electrical power systems. The reason for this disturbance is mainly the large nonlinear loads such as electric arc furnaces. Synchronous static compensator (STATCOM) is considered as a proper technique to mitigate the voltage flicker. Application of more suitable and precise power electronic converter leads to a more precise performance of the compensator. In this paper a three-level 12-pulse voltage source inverter (VSI) with a 12-term...

  10. Mitigation of grid-current distortion for LCL-filtered grid-connected voltage-source inverter with inverter-side current control

    DEFF Research Database (Denmark)

    Xin, Zhen; Mattavelli, Paolo; Yao, WenLi

    2017-01-01

    Due to the low inductance of an LCL-filter, the grid current generated by an LCL-filtered Voltage Source Inverter (VSI) is sensitive to low-order grid-voltage harmonics. This issue is especially tough for the control system with Inverter Current Feedback (ICF), because the grid-current harmonics...... can freely flow into the filter capacitor without control. To cope with this issue, this paper develops an approach for the ICF control system to suppress the grid-current harmonics without adding extra sensors. The proposed method applies harmonic controllers and feedforward scheme simultaneously...

  11. Variable speed wind turbine generator system with current controlled voltage source inverter

    International Nuclear Information System (INIS)

    Muyeen, S.M.; Al-Durra, Ahmed; Tamura, J.

    2011-01-01

    highlights: → Current controlled voltage source inverter scheme for wind power application. → Low voltage ride through of wind farm. → Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  12. Variable speed wind turbine generator system with current controlled voltage source inverter

    Energy Technology Data Exchange (ETDEWEB)

    Muyeen, S.M., E-mail: muyeen0809@yahoo.co [Dept. of Electrical Engineering, Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Al-Durra, Ahmed [Dept. of Electrical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Tamura, J. [Dept. of EEE, Kitami Institute of Technology, 165 Koen-cho, Kitami 090-8507 (Japan)

    2011-07-15

    highlights: {yields} Current controlled voltage source inverter scheme for wind power application. {yields} Low voltage ride through of wind farm. {yields} Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  13. Induced over voltage test on transformers using enhanced Z-source inverter based circuit

    Science.gov (United States)

    Peter, Geno; Sherine, Anli

    2017-09-01

    The normal life of a transformer is well above 25 years. The economical operation of the distribution system has its roots in the equipments being used. The economy being such, that it is financially advantageous to replace transformers with more than 15 years of service in the second perennial market. Testing of transformer is required, as its an indication of the extent to which a transformer can comply with the customers specified requirements and the respective standards (IEC 60076-3). In this paper, induced over voltage testing on transformers using enhanced Z source inverter is discussed. Power electronic circuits are now essential for a whole array of industrial electronic products. The bulky motor generator set, which is used to generate the required frequency to conduct the induced over voltage testing of transformers is nowadays replaced by static frequency converter. First conventional Z-source inverter, and second an enhanced Z source inverter is being used to generate the required voltage and frequency to test the transformer for induced over voltage test, and its characteristics is analysed.

  14. CSI cardiac prevent 2015

    Directory of Open Access Journals (Sweden)

    S Ramakrishnan

    2015-01-01

    Full Text Available The CSI Cardiac Prevent 2015 was held at Hotel Taj Palace, New Delhi, on September 25-27, 2015. The major challenge was to create interest among cardiologists and physicians on preventive cardiology, a neglected area. The theme of the conference was "Innovations in Heart Disease Prevention.′′ This conference included "CSI at WHF Roadmap Workshop, Inauguration Ceremony, scientific program, plenary sessions, Nursing/Dietician track, Industry Exhibition, Social Events," Great India blood pressure Survey, and CSI Smart Heart App. A total of 848 delegates/faculties attended this conference against a total of 1140 people registered for the meeting.

  15. Selective Harmonic Virtual Impedance for Voltage Source Inverters with LCL filter in Microgrids

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Vasquez, Juan Carlos; Jalilian, Alireza Jalilian

    2012-01-01

    This paper presents a new control approach for voltage source inverters ended with LCL filters for microgrid applications. The control approach consists of voltage and current inner control loops in order to fix the filter capacitor voltage and a virtual impedance loop. The virtual impedance...... is added in order to mitigate the voltage distortion after the output inductor and improve the load sharing among parallel inverters. A general case with a combined voltage harmonic and unbalance distortion is considered. In such a case, voltage distortion is mitigated by inserting capacitive virtual...... impedance for negative sequence of fundamental component as well as positive and negative sequences of main harmonic components. Furthermore, resistive virtual impedances are added at these components in order to provide a proper load sharing and make the overall system more damped. Simulation results...

  16. Analysis of High Switching Frequency Quasi-Z-Source Photovoltaic Inverter Using Wide Bandgap Devices

    Science.gov (United States)

    Kayiranga, Thierry

    Power inverters continue to play a key role in todays electrical system more than ever. Power inverters employ power semiconductors to converter direct current (DC) into alternating current (AC). The performance of the semiconductors is based on speed and efficiency. Until recently, Silicon (Si) semiconductors had been established as mature. However, the continuous optimization and improvements in the production process of Si to meet today technology requirements have pushed Si materials to their theoretical limits. In an effort to find a suitable replacement, wide bandgap devices mainly Gallium Nitride (GaN) and Silicon Carbide (SiC), have proved to be excellent candidates offering high operation temperature, high blocking voltage and high switching frequency; of which the latter makes GaN a better candidate in high switching low voltage in Distributed Generations (DG). The single stage Quasi-Z-Source Inverter (qZSI) is also able to draw continuous and constant current from the source making ideal for PV applications in addition to allowing shoot-through states. The qZSI find best applications in medium level ranges where multiples qZS inverters can be cascaded (qZS-CMI) by combining the benefit of the qZSI, boost capabilities and continuous and constant input current, and those of the CMI, low output harmonic content and independent MPPT. When used with GaN devices operating at very high frequency, the qZS network impedance can be significantly reduced. However, the impedance network becomes asymmetric. The asymmetric impedance network (AIN-qZSI) has several advantages such as increased power density, increases system lifetime, small size volume and size making it more attractive for module integrated converter (MIC) concepts. However, there are technical challenges. With asymmetric component, resonance is introduced in the system leading to more losses and audible noise. With small inductances, new operation states become available further increasing the system

  17. CSI cardiac prevent 2015

    OpenAIRE

    S Ramakrishnan; Manisha Kaushik

    2015-01-01

    The CSI Cardiac Prevent 2015 was held at Hotel Taj Palace, New Delhi, on September 25-27, 2015. The major challenge was to create interest among cardiologists and physicians on preventive cardiology, a neglected area. The theme of the conference was "Innovations in Heart Disease Prevention.′′ This conference included "CSI at WHF Roadmap Workshop, Inauguration Ceremony, scientific program, plenary sessions, Nursing/Dietician track, Industry Exhibition, Social Events," Great India blood pressur...

  18. Discrete-Time Domain Modelling of Voltage Source Inverters in Standalone Applications

    DEFF Research Database (Denmark)

    Federico, de Bosio; de Sousa Ribeiro, Luiz Antonio; Freijedo Fernandez, Francisco Daniel

    2017-01-01

    modelling of the LC plant with consideration of delay and sample-and-hold effects on the state feedback cross-coupling decoupling is derived. From this plant formulation, current controllers with wide bandwidth and good relative stability properties are developed. Two controllers based on lead compensation......The decoupling of the capacitor voltage and inductor current has been shown to improve significantly the dynamic performance of voltage source inverters in standalone applications. However, the computation and PWM delays still limit the achievable bandwidth. In this paper a discrete-time domain...

  19. An inverted cylindrical sputter magnetron as metal vapor supply for electron cyclotron resonance ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Weichsel, T., E-mail: tim.weichsel@fep.fraunhofer.de; Hartung, U.; Kopte, T. [Fraunhofer Institute for Electron Beam and Plasma Technology, 01277 Dresden (Germany); Zschornack, G. [Institute of Solid State Physics, Dresden University of Technology, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Kreller, M.; Silze, A. [DREEBIT GmbH, 01900 Grossroehrsdorf (Germany)

    2014-05-15

    An inverted cylindrical sputter magnetron device has been developed. The magnetron is acting as a metal vapor supply for an electron cyclotron resonance (ECR) ion source. FEM simulation of magnetic flux density was used to ensure that there is no critical interaction between both magnetic fields of magnetron and ECR ion source. Spatially resolved double Langmuir probe and optical emission spectroscopy measurements show an increase in electron density by one order of magnitude from 1 × 10{sup 10} cm{sup −3} to 1 × 10{sup 11} cm{sup −3}, when the magnetron plasma is exposed to the magnetic mirror field of the ECR ion source. Electron density enhancement is also indicated by magnetron plasma emission photography with a CCD camera. Furthermore, photographs visualize the formation of a localized loss-cone - area, when the magnetron is operated at magnetic mirror field conditions. The inverted cylindrical magnetron supplies a metal atom load rate of R > 1 × 10{sup 18} atoms/s for aluminum, which meets the demand for the production of a milliampere Al{sup +} ion beam.

  20. Five-Level Current-Source Inverters With Buck–Boost and Inductive-Current Balancing Capabilities

    DEFF Research Database (Denmark)

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

    2010-01-01

    This paper presents new five-level current-source inverters (CSIs) with voltage/current buck–boost capability, unlike existing five-level CSIs where only voltage–boost operation is supported. The proposed inverters attain self-inductive-currentbalancing per switching cycle at their dc front ends...... without having to include additional balancing hardware or complex control manipulation. The inverters can conveniently be controlled by using the well-established phase-shifted carrier modulation scheme with only two additional linear references and a mapping logic table needed. Existing modulators can...

  1. An improved design of virtual output impedance loop for droop-controlled parallel three-phase Voltage Source Inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2012-01-01

    -sequence virtual resistance even in the case of feeding a balanced three-phase load. Furthermore, to adapt to the variety of unbalanced loads, a dynamically-tuned negative-sequence resistance loop is designed, such that a good compromise between the quality of inverter output voltage and the performance of load......The virtual output impedance loop is known as an effective way to enhance the load sharing stability and quality of droop-controlled parallel inverters. This paper proposes an improved design of virtual output impedance loop for parallel three-phase voltage source inverters. In the approach...... sharing can be obtained. Finally, laboratory test results of two parallel three-phase voltage source inverters are shown to confirm the validity of the proposed method....

  2. Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters with Reduced Switch Count

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede

    2016-01-01

    This paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along wi...... with simulation and experimental verification are also provided. Possible application fields are discussed, as well as advantages and disadvantages. Finally, future studies are addressed for the new solutions....

  3. Digital Control Techniques Based on Voltage Source Inverters in Renewable Energy Applications: A Review

    Directory of Open Access Journals (Sweden)

    Sohaib Tahir

    2018-02-01

    Full Text Available In the modern era, distributed generation is considered as an alternative source for power generation. Especially, need of the time is to provide the three-phase loads with smooth sinusoidal voltages having fixed frequency and amplitude. A common solution is the integration of power electronics converters in the systems for connecting distributed generation systems to the stand-alone loads. Thus, the presence of suitable control techniques, in the power electronic converters, for robust stability, abrupt response, optimal tracking ability and error eradication are inevitable. A comprehensive review based on design, analysis, validation of the most suitable digital control techniques and the options available for the researchers for improving the power quality is presented in this paper with their pros and cons. Comparisons based on the cost, schemes, performance, modulation techniques and coordinates system are also presented. Finally, the paper describes the performance evaluation of the control schemes on a voltage source inverter (VSI and proposes the different aspects to be considered for selecting a power electronics inverter topology, reference frames, filters, as well as control strategy.

  4. Inverting near-surface models from virtual-source gathers (SM Division Outstanding ECS Award Lecture)

    Science.gov (United States)

    Ruigrok, Elmer; Vossen, Caron; Paulssen, Hanneke

    2017-04-01

    The Groningen gas field is a massive natural gas accumulation in the north-east of the Netherlands. Decades of production have led to significant compaction of the reservoir rock. The (differential) compaction is thought to have reactivated existing faults and to be the main driver of induced seismicity. The potential damage at the surface is largely affected by the state of the near surface. Thin and soft sedimentary layers can lead to large amplifications. By measuring the wavefield at different depth levels, near-surface properties can directly be estimated from the recordings. Seismicity in the Groningen area is monitored primarily with an array of vertical arrays. In the nineties a network of 8 boreholes was deployed. Since 2015, this network has been expanded with 70 new boreholes. Each new borehole consists of an accelerometer at the surface and four downhole geophones with a vertical spacing of 50 m. We apply seismic interferometry to local seismicity, for each borehole individually. Doing so, we obtain the responses as if there were virtual sources at the lowest geophones and receivers at the other depth levels. From the retrieved direct waves and reflections, we invert for P- & S- velocity and Q models. We discuss different implementations of seismic interferometry and the subsequent inversion. The inverted near-surface properties are used to improve both the source location and the hazard assessment.

  5. Novel MSVPWM to reduce the inductor current ripple for Z-source inverter in electric vehicle applications.

    Science.gov (United States)

    Zhang, Qianfan; Dong, Shuai; Xue, Ping; Zhou, Chaowei; Cheng, ShuKang

    2014-01-01

    A novel modified space vector pulse width modulation (MSVPWM) strategy for Z-Source inverter is presented. By rearranging the position of shoot-through states, the frequency of inductor current ripple is kept constant. Compared with existing MSVPWM strategies, the proposed approach can reduce the maximum inductor current ripple. So the volume of Z-source network inductor can be designed smaller, which brings the beneficial effect on the miniaturization of the electric vehicle controller. Theoretical findings in the novel MSVPWM for Z-Source inverter have been verified by experiment results.

  6. A Circulating Current Suppression Method for Parallel Connected Voltage-Source-Inverters (VSI) with Common DC and AC Buses

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    This paper describes a theoretical with experiment study on a control strategy for the parallel operation of threephase voltage source inverters (VSI), to be applied to uninterruptible power systems (UPS). A circulating current suppression strategy for parallel VSIs is proposed in this paper based...... on circulating current control loops used to modify the reference currents by compensating the error currents among parallel inverters. Both of the cross and zero-sequence circulating currents are considered. The proposed method is coordinated together with droop and virtual impedance control. In this paper......, droop control is used to generate the reference voltage of each inverter, and the virtual impedance is used to fix the output impedance of the inverters. In addition, a secondary control is used in order to recover the voltage deviation caused by the virtual impedance. And the auxiliary current control...

  7. 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....

  8. Performance Evaluation of Three Different Inverter Configurations of DVR for Mitigation of Voltage Events

    Directory of Open Access Journals (Sweden)

    Miska Prasad

    2016-12-01

    Full Text Available The voltage events namely voltage sags and voltage swells represent the most common, frequent and important power quality events in today’s power system. Dynamic voltage restorer (DVR is one of the key components used to mitigate the supply voltage quality disturbances in terms of voltage sags and swells in the distribution system. It consists of an energy storage unit, a voltage source inverter, a filter, a coupling transformer and the control system. This paper presents three different inverter configurations of dynamic voltage restorer (DVR for mitigation of voltage events such as voltage sags and swells with sudden addition or removal of the nonlinear load. These three configurations are voltage source inverter based DVR (VSI-DVR, current source inverter based DVR (CSI-DVR and impedance or Z-source inverter based DVR (ZSI-DVR. The d-q control technique is used to control the operation of the DVR. The response of ZSI-DVR for mitigation of voltage sags and swells are investigated and compared with VSI-DVR and CSI-DVR using MATLAB/SIMULINK environment.

  9. 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...

  10. FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters

    Science.gov (United States)

    Sudha, L. U.; Baskaran, J.; Elankurisil, S. A.

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results. PMID:25821852

  11. Design and Control of Parallel Three Phase Voltage Source Inverters in Low Voltage AC Microgrid

    Directory of Open Access Journals (Sweden)

    El Hassane Margoum

    2017-01-01

    Full Text Available Design and hierarchical control of three phase parallel Voltage Source Inverters are developed in this paper. The control scheme is based on synchronous reference frame and consists of primary and secondary control levels. The primary control consists of the droop control and the virtual output impedance loops. This control level is designed to share the active and reactive power correctly between the connected VSIs in order to avoid the undesired circulating current and overload of the connected VSIs. The secondary control is designed to clear the magnitude and the frequency deviations caused by the primary control. The control structure is validated through dynamics simulations.The obtained results demonstrate the effectiveness of the control structure.

  12. Comparison between Different Control Strategies of a Z-Source Inverter Based Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    Abolfazl Kazemdehdashti

    2013-01-01

    Full Text Available In this paper, dynamic voltage restorer (DVR compensation methods are compared to each other for the load side connected shunt converter topology of z-source inverter based DVR to choose the best method. Four different topologies are recognized for DVR that two of them have energy storage devices, and two topologies have no energy storage that take ener\\-gy from the grid during the period of compensation. Here the load side connected shunt converter topology that takes necessary energy from the grid is used. Pre-sag compensation, in-phase compensation, energy-optimized methods are the three DVR compensation methods that studied and compared. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived and the characteristics of algorithms are compared with each other. The simulation results done by SIMULINK/ MATLAB shows compensating by this topology based on the compensation methods.

  13. Inverted end-Hall-type low-energy high-current gaseous ion source

    International Nuclear Information System (INIS)

    Oks, E. M.; Vizir, A. V.; Shandrikov, M. V.; Yushkov, G. Yu.; Grishin, D. M.; Anders, A.; Baldwin, D. A.

    2008-01-01

    A novel approach to low-energy, high-current, gaseous ion beam generation was explored and an ion source based on this technique has been developed. The source utilizes a dc high-current (up to 20 A) gaseous discharge with electron injection into the region of ion generation. Compared to the conventional end-Hall ion source, the locations of the discharge anode and cathode are inverted: the cathode is placed inside the source and the anode outside, and correspondingly, the discharge current is in the opposite direction. The discharge operates in a diverging axial magnetic field, similar to the end-Hall source. Electron generation and injection is accomplished by using an additional arc discharge with a ''cold'' (filamentless) hollow cathode. Low plasma contamination is achieved by using a low discharge voltage (avoidance of sputtering), as well as by a special geometric configuration of the emitter discharge electrodes, thereby filtering (removing) the erosion products stemming from the emitter cathode. The device produces a dc ion flow with energy below 20 eV and current up to 2.5 A onto a collector of 500 cm 2 at 25 cm from the source edge, at a pressure ≥0.02 Pa and gas flow rate ≥14 SCCM. The ion energy spread is 2 to 3 eV (rms). The source is characterized by high reliability, low maintenance, and long lifetime. The beam contains less than 0.1% of metallic ions. The specific electric energy consumption is 400 eV per ion registered at the collector. The source operates with noble gases, nitrogen, oxygen, and hydrocarbons. Utilizing biasing, it can be used for plasma sputtering, etching, and other ion technologies

  14. A Circulating-Current Suppression Method for Parallel-Connected Voltage-Source Inverters With Common DC and AC Buses

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid AC/DC microgrid applicat......This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid AC/DC microgrid......, and added into the conventional droop plus virtual impedance control. In the control architecture, the reference voltages of the inverters are generated by the primary control loop which consists of a droop control and a virtual impedance. The secondary control is used to compensate the voltage drop...

  15. Performance Evaluation of the Single-Phase Split-Source Inverter Using an Alternative DC-AC Configuration

    DEFF Research Database (Denmark)

    Abdelhakim, Ahmed; Mattavelli, Paolo; Davari, Pooya

    2018-01-01

    This paper investigates and evaluates the performance of a single-phase split-source inverter (SSI), where an alternative unidirectional dc-ac configuration is used. Such configuration is utilized in order to use two common-cathode diodes in a single-device instead of using two separate diodes, r...

  16. 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....

  17. 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...

  18. A Family of Cost-Effective Magnetically-Coupled Impedance Source Inverters

    DEFF Research Database (Denmark)

    Li, Kerui; Yang, Yongheng; Qin, Zian

    2017-01-01

    of required semiconductor switches is reduced. More important, the elimination of leakage currents makes it particularly suitable for high-efficiency photovoltaic (PV) applications. A comparison among prior-art PV inverters is then performed. The Performances of the inverters are evaluated analytically...

  19. Multifunctional voltage source inverter for renewable energy integration and power quality conditioning.

    Science.gov (United States)

    Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

    2014-01-01

    In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.

  20. Implementation of grid-connected to/from off-grid transference for micro-grid inverters

    OpenAIRE

    Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

    2013-01-01

    This paper presents the transfer of a microgrid converter from/to on-grid to/from off-grid when the converter is working in two different modes. In the first transfer presented method, the converter operates as a Current Source Inverter (CSI) when on-grid and as a Voltage Source Inverter (VSI) when off-grid. In the second transfer method, the converter is operated as a VSI both, when operated on-grid and off-grid. The two methods are implemented successfully in a real pla...

  1. A Single Phase Doubly Grounded Semi-Z-Source Inverter for Photovoltaic (PV Systems with Maximum Power Point Tracking (MPPT

    Directory of Open Access Journals (Sweden)

    Tofael Ahmed

    2014-06-01

    Full Text Available In this paper, a single phase doubly grounded semi-Z-source inverter with maximum power point tracking (MPPT is proposed for photovoltaic (PV systems. This proposed system utilizes a single-ended primary inductor (SEPIC converter as DC-DC converter to implement the MPPT algorithm for tracking the maximum power from a PV array and a single phase semi-Z-source inverter for integrating the PV with AC power utilities. The MPPT controller utilizes a fast-converging algorithm to track the maximum power point (MPP and the semi-Z-source inverter utilizes a nonlinear SPWM to produce sinusoidal voltage at the output. The proposed system is able to track the MPP of PV arrays and produce an AC voltage at its output by utilizing only three switches. Experimental results show that the fast-converging MPPT algorithm has fast tracking response with appreciable MPP efficiency. In addition, the inverter shows the minimization of common mode leakage current with its ground sharing feature and reduction of the THD as well as DC current components at the output during DC-AC conversion.

  2. Buck-Boost Current-Source Inverters With Diode-Inductor Network

    DEFF Research Database (Denmark)

    Gao, Feng; Liang, Chao; Loh, Poh Chiang

    2009-01-01

    This paper presents a number of novel currentsource inverters (CSIs) with enhanced current buck-boost capability. By adding a unique diode-inductor network between the inverter circuitry and current-boost elements, the proposed buck-boost CSIs demonstrate a doubling of current-boost capability......, as compared with other recently reported buck-boost CSIs. For controlling the proposed CSIs, two modulation schemes are designed for achieving either optimized harmonic performance or minimized commutation count without influencing the inverter current buck-boost gain. These theoretical findings were...

  3. Voltage control in Z-source inverter using low cost microcontroller for undergraduate approach

    Science.gov (United States)

    Zulkifli, Shamsul Aizam; Sewang, Mohd Rizal; Salimin, Suriana; Shah, Noor Mazliza Badrul

    2017-09-01

    This paper is focussing on controlling the output voltage of Z-Source Inverter (ZSI) using a low cost microcontroller with MATLAB-Simulink that has been used for interfacing the voltage control at the output of ZSI. The key advantage of this system is the ability of a low cost microcontroller to process the voltage control blocks based on the mathematical equations created in MATLAB-Simulink. The Proportional Integral (PI) control equations are been applied and then, been downloaded to the microcontroller for observing the changes on the voltage output regarding to the changes on the reference on the PI. The system has been simulated in MATLAB and been verified with the hardware setup. As the results, the Raspberry Pi and Arduino that have been used in this work are able to respond well when there is a change of ZSI output. It proofed that, by applying/introducing this method to student in undergraduate level, it will help the student to understand more on the process of the power converter combine with a control feedback function that can be applied at low cost microcontroller.

  4. Online Optimal Switching Frequency Selection for Grid-Connected Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Saher Albatran

    2017-12-01

    Full Text Available Enhancing the performance of the voltage source inverters (VSIs without changing the hardware structure has recently acquired an increased amount of interest. In this study, an optimization algorithm, enhancing the quality of the output power and the efficiency of three-phase grid connected VSIs is proposed. Towards that end, the proposed algorithm varies the switching frequency (fsw to maintain the best balance between switching losses of the insulated-gate-bipolar-transistor (IGBT power module as well as the output power quality under all loading conditions, including the ambient temperature effect. Since there is a contradiction with these two measures in relation to the switching frequency, the theory of multi-objective optimization is employed. The proposed algorithm is executed on the platform of Altera® DE2-115 field-programmable-gate-array (FPGA in which the optimal value of the switching frequency is determined online without the need for heavy offline calculations and/or lookup tables. With adopting the proposed algorithm, there is an improvement in the VSI efficiency without degrading the output power quality. Therefore, the proposed algorithm enhances the lifetime of the IGBT power module because of reduced variations in the module’s junction temperature. An experimental prototype is built, and experimental tests are conducted for the verification of the viability of the proposed algorithm.

  5. A Method of Maximum Power Control in Single-phase Utility Interactive Photovoltaic Generation System by using PWM Current Source Inverter

    Science.gov (United States)

    Neba, Yasuhiko

    This paper deals with a maximum power point tracking (MPPT) control of the photovoltaic generation with the single-phase utility interactive inverter. The photovoltaic arrays are connected by employing the PWM current source inverter to the utility. The use of the pulsating dc current and voltage allows the maximum power point to be searched. The inverter can regulate the array voltage and keep the arrays to the maximum power. This paper gives the control method and the experimental results.

  6. 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.

  7. Modeling, analysis, and design of stationary reference frame droop controlled parallel three-phase voltage source inverters

    DEFF Research Database (Denmark)

    Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi

    2013-01-01

    Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops and the mat......Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops...... control restores the frequency and amplitude deviations produced by the primary control. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control...

  8. Comparative Study of Fault Diagnostic Methods in Voltage Source Inverter Fed Three Phase Induction Motor Drive

    Science.gov (United States)

    Dhumale, R. B.; Lokhande, S. D.

    2017-05-01

    Three phase Pulse Width Modulation inverter plays vital role in industrial applications. The performance of inverter demeans as several types of faults take place in it. The widely used switching devices in power electronics are Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Field Effect Transistors (MOSFET). The IGBTs faults are broadly classified as base or collector open circuit fault, misfiring fault and short circuit fault. To develop consistency and performance of inverter, knowledge of fault mode is extremely important. This paper presents the comparative study of IGBTs fault diagnosis. Experimental set up is implemented for data acquisition under various faulty and healthy conditions. Recent methods are executed using MATLAB-Simulink and compared using key parameters like average accuracy, fault detection time, implementation efforts, threshold dependency, and detection parameter, resistivity against noise and load dependency.

  9. Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Gabriele Grandi

    2013-08-01

    Full Text Available Multiphase systems are nowadays considered for various industrial applications. Numerous pulse width modulation (PWM schemes for multiphase voltage source inverters with sinusoidal outputs have been developed, but no detailed analysis of the impact of these modulation schemes on the output peak-to-peak current ripple amplitude has been reported. Determination of current ripple in multiphase PWM voltage source inverters is important for both design and control purposes. This paper gives the complete analysis of the peak-to-peak current ripple distribution over a fundamental period for multiphase inverters, with particular reference to seven-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index, and a simplified expression to get its maximum value is carried out. Although reference is made to the centered symmetrical PWM, being the most simple and effective solution to maximize the DC bus utilization, leading to a nearly-optimal modulation to minimize the RMS of the current ripple, the analysis can be readily extended to either discontinuous or asymmetrical modulations, both carrier-based and space vector PWM. A similar approach can be usefully applied to any phase number. The analytical developments for all different sub-cases are verified by numerical simulations.

  10. Possibilities by using a self-commutated voltage source inverter connected to a weak grid in wind parks

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Jan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

    1996-12-01

    In this paper the hybrid wind farm connected to a weak grid is investigated. By combining different electrical wind power plant systems a cost-efficient solution is obtained. The point of common connection voltage level can be controlled by injecting reactive power from a phase-compensating capacitor battery and a voltage source inverter (VSI). If the short-circuit impedance ratio is lower than 1, the demanded reactive power injection to keep the voltage at nominal level is unrealistic. For short-circuit impedance ratios of 2 or higher the demanded reactive power level is acceptable. When using both induction generators and thyristor inverters the reactive power injector VSI size should be about 0.2 pu. If the hybrid farm consists of THYs, IGs and VSIs and the active power is equally shared between the systems, the VSI had to be scaled up by 5% to handle both active and reactive power. 7 refs, 10 figs, 2 tabs

  11. Modulation Technique for Four-Leg Voltage Source Inverter without a Look-Up Table

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Farhangi, Shahrokh; Iman-Eini, Hossein

    2016-01-01

    Three-dimensional space-vector modulation (3D SVM) has more popularity among the other modulation techniques of the four-leg inverter due to higher DC-link voltage utilisation. Sequencing schemes of the switching vectors in the 3D SVM are divided into Class I and II categories. Each of these clas...

  12. PWM control of current source type six-phase inverter with improved waveforms by coupling reactor; Ketsugo reactor ni yori hakei kaizen sareta denryugata rokuso inverter no PWM seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Inami, K.; Danjo, M.; Kondo, Y.; Yamada, M. [Niihama Technical College, Ehime (Japan); Toki, K. [Shikoku Electric Power Co., Inc., Kagawa (Japan); Heike, J. [Shikoku Instrumentation Co. Ltd., Kagawa (Japan)

    1998-10-01

    A PWM method has been applied to a high capacity six phase current source inverter system in order to obtain sinusoidal output voltage and current. In this system, the three-phase coupling reactor is connected between the inverter output and an induction motor used as a load. Then the reactor eliminates harmonic components included in the inverter output current except 12k {+-} 1 (k=1,2,3)th order. As a result, the distortion factor of the inverter output current decreases. But the resonant circuit is composed of the capacitance of filter capacitor and the induction motor leakage inductance. Then the resonance current is superimposed on the induction motor phase currents. To solve this problem, the optimal PWM pattern is derived, so that the resonant current becomes very small. The order of the resonant frequency component of the induction motor phase current depend on the inverter frequency. Then total inverter frequency range is divided into several areas. The optimal PWM pattern is derived in each areas. As a result, the use of each optimal PWM pattern allows us to drive the induction motor, over a wide range of speed, under the condition of small distortion factor of phase currents. 5 refs., 10 figs., 1 tab.

  13. Power supply for nuclear power plant home consumption using inverter sources

    International Nuclear Information System (INIS)

    Stepar, V.; Tvrdik, J.

    1988-01-01

    A description is presented of the system configuration of a nuclear power plant with WWER-440 and WWER-1000 units and of a system of guaranteed power supply for the plant home consumption network for a WWER-440 power plant. The power supply network consists of 6 inverter supplies for safety systems, 4 supplies for nonsystem facilities and of a minimum of three power supplies for facilities outside the units. A diagram is shown and the principle described of the currently used ABP 1500 power supply system of Soviet origin. Using the experience from its operation, a Czechoslovak inverter supply system was designed featuring parallel operation of the inverter units. The principles are given for the design of a power supply system of an output of 75 kVA, the diagram is shown and the principle described. The design allows implementing and using the system without redundancy or in redundant operation of the 2 from 3 type at an installed capacity of 66%, or of the 1 from 2 type at an installed capacity of 50% of the output. The system is undergoing tests that should verify its reliability. (J.B.). 3 figs., 1 tab

  14. Modeling, analysis, and design of stationary reference frame droop controlled parallel three-phase voltage source inverters

    DEFF Research Database (Denmark)

    Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi

    2011-01-01

    and discussed. Experimental results are provided to validate the performance and robustness of the VSIs functionality during Islanded and grid-connected operations, allowing a seamless transition between these modes through control hierarchies by regulating frequency and voltage, main-grid interactivity......Power electronics based microgrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models...

  15. 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...

  16. The 50 kV inverted source of polarized electrons at ELSA

    International Nuclear Information System (INIS)

    Hillert, Wolfgang; Gowin, Michael; Neff, Berhold

    2001-01-01

    The future medium energy physics program at the electron stretcher accelerator ELSA of Bonn University mainly relies on experiments requiring a beam of polarized electrons and a polarized target. To provide a polarized beam with high polarization and sufficient intensity a pulsed 50 kV inverted gun of polarized electrons has been set into operation. The gun is operated in space charge limitation, producing a peak current of 100 mA in rectangular 1μs long electron pulses. Photocathode lifetime during operation is higher than 3000 hours. Using a Be-InGaAs/Be-AlGaAs superlattice photocathode a polarization of 80% and a corresponding quantum efficiency of 0.4% could be obtained

  17. CsI and some new photocathodes

    International Nuclear Information System (INIS)

    Anderson, D.F.; Kwan, S.; Peskov, V.

    1993-06-01

    A discussion of the possible sources of discrepancies in the measurements of the quantum efficiency of CsI photocathodes is presented. We propose that the major causes for disagreements in QE are due to the QE dependence on the current density extracted from the photocathode, on the electric field, and on the temperature of the photocathode. Preliminary results on TMAE enhanced GaAs and Si, plus TMAE protected CsTe and SbCs photocathodes, operated in gas, are also presented

  18. 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.

  19. Switching Loss Reduction in the Three-Phase Quasi-Z-Source Inverters Utilizing Modified Space Vector Modulation Strategies

    DEFF Research Database (Denmark)

    Abdelhakim, Ahmed; Davari, Pooya; Blaabjerg, Frede

    2018-01-01

    Several single-stage topologies have been introduced since kicking off the three-phase Z-source inverter (ZSI), and among these topologies, the quasi-ZSI (qZSI) is the most common one due to its simple structure and continuous input current. Furthermore, different modulation strategies, utilizing...... multiple reference signals, have been developed as well. However, prior art modulation methods have some demerits, such as the complexity of generating the gate signals, the increased number of switch commutations with continuous commutation at high current level during the entire fundamental cycle...... the generation of the gate signals by utilizing only three reference signals, and achieving a single switch commutation at a time. These modulation strategies are analyzed and compared to the conventional ones, where a reduced-scale 1 kVA three-phase qZSI is designed and simulated using these different...

  20. 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.

  1. Comparison of the Impedance-Source Networks for Two and Multilevel Buck-Boost Inverter Applications

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Blaabjerg, Frede; Roncero-Clemente, Carlos

    2016-01-01

    Impedance-source networks are an increasingly popular solution in power converter applications, especially in single-stage buck–boost power conversion to avoid additional front-end dc–dc power converters. In the survey papers published, no analytical comparisons of different topologies have been...

  2. A finite-difference contrast source inversion method

    International Nuclear Information System (INIS)

    Abubakar, A; Hu, W; Habashy, T M; Van den Berg, P M

    2008-01-01

    We present a contrast source inversion (CSI) algorithm using a finite-difference (FD) approach as its backbone for reconstructing the unknown material properties of inhomogeneous objects embedded in a known inhomogeneous background medium. Unlike the CSI method using the integral equation (IE) approach, the FD-CSI method can readily employ an arbitrary inhomogeneous medium as its background. The ability to use an inhomogeneous background medium has made this algorithm very suitable to be used in through-wall imaging and time-lapse inversion applications. Similar to the IE-CSI algorithm the unknown contrast sources and contrast function are updated alternately to reconstruct the unknown objects without requiring the solution of the full forward problem at each iteration step in the optimization process. The FD solver is formulated in the frequency domain and it is equipped with a perfectly matched layer (PML) absorbing boundary condition. The FD operator used in the FD-CSI method is only dependent on the background medium and the frequency of operation, thus it does not change throughout the inversion process. Therefore, at least for the two-dimensional (2D) configurations, where the size of the stiffness matrix is manageable, the FD stiffness matrix can be inverted using a non-iterative inversion matrix approach such as a Gauss elimination method for the sparse matrix. In this case, an LU decomposition needs to be done only once and can then be reused for multiple source positions and in successive iterations of the inversion. Numerical experiments show that this FD-CSI algorithm has an excellent performance for inverting inhomogeneous objects embedded in an inhomogeneous background medium

  3. 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.

  4. Ultrabright femtosecond source of biphotons based on a spatial mode inverter.

    Science.gov (United States)

    Jarutis, Vygandas; Juodkazis, Saulius; Mizeikis, Vygantas; Sasaki, Keiji; Misawa, Hiroaki

    2005-02-01

    A method of enhancing the efficiency of entangled biphoton sources based on a type II femtosecond spontaneous parametric downconversion (SPDC) process is proposed and implemented experimentally. Enhancement is obtained by mode inversion of one of the SPDC output beams, which allows the beams to overlap completely, thus maximizing the number of SPDC photon pairs with optimum spatiotemporal overlap. By use of this method, biphoton count rates as high as 16 kHz from a single 0.5-mm-long beta-barium borate crystal pumped by second-harmonic radiation from a Ti:sapphire laser were obtained.

  5. Minimax robust power split in AF relays based on uncertain long-term CSI

    KAUST Repository

    Nisar, Muhammad Danish; Alouini, Mohamed-Slim

    2011-01-01

    An optimal power control among source and relay nodes in presence of channel state information (CSI) is vital for an efficient amplify and forward (AF) based cooperative communication system. In this work, we study the optimal power split (power

  6. Direct model-based predictive control scheme without cost function for voltage source inverters with reduced common-mode voltage

    Science.gov (United States)

    Kim, Jae-Chang; Moon, Sung-Ki; Kwak, Sangshin

    2018-04-01

    This paper presents a direct model-based predictive control scheme for voltage source inverters (VSIs) with reduced common-mode voltages (CMVs). The developed method directly finds optimal vectors without using repetitive calculation of a cost function. To adjust output currents with the CMVs in the range of -Vdc/6 to +Vdc/6, the developed method uses voltage vectors, as finite control resources, excluding zero voltage vectors which produce the CMVs in the VSI within ±Vdc/2. In a model-based predictive control (MPC), not using zero voltage vectors increases the output current ripples and the current errors. To alleviate these problems, the developed method uses two non-zero voltage vectors in one sampling step. In addition, the voltage vectors scheduled to be used are directly selected at every sampling step once the developed method calculates the future reference voltage vector, saving the efforts of repeatedly calculating the cost function. And the two non-zero voltage vectors are optimally allocated to make the output current approach the reference current as close as possible. Thus, low CMV, rapid current-following capability and sufficient output current ripple performance are attained by the developed method. The results of a simulation and an experiment verify the effectiveness of the developed method.

  7. Source Rupture Process of the 2016 Kumamoto, Japan, Earthquake Inverted from Strong-Motion Records

    Science.gov (United States)

    Zhang, Wenbo; Zheng, Ao

    2017-04-01

    On 15 April, 2016 the great earthquake with magnitude Mw7.1 occurred in Kumamoto prefecture, Japan. The focal mechanism solution released by F-net located the hypocenter at 130.7630°E, 32.7545°N, at a depth of 12.45 km, and the strike, dip, and the rake angle of the fault were N226°E, 84˚ and -142° respectively. The epicenter distribution and focal mechanisms of aftershocks implied the mechanism of the mainshock might have changed in the source rupture process, thus a single focal mechanism was not enough to explain the observed data adequately. In this study, based on the inversion result of GNSS and InSAR surface deformation with active structures for reference, we construct a finite fault model with focal mechanism changes, and derive the source rupture process by multi-time-window linear waveform inversion method using the strong-motion data (0.05 1.0Hz) obtained by K-NET and KiK-net of Japan. Our result shows that the Kumamoto earthquake is a right-lateral strike slipping rupture event along the Futagawa-Hinagu fault zone, and the seismogenic fault is divided into a northern segment and a southern one. The strike and the dip of the northern segment are N235°E, 60˚ respectively. And for the southern one, they are N205°E, 72˚ respectively. The depth range of the fault model is consistent with the depth distribution of aftershocks, and the slip on the fault plane mainly concentrate on the northern segment, in which the maximum slip is about 7.9 meter. The rupture process of the whole fault continues for approximately 18-sec, and the total seismic moment released is 5.47×1019N·m (Mw 7.1). In addition, the essential feature of the distribution of PGV and PGA synthesized by the inversion result is similar to that of observed PGA and seismic intensity.

  8. Adaptive robust pole-placement control of 4-leg voltage-source inverters for standalone photovoltaic systems: Considering digital delays

    International Nuclear Information System (INIS)

    Nasiri, Reza; Radan, Ahmad

    2011-01-01

    Three leg inverters for photovoltaic systems have a lot of disadvantages, especially when the load is unbalanced. These disadvantages are for example, small utilization of the DC link voltage, the dependency of the modulation factor of the load current and the superposition of a DC component with the output AC voltage. A solution for these problems is the 4-leg inverter. Most papers dealing with 4-leg inverters ignore the effect of digital delays in control loop and suggest classic controllers, such as PI controller. However, the transient performance of the system does not become adjustable by applying classic control techniques. Additionally, adaptive control techniques have not yet been discussed for 4-leg inverters. This paper proposes the pole-placement control strategy via state feedback with integral state, which is a modern control technique, to control the system. Consequently, resulted system becomes highly robust. In addition, it suggests a Self-Tuner Regulator to guarantee the adaptive performance of the final system. Moreover, it proposes a novel model, considering digital delays, for 4-leg inverters. Simulation results show that transient performance of the system becomes accurately adjustable and the 4-leg inverter generates balanced voltage, with sinusoidal waveform, in spite of the presence of RL time variant loads.

  9. Improved reconstruction for IDEAL spiral CSI

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Mariager, Christian; Laustsen, Christoffer

    2017-01-01

    In this study we demonstrate how reconstruction for IDEAL spiral CSI (spectroscopic imaging scheme developed for hyperpolarized dynamic metabolic MR imaging) can be improved by using regularization with a sparsity constraint. By exploiting sparsity of the spectral domain, IDEAL spiral CSI can...

  10. Development of the CsI Calorimeter Subsystem for AMEGO

    Science.gov (United States)

    Grove, J. Eric; Woolf, Richard; Johnson, W. Neil; Phlips, Bernard

    2018-01-01

    We report on the development of the thallium-doped cesium iodide (CsI:Tl) calorimeter subsystem for the All-Sky Medium-Energy Gamma-ray Observatory (AMEGO). The CsI calorimeter is one of the three main subsystems that comprise the AMEGO instrument suite; the others include the double-sided silicon strip detector (DSSD) tracker/converter and a cadmium zinc telluride (CZT) calorimeter. Similar to the LAT instrument on Fermi, the hodoscopic calorimeter consists of orthogonally layered CsI bars. Unlike the LAT, which uses PIN photodiodes, the scintillation light readout from each end of the CsI bar is done with recently developed large-area silicon photomultiplier (SiPM) arrays. We currently have an APRA program to develop the calorimeter technology for a larger, future space-based gamma-ray observatory. Under this program, we are building and testing a prototype calorimeter consisting of 24 CsI bars (16.7 mm x 16.7 mm x 100 mm) arranged in 4 layers with 6 bars per layer. The ends of each bar are read out with a 2 x 2 array of 6 mm x 6 mm SensL J series SiPMs. Signal readout and processing is done with the IDEAS SIPHRA (IDE3380) ASIC. Performance testing of this prototype will be done with laboratory sources, a beam test, and a balloon flight in conjunction with the other subsystems led by NASA GSFC. Additionally, we will test 16.7 mm x 16.7 mm x 450 mm CsI bars with SiPM readout to understand the performance of longer bars in advance of the developing the full instrument.Acknowledgement: This work was sponsored by the Chief of Naval Research (CNR) and NASA-APRA (NNH15ZDA001N-APRA).

  11. Relay Precoder Optimization in MIMO-Relay Networks With Imperfect CSI

    KAUST Repository

    Pandarakkottilil, Ubaidulla

    2011-11-01

    In this paper, we consider robust joint designs of relay precoder and destination receive filters in a nonregenerative multiple-input multiple-output (MIMO) relay network. The network consists of multiple source-destination node pairs assisted by a MIMO-relay node. The channel state information (CSI) available at the relay node is assumed to be imperfect. We consider robust designs for two models of CSI error. The first model is a stochastic error (SE) model, where the probability distribution of the CSI error is Gaussian. This model is applicable when the imperfect CSI is mainly due to errors in channel estimation. For this model, we propose robust minimum sum mean square error (SMSE), MSE-balancing, and relay transmit power minimizing precoder designs. The next model for the CSI error is a norm-bounded error (NBE) model, where the CSI error can be specified by an uncertainty set. This model is applicable when the CSI error is dominated by quantization errors. In this case, we adopt a worst-case design approach. For this model, we propose a robust precoder design that minimizes total relay transmit power under constraints on MSEs at the destination nodes. We show that the proposed robust design problems can be reformulated as convex optimization problems that can be solved efficiently using interior-point methods. We demonstrate the robust performance of the proposed design through simulations. © 2011 IEEE.

  12. On the Performance Optimization of Two-Level Three-Phase Grid-Feeding Voltage-Source Inverters

    Directory of Open Access Journals (Sweden)

    Issam A. Smadi

    2018-02-01

    Full Text Available The performance optimization of the two-level, three-phase, grid-feeding, voltage-source inverter (VSI is studied in this paper, which adopts an online adaptive switching frequency algorithm (OASF. A new degree of freedom has been added to the employed OASF algorithm for optimal selection of the weighting factor and overall system optimization design. Toward that end, a full mathematical formulation, including the impact of the coupling inductor and the controller response time, is presented. At first, the weighting factor is selected to favor the switching losses, and the controller gains are optimized by minimizing the integral time-weighted absolute error (ITAE of the output active and reactive power. Different loading and ambient temperature conditions are considered to validate the optimized controller and its fast response through online field programmable gate array (FPGA-in-the-loop. Then, the weighting factor is optimally selected to reduce the cost of the L-filter and the heat-sink. An optimization problem to minimize the cost design at the worst case of loading condition for grid-feeding VSI is formulated. The results from this optimization problem are the filter inductance, the thermal resistance of the heat-sink, and the optimal switching frequency with the optimal weighting factor. The VSI test-bed using the optimized parameters is used to verify the proposed work experimentally. Adopting the OASF algorithm that employs the optimal weighting factor for grid-feeding VSI, the percentages of the reductions in the slope of the steady state junction temperature profile compared to fixed frequencies of 10 kHz, 14.434 kHz, and 20 kHz are about 6%, 30%, and 18%, respectively.

  13. A Single-Phase Current Source Solar Inverter with Constant Instantaneous Power, Improved Reliability, and Reduced-Size DC-Link Filter

    Science.gov (United States)

    Bush, Craig R.

    This dissertation presents a novel current source converter topology that is primarily intended for single-phase photovoltaic (PV) applications. In comparison with the existing PV inverter technology, the salient features of the proposed topology are: a) the low frequency (double of line frequency) ripple that is common to single-phase inverters is greatly reduced; b) the absence of low frequency ripple enables significantly reduced size pass components to achieve necessary DC-link stiffness and c) improved maximum power point tracking (MPPT) performance is readily achieved due to the tightened current ripple even with reduced-size passive components. The proposed topology does not utilize any electrolytic capacitors. Instead an inductor is used as the DC-link filter and reliable AC film capacitors are utilized for the filter and auxiliary capacitor. The proposed topology has a life expectancy on par with PV panels. The proposed modulation technique can be used for any current source inverter where an unbalanced three-phase operation is desires such as active filters and power controllers. The proposed topology is ready for the next phase of microgrid and power system controllers in that it accepts reactive power commands. This work presents the proposed topology and its working principle supported by with numerical verifications and hardware results. Conclusions and future work are also presented.

  14. Performance Evaluation and Slip Regulation Control of an Asymmetrical Parameter Type Two-Phase Induction Motor Drive Using a Three-Leg Voltage Source Inverter

    Science.gov (United States)

    Piyarat, Wekin; Kinnares, Vijit

    This paper presents a performance evaluation and a simple speed control method of an asymmetrical parameter type two-phase induction motor drive using a three-leg VSI (Voltage Source Inverter). The two-phase induction motor is adapted from an existing single-phase induction motor resulting in impedance unbalance between main and auxiliary windings. The unbalanced two-phase inverter outputs with orthogonal displacement based on a SPWM (Sinusoidal Pulse Width Modulation) method are controlled with appropriate amplitudes for improving the motor performance. Dynamic simulation of the proposed drive system is given. A simple speed controller based on a slip regulation method is designed. The overall system is implemented on a DSP (Digital Signal Processor) board. The validity of the proposed system is verified by simulation and experimental results.

  15. Current control methods for grid-side three-phase PWM voltage-source inverter in distributed generation systems

    DEFF Research Database (Denmark)

    Lar, Ionut Andrei; Radulescu, Mircea; Ritchie, Ewen

    2012-01-01

    A comparison between two current control methods of grid side inverter, PI current control and Robust Forward control is made. PI control is implemented in d-q synchronous frame while Forward is implemented in abc stationary frames.The report contains both simulations and experimental test wich...

  16. Adaptive Droop Control Applied to Voltage-Source Inverters Operating in Grid-Connected and Islanded Modes

    DEFF Research Database (Denmark)

    Vasquez, J. C.; Guerrero, J. M.; Luna, A.

    2009-01-01

    This paper proposes a novel control for voltagesource inverters with the capability to flexibly operate in gridconnected and islanded modes. The control scheme is based on the droop method, which uses some estimated grid parameters such as the voltage and frequency and the magnitude and angle of ...

  17. GENETIC ALGORITHM BASED SOLUTION IN PWM CONVERTER SWITCHING FOR VOLTAGE SOURCE INVERTER FEEDING AN INDUCTION MOTOR DRIVE

    Directory of Open Access Journals (Sweden)

    V. Jegathesan

    2017-11-01

    Full Text Available This paper presents an efficient and reliable Genetic Algorithm based solution for Selective Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. Determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. Many methods are available to eliminate the higher order harmonics and it can be easily removed. But the greatest challenge is to eliminate the lower order harmonics and this is successfully achieved using Genetic Algorithm without using Dual transformer. Simulations using MATLABTM and Powersim with experimental results are carried out to validate the solution. The experimental results show that the harmonics up to 13th were totally eliminated.

  18. An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2015-07-01

    Full Text Available Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary  frame to suppress the transient fluctuations and the total harmonic distortion (THD of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load. The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.

  19. Power sharing algorithm for vector controlled six-phase AC motor with four customary three-phase voltage source inverter drive

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede

    2015-01-01

    This paper considered a six-phase (asymmetrical) induction motor, kept 30 phase displacement between two set of three-phase open-end stator windings configuration. The drive system consists of four classical three-phase voltage inverters (VSIs) and all four dc sources are deliberately kept isolated......) by nearest three vectors (NTVs) approach is adopted to regulate each couple of VSIs. The proposed power sharing algorithm is verified by complete numerical simulation modeling (Matlab/ Simulink-PLECS software) of whole ac drive system by observing the dynamic behaviors in different designed condition. Set...

  20. Ab initio study of the effects of thin CsI coatings on the work function of graphite cathodes

    Science.gov (United States)

    Vlahos, Vasilios; Booske, John H.; Morgan, Dane

    2007-10-01

    Cesium-iodide (CsI)-coated graphite cathodes are promising electron sources for high power microwave generators, but the mechanism driving the improved emission is not well understood. Therefore, an ab initio modeling investigation on the effects of thin CsI coatings on graphite has been carried out. It is demonstrated that the CsI coatings reduce the work function of the system significantly through a mechanism of induced dipoles. The results suggest that work function modification is a major contribution to the improved emission seen when CsI coatings are applied to C.

  1. Langley's CSI evolutionary model: Phase O

    Science.gov (United States)

    Belvin, W. Keith; Elliott, Kenny B.; Horta, Lucas G.; Bailey, Jim P.; Bruner, Anne M.; Sulla, Jeffrey L.; Won, John; Ugoletti, Roberto M.

    1991-01-01

    A testbed for the development of Controls Structures Interaction (CSI) technology to improve space science platform pointing is described. The evolutionary nature of the testbed will permit the study of global line-of-sight pointing in phases 0 and 1, whereas, multipayload pointing systems will be studied beginning with phase 2. The design, capabilities, and typical dynamic behavior of the phase 0 version of the CSI evolutionary model (CEM) is documented for investigator both internal and external to NASA. The model description includes line-of-sight pointing measurement, testbed structure, actuators, sensors, and real time computers, as well as finite element and state space models of major components.

  2. Power sharing algorithm for vector controlled six-phase AC motor with four customary three-phase voltage source inverter drive

    Directory of Open Access Journals (Sweden)

    Sanjeevikumar Padmanaban

    2015-09-01

    Full Text Available This paper considered a six-phase (asymmetrical induction motor, kept 30° phase displacement between two set of three-phase open-end stator windings configuration. The drive system consists of four classical three-phase voltage inverters (VSIs and all four dc sources are deliberately kept isolated. Therefore, zero-sequence/homopolar current components cannot flow. The original and effective power sharing algorithm is proposed in this paper with three variables (degree of freedom based on synchronous field oriented control (FOC. A standard three-level space vector pulse width modulation (SVPWM by nearest three vectors (NTVs approach is adopted to regulate each couple of VSIs. The proposed power sharing algorithm is verified by complete numerical simulation modeling (Matlab/Simulink-PLECS software of whole ac drive system by observing the dynamic behaviors in different designed condition. Set of results are provided in this paper, which confirms a good agreement with theoretical development.

  3. 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.

  4. 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...

  5. The Status of GLAST CsI Calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Chekhtman, A.

    2003-09-18

    GLAST is a gamma-ray observatory for celestial sources in the energy range from 20 MeV to 300 GeV. This is NASA project with launch anticipated in 2006. The principal instrument of the GLAST mission is the Large Area Telescope (LAT), consisting of an Anti Coincidence Detector (ACD), a silicon-strip detector Tracker (TKR) and a hodoscopic CsI Calorimeter (CAL). It consists of 16 identical modules arranged in a 4 x 4 array. Each module has horizontal dimensions 38 x 38 cm{sup 2} and active thickness 8.5 radiation length. It contains 96 CsI (Tl) crystals arranged in 8 layers with 12 crystals per layer. The scintillation light is measured by PIN photodiodes mounted on both ends of each crystal. The sum of signals at the two ends of the crystal provides the energy measurement. The difference in these signals provides the position measurement along the crystal. The calorimeter was designed to meet the goals of good energy resolution (better than 10% for photon energies 100 MeV-100 GeV), position resolution of {approx} 1 mm for photon energies > 1 GeV, and a rejection factor of > 100 for charged cosmic rays, under limitations on calorimeter weight (95 kg per module) and power consumption (6 W per module). The Monte Carlo simulation and prototype beam test results confirm that proposed design meets the requirements. Calorimeter production is planned to start in 2003.

  6. 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...

  7. Torque harmonics of an asynchronous motor supplied by a voltage- or current-sourced inverter quasi-square operation

    Energy Technology Data Exchange (ETDEWEB)

    Kyyrae, J. [Helsinki University of Technology, Institute of Intelligent Power Electronics, Espoo (Finland)

    1997-12-31

    Voltage- and current-sourced dc-ac converters operating in quasi-square area are compared. Their characteristics are calculated with switching vector, which is space-vector of switching functions. When the load is an asynchronous motor various analytical equations, including torque, are calculated efficiently. Motor current and torque approximations are compared with the simulated ones. (orig.) 6 refs.

  8. Stability of source mechanisms inverted from P-wave amplitude microseismic monitoring data acquired at the surface

    Czech Academy of Sciences Publication Activity Database

    Staněk, František; Eisner, Leo; Moser, T.J.

    2014-01-01

    Roč. 62, č. 3 (2014), s. 475-490 ISSN 0016-8025 R&D Projects: GA ČR GAP210/12/2451 Institutional support: RVO:67985891 Keywords : microseismic monitoring * inversion * ray modelling * source mechanism Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.506, year: 2013

  9. Design of current source DC/DC converter and inverter for 2kW fuel cell application

    DEFF Research Database (Denmark)

    Andreiciks, A.; Steiks, I.; Krievs, O.

    2013-01-01

    In order to use hydrogen fuel cell in domestic applications either as main power supply or backup power source, the low DC output voltage of the fuel cell has to be matched to the voltage level and frequency of the utility grid AC voltage. The interfacing power converter systems usually consist...... system is designed for interfacing a 2kW proton exchange membrane (PEM) fuel cell....

  10. CSI-EPT in Presence of RF-Shield for MR-Coils.

    Science.gov (United States)

    Arduino, Alessandro; Zilberti, Luca; Chiampi, Mario; Bottauscio, Oriano

    2017-07-01

    Contrast source inversion electric properties tomography (CSI-EPT) is a recently developed technique for the electric properties tomography that recovers the electric properties distribution starting from measurements performed by magnetic resonance imaging scanners. This method is an optimal control approach based on the contrast source inversion technique, which distinguishes itself from other electric properties tomography techniques for its capability to recover also the local specific absorption rate distribution, essential for online dosimetry. Up to now, CSI-EPT has only been described in terms of integral equations, limiting its applicability to homogeneous unbounded background. In order to extend the method to the presence of a shield in the domain-as in the recurring case of shielded radio frequency coils-a more general formulation of CSI-EPT, based on a functional viewpoint, is introduced here. Two different implementations of CSI-EPT are proposed for a 2-D transverse magnetic model problem, one dealing with an unbounded domain and one considering the presence of a perfectly conductive shield. The two implementations are applied on the same virtual measurements obtained by numerically simulating a shielded radio frequency coil. The results are compared in terms of both electric properties recovery and local specific absorption rate estimate, in order to investigate the requirement of an accurate modeling of the underlying physical problem.

  11. Fault diagnosis and fault-tolerant finite control set-model predictive control of a multiphase voltage-source inverter supplying BLDC motor.

    Science.gov (United States)

    Salehifar, Mehdi; Moreno-Equilaz, Manuel

    2016-01-01

    Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of a five-phase BLDC motor. The developed control method is fast, simple, and flexible. A FD method based on available information from the control block is proposed; this method is simple, robust to common transients in motor and able to localize multiple open circuit faults. The proposed FD and FT control algorithm are embedded in a five-phase BLDC motor drive. In order to validate the theory presented, simulation and experimental results are conducted on a five-phase two-level VSI supplying a five-phase BLDC motor. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  12. 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.

  13. 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.

  14. Brushless DC motor drives supplied by PV power system based on Z-source inverter and FL-IC MPPT controller

    International Nuclear Information System (INIS)

    Mozaffari Niapour, S.A.KH.; Danyali, S.; Sharifian, M.B.B.; Feyzi, M.R.

    2011-01-01

    Highlights: → Employing the BLDC motor in water pumping systems. → Utilizing the ZSI as a single-stage power converter in the PV water pumping systems based on BLDC motor. → Improvement of the conventional IC MPPT method with the fuzzy logic control scheme to save more energy from the PV array. → Taking the advantages of the DTC drive of the BLDC motor. → Optimizing the water pumping system speed response characteristic by PSO. - Abstract: This paper discusses operation performance of a water pumping system consist of a brushless dc (BLDC) motor coupled a centrifugal pump and accompanying a Z-source inverter (ZSI) fed by a photovoltaic (PV) array, to be improved. Despite conventional double-stage power converters, this paper proposes utilizing a single-stage ZSI to extract the maximum power of the PV array and supply the BLDC motor simultaneously. Utilizing the ZSI provides some inherent advantages such as high efficiency and low cost, which is very promising for PV systems due to its novel voltage buck/boost capability. In addition, in order to precisely perform the maximum power point tracking (MPPT) of the PV array the fuzzy logic-incremental conductance (FL-IC) MPPT scheme is proposed. The proposed FL-IC MPPT scheme provides enough modification to the conventional IC method to enjoy an appropriate variable step size MPPT control signal for the ZSI. Moreover, direct torque control (DTC) is found more effective in comparison with hysteresis current control with current shaping to drive the BLDC motor, because it benefits from faster torque response, reduced torque ripple, less sensitivity to parameters variations, and simple implementation. In the mean time, due to the frequently variations of the PV power generation; delivered mechanical power to the centrifugal pump is variable. Thus, the BLDC motor should be driven with variable reference speed. In order to improve the speed transient response of the BLDC motor and enhance the energy saving aspect of

  15. Minimax robust power split in AF relays based on uncertain long-term CSI

    KAUST Repository

    Nisar, Muhammad Danish

    2011-09-01

    An optimal power control among source and relay nodes in presence of channel state information (CSI) is vital for an efficient amplify and forward (AF) based cooperative communication system. In this work, we study the optimal power split (power control) between the source and relay node in presence of an uncertainty in the CSI. The prime contribution is to solve the problem based on an uncertain long-term knowledge of both the first and second hop CSI (requiring less frequent updates), and under an aggregate network-level power constraint. We employ the minimax optimization methodology to arrive at the minimax robust optimal power split, that offers the best possible guarantee on the end-to-end signal to noise ratio (SNR). The derived closed form analytical expressions admit simple intuitive interpretations and are easy to implement in real-world AF relaying systems. Numerical results confirm the advantages of incorporating the presence of uncertainty into the optimization problem, and demonstrate the usefulness of the proposed minimax robust optimal power split. © 2011 IEEE.

  16. 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).

  17. 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.

  18. MIMO channel capacity with full CSI at Low SNR

    KAUST Repository

    Tall, Abdoulaye

    2012-10-01

    In this paper, we characterize the ergodic capacity of Multiple Input Multiple Output (MIMO) Rayleigh fading channels with full channel state information (CSI) at both the transmitter (CSI-T) and the receiver (CSI-R) at asymptotically low signal-to-noise ratio (SNR). A simple analytical expression of the capacity is derived for any number of transmit and receive antennas. This characterization clearly shows the substantial gain in terms of capacity over the no CSI-T case and gives a good insight on the effect of the number of antennas used. In addition, an On-Off transmission scheme is proposed and is shown to be asymptotically capacity-achieving. © 2012 IEEE.

  19. Non-traditional method-based solution for elimination of lower order harmonics in voltage source inverter feeding an induction motor drive

    Directory of Open Access Journals (Sweden)

    Vargese Jegathesan

    2008-01-01

    Full Text Available This paper presents an efficient and reliable Genetic Algorithm-based solution for Specific Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. The determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. In this proposed method, harmonics up to 17th are eliminated using Genetic Algorithm without using Dual transformer. Simulations using Matlab 7.0 and PSIM 6.1 are carried out so as to validate the solution.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. Novel Control Strategy for VSI and CSI Active Filters and Comparing These Two Types of Filters

    Directory of Open Access Journals (Sweden)

    Gholam Reza Arab

    2014-10-01

    Full Text Available Recently to eliminate the harmonics and improve the power factor of the power networks, much attention has been attracted to active filters. The advantages of these filters are lower volume and their better compensating characteristics than the passive filters. In conventional sliding mode controllers, the source current waveform is fluctuated in near to zero values. In this paper, using a new sliding technique, lower Total Harmonic Distortion (THD in source current is obtained and the current waveform is improved. As well as, two novel control strategies for two types of active filters, VSI and CSI is proposed and then these two types of filters are compared to reduce THD value of source current.The proposed controlled strategies are simulated by MATLAB/Simulink. The Simulation results confirm that the proposed strategies reduce the THD of source current more than other strategies, and active filter based on CSI has a better performance than active filter based on VSI with a dead time area (for avoiding short circuit of the source in high powers.

  5. 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.

  6. CsI calorimeter of the CMD-3 detector

    International Nuclear Information System (INIS)

    Aulchenko, V.M.; Bondar, A.E.; Erofeev, A.L.; Kovalenko, O.A.; Kozyrev, A.N.; Kuzmin, A.S.; Logashenko, I.B.; Razuvaev, G.P.; Ruban, A.A.; Shebalin, V.E.; Shwartz, B.A.; Talyshev, A.A.; Titov, V.M.; Yudin, Yu.V.; Epifanov, D.A.

    2015-01-01

    The VEPP-2000 e + e − collider has been operated at Budker Institute of Nuclear Physics since 2010. The experiments are performed with two detectors CMD-3 and SND. The calorimetry at the CMD-3 detector is based on three subsystems, two coaxial barrel calorimeters—Liquid Xenon Calorimeter and crystal CsI calorimeter, and endcap calorimeter with BGO crystals. This paper describes the CsI calorimeter of the CMD-3 detector. The calorimeter design, its electronics and calibration procedures are discussed

  7. 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.

  8. 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

  9. 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].

  10. 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.

  11. 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

  12. 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.

  13. Investigation of spectral distribution and variation of irradiance with the passage time of CSI lamps which constitute a solar simulator; Solar simulator ni shiyosuru CSI lamp no supekutoru bunpu, hosha shodo no keiji henka ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, T; Yamada, T; Noguchi, T [Japan Quality Assurance Organization, Tokyo (Japan)

    1997-11-25

    Study was made on time-variation of the performance of CSI lamps for solar simulators. In order to accurately evaluate the standard heat collection performance of solar systems in a room, MITI installed an artificial solar light source in the Solar Techno-Center of Japan Quality Assurance Organization for trial use and evaluation. CSI lamp is superior in durability, and can simulate the solar light in the daytime. The light source is composed of 72 metal halide lamps of 1kW arranged in a plane of 3.5times3.5m. The study result on time-variation of a spectral distribution and irradiance by intermittent switching of lamps showed a sufficient durability of 2000h. To ensure the accuracy of a solar heat collector measurement system enough, periodic calibration is being carried out using reference goods. To ensure the reliability and stability for a switching system, periodic maintenance of a power source, stabilizer and electric system is also being carried out in addition to CSI lamps. The stable irradiance and accuracy are being kept by such maintenance and periodic exchange of lamps. 6 figs., 4 tabs.

  14. 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

  15. ATDM LANL FleCSI: Topology and Execution Framework

    Energy Technology Data Exchange (ETDEWEB)

    Bergen, Benjamin Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-06

    FleCSI is a compile-time configurable C++ framework designed to support multi-physics application development. As such, FleCSI attempts to provide a very general set of infrastructure design patterns that can be specialized and extended to suit the needs of a broad variety of solver and data requirements. This means that FleCSI is potentially useful to many different ECP projects. Current support includes multidimensional mesh topology, mesh geometry, and mesh adjacency information, n-dimensional hashed-tree data structures, graph partitioning interfaces, and dependency closures (to identify data dependencies between distributed-memory address spaces). FleCSI introduces a functional programming model with control, execution, and data abstractions that are consistent with state-of-the-art task-based runtimes such as Legion and Charm++. The model also provides support for fine-grained, data-parallel execution with backend support for runtimes such as OpenMP and C++17. The FleCSI abstraction layer provides the developer with insulation from the underlying runtimes, while allowing support for multiple runtime systems, including conventional models like asynchronous MPI. The intent is to give developers a concrete set of user-friendly programming tools that can be used now, while allowing flexibility in choosing runtime implementations and optimizations that can be applied to architectures and runtimes that arise in the future. This project is essential to the ECP Ristra Next-Generation Code project, part of ASC ATDM, because it provides a hierarchically parallel programming model that is consistent with the design of modern system architectures, but which allows for the straightforward expression of algorithmic parallelism in a portably performant manner.

  16. 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.

  17. 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 (

  18. 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…

  19. 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.

  20. The TiO2 Refraction Film for CsI Scintillator

    OpenAIRE

    C. C. Chen; C. W. Hun; C. J. Wang; C. Y. Chen; J. S. Lin; K. J. Huang

    2015-01-01

    Cesium iodide (CsI) melt was injected into anodic aluminum oxide (AAO) template and was solidified to CsI column. The controllable AAO channel size (10~500 nm) can makes CsI column size from 10 to 500 nm in diameter. In order to have a shorter light irradiate from each singe CsI column top to bottom the AAO template was coated a TiO2 nano-film. The TiO2 film acts a refraction film and makes X-ray has a shorter irradiation path in the CsI crystal making a stronger the photo-electron signal. Wh...

  1. SU-E-I-11: Cascaded Linear System Model for Columnar CsI Flat Panel Imagers with Depth Dependent Gain and Blur

    International Nuclear Information System (INIS)

    Peng, B; Lubinsky, A; Zheng, H; Zhao, W; Teymurazyan, A

    2014-01-01

    Purpose: To implement a depth dependent gain and blur cascaded linear system model (CLSM) for optimizing columnar structured CsI indirect conversion flat panel imager (FPI) for advanced imaging applications. Methods: For experimental validation, depth dependent escape efficiency, e(z), was extracted from PHS measurement of different CsI scintillators (thickness, substrate and light output). The inherent MTF and DQE of CsI was measured using high resolution CMOS sensor. For CLSM, e(z) and the depth dependent MTF(f,z), were estimated using Monte Carlo simulation (Geant4) of optical photon transport through columnar CsI. Previous work showed that Monte Carlo simulation for CsI was hindered by the non-ideality of its columnar structure. In the present work we allowed variation in columnar width with depth, and assumed diffusive reflective backing and columns. Monte Carlo simulation was performed using an optical point source placed at different depth of the CsI layer, from which MTF(z,f) and e(z) were computed. The resulting e(z) with excellent matching with experimental measurements were then applied to the CLSM, Monte Carlo simulation was repeated until the modeled MTF, DQE(f) also match experimental measurement. Results: For a 150 micron FOS HL type CsI, e(z) varies between 0.56 to 0.45, and the MTF at 14 cycles/mm varies between 62.1% to 3.9%, from the front to the back of the scintillator. The overall MTF and DQE(f) at all frequencies are in excellent agreement with experimental measurements at all frequencies. Conclusion: We have developed a CLSM for columnar CsI scintillators with depth dependent gain and MTF, which were estimated from Monte Carlo simulation with novel optical simulation settings. Preliminary results showed excellent agreement between simulation results and experimental measurements. Future work is aimed at extending this approach to optimize CsI screen optic design and sensor structure for achieving higher DQE(f) in cone-beam CT, which uses

  2. Analysis to Inform CA Grid Integration Rules for PV: Final Report on Inverter Settings for Transmission and Distribution System Performance

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jeff [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Rylander, Matthew [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Boemer, Jens [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Broderick, Robert Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reno, Matthew J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mather, Barry [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    The fourth solicitation of the California Solar Initiative (CSI) Research, Development, Demonstration and Deployment (RD&D) Program established by the California Public Utilities Commission (CPUC) supported the Electric Power Research Institute (EPRI), National Renewable Energy Laboratory (NREL), and Sandia National Laboratories (SNL) with data provided from Pacific Gas and Electric (PG&E), Southern California Edison (SCE), and San Diego Gas and Electric (SDG&E) conducted research to determine optimal default settings for distributed energy resource advanced inverter controls. The inverter functions studied are aligned with those developed by the California Smart Inverter Working Group (SIWG) and those being considered by the IEEE 1547 Working Group. The advanced inverter controls examined to improve the distribution system response included power factor, volt-var, and volt-watt. The advanced inverter controls examined to improve the transmission system response included frequency and voltage ride-through as well as Dynamic Voltage Support. This CSI RD&D project accomplished the task of developing methods to derive distribution focused advanced inverter control settings, selecting a diverse set of feeders to evaluate the methods through detailed analysis, and evaluating the effectiveness of each method developed. Inverter settings focused on the transmission system performance were also evaluated and verified. Based on the findings of this work, the suggested advanced inverter settings and methods to determine settings can be used to improve the accommodation of distributed energy resources (PV specifically). The voltage impact from PV can be mitigated using power factor, volt-var, or volt-watt control, while the bulk system impact can be improved with frequency/voltage ride-through.

  3. 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.

  4. A Controller For The Three-phase To Three-phase Matrix Converter And For The Voltage Source Three-phase Inverter Without Dc-link Capacitor [um Controlador De Corrente De Carga Para O Conversor Em Matriz Trifásico Para Trifásico E Para O Inversor De Frequência Sem Capacitor Do Elo De Corrente Contínua

    OpenAIRE

    Filho M.E.O.; Gazoli J.R.; Filho A.J.S.; Ruppert E.

    2010-01-01

    Voltage source three-phase inverter plays an important role in modern industry. The conventional voltage source inverter has a large electrolytic capacitor as energy store element in order to keep the DC-link voltage constant. However, a large electrolytic capacitor increases the input current distortion. Replacing the large electrolytic capacitor by a small film capacitor, the input current quality is improved but the DC-link voltage and the output currents are distorted by low order harmoni...

  5. 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.

  6. 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.

  7. Enhanced columnar structure in CsI layer by substrate patterning

    Energy Technology Data Exchange (ETDEWEB)

    Jing, T.; Cho, G.; Drewery, J.; Kaplan, S.N.; Mireshghi, A.; Perez-Mendez, V.; Wildermuth, D. [Lawrence Berkeley Lab., CA (United States); Fujieda, I. [Xerox Palo Alto Research Center, CA (United States)

    1991-10-01

    Columnar structure in evaporated CsI layers can be controlled by patterning substrates as well as varying evaporation conditions. Mesh-patterned substrates with various dimensions were created by spin-coating polyimide on glass or amorphous silicon substrates and defining patterns with standard photolithography technique. CsI(Tl) layers 200--1000 {mu}m were evaporated. Scintillation properties of these evaporated layers, such as light yield and speed, were equivalent to those of the source materials. Spatial resolution of X-ray detectors consisting of these layers and a linear array of X-ray detectors consisting of these layers and a linear array of Si photodiodes was evaluated by exposing them to a 25{mu}m narrow beam of X-ray. The results obtained with 200{mu}m thick CsI layers coupled to a linear photodiode array with 20 dots/mm resolution showed that the spatial resolution of CsI(Tl) evaporated on patterned substrates was about 75 {mu}m FWHM, whereas that on CsI(Tl) on flat substrates was about 230 {mu}m FWHM. Micrographs taken by SEM revealed that these layers retained the well-defined columnar structure originating from substrate patterns. Adhesion and light transmission of CsI(Tl) were also improved by patterning the substrate.

  8. Optical properties of CsI single crystals irradiated with neutrons at low temperature

    International Nuclear Information System (INIS)

    Okada, M.; Atobe, K.; Itatani, N.; Ozawa, K.

    1998-01-01

    Optical properties of the irradiation-induced-defects in neutron-irradiated CsI single crystals have been investigated. The nominally pure CsI crystals are irradiated by reactor fast neutrons (E>0.1 MeV) with a fluence of 1.4 x 10 15 n/cm 2 at 20 K and by γ-rays from 60 Co source to a dose of 1.5 x 10 4 Gy at liquid nitrogen temperature (LNT). After the irradiations, isochronal annealings are performed to investigate the thermal behavior of the defects. The glow peaks of the thermoluminescence (TL) in each sample irradiated with neutrons at 20 K and with γ-rays at LNT are observed at about 100, 160 and 220 K. In the neutron-irradiated samples at 20 K, the emission band at 338 nm is observed at LNT. It is supposed that this emission band occurs by an excitation of γ-rays from 134 Cs, which is radioactivated by thermal neutrons among the reactor radiations. It is confirmed that the temperature dependence of the 338 nm band is similar with that of the emission band due to the self-trapped exciton which is introduced into the non-irradiated samples illuminated by higher energy photons. (orig.)

  9. Optical properties of CsI single crystals irradiated with neutrons at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Okada, M. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Nakagawa, M. [Faculty of Education, Kagawa Univ., Takamatsu, Kagawa (Japan); Atobe, K. [Faculty of Science, Naruto Univ. of Education, Naruto, Tokushima (Japan); Itatani, N.; Ozawa, K. [Horiba Ltd., Minamiku, Kyoto (Japan)

    1998-05-01

    Optical properties of the irradiation-induced-defects in neutron-irradiated CsI single crystals have been investigated. The nominally pure CsI crystals are irradiated by reactor fast neutrons (E>0.1 MeV) with a fluence of 1.4 x 10{sup 15} n/cm{sup 2} at 20 K and by {gamma}-rays from {sup 60}Co source to a dose of 1.5 x 10{sup 4} Gy at liquid nitrogen temperature (LNT). After the irradiations, isochronal annealings are performed to investigate the thermal behavior of the defects. The glow peaks of the thermoluminescence (TL) in each sample irradiated with neutrons at 20 K and with {gamma}-rays at LNT are observed at about 100, 160 and 220 K. In the neutron-irradiated samples at 20 K, the emission band at 338 nm is observed at LNT. It is supposed that this emission band occurs by an excitation of {gamma}-rays from {sup 134}Cs, which is radioactivated by thermal neutrons among the reactor radiations. It is confirmed that the temperature dependence of the 338 nm band is similar with that of the emission band due to the self-trapped exciton which is introduced into the non-irradiated samples illuminated by higher energy photons. (orig.) 13 refs.

  10. Opportunistic Energy-Aware Amplify-and-Forward Cooperative Systems with Imperfect CSI

    KAUST Repository

    Amin, Osama

    2015-07-29

    Recently, much attention has been paid to the green design of wireless communication systems using energy efficiency (EE) metrics that should capture all energy consumption sources to deliver the required data. In this paper, we design an energyefficient relay assisted communication system based on estimated channel state information (CSI). It employs amplify-andforward relaying and switches between different communication schemes, which are known as direct-transmission, two-hop and cooperative-transmission schemes, using the estimated CSI in order to maximize the EE. Two estimation strategies are assumed, namely disintegrated channel estimation and cascaded channel estimation. To formulate an accurate EE metric for the proposed opportunistic amplify-and-forward system, the channel estimation cost is reflected on the EE metric by including its impact in the signal-to-noise ratio term and in the energy consumption during the channels estimation phase. Based on the formulated EE metric, we propose an adaptive power allocation algorithm to maximize the EE of the proposed opportunistic amplify-andforward system with channel estimation. Furthermore, we study the impact of the estimation parameters on the proposed system via simulation examples.

  11. Chemical Shift Imaging (CSI) by precise object displacement

    OpenAIRE

    Leclerc, Sebastien; Trausch, Gregory; Cordier, Benoit; Grandclaude, Denis; Retournard, Alain; Fraissard, Jacques; Canet, Daniel

    2006-01-01

    International audience; A mechanical device (NMR lift) has been built for displacing vertically an object (typically a NMR sample tube) inside the NMR probe with an accuracy of 1 Μm. A series of single pulse experiments are performed for incremented vertical positions of the sample. With a sufficiently spatially selective rf field, one obtains chemical shift information along the displacement direction (one dimensional Chemical Shift Imaging – CSI). Knowing the vertical radio-frequency (rf) f...

  12. Influence of air exposure on CsI photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yuguang, E-mail: ygxie@mail.ihep.ac.cn [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, CAS and University of Science and Technology of China, Beijing 100049 (China); Zhang, Aiwu; Liu, Yingbiao [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, CAS and University of Science and Technology of China, Beijing 100049 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Hongbang [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Guangxi University, Naning 530004 (China); Hu, Tao; Zhou, Li; Cai, Xiao; Fang, Jian; Yu, Boxiang [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, CAS and University of Science and Technology of China, Beijing 100049 (China); Ge, Yongshuai [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, CAS and University of Science and Technology of China, Beijing 100049 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Lue, Qiwen [Shanxi University, Taiyuan 030006 (China); Sun, Xilei; Sun, Lijun; Xue, Zheng [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, CAS and University of Science and Technology of China, Beijing 100049 (China); Xie, Yigang; Zheng, Yangheng [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Lue, Junguang [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, CAS and University of Science and Technology of China, Beijing 100049 (China)

    2012-10-11

    We investigate the influence of air exposure on the quantum efficiency (QE) and surface morphology of CsI photocathodes (PCs), at relative humidities (RH) higher than 80% down to nearly 3% (both at room temperature) and a 60 Degree-Sign C baking condition. By atomic force microscopy (AFM) surface analysis, it is clearly seen that RH >60% speeds up water film formation and CsI dissolution on the surface of the photocathode at the minute scale, while both grain size and QE change slowly at RH <30% at the hour scale. In the baking environment, the peak QE decreases less than 1.5% (absolute) within one week, and a stainless steel substrate and electron beam evaporation technique tend to effectively weaken the influence of air. With an Au-coated FR-4 substrate, the QE degradation is found to strongly depend on wavelength in the range of 120-210 nm. According to spectra of X-ray photoelectron spectroscopy (XPS), an excess of cesium was observed and the chemical reaction between water and CsI when exposed to humid air is proved. It is found that carbon, and not H{sub 2}O or O{sub 2}, is the main pollutant in the baking condition.

  13. 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...

  14. 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...

  15. 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.

  16. Characteristics of Pb{sup 2+} doped CsI matrix under gamma and neutron excitations

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceição Costa; Madi Filho, Tufic; Berretta, José Roberto; Tomaz, Lucas Faustino; Pinto, Marlene Cristina, E-mail: macoper@ipen.br, E-mail: tmfilho@ipen.br, E-mail: jrretta@ipen.br, E-mail: lucasfaus@gmail.com, E-mail: tynapinto@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    In recent years, there has been an increasing interest in finding new fast scintillating material or improve the characteristics of known scintillators for the demand of high energy physics, industrial and nuclear medical applications. Ions divalent lead Pb{sup 2+} built in some crystal structures are efficient emission centers and their applications in scintillators was and still is the reason of an intensive study of emission properties of different compounds containing these ions. The aggregation of impurities in CsI is poorly studied. The problem of impurity aggregation in CsI is of interest from point of view of the luminescent properties modification of this scintillation material. In this context, the crystals of Pb{sup 2+} doped CsI matrix were grown by the vertical Bridgman technique and subjected to annealing in vacuum of 10{sup -6} mbar and continuous temperature of 350°C, for 24 hours, and then they were employed. To evaluate the response of the CsI:Pb scintillator crystal to gamma radiation, radioactive sources of {sup 137}Cs (662 keV), {sup 60}Co (1173 keV and 1333 keV), {sup 22}Na (511 keV and 1275 keV) and {sup 13}3Ba (355 keV) was used. The operating voltage of the photomultiplier was 2700 V for the detection of gamma rays and the accumulation time in the counting process was 600 s. The crystals used in gamma spectroscopy were cut with dimensions of 20 mm in diameter and 20 mm in height. The scintillator response to neutron radiation from a radioactive source of Am/Be with energy range of 1 MeV to 12 MeV was available. The activity of the AmBe source was 1Ci Am. The fluency was 2.6 x 10{sup 6} neutrons / second. The operating voltage of the photomultiplier tube was 1300 V. The accumulation time in the counting process was 600 s. The scintillator crystals were cut with dimensions of 20 mm diameter and 10 mm height. With the results obtained, it may be observed that the crystals are sensitive to these radiations. (author)

  17. Modelling of the modified-LLCL-filter-based single-phase grid-tied Aalborg inverter

    DEFF Research Database (Denmark)

    Liu, Zifa; Wu, Huiyun; Liu, Yuan

    2017-01-01

    Owing to less conduction and switching power losses, the recently proposed Aalborg inverter has high efficiency within a wide range of input DC voltage for single-phase DC/AC power conversion. In theory, the conduction power losses can be further decreased, if an LLCL-filter is adopted instead...... of an LCL-filter for a voltage source inverter, mainly due to the reduced inductance. The Aalborg inverter shows the characteristic of a current source inverter, when working in the `boost' state. Whether the LLCL-filter can meet the control requirement of this type inverter needs to be further explored....... In this study, the small signal analysis for the modified-LLCL-filter-based Aalborg inverter is addressed. Through the modelling, it can be proven that compared with the LCL-filter, the modified-LLCL-filter causes no extra control challenge for the Aalborg inverter, and therefore more inductance in the power...

  18. 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...

  19. 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

  20. The adsorption of Sr(II) and Cs(I) ions by irradiated Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Yiming Tan; Jundong Feng; Liang Qiu; Zhentian Zhao; Xiaohong Zhang; Haiqian Zhang

    2017-01-01

    Adsorption behavior and mechanism of Sr(II) and Cs(I) in single and binary solutions using irradiated Saccharomyces cerevisiae was investigated. The effects of several environmental factors on Sr(II) and Cs(I) adsorption to irradiated Saccharomyces cerevisiae was determined. The equilibrium experimental data were simulated by different kinetic models and isotherm models. The combined effect of Sr(II) and Cs(I) on Saccharomyces cerevisiae is generally antagonistic. SEM and EDS analyses indicate that crystals formed on the cell surface are precipitate of Sr(II) and Cs(I), respectively. (author)

  1. 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.

  2. 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.

  3. 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.

  4. On the secrecy capacity of the broadcast wiretap channel with limited CSI feedback

    KAUST Repository

    Hyadi, Amal

    2016-10-27

    In this paper, we investigate the problem of secure broadcasting over block-fading channels with limited channel knowledge at the transmitter. More particularly, we analyze the effect of having imperfect channel state information (CSI) via a finite rate feedback on the throughput of a broadcast channel where the transmission is intended for multiple legitimate receivers in the presence of an eavesdropper. First, we partially characterize the ergodic secrecy capacity of the system when the source broadcasts the same information to all the receivers, i.e., common message transmission. Then, we look at the independent messages case, where the transmitter broadcasts multiple independent messages to the legitimate receivers. For this case, we present lower and upper bounds on the ergodic secrecy sum-capacity. In both scenarios, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback links becomes large, hence, fully characterizing the secrecy capacity in this case.

  5. Outage Probability versus Fairness Trade-off in Opportunistic Relay Selection with Outdated CSI

    Directory of Open Access Journals (Sweden)

    Vicario JoseLopez

    2009-01-01

    Full Text Available We analyze the existing trade-offs in terms of system performance versus fairness of a cooperative system based on opportunistic relay selection (ORS and with outdated channel state information (CSI. In particular, system performance is analytically evaluated in terms of outage probability, and the fairness behavior is assessed based on the power consumption at the different relays. In order to improve the fairness behavior of ORS while keeping the selection diversity gain, we propose a relay selection mechanism where the relay with the highest normalized signal-to-noise ratio (SNR is selected for relaying the source's information. The proposed strategy is compared with existing relay selection strategies by adopting a novel graphical representation inspired by expected profit versus risk plots used in modern portfolio theory. As shown in the paper, this strategy allows operating the system in more favorable points of the outage versus fairness region.

  6. 3D Imaging of Dielectric Objects Buried under a Rough Surface by Using CSI

    Directory of Open Access Journals (Sweden)

    Evrim Tetik

    2015-01-01

    Full Text Available A 3D scalar electromagnetic imaging of dielectric objects buried under a rough surface is presented. The problem has been treated as a 3D scalar problem for computational simplicity as a first step to the 3D vector problem. The complexity of the background in which the object is buried is simplified by obtaining Green’s function of its background, which consists of two homogeneous half-spaces, and a rough interface between them, by using Buried Object Approach (BOA. Green’s function of the two-part space with planar interface is obtained to be used in the process. Reconstruction of the location, shape, and constitutive parameters of the objects is achieved by Contrast Source Inversion (CSI method with conjugate gradient. The scattered field data that is used in the inverse problem is obtained via both Method of Moments (MoM and Comsol Multiphysics pressure acoustics model.

  7. On the secrecy capacity of the broadcast wiretap channel with limited CSI feedback

    KAUST Repository

    Hyadi, Amal; Rezki, Zouheir; Alouini, Mohamed-Slim

    2016-01-01

    In this paper, we investigate the problem of secure broadcasting over block-fading channels with limited channel knowledge at the transmitter. More particularly, we analyze the effect of having imperfect channel state information (CSI) via a finite rate feedback on the throughput of a broadcast channel where the transmission is intended for multiple legitimate receivers in the presence of an eavesdropper. First, we partially characterize the ergodic secrecy capacity of the system when the source broadcasts the same information to all the receivers, i.e., common message transmission. Then, we look at the independent messages case, where the transmitter broadcasts multiple independent messages to the legitimate receivers. For this case, we present lower and upper bounds on the ergodic secrecy sum-capacity. In both scenarios, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback links becomes large, hence, fully characterizing the secrecy capacity in this case.

  8. Controllable Nanoscale Inverted Pyramids for High-Efficient Quasi-Omnidirectional Crystalline Silicon Solar Cells.

    Science.gov (United States)

    Xu, Haiyuan; Zhong, Sihua; Zhuang, Yufeng; Shen, Wenzhong

    2017-11-14

    Nanoscale inverted pyramid structures (NIPs) have always been regarded as one of the most paramount light management schemes to achieve the extraordinary performance in various devices, especially in solar cells, due to their outstanding antireflection ability with relative lower surface enhancement ratio. However, the current approaches to fabricating the NIPs are complicated and not cost-effective for the massive cell production in the photovoltaic industry. Here, controllable NIPs are fabricated on crystalline silicon (c-Si) wafers by Ag catalyzed chemical etching and alkaline modification, which is a preferable all-solution-processed method. Through applying the NIPs to c-Si solar cells and optimizing the cell design, we have successfully achieved highly efficient NIPs textured solar cells with the champion efficiency of 20.5%. Importantly, the NIPs textured solar cells are further demonstrated to possess the quasi-omnidirectional property over the broad sunlight incident angles of approximately 0°-60°. Moreover, the NIPs are theoretically revealed to offer light trapping advantage for ultrathin c-Si solar cells. Hence, the NIPs formed by the controllable method exhibit a great potential to be used in the future photovoltaic industry as surface texture. © 2017 IOP Publishing Ltd.

  9. 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 ...

  10. 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)

  11. CSI flight experiment projects of the Naval Research Laboratory

    Science.gov (United States)

    Fisher, Shalom

    1993-02-01

    The Naval Research Laboratory (NRL) is involved in an active program of CSI flight experiments. The first CSI flight experiment of the Naval Research Laboratory, the Low Power Atmospheric Compensation Experiment (LACE) dynamics experiment, has successfully measured vibrations of an orbiting satellite with a ground-based laser radar. The observations, made on January 7, 8 and 10, 1991, represent the first ever measurements of this type. In the tests, a narrowband heterodyne CO2 laser radar, operating at a wavelength of 10.6 microns, detected vibration induced differential-Doppler signatures of the LACE satellite. Power spectral densities of forced oscillations and modal frequencies and damping rates of free-damped vibrations were obtained and compared with finite element structural models of the LACE system. Another manifested flight experiment is the Advanced Controls Technology Experiment (ACTEX) designed to demonstrate active and passive damping with piezo-electric (PZT) sensors and actuators. This experiment was developed under the management of the Air Force Phillips Laboratory with integration of the experiment at NRL. It is to ride as a secondary, or 'piggyback,' experiment on a future Navy satellite.

  12. CsI Calorimeter for a Compton-Pair Telescope

    Science.gov (United States)

    Grove, Eric J.

    We propose to build and test a hodoscopic CsI(Tl) scintillating-crystal calorimeter for a medium-energy γ-ray Compton and pair telescope. The design and technical approach for this calorimeter relies deeply on heritage from the Fermi LAT CsI Calorimeter, but it dramatically improves the low-energy performance of that design by reading out the scintillation light with silicon photomultipliers (SiPMs), making the technology developed for Fermi applicable in the Compton regime. While such a hodoscopic calorimeter is useful for an entire class of medium-energy γ-ray telescope designs, we propose to build it explicitly to support beam tests and balloon flight of the Proto-ComPair telescope, the development and construction of which was funded in a four-year APRA program beginning in 2015 ("ComPair: Steps to a Medium Energy γ-ray Mission" with PI J. McEnery of GSFC). That award did not include funding for its CsI calorimeter subsystem, and this proposal is intended to cover that gap. ComPair is a MIDEX-class instrument concept to perform a high-sensitivity survey of the γ-ray sky from 0.5 MeV to 500 MeV. ComPair is designed to provide a dramatic increase in sensitivity relative to previous instruments in this energy range (predominantly INTEGRAL/SPI and Compton COMPTEL), with the same transformative sensitivity increase - and corresponding scientific return- that the Fermi Large Area Telescope provided relative to Compton EGRET. To enable transformative science over a broad range of MeV energies and with a wide field of view, ComPair is a combined Compton telescope and pair telescope employing a silicon-strip tracker (for Compton scattering and pair conversion and tracking) and a solid-state CdZnTe calorimeter (for Compton absorption) and CsI calorimeter (for pair calorimetry), surrounded by a plastic scintillator anti-coincidence detector. Under the current proposal, we will complete the detailed design, assembly, and test of the CsI calorimeter for the risk

  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. Perception-Induced Effects of Corporate Social Irresponsibility (CSiR) for Stereotypical and Admired Firms.

    Science.gov (United States)

    Voliotis, Seraphim; Vlachos, Pavlos A; Epitropaki, Olga

    2016-01-01

    How do stakeholders react to Corporate Social Irresponsibility (CSiR)? What are the emotional mechanisms and behavioral outcomes following CSiR perception? The psychology of CSR literature has yet to address these important questions and has largely considered CSR and CSiR as the opposite poles of the same continuum. In contrast, we view CSR and CSiR as distinct constructs and theorize about the cognitive (perceptual), emotional, and behavioral effects of CSiR activity on observers (i.e., primary and secondary stakeholders) building on theories of intergroup perception. Specifically, building on the Stereotype Content Model (SCM; Fiske et al., 2002) and the BIAS map (i.e., Behaviors from Intergroup Affect and Stereotypes; Cuddy et al., 2007)-which extends the SCM by predicting behavioral responses-we make predictions on potential stakeholder reactions to CSiR focusing on two practice-relevant cases: (a) a typical for-profit firm that engages in a CSiR activity, (b) an atypical admired firm that engages in CSiR activity.

  15. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    Science.gov (United States)

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  16. 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...

  17. 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).

  18. The Communication Styles Inventory (CSI): a six-dimensional behavioral model of communication styles and its relation with personality

    NARCIS (Netherlands)

    de Vries, R.E.; Bakker-Pieper, A.; Konings, F.E.; Schouten, B.

    2013-01-01

    In this study, a six-dimensional model of communication styles is proposed and operationalized using the Communication Styles Inventory (CSI). The CSI distinguishes between six domain-level communicative behavior scales, Expressiveness, Preciseness, Verbal Aggressiveness, Questioningness,

  19. Temporal resolution limit estimation of x-ray streak cameras using a CsI photocathode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang; Gu, Li; Zong, Fangke; Zhang, Jingjin; Yang, Qinlao, E-mail: qlyang@szu.edu.cn [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China)

    2015-08-28

    A Monte Carlo model is developed and implemented to calculate the characteristics of x-ray induced secondary electron (SE) emission from a CsI photocathode used in an x-ray streak camera. Time distributions of emitted SEs are investigated with an incident x-ray energy range from 1 to 30 keV and a CsI thickness range from 100 to 1000 nm. Simulation results indicate that SE time distribution curves have little dependence on the incident x-ray energy and CsI thickness. The calculated time dispersion within the CsI photocathode is about 70 fs, which should be the temporal resolution limit of x-ray streak cameras that use CsI as the photocathode material.

  20. Magnetically Coupled Impedance-Source Inverters

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    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...

  1. Performance study of single undoped CsI crystals for the Mu2e experiment

    International Nuclear Information System (INIS)

    Donghia, R.

    2016-01-01

    The Mu2e experiment at Fermilab aims to measure the neutrinoless muon-to-electron conversion, which is a charged-lepton flavor-violating process. The goal of the experiment is to reach a single event sensitivity of 2.5 × 10"−"1"7, to set an upper limit on the muon conversion rate at 6.7 × 10"−"1"7 in a three-year run. For this purpose, the Mu2e detector is designed to identify electrons from muon conversion and reduce the background to a negligible level. It consists of a low-mass straw tracker and a pure CsI crystal calorimeter. In this paper, the performance of undoped CsI single crystal is reported. Crystals from many vendors have been characterized by determining their Light Yield (LY) and Longitudinal Response Uniformity (LRU), when read with a UV extended PMT, and their time resolution when coupled to a silicon photomultiplier. The crystals show a LY of ∼ 100 photoelectrons per MeV when wrapped with Tyvek and coupled to the PMT without optical grease. The LRU is well represented by a linear slope that is on average 0.6%/cm. Both measurements have been performed using a "2"2Na source. The timing performance has been evaluated exploiting cosmic rays, with MPPC readout. A timing resolution lower than 400 ps has been achieved (at ∼ 20 MeV, which is the energy released by a minimum ionizing particle in the crystal).

  2. Single-stage MPPT control realization for Aalborg inverter in photovoltaic system

    DEFF Research Database (Denmark)

    Zhang, Shuai; Wu, Weimin; Wang, Houqing

    2017-01-01

    In this paper, the single-stage Maximum Power Point Tracking (MPPT) control strategy for the Aalborg photovoltaic inverter is presented. Aalborg inverter has many advantages, such as high efficiency, wide range of input voltage, minimum voltage drop of the filtering inductors, etc. Nevertheless......, it is essentially a “half-bridge” inverter with two input sources, where one source works in MPPT mode, the other is out of control. If without the reasonable parameter design and the proper control, the bus-voltage of this inverter may change greatly, resulting in the serious power oscillation around maximum power...

  3. 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.

  4. 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.

  5. Security-Reliability Analysis of Noma-Based Multi-Hop Relay Networks in Presence of an Active Eavesdropper with Imperfect Eavesdropping CSI

    Directory of Open Access Journals (Sweden)

    Tran Tin Phu

    2017-01-01

    Full Text Available In this paper, we evaluate system performances of a multi-hop relay protocol with presence of an active eavesdropper. In the proposed protocol, a source attempts to transmit its data to a destination with assistance of multiple intermediate relays. From the eavesdropping Channel State Information (CSI estimated, the source and relays adjust their transmit power so that the eavesdropper cannot overhear the transmitted data. Moreover, to enhance throughput for the proposed system, Non-Orthogonal Multiple Access (NOMA technique with a simple power allocation is also proposed. We derive exact closed-form expressions of the Outage Probability (OP and throughput for the data transmission over Rayleigh fading channel. In addition, when the CSI estimation is imperfect, Intercept Probability (IP at the eavesdropper is derived. Finally, Monte Carlo simulations are presented to verify the theoretical derivations.

  6. Three Level Diode Clamped Inverter Fed Induction Motor with Dtc-Svm

    OpenAIRE

    V. Ranjith Kumar

    2013-01-01

    This project presents a three-level diode-clamped inverter feeding an asynchronous motor drive with direct torque control (DTC). The control method is based on DTC operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a diode-clamped inverter, where each phase of the inverter can be implemented using a dc source, which would be available from fuel c...

  7. 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...

  8. Coupled-Inductor-Based Aalborg Inverter With Input DC Energy Regulation

    DEFF Research Database (Denmark)

    Wang, Houqing; Wu, Weimin; Chung, Henry Shu-hung

    2018-01-01

    Due to the global environmental issues and energy crisis, the injection of renewable energy sources (RESs) into the power system is continuously increasing. As the interface between RESs and power grid, grid-tied inverters using MOSFET switches, without traditional line frequency transformers, show...... some potential advantages, in terms of low cost, high efficiency, and lightweight and small size. Among several proposed configurations, the Aalborg inverter was proposed as a new family of high efficiency MOSFET-switch-based hybrid source inverters. For a conventional “half bridge” type Aalborg...... inverter, due to the imbalance of two independent dc sources, the input dc energies may not be fully utilized, which may reduce the efficiency of whole system. In order to extract the maximum energy from two independent dc sources, a coupled-inductor-based “half bridge” type Aalborg inverter is proposed...

  9. 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

  10. Proton magnetic resonance chemical shift imaging (1H CSI)-directed stereotactic biopsy

    International Nuclear Information System (INIS)

    Son, B.-C.; Kim, B.-C.; Kang, J.-K.; Choi, B.-G.; Kim, E.-N.; Baik, H.-M.; Choe, B.-Y.; Naruse, S.

    2001-01-01

    Introduction. To add metabolic information during stereotactic biopsy target selection, the authors adopted proton chemical shift imaging ( 1 H CSI)-directed stereotactic biopsy. Currently, proton single voxel spectroscopy (SVS) technique has been reported in stereotactic biopsy. We performed 1 H CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, and evaluated the pathological results. Patients and Method. The 1 H CSI-directed stereotactic biopsy was performed in four patients. 1 H CSI and conventional Gd-enhancement stereotactic MRI were performed simultaneously after the fitting of a stereotactic frame. After reconstructing the metabolic maps of N-acetylaspartate (NAA)/phosphocreatine (Cr), phosphocholine (Cho)/Cr, and Lactate/Cr ratios, focal areas of increased Cho/Cr ratio and Lac/Cr ratios were selected as target sites in the stereotactic MR images. Result. 1 H CSI is possible with the stereotactic headframe in place. No difficulty was experienced performing 1 H CSI or making a diagnosis. Pathological samples taken from areas of increased Cho/Cr ratios and decreased NAA/Cr ratios provided information upon increased cellularity, mitoses and cellular atypism, and facilitated diagnosis. Pathological samples taken from areas of increased Lac/ Cr ratio snowed predominant feature of necrosis. Conclusion. 1 H CSI was feasible with the stereotactic headframe in place. The final pathological results obtained were concordant with the local metabolic information from 1 H CSI. We believe that 1 H CSI-directed stereotactic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting. (author)

  11. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2013-07-15

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and {sup 131}I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical

  12. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J.

    2013-07-01

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and 131 I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical speciation of

  13. 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%

  14. 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%.

  15. Experimental study on the CsI (Tl) crystal anti-compton detector in CDEX

    International Nuclear Information System (INIS)

    Liu Shukui; Yue Qian; Tang Changjian

    2012-01-01

    CDEX (China Dark matter Experiment) Collaboration will carry out direct search for dark matter with Ultra-Low Energy Threshold High Purity germanium (ULE-HPGe) detector at CJPL (China Jinping deep underground Laboratory). Before underground research, some experiments of the CsI (Tl) crystal Anti-Compton detector have been done on the ground, including light guide choice, wrapping material choice, height uniformity of CsI (Tl) crystal, side uniformity of CsI (Tl) crystal and the test results of all the crystals. Through the preliminary work on the ground, we have got some knowledge of the anti-compton detector and prepared for the underground experiment. (authors)

  16. Structural transformation of CsI thin film photocathodes under exposure to air and UV irradiation

    CERN Document Server

    Tremsin, A S; Siegmund, O H W

    2000-01-01

    Transmission electron microscopy has been employed to study the structure of polycrystalline CsI thin films and its transformation under exposure to humid air and UV irradiation. The catastrophic degradation of CsI thin film photocathode performance is shown to be associated with the film dissolving followed by its re-crystallization. This results in the formation of large lumps of CsI crystal on the substrate surface, so that the film becomes discontinuous and its performance as a photocathode is permanently degraded. No change in the surface morphology and the film crystalline structure was observed after the samples were UV irradiated.

  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. 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.

  19. Control Aspects of a LCL Grid-Connected Green Power Inverter

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj; Andersen, Gert Karmisholt; Klumpner, Christian

    2002-01-01

    A full-bridge inverter for interfacing the utility grid is developed for using in a Green Power Inverter application. The inverter is feed from an arbitrary green power source (fuel cell, photovoltaic, small wind turbine etc.) through a rectifier into the dc-link. In order to maintain a sinusoidal...... grid current with low harmonic distortion and a high power factor, the inverter is controlled to emulate a negative resistance towards the grid. The size of the emulated resistor is determined by the dc-link voltage controller, which tries to maintain a constant dc-link voltage. This is however...

  20. H-Bridge Transformerless Inverter with Common Ground for Single-Phase Solar-Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2017-01-01

    This paper proposes a new single-phase H-Bridge transformerless inverter with common ground for grid-connected photovoltaic systems (hereafter it is called ‘Siwakoti-H’ inverter). The inverter works on the principle of flying capacitor and consists of only four power switches (two reverse blocking...... IGBT's (RB-IGBT) and two MOSFET's), a capacitor and a small filter at the output stage. The proposed topology share a common ground with the grid and the PV source. A Unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to minimize switching loss, output current...

  1. LLCL-Filter Based Single-Phase Grid-Tied Aalborg Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Feng, Shuangshuang; Ji, Junhao

    2014-01-01

    The Aalborg Inverter is a new type of high efficient DC/AC grid-tied inverter, where the input DC voltage can vary in a wide range. Compared with the LCL-filter, the LLCL-filter can save the total inductance for the conventional voltage source inverter. In this paper, an LLCL-filter based Aalborg...... Inverter is proposed and its character is illustrated through the small signal analysis in both “Buck” and “Buck-Boost” mode. From the modeling, it can be seen that the resonant inductor in the capacitor loop has not brought extra control difficulties, whereas more inductance in the power loop can be saved...

  2. Proposed Novel Multiphase-Multilevel Inverter Configuration for Open-End Winding Loads

    DEFF Research Database (Denmark)

    Padamanaban, Sanjeevi Kumar; Wheeler, Patrick; Blaabjerg, Frede

    2016-01-01

    This paper presents a new multiphase-multilevel inverter configuration for open-winding loads and suitable for medium power (low-voltage/high-current) applications such as `More Electric Aircraft'. Modular structure comprised of standard dual three-phase voltage source inverter (VSI) along with one...... is developed in this work and overcomes the complexity of standard space vector modulations, easy for real implementation purposes in digital processors. Proposed six-phase multilevel inverter configuration generates multilevel outputs with benefit in comprises with standard multilevel inverter topologies...

  3. Three-phase multilevel inverter configuration for open-winding high power application

    DEFF Research Database (Denmark)

    Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick William

    2015-01-01

    This paper work exploits a new dual open-winding three-phase multilevel inverter configuration suitable for high power medium-voltage applications. Modular structure comprised of standard three-phase voltage source inverter (VSI) along with one additional bi-directional semiconductor device (MOSFET...... for implementation purpose. Proposed dual-inverter configuration generates multilevel outputs with benefit includes reduced THD and dv/dt in comparison to other dual-inverter topologies. Complete model of the multilevel ac drive is developed with simple MSCFM modulation in Matlab/PLECs numerical software...

  4. A Coordinate Control Strategy for Circulating Current Suppression in Multiparalleled Three-Phase Inverters

    DEFF Research Database (Denmark)

    Zhang, Xueguang; Wang, Tianyi; Wang, Xiongfei

    2017-01-01

    This paper addresses the zero-sequence circulating current control in the multiparalleled three-phase voltage-source inverters. The model of the zero-sequence circulating current in the N-paralleled (N ≥ 3) inverters is derived. It is shown that the circulating current is not only susceptible...... to the mismatches of circuit parameters, but it is also influenced by the interactions of circulating current controllers used by other paralleled inverters. To eliminate these adverse effects on the circulating current control loop, a coordinate control strategy for the N-paralleled inverter is proposed based...... on the zero-vector feedforward method with the space-vector pulse width modulation. Moreover, a virtual inverter method is introduced to facilitate the implementation of the proposed controller, which decouples the interactions of circulating current controllers in the paralleled inverters. Finally...

  5. dSPACE based adaptive neuro-fuzzy controller of grid interactive inverter

    International Nuclear Information System (INIS)

    Altin, Necmi; Sefa, İbrahim

    2012-01-01

    Highlights: ► We propose a dSPACE based neuro-fuzzy controlled grid interactive inverter. ► The membership functions and rule base of fuzzy logic controller by using ANFIS. ► A LCL output filter is designed. ► A high performance controller is designed. - Abstract: In this study, design, simulation and implementation of a dSPACE based grid interactive voltage source inverter are proposed. This inverter has adaptive neuro-fuzzy controller and capable of importing electrical energy, generated from renewable energy sources such as the wind, the solar and the fuel cells to the grid. A line frequency transformer and a LCL filter are used at the output of the grid interactive inverter which is designed as current controlled to decrease the susceptibility to phase errors. Membership functions and rule base of the fuzzy logic controller, which control the inverter output current, are determined by using artificial neural networks. Both simulation and experimental results show that, the grid interactive inverter operates synchronously with the grid. The inverter output current which is imported to the grid is in sinusoidal waveform and the harmonic level of it meets the international standards (4.3 < 5.0%). In addition, simulation and experimental results of the neuro-fuzzy and the PI controlled inverter are given together and compared in detail. Simulation and experimental results show that the proposed inverter has faster response to the reference variations and lower steady state error than PI controller.

  6. 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.

  7. Adaptive Droop Control Applied to Distributed Generation Inverters Connected to the Grid

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Teodorescu, Remus; Vásquez, Juan C.

    2008-01-01

    This paper proposes a novel control for voltage source inverters connected to the grid. The control scheme is based on the droop method, and it uses some estimated variables from the grid such as the voltage and the frequency, and the magnitude and angle of the grid impedance. Hence, the inverter...

  8. Analyses of CsI aerosol deposition tests in WIND project with ART and VICTORIA codes

    International Nuclear Information System (INIS)

    Yuchi, Y.; Shibazaki, H.; Kudo, T.

    2000-01-01

    Deposition behavior of cesium iodide (CsI) was analyzed with ART and VICTORIA-92 codes for a test of the aerosol re-vaporization test series performed in WIND project at JAERI. In the test analyzed, CsI aerosol was injected into piping of test section where metaboric acid (HBO 2 ) was placed in advance on the floor area. It was confirmed in the present analysis that similar results on the CsI deposition were obtained between ART and VICTORIA when influences of chemical interactions were negligibly small. The analysis with VICTORIA agreed satisfactorily with the test results in analytical cases that cesium metaborate (CsBO 2 ) was injected into the test section instead of CsI to simulate the pre-existence of HBO 2 effect. (author)

  9. Investigating CSI: portrayals of DNA testing on a forensic crime show and their potential effects.

    Science.gov (United States)

    Ley, Barbara L; Jankowski, Natalie; Brewer, Paul R

    2012-01-01

    The popularity of forensic crime shows such as CSI has fueled debate about their potential social impact. This study considers CSI's potential effects on public understandings regarding DNA testing in the context of judicial processes, the policy debates surrounding crime laboratory procedures, and the forensic science profession, as well as an effect not discussed in previous accounts: namely, the show's potential impact on public understandings of DNA and genetics more generally. To develop a theoretical foundation for research on the "CSI effect," it draws on cultivation theory, social cognitive theory, and audience reception studies. It then uses content analysis and textual analysis to illuminate how the show depicts DNA testing. The results demonstrate that CSI tends to depict DNA testing as routine, swift, useful, and reliable and that it echoes broader discourses about genetics. At times, however, the show suggests more complex ways of thinking about DNA testing and genetics.

  10. Heat enhancement of radiation resistivity of evaporated CsI, KI and KBr photocathodes

    CERN Document Server

    Tremsin, A S

    2000-01-01

    The photoemissive stability of as-deposited and heat-treated CsI, KI and KBr evaporated thin films under UV radiation is examined in this paper. After the deposition, some photocathodes were annealed for several hours at 90 deg. C in vacuum and their performance was then compared to the performance of non-heated samples. We observed that the post-evaporation thermal treatment not only increases the photoyield of CsI and KI photocathodes in the spectral range of 115-190 nm, but also reduces CsI, KI and KBr photocurrent degradation that occurs after UV irradiation. KBr evaporated layers appeared to be more radiation-resistant than CsI and KI layers. Post-deposition heat treatment did not result in any significant variation of KBr UV sensitivity.

  11. Opportunistic Energy-Aware Amplify-and-Forward Cooperative Systems with Imperfect CSI

    KAUST Repository

    Amin, Osama; Bedeer, Ebrahim; Ahmed, Mohamed Hossam; Dobre, Octavia; Alouini, Mohamed-Slim

    2015-01-01

    an energyefficient relay assisted communication system based on estimated channel state information (CSI). It employs amplify-andforward relaying and switches between different communication schemes, which are known as direct-transmission, two-hop and cooperative

  12. Achievable Rates of Cognitive Radio Networks Using Multi-Layer Coding with Limited CSI

    KAUST Repository

    Sboui, Lokman; Rezki, Zouheir; Alouini, Mohamed-Slim

    2016-01-01

    In a Cognitive Radio (CR) framework, the channel state information (CSI) feedback to the secondary transmitter (SU Tx) can be limited or unavailable. Thus, the statistical model is adopted in order to determine the system performance using

  13. Performance Analysis of Communications under Energy Harvesting Constraints with noisy CSI

    KAUST Repository

    Znaidi, Mohamed Ridha; Rezki, Zouheir; Tembine, Hamidou; Alouini, Mohamed-Slim

    2016-01-01

    to environmental changes. In this work, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, to maximize the throughput. Differently from

  14. Enhanced quantum efficiency for CsI grown on a graphite-based substrate coating

    CERN Document Server

    Friese, J; Homolka, J; Kastenmüller, A; Maier-Komor, P; Peter, M; Zeitelhack, K; Kienle, P; Körner, H J

    1999-01-01

    Quantum efficiencies (QE) in the vacuum ultraviolet (VUV) wavelength region have been measured for solid CsI layers on various substrates. The CsI films were deposited applying electron beam evaporation. The QE measurements were performed utilizing synchrotron radiation as well as light from a deuterium lamp. A GaAsP diode with a sensitivity calibration traceable to a primary radiation standard was used for normalization. For CsI layers grown on resin-stabilized graphite films a significant enhancement of QE was observed. Substrates suitable for gas detector applications and aging properties were investigated. The procedures to prepare and reproduce high quantum efficient CsI layers are described.

  15. 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....

  16. Corporate Social Irresponsibility (CSI): Everything you say, or not say, can be held against you

    OpenAIRE

    Jonsson, Veronica; Stéen, Josefine

    2016-01-01

    Corporate social irresponsibility (CSI), as an opposite of corporate social responsibility (CSR), refers to corporation’s failure to act responsibly. To address the actions connected to CSR and CSI, corporations need to overcome the challenges of communicating to their stakeholders and to be transparent. Stakeholders have become more skeptical regarding if the corporations are actually living up to the communicated standards. In other words, if corporations are ‘doing as they say’ and if they...

  17. TOTAL NUCLEAR-REACTION PROBABILITY OF 270 TO 390 N-14 IONS IN SI AND CSI

    NARCIS (Netherlands)

    WARNER, RE; CARPENTER, CL; FETTER, JM; WAITE, WF; WILSCHUT, HW; HOOGDUIN, JM

    A magnetic spectrograph and position-sensitive detectors were used to measure the total nuclear reaction probability eta(R) for alpha + CsI at 116 MeV, N-14 + CsI at 265 and 385 MeV, and N-14 + Si at 271 and 390 MeV. From these eta(R)'s, average reaction cross sections sigma(R) were deduced for

  18. Role of the substrate reflectance and surface-bulk treatments in CsI quantum efficiency

    CERN Document Server

    Singh, B K; Nitti, M A; Valentini, A

    2003-01-01

    We have experimentally investigated the following aspects related to the quantum efficiency of CsI photocathodes: the type of substrate, the film thickness and the effect of a 'bulk treatment' during the film growth. We discovered that, using a high reflectivity aluminium substrate, the photoemission of very thin CsI film is enhanced. Our study also revealed that photocathodes become less sensitive to moisture when a negative bias voltage is applied to the substrate during the film deposition process.

  19. 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.

  20. 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

  1. 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…

  2. Waveform control method for mitigating harmonics of inverter systems with nonlinear load

    DEFF Research Database (Denmark)

    Wang, Haoran; Zhu, Guorong; Fu, Xiaobin

    2015-01-01

    instability in the DC power system, lower its efficiency, and shorten the lifetime of the DC source. This paper presents a general waveform control method that can mitigate the injection of the low-frequency ripple current by the single-phase DC/AC inverter into the DC source. It also discusses the inhibiting......DC power systems connecting to single-phase DC/AC inverters with nonlinear loads will have their DC sources being injected with AC ripple currents containing a low-frequency component at twice the output voltage frequency of the inverter and also other current harmonics. Such a current may create...

  3. The Mu2e undoped CsI crystal calorimeter

    Science.gov (United States)

    Atanov, N.; Baranov, V.; Budagov, J.; Cervelli, F.; Colao, F.; Cordelli, M.; Corradi, G.; Davydov, Y. I.; Di Falco, S.; Diociaiuti, E.; Donati, S.; Donghia, R.; Echenard, B.; Giovannella, S.; Glagolev, V.; Grancagnolo, F.; Happacher, F.; Hitlin, D. G.; Martini, M.; Miscetti, S.; Miyashita, T.; Morescalchi, L.; Murat, P.; Pedreschi, E.; Pezzullo, G.; Porter, F.; Raffaelli, F.; Ricci, M.; Saputi, A.; Sarra, I.; Spinella, F.; Tassielli, G.; Tereshchenko, V.; Usubov, Z.; Zhu, R. Y.

    2018-02-01

    The Mu2e experiment at Fermilab will search for Charged Lepton Flavor Violating conversion of a muon to an electron in an atomic field. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter and an external system, surrounding the solenoid, to veto cosmic rays. The calorimeter plays an important role to provide: a) excellent particle identification capabilities; b) a fast trigger filter; c) an easier tracker track reconstruction. Two disks, located downstream of the tracker, contain 674 pure CsI crystals each. Each crystal is read out by two arrays of UV-extended SiPMs. The choice of the crystals and SiPMs has been finalized after a thorough test campaign. A first small scale prototype consisting of 51 crystals and 102 SiPM arrays has been exposed to an electron beam at the BTF (Beam Test Facility) in Frascati. Although the readout electronics were not final, results show that the current design is able to meet the timing and energy resolution required by the Mu2e experiment.

  4. CSI Frequency Domain Fingerprint-Based Passive Indoor Human Detection

    Directory of Open Access Journals (Sweden)

    Chong Han

    2018-04-01

    Full Text Available Passive indoor personnel detection technology is now a hot topic. Existing methods have been greatly influenced by environmental changes, and there are problems with the accuracy and robustness of detection. Passive personnel detection based on Wi-Fi not only solves the above problems, but also has the advantages of being low cost and easy to implement, and can be better applied to elderly care and safety monitoring. In this paper, we propose a passive indoor personnel detection method based on Wi-Fi, which we call FDF-PIHD (Frequency Domain Fingerprint-based Passive Indoor Human Detection. Through this method, fine-grained physical layer Channel State Information (CSI can be extracted to generate feature fingerprints so as to help determine the state in the scene by matching online fingerprints with offline fingerprints. In order to improve accuracy, we combine the detection results of three receiving antennas to obtain the final test result. The experimental results show that the detection rates of our proposed scheme all reach above 90%, no matter whether the scene is human-free, stationary or a moving human presence. In addition, it can not only detect whether there is a target indoors, but also determine the current state of the target.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. Studies on a modular high-energy photon spectrometer of pure CsI scintillators

    International Nuclear Information System (INIS)

    Kopyto, D.

    1994-04-01

    Aim of the present thesis is the optimization of components for the construction of a high-energy photon spectrometer of pure CsI for the detection of the neutral pseudoscalar mesons π 0 , η, and η' at COSY. These mesons are distinguished by their decay into two γ quanta and can therefore be detected by means of a photon spectrometer. A concept of a 2-arm shower counter of pure CsI is presented. Conclusions on the energy resolution of such a calorimeter shall yield a test module, which is constructed of 5.5 CsI(pure) pyramide trunk, each of which possesses a length of 30 cm and an angular acceptance of 6 .6 . The geometry of the moduls is formed in such a way that its extension to a 2-arm shower counter is possible at any time. Hitherto 14 by teflon foils wrapped up crystals for the test module were tested. Their energy resolution varies at 0.66 MeV between 20 and 25 % FWHM. Furthermore a method was found, which allows to trim the position dependence to the required values. So for the position dependence of a crystal even a value of 1.1 % could be reached. The energy resolution amounted thereby to 22 % FWHM. A measurement of the energy resolution with 20 MeV protons yielded a value of 7 %. For the energy calibration of the single detector elements in a dynamic range between 1 MeV and 12 GeV with low-energy γ sources the charge response function of the photoelectron multiplier to be applied in the test module was determined in dependence on the light intensity. The measurement resulted that the photomultiplier at 40 MeV (related to a CsI(pure) reference crystal with an about twofold so high efficiency of the detectable light in comparison to the long pyramide trunks) deviates by 4 % and at 300 MeV by 38 % from the linear behaviour, while it at 500 MeV shows a deviation of 50 %

  10. 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...

  11. An application of CCD read-out technique to neutron distribution measurement using the self-activation method with a CsI scintillator plate

    International Nuclear Information System (INIS)

    Nohtomi, Akihiro; Kurihara, Ryosuke; Kinoshita, Hiroyuki; Honda, Soichiro; Tokunaga, Masaaki; Uno, Heita; Shinsho, Kiyomitsu; Wakabayashi, Genichiro; Koba, Yusuke; Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Ohga, Saiji

    2016-01-01

    In our previous paper, the self-activation of an NaI scintillator had been successfully utilized for detecting photo-neutrons around a high-energy X-ray radiotherapy machine; individual optical pulses from the self-activated scintillator are read-out by photo sensors such as a photomultiplier tube (PMT). In the present work, preliminary observations have been performed in order to apply a direct CCD read-out technique to the self-activation method with a CsI scintillator plate using a Pu-Be source and a 10-MV linac. In conclusion, it has been revealed that the CCD read-out technique is applicable to neutron measurement around a high-energy X-ray radiotherapy machine with the self-activation of a CsI plate. Such application may provide a possibility of novel method for simple neutron dose-distribution measurement. - Highlights: • Preliminary observations have been performed by a CCD for the CsI self-activation method. • It has been revealed that the CCD read-out technique is applicable to neutron measurement. • Such application may provide a novel method for simple neutron distribution measurement.

  12. An application of CCD read-out technique to neutron distribution measurement using the self-activation method with a CsI scintillator plate

    Energy Technology Data Exchange (ETDEWEB)

    Nohtomi, Akihiro, E-mail: nohtomi@hs.med.kyushu-u.ac.jp [Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Kurihara, Ryosuke; Kinoshita, Hiroyuki; Honda, Soichiro; Tokunaga, Masaaki; Uno, Heita [Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Shinsho, Kiyomitsu [Graduate School of Human Sciences, Tokyo Metropolitan University, 7-2-10 Higashi-oku, Arakawa-ku, Tokyo 116-8551 (Japan); Wakabayashi, Genichiro [Atomic Energy Research Institute, Kinki University, 3-4-1 Kowakae, Higashiosaka-shi, Osaka 577-8502 (Japan); Koba, Yusuke [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko [Department of Radiology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Ohga, Saiji [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan)

    2016-10-01

    In our previous paper, the self-activation of an NaI scintillator had been successfully utilized for detecting photo-neutrons around a high-energy X-ray radiotherapy machine; individual optical pulses from the self-activated scintillator are read-out by photo sensors such as a photomultiplier tube (PMT). In the present work, preliminary observations have been performed in order to apply a direct CCD read-out technique to the self-activation method with a CsI scintillator plate using a Pu-Be source and a 10-MV linac. In conclusion, it has been revealed that the CCD read-out technique is applicable to neutron measurement around a high-energy X-ray radiotherapy machine with the self-activation of a CsI plate. Such application may provide a possibility of novel method for simple neutron dose-distribution measurement. - Highlights: • Preliminary observations have been performed by a CCD for the CsI self-activation method. • It has been revealed that the CCD read-out technique is applicable to neutron measurement. • Such application may provide a novel method for simple neutron distribution measurement.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Methods for the Optimal Design of Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    and the efficient processing of this power by the DC/AC inverter. In this paper two new methods are presented for the optimal design of a PV inverter power section, output filter and MPPT control strategy. The influences of the electric grid regulations and standards as well as the PV array operational......The DC/AC inverters are used in grid-connected PV energy production systems as the power processing interface between the PV energy source and the electric grid. The energy injected into the electric grid by the PV installation depends on the amount of power extracted from the PV power source...

  19. Novel Family of modified qZS buck-boost multilevel inverters with reduced switch count

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede

    2015-01-01

    This paper describes a novel family of modified quasi-Z-source buck-boost multilevel inverters with reduced switch count. The inverters are derived by means of the modified inverter configuration with quasi-Z-source networks. The main benefits of the proposed solutions lie in the increased amount...... of levels with all possible sequences: reduced THD, reduced voltage stress on the transistors and size of the output filter. Also their modulation techniques are proposed and described. Simulation results have confirmed all theoretical predictions. The pros and cons are discussed in the conclusions....

  20. Tuning the colors of c-Si solar cells by exploiting plasmonic effects

    Science.gov (United States)

    Peharz, G.; Grosschädl, B.; Prietl, C.; Waldhauser, W.; Wenzl, F. P.

    2016-09-01

    The color of a crystalline silicon (c-Si) solar cell is mainly determined by its anti-reflective coating. This is a lambda/4 coating made from a transparent dielectric material. The thickness of the anti-reflective coating is optimized for maximal photocurrent generation, resulting in the typical blue or black colors of c-Si solar cells. However, for building-integrated photovoltaic (BiPV) applications the color of the solar cells is demanded to be tunable - ideally by a cheap and flexible coating process on standard (low cost) c-Si solar cells. Such a coating can be realized by applying plasmonic coloring which is a rapidly growing technology for high-quality color filtering and rendering for different fields of application (displays, imaging,…). In this contribution, we present results of an approach for tuning the color of standard industrial c-Si solar cells that is based on coating them with metallic nano-particles. In particular, thin films (green and brownish/red. The position of the resonance peak in the reflection spectrum was found to be almost independent from the angle of incidence. This low angular sensitivity is a clear advantage compared to alternative color tuning methods, for which additional dielectric thin films are deposited on c-Si solar cells.

  1. Visualization of a City Sustainability Index (CSI: Towards Transdisciplinary Approaches Involving Multiple Stakeholders

    Directory of Open Access Journals (Sweden)

    Koichiro Mori

    2015-09-01

    Full Text Available We have developed a visualized 3-D model of a City Sustainability Index (CSI based on our original concept of city sustainability in which a sustainable city is defined as one that maximizes socio-economic benefits while meeting constraint conditions of the environment and socio-economic equity on a permanent basis. The CSI is based on constraint and maximization indicators. Constraint indicators assess whether a city meets the necessary minimum conditions for city sustainability. Maximization indicators measure the benefits that a city generates in socio-economic aspects. When used in the policy-making process, the choice of constraint indicators should be implemented using a top-down approach. In contrast, a bottom-up approach is more suitable for defining maximization indicators because this technique involves multiple stakeholders (in a transdisciplinary approach. Using different materials of various colors, shapes, sizes, we designed and constructed the visualized physical model of the CSI to help people evaluate and compare the performance of different cities in terms of sustainability. The visualized model of the CSI can convey complicated information in a simple and straightforward manner to diverse stakeholders so that the sustainability analysis can be understood intuitively by ordinary citizens as well as experts. Thus, the CSI model helps stakeholders to develop critical thinking about city sustainability and enables policymakers to make informed decisions for sustainability through a transdisciplinary approach.

  2. Design and Control of an Inverter for Photovoltaic Applications

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj

    The energy demand in the world is steadily increasing and new types of energy sources must be found in order to cover the future demands, since the conventional sources are about to be emptied. One type of renewable energy source is the photovoltaic (PV) cell, which converts sunlight to electrical...... current, without any form for mechanical or thermal interlink. PV cells are usually connected together to make PV modules, consisting of 72 PV cells, which generates a DC voltage between 23 Volt to 45 Volt and a typical maximum power of 160 Watt, depending on temperature and solar irradiation....... The electrical infrastructure around the world is based on AC voltage, with a few exceptions, with a voltage of 120 Volt or 230 Volt in the distribution grid. PV modules can therefore not be connected directly to the grid, but must be connected through an inverter. The two main tasks for the inverter are to load...

  3. Design and Implementation of 13 Levels Multilevel Inverter for Photovoltaic System

    Science.gov (United States)

    Subramani, C.; Dhineshkumar, K.; Palanivel, P.

    2018-04-01

    This paper approaches the appearing and modernization of S-Type PV based 13- level multilevel inverter with less quantity of switch. The current S-Type Multi level inverter contains more number of switches and voltage sources. Multilevel level inverter is a be understandable among the most gainful power converters for high power application and present day applications with reduced switches. The fundamental good arrangement of the 13-level multilevel inverter is to get ventured voltage from a couple of levels of DC voltages.. The controller gives actual way day and age to switches through driver circuit using PWM methodology. The execution assessment of proposed multilevel inverter is checked using MATLAB/Simulink. This is the outstanding among other techniquem appeared differently in relation to all other existing system

  4. Quality Assurance on Undoped CsI Crystals for the Mu2e Experiment

    Science.gov (United States)

    Atanov, N.; Baranov, V.; Budagov, J.; Davydov, Yu. I.; Glagolev, V.; Tereshchenko, V.; Usubov, Z.; Cervelli, F.; Di Falco, S.; Donati, S.; Morescalchi, L.; Pedreschi, E.; Pezzullo, G.; Raffaelli, F.; Spinella, F.; Colao, F.; Cordelli, M.; Corradi, G.; Diociaiuti, E.; Donghia, R.; Giovannella, S.; Happacher, F.; Martini, M.; Miscetti, S.; Ricci, M.; Saputi, A.; Sarra, I.; Echenard, B.; Hitlin, D. G.; Hu, C.; Miyashita, T.; Porter, F.; Zhang, L.; Zhu, R.-Y.; Grancagnolo, F.; Tassielli, G.; Murat, P.

    2018-02-01

    The Mu2e experiment is constructing a calorimeter consisting of 1,348 undoped CsI crystals in two disks. Each crystal has a dimension of 34 x 34 x 200 mm, and is readout by a large area silicon PMT array. A series of technical specifications was defined according to physics requirements. Preproduction CsI crystals were procured from three firms: Amcrys, Saint-Gobain and Shanghai Institute of Ceramics. We report the quality assurance on crystal's scintillation properties and their radiation hardness against ionization dose and neutrons. With a fast decay time of 30 ns and a light output of more than 100 p.e./MeV measured with a bi-alkali PMT, undoped CsI crystals provide a cost-effective solution for the Mu2e experiment.

  5. Secrecy performance analysis of SIMO underlay cognitive radio systems with outdated CSI

    KAUST Repository

    Lei, Hongjiang; Zhang, Jianming; Park, Kihong; Ansari, Imran Shafique; Pan, Gaofeng; Alouini, Mohamed-Slim

    2017-01-01

    This study investigates the secrecy outage performance of a single-input multiple-output underlay cognitive radio network (CRN) with outdated channel state information (CSI). The confidential messages are transmitted from transmitter to the destination, while a multi-antenna eavesdropper exists. The maximal ratio combining and selection combining schemes are utilised at the receivers to improve the quality of the received signal-to-noise ratio. The exact and asymptotic closed-form expressions of secrecy outage probability are derived, and simulation results are provided to verify the authors' proposed analytical results. The results reveal that imperfect CSI of main channels deteriorates the secrecy outage performance while that of eavesdropping and interfering channels has contrary effect, and only a unity diversity order can be obtained in underlay CRNs with imperfect CSI.

  6. Performance Analysis of Communications under Energy Harvesting Constraints with noisy CSI

    KAUST Repository

    Znaidi, Mohamed Ridha Ali

    2016-01-06

    In energy harvesting communications, the transmitters have to adapt transmission to availability of energy harvested during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to environmental changes. In this work, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, to maximize the throughput. Differently from previous work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the Energy Harvesting constraints. We determine the optimal power in the case where the channel is assumed to be perfectly known at the receiver. Also, we obtain the power policy when the transmitter has no CSI. Furthermore, we analyze the asymptotic average throughput in a system where the average recharge rate goes asymptotically to zero and when it is very high.

  7. Study of the Quantum Efficiency of CsI Photocathodes Exposed to Oxygen and Water Vapour

    CERN Document Server

    Di Mauro, A; Piuz, François; Schyns, E M; Van Beelen, J B; Williams, T D

    2000-01-01

    The operation of CsI photocathodes in gaseous detectors requires special attention to the purity of the applied gas mixtures.We have studied the influence of oxygen and water vapour contaminations on the performance of CsI photocathodes for theALICE HMPID RICH prototype. Measurements were done through comparison of Cherenkov rings obtained from beamtests. Increased levels of oxygen and water vapour did not show any effect on the performance. The results of this studyfound a direct application in the way of storing CsI photocathodes over long periods nad in particular in the shipment of theHMPID prototype from CERN to the STAR experiment at BNL. (Abstract only available,full text to follow)

  8. Preparation of reflective CsI photocathodes with reproducible high quantum efficiency

    Science.gov (United States)

    Maier-Komor, P.; Bauer, B. B.; Friese, J.; Gernhäuser, R.; Kienle, P.; Körner, H. J.; Montermann, G.; Zeitelhack, K.

    1995-02-01

    CsI as a solid UV-photocathode material has many promising applications in fast gaseous photon detectors. They are proposed in large area Ring Imaging CHerenkov (RICH) devices in forthcoming experiments at various high-energy particle accelerators. A high photon-to-electron conversion efficiency is a basic requirement for the successful operation of these devices. High reproducible quantum efficiencies could be achieved with CsI layers prepared by electron beam evaporation from a water-cooled copper crucible. CsI films were deposited in the thickness range of 30 to 500 μg/cm 2. Absorption coefficients and quantum efficiencies were measured in the wavelength region of 150 nm to 250 nm. The influence of various evaporation parameters on the quantum efficiency were investigated.

  9. Preparation of reflective CsI photocathodes with reproducible high quantum efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Maier-Komor, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Bauer, B.B. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Friese, J. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Gernhaeuser, R. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Kienle, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Koerner, H.J. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Montermann, G. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Zeitelhack, K. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    1995-08-01

    CsI as a solid UV-photocathode material has many promising applications in fast gaseous photon detectors. They are proposed in large area Ring Imaging CHerenkov (RICH) devices in forthcoming experiments at various high-energy particle accelerators. A high photon-to-electron conversion efficiency is a basic requirement for the successful operation of these devices. High reproducible quantum efficiencies could be achieved with CsI layers prepared by electron beam evaporation from a water-cooled copper crucible. CsI films were deposited in the thickness range of 30 to 500 {mu}g/cm{sup 2}. Absorption coefficients and quantum efficiencies were measured in the wavelength region of 150 nm to 250 nm. The influence of various evaporation parameters on the quantum efficiency were investigated. (orig.).

  10. Secrecy performance analysis of SIMO underlay cognitive radio systems with outdated CSI

    KAUST Repository

    Lei, Hongjiang

    2017-06-13

    This study investigates the secrecy outage performance of a single-input multiple-output underlay cognitive radio network (CRN) with outdated channel state information (CSI). The confidential messages are transmitted from transmitter to the destination, while a multi-antenna eavesdropper exists. The maximal ratio combining and selection combining schemes are utilised at the receivers to improve the quality of the received signal-to-noise ratio. The exact and asymptotic closed-form expressions of secrecy outage probability are derived, and simulation results are provided to verify the authors\\' proposed analytical results. The results reveal that imperfect CSI of main channels deteriorates the secrecy outage performance while that of eavesdropping and interfering channels has contrary effect, and only a unity diversity order can be obtained in underlay CRNs with imperfect CSI.

  11. Behind the Nature of Titanium Oxide Excellent Surface Passivation and Carrier Selectivity of c-Si

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym; Crovetto, Andrea; Hansen, Ole

    We present an expanded study of the passivation properties of titanium dioxide (TiO2) on p-type crystalline silicon (c-Si). We report a low surface recombination velocity (16 cm/s) for TiO2 passivation layers with a thin tunnelling oxide interlayer (SiO2 or Al2O3) on p-type crystalline silicon (c-Si......), and post-deposition annealing temperature were investigated. We have observed that that SiO2 and Al2O3 interlayers enhance the TiO2 passivation of c-Si. TiO2 thin film passivation layers alone result in lower effective carrier lifetime. Further annealing at 200  ̊C in N2 gas enhances the surface...

  12. Influence of bias voltage on the stability of CsI photocathodes exposed to air

    CERN Document Server

    Nitti, M A; Nappi, E; Singh, B K; Valentini, A

    2002-01-01

    We describe a possible correlation between the bias voltage applied to the substrate during the growth of CsI photocathodes and the variation of quantum efficiency (QE) after one day exposure to humid air. It was found that fresh samples are much less sensitive to humid air when a high negative bias voltage was applied during film growth. A model based on surface film interaction with water molecules is presented for the observed effect. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements have been performed to examine, respectively, the bulk structure and the surface of fresh and exposed CsI samples. Also reported are transmittance measurements for fresh and aged CsI samples in the wavelength range 190-850 nm.

  13. 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.

  14. Stability Assessment of a System Comprising a Single Machine and Inverter with Scalable Ratings

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lin, Yashen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Purba, Victor [University of Minnesota; Dhople, Sairaj [University of Minnesota

    2017-09-28

    From the inception of power systems, synchronous machines have acted as the foundation of large-scale electrical infrastructures and their physical properties have formed the cornerstone of system operations. However, power electronics interfaces are playing a growing role as they are the primary interface for several types of renewable energy sources and storage technologies. As the role of power electronics in systems continues to grow, it is crucial to investigate the properties of bulk power systems in low inertia settings. In this paper, we assess the properties of coupled machine-inverter systems by studying an elementary system comprised of a synchronous generator, three-phase inverter, and a load. Furthermore, the inverter model is formulated such that its power rating can be scaled continuously across power levels while preserving its closed-loop response. Accordingly, the properties of the machine-inverter system can be assessed for varying ratios of machine-to-inverter power ratings and, hence, differing levels of inertia. After linearizing the model and assessing its eigenvalues, we show that system stability is highly dependent on the interaction between the inverter current controller and machine exciter, thus uncovering a key concern with mixed machine-inverter systems and motivating the need for next-generation grid-stabilizing inverter controls.

  15. Review of sustainability indices and indicators: Towards a new City Sustainability Index (CSI)

    International Nuclear Information System (INIS)

    Mori, Koichiro; Christodoulou, Aris

    2012-01-01

    The purpose of this paper is to discuss conceptual requirements for a City Sustainability Index (CSI) and to review existing major sustainability indices/indicators in terms of the requirements. The following indices are reviewed: Ecological Footprint (EF), Environmental Sustainability Index (ESI), Dashboard of Sustainability (DS), Welfare Index, Genuine Progress Indicator (GPI), Index of Sustainable Economic Welfare, City Development Index, emergy/exergy, Human Development Index (HDI), Environmental Vulnerability Index (EVI), Environmental Policy Index (EPI), Living Planet Index (LPI), Environmentally-adjusted Domestic Product (EDP), Genuine Saving (GS), and some applications of composite indices or/and multivariate indicators to local or regional context as case studies. The key conceptual requirements for an adequate CSI are: (i) to consider environmental, economic and social aspects (the triple bottom line of sustainability) from the viewpoint of strong sustainability; (ii) to capture external impacts (leakage effects) of city on other areas beyond the city boundaries particularly in terms of environmental aspects; (iii) to create indices/indicators originally for the purpose of assessing city sustainability; and (iv) to be able to assess world cities in both developed and developing countries using common axes of evaluation. Based on the review, we conclude that it is necessary to create a new CSI that enables us to assess and compare cities' sustainability performance in order to understand the global impact of cities on the environment and human life as compared with their economic contribution. In the future, the CSI will be able to provide local authorities with guidance toward sustainable paths. - Highlights: ► We derive the four key requirements for a new City Sustainability Index (CSI) system. ► First, the triple bottom line must be considered in terms of strong sustainability. ► Second, environmental leakage effects beyond city boundaries should

  16. Properties of CsI and CsI-TMAE photocathodes

    International Nuclear Information System (INIS)

    Anderson, D.F.; Kwan, S.; Peskov, V.; Hoeneisen, B.

    1992-06-01

    The importance of heating the CsI or CsI-TMAE photocathodes during preparation, as well as the importance of the gas environment on the quantum efficiency is presented. The dependence of the aging characteristics of these photocathodes on the operating temperature, on the presence of gas, and on the charge amplification of the chamber is also discussed. For CsI photocathodes charges in excess of 2x10 14 e - /mm 2 can be collected with little degradation of performance. A timing resolution of 0.55 ns is also achieved for single photoelectrons suggesting a possible time-of-flight detector

  17. Uplink Contention-based CSI Feedback with Prioritized Layers for a Multi-Carrier System

    DEFF Research Database (Denmark)

    Kaneko, Megumi; Hayashi, Kazunori; Popovski, Petar

    2012-01-01

    , several works have considered contention-based CSI feedback in the UL control channel. We propose such a feedback scheme for a generic MC system, based on the idea of variable collision protection, where the probability that a feedback information experiences a collision depends on its importance......Optimized resource allocation of the Downlink (DL) in wireless systems utilizing Multi-Carrier (MC) transmission requires Channel State Information (CSI) feedback for each user/subchannel to the Base Station (BS), consuming a high amount of Uplink (UL) radio resources. To alleviate this problem...

  18. An analysis of the sectorial influence of CSI300 stocks within the directed network

    Science.gov (United States)

    Mai, Yong; Chen, Huan; Meng, Lei

    2014-02-01

    This paper uses the Partial Correlation Planar maximally filtered Graph (PCPG) method to construct a directed network for the constituent stocks underlying the China Securities Index 300 (CSI300). We also analyse the impact of individual stocks. We find that the CSI300 market is a scale-free network with a relatively small power law exponent. The volatility of the stock prices has significant impact on other stocks. In the sectorial network, the industrial sector is the most influential one over other sectors, the financial sector only has a modest influence, while the telecommunication services sector’s influence is marginal. In addition, such inter-sector influence displays quarterly stability.

  19. Highly efficient holograms based on c-Si metasurfaces in the visible range.

    Science.gov (United States)

    Martins, Augusto; Li, Juntao; da Mota, Achiles F; Wang, Yin; Neto, Luiz G; do Carmo, João P; Teixeira, Fernando L; Martins, Emiliano R; Borges, Ben-Hur V

    2018-04-16

    This paper reports on the first hologram in transmission mode based on a c-Si metasurface in the visible range. The hologram shows high fidelity and high efficiency, with measured transmission and diffraction efficiencies of ~65% and ~40%, respectively. Although originally designed to achieve full phase control in the range [0-2π] at 532 nm, these holograms have also performed well at 444.9 nm and 635 nm. The high tolerance to both fabrication and wavelength variations demonstrate that holograms based on c-Si metasurfaces are quite attractive for diffractive optics applications, and particularly for full-color holograms.

  20. Generation of CsI cluster ions for mass calibration in matrix-assisted laser desorption/ionization mass spectrometry

    NARCIS (Netherlands)

    Lou, X.; Dongen, van J.L.J.; Meijer, E.W.

    2010-01-01

    A simple method was developed for the generation of cesium iodide (CsI) cluster ions up to m/z over 20,000 in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). Calibration ions in both positive and negative ion modes can readily be generated from a single MALDI spot of CsI(3)

  1. Comparison of Output Current Ripple in Single and Dual Three-Phase Inverters for Electric Vehicle Motor Drives

    Directory of Open Access Journals (Sweden)

    Jelena Loncarski

    2015-04-01

    Full Text Available The standard solution for the traction system in battery powered electric vehicles (EVs is a two-level (2L inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple reduction, increment of phase motor voltage with limited voltage ratings of the two battery banks, improvement in system reliability, etc. The reduction in current ripple amplitude is particularly relevant since it is a source of electromagnetic interference and audio noise from the inverter-motor power connection cables and from the motor itself. By increasing the inverter switching frequency the ripple amplitude is reduced, but the drive efficiency decreases due to the proportionally increased switching losses. In this paper the peak-to-peak ripple amplitude of the dual-2L inverter is evaluated and compared with the corresponding ripple of the single-2L inverter, considering the same voltage and power motor ratings. The ripple analysis is carried out as a function of the modulation index to cover the whole modulation range of the inverter, and the theoretical results are verified with experimental tests carried out by an inverter-motor drive prototype.

  2. 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.

  3. Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay.

    Science.gov (United States)

    Kasar, Sharayu; Kumar, Sumit; Bajpai, R K; Tomar, B S

    2016-01-01

    Diffusion of Na(I), Cs(I), Sr(II) and Eu(III) in smectite rich natural clay, proposed as a backfill material in the Indian geological repository, was studied using the out-diffusion method. Radiotracers (22)Na, (137)Cs, (85)Sr and (154)Eu were used; the first three are carrier-free enabling experimental work at sub-micromolar metal ion concentration, and Eu(III) tracer (154)Eu was used at sub millimolar concentration. An out-diffusion methodology, wherein a thin planar source of radioactivity placed between two clay columns diffuses out, was used to obtain the apparent diffusion coefficient (Da) values. This methodology enabled determination of diffusion coefficient even for strongly sorbing (154)Eu. Da values for (22)Na, (137)Cs, (85)Sr and (154)Eu were 2.35 (±0.14) × 10(-11), 2.65 (±0.09) × 10(-12), 3.32 (±0.15) × 10(-11) and 1.23 (±0.15) × 10(-13) m(2) s(-1), respectively. Da values were found to be in fair agreement with literature data reported for similar mineralogical sediments. Sorption of radionuclides on the clay was also determined in the present study and differences in Da values were rationalized on the basis of sorption data. Distribution ratios (Kd) for Cs(I) and Eu(III) were higher than that for Sr(II), which in turn was higher than that for Na(I). Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Integration of supercapacitive storage in renewable energy system to compare the response of two level and five level inverter with RL type load

    Science.gov (United States)

    Jana, Suman; Biswas, Pabitra Kumar; Das, Upama

    2018-04-01

    The analytical and simulation-based study in this presented paper shows a comparative report between two level inverter and five-level inverter with the integration of Supercapacitive storage in Renewable Energy system. Sometime dependent numerical models are used to measure the voltage and current response of two level and five level inverter in MATLAB Simulink based environment. In this study supercapacitive sources, which are fed by solar cells are used as input sources to experiment the response of multilevel inverter with integration of su-percapacitor as a storage device of Renewable Energy System. The RL load is used to compute the time response in MATLABSimulink based environment. With the simulation results a comparative study has been made of two different level types of inverters. Two basic types of inverter are discussed in the study with reference to their electrical behavior. It is also simulated that multilevel inverter can convert stored energy within supercapacitor which is extracted from Renewable Energy System.

  5. 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

  6. Power Loss Calculation and Thermal Modelling for a Three Phase Inverter Drive System

    Directory of Open Access Journals (Sweden)

    Z. Zhou

    2005-12-01

    Full Text Available Power losses calculation and thermal modelling for a three-phase inverter power system is presented in this paper. Aiming a long real time thermal simulation, an accurate average power losses calculation based on PWM reconstruction technique is proposed. For carrying out the thermal simulation, a compact thermal model for a three-phase inverter power module is built. The thermal interference of adjacent heat sources is analysed using 3D thermal simulation. The proposed model can provide accurate power losses with a large simulation time-step and suitable for a long real time thermal simulation for a three phase inverter drive system for hybrid vehicle applications.

  7. Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

    Science.gov (United States)

    Hassaine, L.; Mraoui, A.

    2017-02-01

    Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

  8. 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...

  9. 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...

  10. Nine-phase hex-tuple inverter for five-level output based on double carrier PWM technique

    DEFF Research Database (Denmark)

    Padmanaban, S.; Bhaskar, M.S.; Blaabjerg, F.

    2016-01-01

    This work articulates double carrier based five-level pulsewidth modulation for a nine-phase hex-tuple inverter AC drive. A set of standard three-phase voltage source inverter (VSI) with slight modification is used for framing the ninephase AC drive. In particular VSI packed with one bidirectiona...

  11. Optimized Carrier Based Multilevel Generated Modified Dual Three-Phase Open-Winding Inverter for Medium Power Applications

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

    2016-01-01

    This paper presents a novel carrier based multilevel modulation for modified dual three-phase open-winding inverter applicable for low-voltage/high-current applications. A standard three-phase voltage source inverter (VSI) is connected across the open-winding of both ends of the motor. Each VSI i...

  12. An LLCL Power Filter for Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; He, Yuanbin; Blaabjerg, Frede

    2012-01-01

    This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency. Particul......This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency...... to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter...

  13. 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...

  14. 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.

  15. Detection of Potential Induced Degradation in c-Si PV Panels Using Electrical Impedance Spectroscopy

    DEFF Research Database (Denmark)

    Oprea, Matei-lon; Spataru, Sergiu; Sera, Dezso

    2016-01-01

    This work, for the first time, investigates an Impedance Spectroscopy (IS) based method for detecting potential-induced degradation (PID) in crystalline silicon photovoltaic (c-Si PV) panels. The method has been experimentally tested on a set of panels that were confirmed to be affected by PID...

  16. IBC c-Si solar cells based on ion-implanted poly-silicon passivating contacts

    NARCIS (Netherlands)

    Yang, G.; Ingenito, A.; Isabella, O.; Zeman, M.

    2016-01-01

    Ion-implanted poly-crystalline silicon (poly-Si), in combination with a tunnel oxide layer, is investigated as a carrier-selective passivating contact in c-Si solar cells based on an interdigitated back contact (IBC) architecture. The optimized poly-Si passivating contacts enable low interface

  17. Achievable Rates of Cognitive Radio Networks Using Multi-Layer Coding with Limited CSI

    KAUST Repository

    Sboui, Lokman

    2016-03-01

    In a Cognitive Radio (CR) framework, the channel state information (CSI) feedback to the secondary transmitter (SU Tx) can be limited or unavailable. Thus, the statistical model is adopted in order to determine the system performance using the outage concept. In this paper, we adopt a new approach using multi-layer-coding (MLC) strategy, i.e., broadcast approach, to enhance spectrum sharing over fading channels. First, we consider a scenario where the secondary transmitter has no CSI of both the link between SU Tx and the primary receiver (cross-link) and its own link. We show that using MLC improves the cognitive rate compared to the rate provided by a singlelayer- coding (SLC). In addition, we observe numerically that 2-Layer coding achieves most of the gain for Rayleigh fading. Second, we analyze a scenario where SU Tx is provided by partial CSI about its link through quantized CSI. We compute its achievable rate adopting the MLC and highlight the improvement over SLC. Finally, we study the case in which the cross-link is perfect, i.e., a cooperative primary user setting, and compare the performance with the previous cases. We present asymptotic analysis at high power regime and show that the cooperation enhances considerably the cognitive rate at high values of the secondary power budget.

  18. CSI Web Adventures: A Forensics Virtual Apprenticeship for Teaching Science and Inspiring STEM Careers

    Science.gov (United States)

    Miller, Leslie; Chang, Ching-I; Hoyt, Daniel

    2010-01-01

    CSI: The Experience, a traveling museum exhibit and a companion web adventure, was created through a grant from the National Science Foundation as a potential model for informal learning. The website was designed to enrich and complement the exhibit by modeling the forensic process. Substantive science, real-world lab techniques, and higher-level…

  19. Children and Crime Scenes: Have Schools Fallen Victim to the CSI Effect?

    Science.gov (United States)

    Eskriett, Angela

    2011-01-01

    Whilst there continues to be debate regarding the influence of the "CSI effect" upon the criminal justice system, there appears to be a general consensus that the popularisation of work within the field, particularly through a number of "procedural cop shows", has fuelled an explosion in the number of young people choosing to pursue a career in…

  20. Atomic-layer deposited passivation schemes for c-Si solar cells

    NARCIS (Netherlands)

    van de Loo, B.W.H.; Macco, B.; Melskens, J.; Verheijen, M.A.; Kessels, W.M.M.E.

    2016-01-01

    A review of recent developments in the field of passivation of c-Si surfaces is presented, with a particular focus on materials that can be prepared by atomic layer deposition (ALD). Besides Al2O3, various other novel passivation schemes have recently been developed, such as Ga2O3, Ta2O5,

  1. Simulated UO{sub 2} fuel containing CsI by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Wangle, T. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, Praha 1, 115 19 (Czech Republic); Tyrpekl, V. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Cologna, M., E-mail: marco.cologna@ec.europa.eu [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Somers, J. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany)

    2015-11-15

    Herein, an innovative preparation procedure has been deployed enabling, for the first time, the incorporation of volatile fission product simulant into highly dense nuclear fuel pellets. Highly volatile fission products were embedded in a dense UO{sub 2} matrix in the form of CsI by simply mixing starting materials and consolidation in a Spark Plasma Sintering step at 1000 °C with a 5 min dwell time. CsI particles were evenly distributed throughout the pellet and were located at the grain boundaries. The sintering rate is dependent on the O/U ratio of the powder. Addition of CsI also acts as a sintering aid, reducing the temperature of maximum densification. - Highlights: • A new method was developed to incorporation of volatile fission products simulants into dense nuclear fuel pellets. • CsI doped UO{sub 2} pellets were synthetized for the first time, by Spark Plasma Sintering. • The sintering rate in Spark Plasma Sintering is dependent on the O/U ratio of UO{sub 2+x}.

  2. Decay-time measurements on 'pure' CsI scintillators prepared by different methods

    International Nuclear Information System (INIS)

    Keszthelyi-Landori, S.; Foeldvari, I.; Voszka, R.; Fodor, Z.; Seres, Z.

    1990-05-01

    The discovery of the fast decay time of the pure CsI and the various results of the measured samples led to the investigation of decay time of CsI crystals prepared by different methods. Carefully grown or prepared pure CsI behaves as fast scintillators with well or totally suppressed slow decay component. The estimated fast/slow or fast/total ratio is related to the preparation method and to the remaining built-in contamination of the samples. The fast decay of pure CsI consists of two components with decay times of ≅1 and ≅10 ns - with an intensity ratio of 0.3 and 0.65 for gamma and for alpha radiation, respectively. This new ≅1 ns component and the ≅0.8 fast/total ratio may achieve an important role in many applications where fast timing properties are needed, substituting BaF 2 . (author) 18 refs.; 8 figs.; 3 tabs

  3. The CSI Academy: Encouraging Diverse Students to Consider Science Careers and Science Teaching

    Science.gov (United States)

    Kaye, Karen; Turner, John F.; Emigh, James

    2011-01-01

    The CSI academies employed a multi-layered, collaborative approach to encourage diverse students to consider STEM careers, including science teaching. The academies recruited a diverse group of high school students. This was due, in large part, to the creation of a unique selection process that identified students with unrealized potential. The…

  4. Exploring K-3 Teachers' Implementation of Comprehension Strategy Instruction (CSI) Using Expectancy-Value Theory

    Science.gov (United States)

    Foley, Laura S.

    2011-01-01

    This research investigated factors that influence the implementation levels of evidence-based comprehension strategy instruction (CSI) among K-3 teachers. An explanatory design was chosen to gather and probe the data. Quantitative data were gathered via a mailed survey distributed through a representative sample of the 40 school districts (through…

  5. Distributed cognitive two-way relay beamformer designs under perfect and imperfect CSI

    KAUST Repository

    Pandarakkottilil, Ubaidulla

    2011-09-01

    In this paper, we present distributed two-way relay beamformer designs for a cognitive radio network (CRN) in which a pair of cognitive (or secondary) transceiver nodes communicate with each other assisted by a set of cognitive two-way relay nodes. The secondary nodes share the spectrum with a licensed primary user (PU) node, and each node is assumed to be equipped with a single transmit/receive antenna. The interference to the PU resulting from the transmission from the cognitive nodes is kept below a specified limit. First, we consider relay beamformer designs assuming the availability of perfect channel state information (CSI). For this case, a mean-square error (MSE)-constrained beamformer that minimizes the total relay transmit power, and an MSE-balancing beamformer with a constraint on the total relay transmit power are proposed. Next, we consider relay beamformer designs assuming that the available CSI is imperfect. For this case too, we consider the same problems as those in the case of perfect CSI, and propose beamformer designs that are robust to the errors in the CSI. We show that the proposed designs can be reformulated as convex optimization problems that can be solved efficiently. Through numerical simulations, we illustrate the performance of the proposed designs. © 2011 IEEE.

  6. Non-Cartesian Parallel Imaging Reconstruction of Undersampled IDEAL Spiral 13C CSI Data

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Hanson, Lars G.; Ardenkjær-Larsen, Jan Henrik

    scan times based on spatial information inherent to each coil element. In this work, we explored the combination of non-cartesian parallel imaging reconstruction and spatially undersampled IDEAL spiral CSI1 acquisition for efficient encoding of multiple chemical shifts within a large FOV with high...

  7. Iterative Equalization and Interference Alignment for Multiuser MIMO HetNets with Imperfect CSI

    Directory of Open Access Journals (Sweden)

    Daniel Castanheira

    2015-01-01

    Full Text Available In this paper we consider a scenario, where several small-cells work under the same coverage area and spectrum of a macrocell. The signals stemming from the small-cell (macrocell users if not carefully dealt with will generate harmful interference into the macrocell (small-cell. To tackle this problem interference alignment and iterative equalization techniques are considered. By using IA all interference generated by the small-cell (macrocell users is aligned along a low dimensional subspace, at the macrocell (small-cells. This reduces considerably the amount of resources allocated, to enable the coexistence of the two systems. However, perfect IA requires the availability of error-free channel state information (CSI at the transmitters. Due to CSI errors one can have substantial performance degradation due to imperfect alignments. Since in this work the IA precoders are based on imperfect CSI, an efficient iterative space-frequency equalization is designed at the receiver side to cope with the residual aligned interference. The results demonstrate that iterative equalization is robust to imperfect CSI and removes efficiently the interference generated by the poorly aligned interference. Close to matched filter bound performance is achieved, with a very few number of iterations.

  8. Sequential C-Si Bond Formations from Diphenylsilane: Application to Silanediol Peptide Isostere Precursors

    DEFF Research Database (Denmark)

    Nielsen, Lone; Skrydstrup, Troels

    2008-01-01

    and the first new carbon-silicon bond. The next step is the reduction of this hydridosilane with lithium metal providing a silyl lithium reagent, which undergoes a highly diastereoselective addition to an optically active tert-butanesulfinimine, thus generating the second C-Si bond. This method allows...

  9. Two-way CSI-assisted AF relaying with HPA nonlinearity

    KAUST Repository

    Qi, Jian; Aissa, Sonia; Alouiniz, Mohamed-Slim

    2015-01-01

    In this paper, we investigate half-duplex two-way dual-hop channel state information (CSI)-assisted amplify-andforward (AF) relaying in the presence of high-power amplifier (HPA) nonlinearity at relays. The expression for the end-toend signal

  10. 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

  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. 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.

  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. Deposition of CsI aerosol in horizontal straight pipes in WIND project

    International Nuclear Information System (INIS)

    Sugimoto, J.; Maruyama, Y.; Igarashi, M.; Hidaka, A.; Maeda, A.; Harada, Y.; Hashimoto, K.

    1996-01-01

    In the WIND Project at Japan Atomic Energy Research Institute, the aerosol behaviors such as deposition, revaporization and resuspension have been investigated under the severe accident conditions. The present paper describes the deposition of CsI aerosol in horizontal straight pipes. The test results showed that the aerosol deposition depended on thermo-fluid dynamic characteristics of the carrier gas. In the test with the temperature gradient of the pipe, the deposition of CsI was remarkable within the downstream side, where the temperature of the gas was higher than that of the pipe wall. It is thus supposed that the major mechanism of the deposition was thermophoresis caused by the temperature gradient within the gas phase. However, circumferential distribution of the deposited CsI was influenced by the argon flow rate. In laminar flow case, larger amount of CsI was deposited on the ceiling than the floor area. Three-dimensional thermo-fluid dynamic analysis suggested that much sharper radial temperature gradient was developed within the gas near the ceiling area due to the formation of a natural convective secondary flow. This could result in the promotion of the thermophoretic aerosol deposition. On the other hand, slight circumferential distribution was observed in case of the high flow rate, probably due to a uniform temperature field. It was also found that the close coupling of the FP behavior and the detailed thermohydraulic analyses is essential in order to accurately predict the CsI deposition in the pipe. The findings on aerosol behaviors will also be utilized for the evaluation of sodium aerosol behaviors of fast reactors. (author)

  16. High-Performance CH3NH3PbI3-Inverted Planar Perovskite Solar Cells with Fill Factor Over 83% via Excess Organic/Inorganic Halide.

    Science.gov (United States)

    Jahandar, Muhammad; Khan, Nasir; Lee, Hang Ken; Lee, Sang Kyu; Shin, Won Suk; Lee, Jong-Cheol; Song, Chang Eun; Moon, Sang-Jin

    2017-10-18

    The reduction of charge carrier recombination and intrinsic defect density in organic-inorganic halide perovskite absorber materials is a prerequisite to achieving high-performance perovskite solar cells with good efficiency and stability. Here, we fabricated inverted planar perovskite solar cells by incorporation of a small amount of excess organic/inorganic halide (methylammonium iodide (CH 3 NH 3 I; MAI), formamidinium iodide (CH(NH 2 ) 2 I; FAI), and cesium iodide (CsI)) in CH 3 NH 3 PbI 3 perovskite film. Larger crystalline grains and enhanced crystallinity in CH 3 NH 3 PbI 3 perovskite films with excess organic/inorganic halide reduce the charge carrier recombination and defect density, leading to enhanced device efficiency (MAI+: 14.49 ± 0.30%, FAI+: 16.22 ± 0.38% and CsI+: 17.52 ± 0.56%) compared to the efficiency of a control MAPbI 3 device (MAI: 12.63 ± 0.64%) and device stability. Especially, the incorporation of a small amount of excess CsI in MAPbI 3 perovskite film leads to a highly reproducible fill factor of over 83%, increased open-circuit voltage (from 0.946 to 1.042 V), and short-circuit current density (from 18.43 to 20.89 mA/cm 2 ).

  17. 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.

  18. 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

  19. A PWM strategy for acoustic noise reduction for grid-connected single-phase inverters

    Energy Technology Data Exchange (ETDEWEB)

    Shao, R.; Guo, Z.; Chang, L. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Electrical and Computer Engineering

    2006-07-01

    This paper presented a newly proposed and improved pulse width modulation (PWM) strategy for grid-connected single-phase inverters. Small distributed generators using energy from renewable resources such as PV and wind systems typically use grid-connected single-phase inverters as voltage source inverters for good acoustic performance. PWM is generally applied in these inverters in order to achieve good waveforms of output current as required by interconnection standards. In routine simultaneous switching PWM methods, the current ripples through the inverter output filter inductor are at the carrier switching frequency, which is one of the major causes for inverter acoustic noise. The new PWM strategy effectively alleviates acoustic noise and improves output power quality. It is based on the principle of evenly splitting the switching of Insulated Gate Bipolar Transistors (IGBT) in each switching cycle among all IGBTs of the full bridge, thereby using a non-simultaneous mode of PWM which doubles the output current ripple frequency. This increases the inductor current ripple frequency to twice the carrier frequency. It is therefore possible to increase the current ripple frequency, or noise frequency into the range of ultrasonic which is inaudible to the human ear, without increasing the inverter's switching frequency to which the inverter's switching loss is proportional. In addition, this new PWM scheme can reduce the output current harmonics distortion and dc link current ripples. As such, lower capacitance in dc link capacitors and lower inductance of output inductor are needed. The improved PWM scheme was verified in a 3 kW grid-connected single-phase inverter. It was shown that the PWM strategy can be readily implemented with a digital signal processing microcontroller. 8 refs., 11 figs.

  20. 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...

  1. 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.

  2. 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.

  3. Review of sustainability indices and indicators: Towards a new City Sustainability Index (CSI)

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Koichiro, E-mail: kmori@iis.u-tokyo.ac.jp [Institute of Industrial Science, University of Tokyo (Japan); Christodoulou, Aris, E-mail: aris.christodoulou@ucl.ac.uk [Centre for Transport Studies, University College London (United Kingdom)

    2012-01-15

    The purpose of this paper is to discuss conceptual requirements for a City Sustainability Index (CSI) and to review existing major sustainability indices/indicators in terms of the requirements. The following indices are reviewed: Ecological Footprint (EF), Environmental Sustainability Index (ESI), Dashboard of Sustainability (DS), Welfare Index, Genuine Progress Indicator (GPI), Index of Sustainable Economic Welfare, City Development Index, emergy/exergy, Human Development Index (HDI), Environmental Vulnerability Index (EVI), Environmental Policy Index (EPI), Living Planet Index (LPI), Environmentally-adjusted Domestic Product (EDP), Genuine Saving (GS), and some applications of composite indices or/and multivariate indicators to local or regional context as case studies. The key conceptual requirements for an adequate CSI are: (i) to consider environmental, economic and social aspects (the triple bottom line of sustainability) from the viewpoint of strong sustainability; (ii) to capture external impacts (leakage effects) of city on other areas beyond the city boundaries particularly in terms of environmental aspects; (iii) to create indices/indicators originally for the purpose of assessing city sustainability; and (iv) to be able to assess world cities in both developed and developing countries using common axes of evaluation. Based on the review, we conclude that it is necessary to create a new CSI that enables us to assess and compare cities' sustainability performance in order to understand the global impact of cities on the environment and human life as compared with their economic contribution. In the future, the CSI will be able to provide local authorities with guidance toward sustainable paths. - Highlights: Black-Right-Pointing-Pointer We derive the four key requirements for a new City Sustainability Index (CSI) system. Black-Right-Pointing-Pointer First, the triple bottom line must be considered in terms of strong sustainability. Black

  4. Hybrid PV/wind system with quinary asymmetric inverter without increasing DC-link number

    Directory of Open Access Journals (Sweden)

    Aida Baghbany Oskouei

    2016-06-01

    Full Text Available This paper suggests quinary asymmetric inverter with coupled inductors and transformer, and uses it in hybrid system including photovoltaic (PV and wind. This inverter produces twenty-five-level voltage in addition to merits of multilevel inverter, has only one DC source. Then, it is adequate for hybrid systems, which prevents increasing DC-link and makes control of system easy. Proposed structure also provides isolation in the system and the switch numbers are reduced in this topology compared with other multilevel structures. In this system, battery is used as backup, where PV and wind have complementary nature. The performance of proposed inverter and hybrid system is validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system.

  5. A novel circuit topology of modified switched boost hybrid resonant inverter fitted induction heating equipment

    Directory of Open Access Journals (Sweden)

    Bhattacharya Ananyo

    2016-12-01

    Full Text Available A novel circuit topology of modified switched boost high frequency hybrid resonant inverter fitted induction heating equipment is presented in this paper for efficient induction heating. Recently, induction heating technique is becoming very popular for both domestic and industrial purposes because of its high energy efficiency and controllability. Generally in induction heating, a high frequency alternating magnetic field is required to induce the eddy currents in the work piece. High frequency resonant inverters are incorporated in induction heating equipment which produce a high frequency alternating magnetic field surrounding the coil. Previously this high frequency alternating magnetic field was produced by voltage source inverters. But VSIs have several demerits. So, in this paper, a new scheme of modified switched boost high frequency hybrid resonant inverter fitted induction heating equipment has been depicted which enhances the energy efficiency and controllability and the same is validated by PSIM.

  6. 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...

  7. A surfeit of science: The "CSI effect" and the media appropriation of the public understanding of science.

    Science.gov (United States)

    Cole, Simon A

    2015-02-01

    Over the past decade, popular media has promulgated claims that the television program CSI and its spinoffs and imitators have had a pernicious effect on the public understanding of forensic science, the so-called "CSI effect." This paper analyzes those media claims by documenting the ways in which the media claims that CSI "distorts" an imagined "reality." It shows that the media appropriated the analytic stance usually adopted by science advocates, portraying the CSI effect as a social problem in science communication. This appropriation was idiosyncratic in that it posited, as a social problem, a "surfeit" of knowledge and positive imagery about science, rather than the more familiar "deficits." In addition, the media simultaneously appropriated both "traditional" and "critical" PUS discourses. Despite this apparent contradiction, the paper concludes that, in both discourses, the media and its expert informants insist upon their hegemony over "the public" to articulate the "reality" of forensic science. © The Author(s) 2013.

  8. Multifractal property of Chinese stock market in the CSI 800 index based on MF-DFA approach

    Science.gov (United States)

    Zhu, Huijian; Zhang, Weiguo

    2018-01-01

    CSI 800 index consists of CSI 500 index and CSI 300 index, aiming to reflect the performance of stocks with large, mid and small size of China A share market. In this paper we analyze the multifractal structure of Chinese stock market in the CSI 800 index based on the multifractal detrended fluctuation analysis (MF-DFA) method. We find that the fluctuation of the closing logarithmic returns have multifractal properties, the shape and width of multifractal spectrum are depended on the weighing order q. More interestingly, we observe a bigger market crash in June-August 2015 than the one in 2008 based on the local Hurst exponents. The result provides important information for further study on dynamic mechanism of return fluctuation and whether it would trigger a new financial crisis.

  9. 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.

  10. 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

  11. 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.

  12. 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....

  13. Radiation damage in undoped CsI and CsI(Tl)

    International Nuclear Information System (INIS)

    Woody, C.L.; Kierstead, J.A.; Levy, P.W.; Stoll, S.

    1992-01-01

    Radiation damage has been studied in undoped CsI and CsI(TI) crystals using 60 Co gamma radiation for doses up to ∼ 4.2 x 10 6 . Samples from various manufacturers were measured ranging in size from 2.54 cm long cylinders to a 30 cm long block. Measurements were made on the change in optical transmission and scintillation light output as a function of dose. Although some samples showed a small change in transmission, a significant change in light output was observed for all samples. Recovery from damage was also studied as a function of time and exposure to UV light. A short lived phosphorescence was observed in undoped CsI, similar to the phosphorescence seen in CsI(TI)

  14. Outage Performance of Decode-and-Forward in Two-Way Relaying with Outdated CSI

    KAUST Repository

    Hyadi, Amal

    2015-01-07

    In this paper, we analyze the outage behavior of decode-and-forward relaying in the context of selective two-way cooperative systems. First, a new relay selection metric is proposed to take into consideration both transmission rates and instantaneous link conditions between cooperating nodes. Afterwards, the outage probability of the proposed system is derived for Nakagami-m fading channels in the case when perfect channel state information is available and then extended to the more realistic scenario where the available channel state information (CSI) is outdated due to fast fading. New expressions for the outage probability are obtained, and the impact of imperfect CSI on the performance is evaluated. Illustrative numerical results, Monte Carlo simulations, and comparisons with similar approaches are presented to assess the accuracy of our analytical derivations and confirm the performance gain of the proposed scheme.

  15. Limiting efficiency of generalized realistic c-Si solar cells coupled to ideal up-converters

    Science.gov (United States)

    Johnson, Craig M.; Conibeer, Gavin J.

    2012-11-01

    The detailed balance model of photovoltaic up-conversion is revised for the specific case of a c-Si solar cell under the AM1.5G solar spectrum. The limiting efficiency of an ideal solar cell with a band gap of 1.117 eV may be increased from approximately 33% to 40% with ideal up-conversion. However, real solar cells do not demonstrate the step-function absorption characteristic assumed in the standard detailed balance model. Here, we use tabulated Si refractive index data to develop a generalized model of a realistic conventional c-Si solar cell. The model incorporates optical design and material parameters such as free carrier absorption that have a non-trivial impact on the operation of the up-conversion layer. While these modifications are shown to decrease the absolute limiting efficiency, the benefit of up-conversion is shown to be relatively greater.

  16. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guijun, E-mail: gliad@connect.ust.hk; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing [State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2014-06-09

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400–800 nm) and bottom (800–1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  17. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    International Nuclear Information System (INIS)

    Li, Guijun; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing

    2014-01-01

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400–800 nm) and bottom (800–1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  18. Opportunistic Fixed Gain Bidirectional Relaying with Outdated CSI

    KAUST Repository

    Khan, Fahd Ahmed; Tourki, Kamel; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2015-01-01

    In a network with multiple relays, relay selection has been shown as an effective scheme to achieve diversity as well as to improve the overall throughput. This paper studies the impact of using outdated channel state information for relay selection on the performance of a network where two sources communicate with each other via fixed-gain amplify-and-forward relays. For a Rayleigh faded channel, closed-form expressions for the outage probability, moment generating function and symbol error rate are derived. Simulations results are also presented to corroborate the derived analytical results. It is shown that adding relays does not improve the performance if the channel is substantially outdated. Furthermore, relay location is also taken into consideration and it is shown that the performance can be improved by placing the relay closer to the source whose channel is more outdated. © 2015 IEEE.

  19. Opportunistic Fixed Gain Bidirectional Relaying with Outdated CSI

    KAUST Repository

    Khan, Fahd Ahmed

    2015-05-01

    In a network with multiple relays, relay selection has been shown as an effective scheme to achieve diversity as well as to improve the overall throughput. This paper studies the impact of using outdated channel state information for relay selection on the performance of a network where two sources communicate with each other via fixed-gain amplify-and-forward relays. For a Rayleigh faded channel, closed-form expressions for the outage probability, moment generating function and symbol error rate are derived. Simulations results are also presented to corroborate the derived analytical results. It is shown that adding relays does not improve the performance if the channel is substantially outdated. Furthermore, relay location is also taken into consideration and it is shown that the performance can be improved by placing the relay closer to the source whose channel is more outdated. © 2015 IEEE.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. To Think and Watch the Evil: The Turn of the Screw as Cultural Reference in Television from Dark Shadows to C.S.I.

    Directory of Open Access Journals (Sweden)

    Anna Viola Sborgi

    2012-07-01

    Full Text Available Since its first publication, Henry James’s The Turn of the Screw (1898 has always haunted the imagination of artists (Benjamin Britten, Jack Clayton, Amenábar and has been widely used as a source for television narratives (Dan Curtis, US TV version starring Colin Firth, Tim Fywell. In serial productions, James’s story has been the object of extensive quotation and allusion, from the 1960 gothic soap opera Dark Shadows to the C.S.I. episode Turn of the Screw (Season 4, Episode 21. A milestone in literary history, the story now embodies a set of cultural references conveying different, complex meanings, which can only be disclosed in the light of contemporary forms of representing reality. The novella appeals to two apparently opposite tendencies in contemporary television: the morbid display of the real (C.S.I. and the quest for the supernatural (Buffy The Vampire Slayer, among others. A line can be traced from Dark Shadows, the show that pioneered the genre, to contemporary horror soaps about vampires and supernatural phenomena. This paper shows the ways in which James’ sophisticated novella makes its way through popular culture, and how its constant ambiguous, dilemmatic interplay between reality and imagination can be related to the double-sided drive of the contemporary public towards hyper-reality and the supernatural.

  7. Cellulose synthesis genes CESA6 and CSI1 are important for salt stress tolerance in Arabidopsis.

    Science.gov (United States)

    Zhang, Shuang-Shuang; Sun, Le; Dong, Xinran; Lu, Sun-Jie; Tian, Weidong; Liu, Jian-Xiang

    2016-07-01

    Two salt hypersensitive mutants she1 and she2 were identified through genetic screening. SHE1 encodes a cellulose synthase CESA6 while SHE2 encodes a cellulose synthase-interactive protein CSI1. Both of them are involved in cellulose deposition. Our results demonstrated that the sustained cellulose synthesis is important for salt stress tolerance in Arabidopsis. © 2015 Institute of Botany, Chinese Academy of Sciences.

  8. A self-calibrating ion beam profiler based on a CsI scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Finocchiaro, P. E-mail: finocchiaro@lns.infn.it; Ciavola, G.; Cosentino, L.; Gu, M.; Raia, G.; Rovelli, A

    1999-11-21

    We report on the test results obtained with a prototype beam profiler based on a thin slit and a CsI scintillator, read out by means of a compact photomultiplier. Such a device has proven to be suitable to perform ion beam diagnostics at low and very low intensities. In particular, our device is suitable for being used in the energy and intensity ranges expected at the EXCYT radioactive ion beam facility, that is currently under development at LNS Catania.

  9. A self-calibrating ion beam profiler based on a CsI scintillator

    International Nuclear Information System (INIS)

    Finocchiaro, P.; Ciavola, G.; Cosentino, L.; Gu, M.; Raia, G.; Rovelli, A.

    1999-01-01

    We report on the test results obtained with a prototype beam profiler based on a thin slit and a CsI scintillator, read out by means of a compact photomultiplier. Such a device has proven to be suitable to perform ion beam diagnostics at low and very low intensities. In particular, our device is suitable for being used in the energy and intensity ranges expected at the EXCYT radioactive ion beam facility, that is currently under development at LNS Catania

  10. Clinical application of 1H-chemical-shift imaging (CSI) to brain diseases

    International Nuclear Information System (INIS)

    Naruse, Shoji; Furuya, Seiichi; Ide, Mariko

    1992-01-01

    An H-1 chemical shift imaging (CSI) was developed as part of the clinical MRI system, by which magnetic resonance spectra (MRS) can be obtained from multiple small voxels and metabolite distribution in the brain can be visualized. The present study was to determine the feasibility and clinical potential of using an H-1 CSI. The device used was a Magnetom H 15 apparatus. The study population was comprised of 25 healthy subjects, 20 patients with brain tumor, 4 with ischemic disease, and 6 with miscellaneous degenerative disease. The H-1 CSI was obtained by the 3-dimensional Fourier transformation. After suppressing the lipid signal by the inversion-recovery method and the water signal by the chemical-shift selective pulse with a following dephasing gradient, 2-directional 16 x 16 phase encodings were applied to the 16 x 16∼18 x 18 cm field of view, in which a 8 x 8 x 2∼10 x 10 x 2 cm area was selected by the stimulated echo or spin-echo method. The metabolite mapping and its contour mapping were created by using the curve-fitted area, with interpolation to the 256 x 256 matrix. In the healthy group, high resolution spectra for N-acetyl aspartate (NAA), creatine, choline (Cho), and glutamine/glutamate were obtained from each voxel; and metabolite mapping and contour mapping also clearly showed metabolite distribution in the brain. In the group of brain tumor, an increased Cho and lactate and loss of NAA were observed, along with heterogeneity within the tumor and changes in the surrounding tissue; and there was a good correlation between lactate peak and tumor malignancy. The group of ischemic and degenerative disease had a decreased NAA and increased lactate on both spectra and metabolite mapping, depending on disease stage. These findings indicated that H-1 CSI is helpful for detecting spectra over the whole brain, as well as for determining metabolite distribution. (N.K.)

  11. 49th Annual Convention of the Computer Society of India CSI

    CERN Document Server

    Govardhan, A; Raju, K; Mandal, J

    2015-01-01

    Volume 1 contains 73 papers presented at CSI 2014: Emerging ICT for Bridging the Future: Proceedings of the 49th Annual Convention of Computer Society of India. The convention was held during 12-14, December, 2014 at Hyderabad, Telangana, India. This volume contains papers mainly focused on Fuzzy Systems, Image Processing, Software Engineering, Cyber Security and Digital Forensic, E-Commerce, Big Data, Cloud Computing and ICT applications.

  12. A fast position sensitive photodetector based on a CsI reflective photocathode

    International Nuclear Information System (INIS)

    Arnold, R.; Christophel, E.; Guyonnet, J.L.

    1991-01-01

    A fast detector was built for UV photon detection that depends on a CsI sensitized pad cathode. The rapidity of the detector is compared with that of a more classical chamber filled with photosensitive gases such as TEA or TMAE. Estimates of the quantum yield of the photocathode at 160 and 200 nm are given. The performances obtained make it a good photodetector candidate to be operated at high luminosity accelerators. (author) 7 refs., 19 figs

  13. Simulation of Processes in Dual Three-Phase System on the Base of Four Inverters with Synchronized Modulation

    OpenAIRE

    Oleschuk, Valentin; Grandi, Gabriele; Sanjeevikumar, Padmanaban

    2011-01-01

    Novel method of space-vector-based pulse-width modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage-source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC sources. Detailed MATLA...

  14. Precoding Design of MIMO Amplify-and-Forward Communication System With an Energy Harvesting Relay and Possibly Imperfect CSI

    KAUST Repository

    Benkhelifa, Fatma

    2017-03-02

    In this paper, we investigate the simultaneous wireless information and power transfer (SWIPT) in a Multiple-Input Multiple-Output (MIMO) Amplify-and-Forward (AF) relay communication system where the relay is an energy harvesting (EH) node and harvests the energy the signals transmitted from the source. The harvested energy is partially used to forward signals from the source to the destination, and the remaining energy is stored for other usages. The SWIPT in relay-assisted communication is interesting as long as the relay stores energy from the source and the destination receives successfully the data from the source. In this context, we propose to investigate the source and relay precoders that characterize the relationship between the achievable stored energy at the relay and the achievable sourceto- destination rate, namely the rate-stored energy (R-E) tradeo region. First, we consider the ideal scheme where there is the simultaneous operation of the EH and ID receivers at the relay. Then, we consider practical schemes such as the power splitting (PS) and the time switching (TS) that separate the operation of EH and information decoding (ID) receivers over power domain or time domain, respectively. Moreover, we study the case of imperfect channel state information (CSI) at the relay and the destination and characterize its impact on the achievable R-E region. Through the simulation results, we show the eect of the position of the relay and the channel uncertainty on the achievable R-E regions of all the schemes when the used energy at the relay is constant or variable. We also show that, although it provides an outer bound on the achievable rate-energy region in one-hop MIMO systems, the ideal scheme provides only an upper bound on the maximum achievable end-to-end rate and not an outer bound on the R-E region.

  15. A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology.

    Science.gov (United States)

    Pakdel, Majid; Jalilzadeh, Saeid

    2017-09-29

    In this paper a novel packed U cell (PUC) based multilevel grid connected inverter is proposed. Unlike the U cell arrangement which consists of two power switches and one capacitor, in the proposed converter topology a lower DC power supply from renewable energy resources such as photovoltaic arrays (PV) is used as a base power source. The proposed topology offers higher efficiency and lower cost using a small number of power switches and a lower DC power source which is supplied from renewable energy resources. Other capacitor voltages are extracted from the base lower DC power source using isolated DC-DC power converters. The operation principle of proposed transformerless multilevel grid connected inverter is analyzed theoretically. Operation of the proposed multilevel grid connected inverter is verified through simulation studies. An experimental prototype using STM32F407 discovery controller board is performed to verify the simulation results.

  16. B1-based SAR reconstruction using contrast source inversion-electric properties tomography (CSI-EPT)

    NARCIS (Netherlands)

    Balidemaj, Edmond; van den Berg, Cornelis A T; van Lier, A.L.H.M.W.; Nederveen, Aart J; Stalpers, Lukas J A; Crezee, Hans; Remis, Rob F

    Specific absorption rate (SAR) assessment is essential for safety purposes during MR acquisition. Online SAR assessment is not trivial and requires, in addition, knowledge of the electric tissue properties and the electric fields in the human anatomy. In this study, the potential of the recently

  17. B1-based SAR reconstruction using contrast source inversion–electric properties tomography (CSI-EPT)

    NARCIS (Netherlands)

    Balidemaj, E.; van den Berg, CAT; van Lier, ALHMW; Nederveen, AJ; Stalpers, LJA; Crezee, H; Remis, R.F.

    2016-01-01

    Specific absorption rate (SAR) assessment is essential for safety purposes during MR acquisition. Online SAR assessment is not trivial and requires, in addition, knowledge of the electric tissue properties and the electric fields in the human anatomy. In this study, the potential of the recently

  18. Development of Large Area CsI Photocathodes for the ALICE/HMPID RICH Detector

    CERN Document Server

    Hoedlmoser, H; Schyns, E

    2005-01-01

    The work carried out within the framework of this PhD deals with the measurement of the photoelectric properties of large area thin film Cesium Iodide (CsI) photocathodes (PCs) which are to be used as a photon converter in a proximity focusing RICH detector for High Momentum Particle Identification (HMPID) in the ALICE experiment at the LHC. The objective was to commission a VUV-scanner setup for in-situ measurements of the photoelectric response of the CsI PCs immediately after the thin film coating process and the use of this system to investigate the properties of these photon detectors. Prior to this work and prior to the finalization of the ALICE/HMPID detector design, R&D work investigating the properties of CsI PCs had been performed at CERN and at other laboratories in order to determine possible substrates and optimized thin film coating procedures. These R&D studies were usually carried out with small samples on different substrates and with various procedures with sometimes ambiguous result...

  19. Luminescent properties of BaCl2-Eu microcrystals embedded in a CsI matrix

    International Nuclear Information System (INIS)

    Pushak, A.; Vistovskyy, V.; Voloshinovskii, A.; Savchyn, P.; Antonyak, O.; Demkiv, T.; Dacyuk, Yu.; Myagkota, S.; Gektin, A.

    2013-01-01

    The spectral-luminescent properties of CsI-BaCl 2 (1 mol%)-Eu(0.02 mol%) crystalline system are studied. Europium ion doped BaCl 2 microcrystals embedded in a CsI matrix are revealed on CsI-BaCl 2 (1 mol%)-Eu(0.02 mol%) freshly cleaved surface by the scanning electron microscopy. The size of microcrystals is shown to be within 0.5–5 microns. The luminescent parameters of the BaCl 2 -Eu 2+ microcrystals are shown to be similar to ones of a single crystal analogue. The 4f → 5d absorption transitions in europium ions and the reabsorption of the intrinsic emission of the CsI host are the main excitation mechanisms of europium luminescence in the BaCl 2 microcrystals. -- Highlights: ► The formation of chloride BaCl 2 :Eu microcrystals in the case of BaCl 2 doped CsI crystal has been revealed. ► The observed size of microcrystals at BaCl 2 concentration of 1% is about 0.5–5 μm. ► Majority of Eu 2+ ions in CsI-BaCl 2 -EuCl 3 crystalline system enters into BaCl 2 microcrystals. ► The luminescent parameters of the BaCl 2 :Eu 2+ microcrystals and its bulk analogue are similar

  20. Approaching total absorption of graphene strips using a c-Si subwavelength periodic membrane

    Science.gov (United States)

    Sang, Tian; Wang, Rui; Li, Junlang; Zhou, Jianyu; Wang, Yueke

    2018-04-01

    Approaching total absorption of graphene strips at near infrared using a crystalline-silicon (c-Si) subwavelength periodic membrane (SPM) is presented. The absorption in graphene strips in a c-Si SPM is enhanced by a resonant tip, which is resulted from the coupling between the guided mode and the radiation mode through symmetry breaking of the structure at near-normal incidence. The enhancement of the electric field intensity is increased 1939 times and the group velocity of light is decreased to 3.55 ×10-4c at resonance, and 99.3% absorption in graphene strips can be achieved by critical coupling at the incident angle of 2°. High absorption of the graphene strips can be maintained as the etching thickness, the strip width, and the period are altered. When this type of c-Si SPM with graphene strips is used in refractive index sensors, it shows excellent sensing properties due to its stable near-unity absorption.

  1. On the Secrecy Capacity Region of the Block-Fading BCC with Limited CSI Feedback

    KAUST Repository

    Hyadi, Amal

    2017-02-07

    In this work, we examine the secrecy capacity region of the block-fading broadcast channel with confidential messages (BCC) when the transmitter has limited knowledge of the channel. In particular, we consider a two-user communication system where the transmitter has one common message to be transmitted to both users and one confidential message intended to only one of them. The confidential message has to be kept secret from the other user to whom the information is not intended. The transmitter is not aware of the channel state information (CSI) of neither channel and is only provided by limited CSI feedback sent at the beginning of each fading block. Assuming an error-free feedback link, we characterize the secrecy capacity region of this channel and show that even with a 1-bit CSI feedback, a positive secrecy rate can still be achieved. Then, we look at the case where the feedback link is not error- free and is rather a binary erasure channel (BEC). In the latter case, we provide an achievable secrecy rate region and show that as long as the erasure event is not a probability 1 event, the transmitter can still transmit the confidential information with a positive secrecy rate.

  2. Secure Communication for Two-Way Relay Networks with Imperfect CSI

    Directory of Open Access Journals (Sweden)

    Cong Sun

    2017-09-01

    Full Text Available This paper considers a two-way relay network, where two legitimate users exchange messages through several cooperative relays in the presence of an eavesdropper, and the Channel State Information (CSI of the eavesdropper is imperfectly known. The Amplify-and-Forward (AF relay protocol is used. We design the relay beamforming weights to minimize the total relay transmit power, while requiring the Signal-to-Noise-Ratio (SNRs of the legitimate users to be higher than the given thresholds and the achievable rate of the eavesdropper to be upper-bounded. Due to the imperfect CSI, a robust optimization problem is summarized. A novel iterative algorithm is proposed, where the line search technique is applied, and the feasibility is preserved during iterations. In each iteration, two Quadratically-Constrained Quadratic Programming (QCQP subproblems and a one-dimensional subproblem are optimally solved. The optimality property of the robust optimization problem is analyzed. Simulation results show that the proposed algorithm performs very close to the non-robust model with perfect CSI, in terms of the obtained relay transmit power; it~achieves higher secrecy rate compared to the existing work. Numerically, the proposed algorithm converges very quickly, and more than 85% of the problems are solved optimally.

  3. 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...

  4. Sources

    International Nuclear Information System (INIS)

    Duffy, L.P.

    1991-01-01

    This paper discusses the sources of radiation in the narrow perspective of radioactivity and the even narrow perspective of those sources that concern environmental management and restoration activities at DOE facilities, as well as a few related sources. Sources of irritation, Sources of inflammatory jingoism, and Sources of information. First, the sources of irritation fall into three categories: No reliable scientific ombudsman to speak without bias and prejudice for the public good, Technical jargon with unclear definitions exists within the radioactive nomenclature, and Scientific community keeps a low-profile with regard to public information. The next area of personal concern are the sources of inflammation. This include such things as: Plutonium being described as the most dangerous substance known to man, The amount of plutonium required to make a bomb, Talk of transuranic waste containing plutonium and its health affects, TMI-2 and Chernobyl being described as Siamese twins, Inadequate information on low-level disposal sites and current regulatory requirements under 10 CFR 61, Enhanced engineered waste disposal not being presented to the public accurately. Numerous sources of disinformation regarding low level radiation high-level radiation, Elusive nature of the scientific community, The Federal and State Health Agencies resources to address comparative risk, and Regulatory agencies speaking out without the support of the scientific community

  5. Selection of DC voltage magnitude using Fibonacci series for new hybrid asymmetrical multilevel inverter with minimum PIV

    Directory of Open Access Journals (Sweden)

    M.R. Banaei

    2014-09-01

    Full Text Available Multilevel inverters are suggested to obtain high quality output voltage. In this paper, a new hybrid configuration is proposed, obtained by cascading one four switches H-bridge cell with a family of multilevel inverters. In addition, by the use of specific sequence for value of DC sources named Fibonacci series, asymmetrical topology of proposed inverter is introduced. Main advantages are that proposed inverter has least Peak Inverse Voltage (PIV than other conventional multilevel converters in both symmetric and asymmetric modes. Also, this topology doubles the number of output levels using only one cascaded four switches H-bridge cell. The PCI-1716 DAQ using PC has been used to generate switching pulses in experimental results. For presenting valid performance of proposed configuration, simulation results carried out by MATLAB/SIMULINK software and the validity of the proposed multilevel inverter is verified by experimental results.

  6. On some regularities of metal oxide solubility in molten CsI at T = 973 K

    Energy Technology Data Exchange (ETDEWEB)

    Cherginets, V.L., E-mail: v_cherginets@ukr.net [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, Lenin Avenue, 60, Kharkov 61001 (Ukraine); National Technical University ' Kharkiv Polytechnical Institute' , 21 Frunze St., 61002 Kharkov (Ukraine); Rebrova, T.P.; Datsko, Yu.N.; Shtitelman, V.A. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, Lenin Avenue, 60, Kharkov 61001 (Ukraine); Bryleva, E.Yu. [State Scientific Organization STC ' Institute for Single Crystals' , National Academy of Sciences of Ukraine, Lenin Avenue, 60, Kharkov 61001 (Ukraine)

    2011-08-15

    Highlights: > CdO, ZnO, NiO, and EuO are insoluble in CsI melt at 973 K. > The oxide solubilities are lower than those in chloride melts. > The oxide solubilities reduce with the cation radius. > ZnO, NiO, and EuO are suitable for scavenging CsO from oxide ion traces. - Abstract: Solubility products of CdO (pK{sub s,CdO} = 6.80 {+-} 0.2), ZnO (pK{sub s,ZnO} = 10.0 {+-} 0.5), NiO (pK{sub s,NiO} = 11.2 {+-} 0.2) and EuO (pK{sub s,EuO} = 13.1 {+-} 0.2) in molten CsI at T = 973 K are determined by potentiometric titration of (0.02 to 0.03) mol . kg{sup -1} solutions of the corresponding metal chlorides by strong base (KOH) using a membrane oxygen electrode Pt(O{sub 2})|ZrO{sub 2}(Y{sub 2}O{sub 3}) as an indicator. On the basis of pK{sub s,MeO} values, all the oxides studied are referred to practically insoluble in molten CsI. The values of the oxide solubility in CsI melt are lower than the corresponding values in molten alkali metal chlorides. This can be explained by 'softer' basic properties of I{sup -} as compared with Cl{sup -} in the frames of the Pearson 'hard' and 'soft' acid-base concept. In the oxide samples studied, the values of the solubility fall with the decreasing cation radius. The correlation between pK{sub s,MeO} and the polarizing action by Goldshmidt (Zr{sub Me{sup 2+}}{sup -2}) of the cation is practically linear and may be proposed for estimation of the solubility of s- and d- element oxides in molten CsI on the basis of their cation radii.

  7. 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

  8. Does human papilloma virus play a role in sinonasal inverted papilloma?

    Science.gov (United States)

    Govindaraj, Satish; Wang, Hailun

    2014-02-01

    Inverted papillomas are a benign sinonasal tumor with a propensity for recurrence and malignant transformation. Although many investigations have been made into the nature of this disease, its etiology and causes for malignant transformation have yet to be fully elucidated. It is the authors' objective to present a review on management of the disease and evaluate the present relationship between human papilloma virus (HPV) and inverted papilloma. A causal relationship between HPV and the pathogenesis and progression of inverted papilloma has been posited since the 1980s. Although widely varied HPV detection rates have been reported, recent studies have noted a substantial increase in both recurrence and malignant transformation in HPV-infected inverted papillomas. However, exact cellular mechanisms by which infection leads to subsequent recurrence and development of carcinoma have yet to be elucidated. Evidence exists suggesting that HPV infection plays a role in the progression of inverted papilloma and confers an increased risk for recurrence and malignant transformation. PCR is the preferred detection method, and fresh or frozen specimens are the ideal source of tissue for evaluation. Although multiple studies have detected an association between HPV and inverted papilloma (both recurrent and malignant transformation), further studies are necessary to elucidate the underlying molecular pathways before an association can be changed to causation.

  9. 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.

  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. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  12. 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

  13. 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

  14. 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.

  15. 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...

  16. A comprehensive study on partial shading response of c-Si modules and yield modeling of string inverter and module level power electronics

    NARCIS (Netherlands)

    Sinapis, K.; Tzikas, C.; Litjens, G.; van den Donker, M.; Folkerts, W.; van Sark, W.G.J.H.M.; Smets, A.

    2016-01-01

    Building Integrated and Building Attached Photovoltaic (BIPV, BAPV) systems may suffer from lower performance than predicted as a result of not considered partial shading. New system architectures have been proposed to optimize performance. The common approach of these new architectures is to track

  17. A novel five-level optimized carrier multilevel PWM quad-inverter six-phase AC drive

    DEFF Research Database (Denmark)

    Sanjeevikumar, P.; Blaabjerg, F.; Wheeler, Pat

    2016-01-01

    A novel single carrier pulse-width modulation (PWM) for a new quad-inverter configuration for multilevel six-phase asymmetrical open-winding ac converter is proposed in this article. Modularity of the circuit consist of four standard two-level voltage source inverters (VSIs) with slight modificat......A novel single carrier pulse-width modulation (PWM) for a new quad-inverter configuration for multilevel six-phase asymmetrical open-winding ac converter is proposed in this article. Modularity of the circuit consist of four standard two-level voltage source inverters (VSIs) with slight...... modifications, i.e. one additional bi-direction switch (MOSFET/IGBT) in each phase and a link to neutral with two capacitors to generate increased output levels. Furthermore, original optimal single carrier zero-shifted five-level modulation (SCZSFM) algorithm is developed for each VSI to behave as equivalent...

  18. Examination of the "CSI Effect" on Perceptions of Scientific and Testimonial Evidence in a Hong Kong Chinese Sample.

    Science.gov (United States)

    Hui, Cora Y T; Lo, T Wing

    2017-05-01

    Television is a powerful medium through which to convey information and messages to the public. The recent proliferation of forensic science and criminal justice information throughout all forms of media, coupled with raised expectations toward forensic evidence, has led some to suspect that a "CSI effect" ( Crime Scene Investigation effect) is taking place. The present study contributes to the literature addressing the CSI effect in two ways. First, it examines whether the CSI effect exists in the Chinese population of Hong Kong. Second, using a mock-jury paradigm, it empirically examines a more integrative perspective of the CSI effect. It was found that, although the amount of media coverage involving forensic evidence does influence participants' perception of legal evidence to some degree, such a perception does not affect participants' legal decision making. Viewers of forensic dramas were not more likely to convict the defendant when forensic evidence was presented and not less likely to convict when only testimonial evidence was presented. The only significant predictor of the defendant's culpability when scientific evidence was presented was participants' ratings of the reliability of scientific evidence. Results from the present study lend no support to the existence of the CSI effect in Hong Kong.

  19. On the low SNR capacity of log-normal turbulence channels with full CSI

    KAUST Repository

    Benkhelifa, Fatma; Tall, Abdoulaye; Rezki, Zouheir; Alouini, Mohamed-Slim

    2014-01-01

    In this paper, we characterize the low signal-To-noise ratio (SNR) capacity of wireless links undergoing the log-normal turbulence when the channel state information (CSI) is perfectly known at both the transmitter and the receiver. We derive a closed form asymptotic expression of the capacity and we show that it scales essentially as λ SNR where λ is the water-filling level satisfying the power constraint. An asymptotically closed-form expression of λ is also provided. Using this framework, we also propose an on-off power control scheme which is capacity-achieving in the low SNR regime.

  20. Global Annual Final AC Yield Comparison between HCPV and c-Si PV

    Directory of Open Access Journals (Sweden)

    Juan Pablo Ferrer-Rodríguez

    2015-01-01

    Full Text Available A worldwide comparison of the annual yield between conventional c-Si photovoltaic (PV technology and high concentrated photovoltaic (HCPV technology is presented. The idea of this paper is to find the most appropriate locations for HCPV systems in terms of the annual energy produced when comparing to fixed tilt PV systems and two-axis oriented PY systems. For estimating the annual energy generation, the method of the Performance Ratio is used. For some locations with high annual direct normal irradiation values, which are distributed around the world, HCPV systems are found to be more advantageous than fixed tilt PV systems. World maps showing this comparison are presented.

  1. Development of large area CsI photocathodes for the Alice/Humped Rich detector

    International Nuclear Information System (INIS)

    Hoedlmoser, H.

    2005-03-01

    The work carried out within the framework of this PhD deals with the measurement of the photoelectric properties of large area thin film cesium iodide photocathodes (PCs) which are to be used as a photon converter in a proximity focusing RICH detector for High Momentum Particle Identification (HMPID) in the ALICE experiment at the LHC. The objective was to commission a VUV-scanner setup for in-situ measurements of the photoelectric response of the CsI PCs and the use of this system to investigate the properties of these photon detectors. Among the investigated phenomena the most important ones were: - Post deposition treatment: from R and D studies it was known, that the PC response can be increased by heating the PC after the coating process. Within this thesis it was shown that the enhancement effect is mandatory to achieve the photon conversion efficiency required by the detector design and that any difference in PC quality is due to differences in this enhancement effect. - Ageing effects: CsI PCs age under exposure to humidity due to the hygroscopicity of CsI and under high photon flux and ion bombardment inside the Multi Wire Proportional Chamber (MWPC) of the detector. All three effects have been investigated with the VUV scanner. The first effect requires a careful treatment of the CsI PCs to avoid exposure to humid air. Furthermore this effect was found to be reversible if the PC is heated. High photon fluxes are irrelevant in a Cherenkov detector dealing with single photons, however, the problem needed to be investigated to verify that the measurement process itself does not damage the PCs. The third mechanism is very important as it occurs during normal detector operation and depends only on the radiation environment of the experiment. For a dose corresponding to 20 years of operation inside ALICE an accelerated test showed a clear degradation of up to 40 % of the PC response. With the results of these studies the first 17 PCs (of 42) for the detector

  2. On the low SNR capacity of log-normal turbulence channels with full CSI

    KAUST Repository

    Benkhelifa, Fatma

    2014-09-01

    In this paper, we characterize the low signal-To-noise ratio (SNR) capacity of wireless links undergoing the log-normal turbulence when the channel state information (CSI) is perfectly known at both the transmitter and the receiver. We derive a closed form asymptotic expression of the capacity and we show that it scales essentially as λ SNR where λ is the water-filling level satisfying the power constraint. An asymptotically closed-form expression of λ is also provided. Using this framework, we also propose an on-off power control scheme which is capacity-achieving in the low SNR regime.

  3. Quantum efficiency measurement system for large area CsI photodetectors

    CERN Document Server

    Cusanno, F; Colilli, S; Crateri, R; Fratoni, R; Frullani, S; Garibaldi, F; Giuliani, F; Gricia, M; Lucentini, M; Mostarda, A; Santavenere, F; Veneroni, P; Breuer, H; Iodice, M; Urciuoli, G M; De Cataldo, G; De Leo, R; Lagamba, L; Braem, André

    2003-01-01

    A proximity focusing freon/CsI RICH detector has been built for kaon physics at Thomas Jefferson National Accelerator Facility (TJNAF or Jefferson Lab), Hall A. The Cherenkov photons are detected by a UV photosensitive CsI film which has been obtained by vacuum evaporation. A dedicated evaporation facility for large area photocathodes has been built for this task. A measuring system has been built to allow the evaluation of the absolute quantum efficiency (QE) just after the evaporation. The evaporation facility is described here, as well as the quantum efficiency measurement device. Results of the QE on-line measurements, for the first time on large area photocathodes, are reported.

  4. Energy-Efficient Power Allocation of Cognitive Radio Systems without CSI at the Transmitter

    KAUST Repository

    Sboui, Lokman

    2015-01-07

    Two major issues are facing today’s wireless communications evolution: -Spectrum scarcity: Need for more bandwidth. As a solution, the Cognitive Radio (CR) paradigm, where secondary users (unlicensed) share the spectrum with licensed users, was introduced. -Energy consumption and CO2 emission: The ICT produce 2% of global CO2 emission (equivalent to the aviation industry emission). The cellular networks produces 0.2%. As solution energy efficient systems should be designed rather than traditional spectral efficient systems. In this work, we aim to determine the optimal energy efficient power allocation of CR when the channel state information at the transmitter CSI-T is not available.

  5. Energy-Efficient Power Allocation of Cognitive Radio Systems without CSI at the Transmitter

    KAUST Repository

    Sboui, Lokman; Rezki, Zouheir; Alouini, Mohamed-Slim

    2015-01-01

    Two major issues are facing today’s wireless communications evolution: -Spectrum scarcity: Need for more bandwidth. As a solution, the Cognitive Radio (CR) paradigm, where secondary users (unlicensed) share the spectrum with licensed users, was introduced. -Energy consumption and CO2 emission: The ICT produce 2% of global CO2 emission (equivalent to the aviation industry emission). The cellular networks produces 0.2%. As solution energy efficient systems should be designed rather than traditional spectral efficient systems. In this work, we aim to determine the optimal energy efficient power allocation of CR when the channel state information at the transmitter CSI-T is not available.

  6. 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

  7. 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.

  8. 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.

  9. An inverted-geometry, high voltage polarized electron gun with UHV load lock

    International Nuclear Information System (INIS)

    Breidenbach, M.; Foss, M.; Hodgson, J.; Kulikov, A.; Odian, A.; Putallaz, G.; Rogers, H.; Schindler, R.; Skarpaas, K.; Zolotorev, M.

    1994-01-01

    The design of a high voltage electron source with a GaAs photocathode and a load lock system is described. The inverted high voltage structure of the gun permits a compact and simple design. Test results demonstrate that the load lock system provides a reliable way to achieve high quantum efficiency of the photocathode in a high voltage device. ((orig.))

  10. Elimination of zero sequence circulating current between parallel operating three-level inverters

    DEFF Research Database (Denmark)

    Li, Kai; Wang, Xiaodong; Dong, Zhenhua

    2016-01-01

    In order to suppress the zero sequence circulating currents (ZSCCs) between parallel operating three level voltage source inverters with common AC and DC buses, a common mode voltage reduction PWM (CMVR-PWM) technique and neural point potentials (NPPs) control based method is proposed in this paper...

  11. Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    This paper presents results of analysis and comparison of novel synchronised schemes of pulsewidth modulation (PWM), applied to three-level voltage source inverters with control algorithms providing elimination of the common-mode voltage. The proposed approach is based on a new strategy of digital...

  12. Impact of grid impedance variations on harmonic emission of grid-connected inverters

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar; Bak, Claus Leth; Blaabjerg, Frede

    2017-01-01

    This paper addresses harmonic magnification due to resonance circuits resulting from interaction between uncertain grid impedance and converter. The source of harmonic may be either the grid or inverter. It is demonstrated that unknown and unpredictable grid impedance may result in variable...

  13. EXAMINING A SERIES RESONANT INVERTER CIRCUIT TO USE IN THE PHOTOVOLTAIC ENERGY CONVERSION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Engin ÇETİN

    2004-03-01

    Full Text Available As we know, solar energy is the energy source which is environment friendly, renewable, and can be found easily. Particularly, in the recent years, interest on producing electrical energy by alternative energy sources increased because of the fact that underground sources are not enough to produce energy in the future and also these sources cause enviromental pollution. The solar energy is one of the most popular one among the alternative energy sources. Photovoltaic systems produce the electrical energy from the sunlight. In this study, a series resonant inverter circuit which is used in the photovoltaic energy conversion systems has been examined.Effects of the series resonant inverter circuit on the photovoltaic energy conversion system have been investigated and examined

  14. 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

  15. 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)

  16. 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....

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. Analysis and integration of multilevel inverter configuration with boost converters in a photovoltaic system

    International Nuclear Information System (INIS)

    Prabaharan, N.; Palanisamy, K.

    2016-01-01

    Highlights: • Integration of MLI with boost converters in photovoltaic system including MPPT. • Results are taken for different irradiations and different temperature condition. • Proposed system is tested with sudden step changes from standard test condition. • Analysis of switching losses and conduction loss is discussed. • Theoretical calculation of % THD using asymptotic formula is discussed. - Abstract: This paper proposes a single phase multilevel inverter configuration that conjoins three series connected full bridge inverter and a single half bridge inverter for renewable energy application especially photo-voltaic system. This configuration of multilevel inverter reduces the value of total harmonic distortion. The half bridge inverter utilized in the proposed configuration increases the output voltage level to nearly twice the output voltage level of a conventional cascaded H-bridge multilevel inverter. This higher output voltage level is generated with lesser number of power semiconductor switches compared to conventional configuration, thus reducing the total harmonic distortion and switching losses. The effectiveness of the proposed configuration is illustrated by replacing the isolated DC sources in multilevel inverter with individual photo-voltaic panels using separate perturb and observer based maximum power point tracking and boost converters. The verification of the proposed system is demonstrated successfully using MATLAB/Simulink based simulation with different irradiation and temperature conditions. Also, the transient operation of the system is verified with results depicted using step change in standard test condition. In the proposed system, total harmonic distortion of the output voltage is 9.85% without using passive filters and 3.91% with filter inductance. Theoretical calculation of the power losses and total harmonic distortion with mathematical equations are discussed. Selective experimental results are presented to prove the

  2. Fast Self-Synchronization between LowVoltage Microgrid and Inverter using Virtual Synchronous Converter

    Directory of Open Access Journals (Sweden)

    Md Ruhul Amin

    2017-12-01

    Full Text Available In this paper, a fast self-synchronization known as virtual synchronous converter (VSCon between single-phase microgrid and inverter in low-voltage microgrid, has been developed in Matlab/Simulink. The idea is to any phase locked loop (PLL circuit for inverter-microgrid synchronization in order to improve the synchronization time. As known, it is difficult and lengthy process to tune the PLL gain parameters to reach suitable performance for synchronizing among the voltage, phase-angle and frequency between them. Due to this problem, a fast self synchronization technique is needed in order to minimize the time losses at the microgrid connection. Therefore, the VSCon has been developed which is based on the synchronous generator mathematical model but in virtual environment representation. It has been applied in the inverter control for generating switching pattern to the inverter switches in order to respond to the grid voltage for improve the synchronization. For a prove of concept, several simulation tests in MATLAB models have been conducted, in order to see the effectiveness of this VSCon. First test has been conducted, when a 240V, 50Hz frequency grid source is used for observing the self-synchronization the system with the power flows output. Furthermore, the next test is conducted when the grid frequency is changed from the rated frequency at 50Hz to 51Hz and the result shows the VSCon in inverter control takes nearly 40ms to synchronize to this new frequency value. The test on grid phase-angle delay also been tested when ac grid voltage has 150 phase delay. As from all the results, the improved inverter control with VSCon structure is able to have fast and self-synchronized between the invertergrid connection before the power from the inverter can be transferred.

  3. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding...

  4. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  5. Power conditioning system for energy sources

    Science.gov (United States)

    Mazumder, Sudip K [Chicago, IL; Burra, Rajni K [Chicago, IL; Acharya, Kaustuva [Chicago, IL

    2008-05-13

    Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

  6. Power inverter with optical isolation

    Science.gov (United States)

    Duncan, Paul G.; Schroeder, John Alan

    2005-12-06

    An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

  7. A Novel Flying Capacitor Transformerless Inverter for Single-Phase Grid Connected Solar Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2016-01-01

    This paper proposes a new single-phase flying capacitor transformerless PV inverter for grid-connected photovoltaic (PV) systems. The neutral of the grid can be directly connected to the negative terminal of the source (PV). It consists of four power switches, one diode, one capacitor and a small...... and some topologies, which requires two times of the peak ac-voltage magnitude) and, (5) the flying capacitor charges every switching cycle, which reduces the size of the required capacitor with switching frequency. In addition, industry standard half bridge module can be used in the new inverter without...

  8. Impacts of PV Array Sizing on PV Inverter Lifetime and Reliability

    OpenAIRE

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso; Blaabjerg, Frede

    2017-01-01

    In order to enable a more wide-scale utilization of PV systems, the cost of PV energy has to be comparable with other energy sources. Oversizing the PV array is one common approach to reduce the cost of PV energy, since it increases the PV energy yield during low solar irradiance conditions. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter lifetime and reliability. In that case, it may result in a negative impact...

  9. A novel double quad-inverter configuration for multilevel twelve-phase open-winding converter

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick William

    2016-01-01

    This paper describes a novel proposal of double quad-inverter configuration for multilevel twelve-phase open-winding ac converter. Modular power units are developed from reconfigured eight classical three-phase voltage source inverters (VSIs). Each VSI has one additional bi-directional switching...... numerical simulation software's (Matlab/PLECS) developments. Further, the results confirm the good agreement to the developed theoretical background. Proposed converter suits the need of low-voltage/high-current applications such as ac tractions and `More-Electric Aircraft' propulsion systems....

  10. Hexuple-Inverter Configuration for Multilevel Nine-Phase Symmetrical Open-Winding Converter

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Bhaskar, Mahajan Sagar; Maroti, Pandav Kiran

    2016-01-01

    Hexuple-inverter configuration for multilevel nine-phase symmetrical open-winding ac converter is articulated in this work. Power modular unit consists of six classical three-phase voltage source inverters (VSI). Each VSI includes one bi-directional device (MOSFET/IGBT) per each phase and link...... software’s (Matlab/PLECS). Results always showed good conformity with the developed theoretical background under working conditions. The proposed converter found suit for (low-voltage/high current) electric vehicles, ac tractions and ‘More-Electric Aircraft’ applications....

  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. 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...

  13. 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)

  14. [The CSI effect and its impact on the perceptions of forensic science experts' work].

    Science.gov (United States)

    Stojer, Joanna

    2011-01-01

    The issue that has been analyzed in this work is the potential effect of crime films and TV series on people's perceptions of forensic medicine and science, and especially on the forming of expectations towards forensic science experts. This syndrome is being called the "CSI effect" after the popular franchise Crime Scene Investigation (CSI). Questionnaire surveys that have been conducted included "experts": 50 experts in various specialities, 77 prosecutors, 119 judges, 64 lay judges, 161 police staff and 80 members of general public. In-depth interviews have been conducted with 20 police staff, and also a focus group has been carried out with 15 law students. In the opinion of the respondents, people's perceptions and expectations of forensic science--as it can be observed during criminal trials--are largely inflated by the entertainment media. Among the surveyed persons, the category that declares watching crime series most rarely, is forensic science experts. Around half of the surveyed experts pointed out to excessive expectations towards they work instigated by TV crime series. The most common expectations towards forensic medicine experts are: immediate conclusiveness of post mortem examinations (going as far as indicating the cause of death at the crime scene), precision of death time estimation and a routine use of sophisticated methods known from TV.

  15. Fission product behavior in high-temperature water: CsI vs MoO4

    Science.gov (United States)

    Kanjana, K.; Silva, K.; Channuie, J.

    2017-09-01

    Fission product behaviors of Cs, a major element released in a severe nuclear accident, still remain unclear. The question frequently addressed is whether Cs released will be in the form of Cs2MoO4 or CsOH. This is a challenging issue since it has been demonstrated that the reaction between Cs2MoO4 and water leading to CsOH production is thermodynamically favored. The present research aims at investigation of CsOH generation through this chemical channel. A high-temperature setup with a flow system based on the cooling system of a water-cooled nuclear reactor has been assembled. The reaction between aqueous solutions of CsI and Na2MoO4 in a high-corrosion-resistant hot cell (Hastelloy) has been studied up to 80 °C in deoxygenated system. The products have been characterized using FTIR and XRD. The results have shown that there is no reaction between CsI and Na2MoO4 under the experimental conditions.

  16. Downlink Linear Precoders Based on Statistical CSI for Multicell MIMO-OFDM

    Directory of Open Access Journals (Sweden)

    Ebrahim Baktash

    2017-01-01

    Full Text Available With 5G communication systems on the horizon, efficient interference management in heterogeneous multicell networks is more vital than ever. This paper investigates the linear precoder design for downlink multicell multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM systems, where base stations (BSs coordinate to reduce the interference across space and frequency. In order to minimize the overall feedback overhead in next-generation systems, we consider precoding schemes that require statistical channel state information (CSI only. We apply the random matrix theory to approximate the ergodic weighted sum rate of the system with a closed form expression. After formulating the approximation for general channels, we reduce the results to a more compact form using the Kronecker channel model for which several multicarrier concepts such as frequency selectivity, channel tap correlations, and intercarrier interference (ICI are rigorously represented. We find the local optimal solution for the maximization of the approximate rate using a gradient method that requires only the covariance structure of the MIMO-OFDM channels. Within this covariance structure are the channel tap correlations and ICI information, both of which are taken into consideration in the precoder design. Simulation results show that the rate approximation is very accurate even for very small MIMO-OFDM systems and the proposed method converges rapidly to a near-optimal solution that competes with networked MIMO and precoders based on instantaneous full CSI.

  17. Environmental Disclosure of Electric Power Companies Listed in the Corporate Sustainability Index (CSI

    Directory of Open Access Journals (Sweden)

    Clésia Ana Gubiani

    2012-12-01

    Full Text Available The study aimed to verify the level of disclosure of environmental information in the administration reports of the energy companies listed in the Corporate Sustainability Index (CSI. A descriptive and quantitative research was done, using the content analysis technique on the administration reports from 2006 to 2008. The sample consisted of 11 electric power companies listed in the CSI. For quantitative analysis of the disclosure index, the data collection instrument was based on the study of Rover, Murcia and Borba (2008, which proposes eight environmental categories and 36 subcategories. For the whole analysis of the data were elaborated networks of the items disclosed in each company, using the software UNICET ®. The survey results showed that there is satisfactory disclosure in the categories of environmental policies and education, training and research environment. However, it was found that there is need for greater disclosure of categories of products impacts and processes in the environment, power polices and financial environmental information. It was concluded that the information disclosed in the administration reports of the companies surveyed about the environmental information do not respect the principle of full disclosure.

  18. Longitudinal uniformity, time performances and irradiation test of pure CsI crystals

    Energy Technology Data Exchange (ETDEWEB)

    Angelucci, M. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Atanova, O. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Baccaro, S.; Cemmi, A. [ENEA UTTMAT-IRR, Casaccia R.C., Roma (Italy); Cordelli, M. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Donghia, R., E-mail: raffaella.donghia@lnf.infn.it [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dipartimento di Fisica, Universitá Roma Tre, Roma (Italy); Giovannella, S.; Happacher, F.; Miscetti, S.; Sarra, I.; Soleti, S.R. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy)

    2016-07-11

    To study an alternative to BaF{sub 2}, as the crystal choice for the Mu2e calorimeter, 13 pure CsI crystals from Opto Materials and ISMA producers have been characterized by determining their light yield (LY) and longitudinal response uniformity (LRU), when read with a UV extended PMT. The crystals show a LY of ~100 p.e./MeV (~150 p.e./MeV) when wrapped with Tyvek and coupled to the PMT without (with) optical grease. The LRU is well represented by a linear slope that is on average δ~ −0.6%/cm. The timing performances of the Opto Materials crystal, read with a UV extended MPPC, have been evaluated with minimum ionizing particles. A timing resolution of ~330 ps (~ 440 ps) is achieved when connecting the photosensor to the MPPC with (without) optical grease. The crystal radiation hardness to a ionization dose has also been studied for one pure CsI crystal from SICCAS. After exposing it to a dose of 900 Gy, a decrease of 33% in the LY is observed while the LRU remains unchanged.

  19. Accelerating Development of Advanced Inverters.

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ropp, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Increasing the penetration of distributed renewable sources, including photovoltaic (PV) generators, poses technical challenges for grid management. The grid has been optimized over decades to rely on large centralized power plants with well-established feedback controls. Conventional generators provide relatively constant dispatchable power and help to regulate both voltage and frequency. In contrast, photovoltaic (PV) power is variable, is only as predictable as the weather, and provides no control action. Thus, as conventional generation is displaced by PV power, utility operation stake holders are concerned about managing fluctuations in grid voltage and frequency. Furthermore, since the operation of these distributed resources are bound by certain rules that require they stop delivering power when measured voltage or frequency deviate from the nominal operating point, there are also concerns that a single grid event may cause a large fraction of generation to turn off, triggering a black out or break-up of an electric power system.

  20. Flexible voltage support control for three-phase distributed generation inverters under grid fault

    DEFF Research Database (Denmark)

    Camacho, Antonio; Castilla, Miguel; Miret, Jaume

    2013-01-01

    Operators describe the behavior of the energy source, regulating voltage limits and reactive power injection to remain connected and support the grid under fault. On the basis that different kinds of voltage sags require different voltage support strategies, a flexible control scheme for three phase grid...... connected inverters is proposed. In three phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one or two phase faults, the main concern of the distributed generation inverter is to equalize voltages by reducing the negative symmetric...... sequence and clear the phase jump. Due to system limitations, a balance between these two extreme policies is mandatory. Thus, over-voltage and undervoltage can be avoided, and the proposed control scheme prevents disconnection while achieving the desired voltage support service. The main contribution...

  1. Japanese power electronics inverter technology and its impact on the American air conditioning industry

    Science.gov (United States)

    Ushimaru, Kenji

    1990-08-01

    Since 1983, technological advances and market growth of inverter-driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries, microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices, were able to direct the development and market success of inverter-driven heat pumps. As a result, leading U.S. variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales.

  2. Japanese power electronics inverter technology and its impact on the American air conditioning industry

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, Kenji.

    1990-08-01

    Since 1983, technological advances and market growth of inverter- driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries-- microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices--were able to direct the development and market success of inverter-driven heat pumps. As a result, leading US variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales. 54 refs., 47 figs., 1 tab.

  3. Modeling And Simulation Of Highly Advanced Multilevel Inverter For Speed Control Of Induction Motor

    Directory of Open Access Journals (Sweden)

    Ravi Raj

    2017-02-01

    Full Text Available In this Paper the problem of removing Power dissipation from single phase Induction Motor with DC sources is considered by the speed control of Induction Motor with highly advanced 9-Level multi-level Inverter which having approximate zero Harmonics. As the demand of power is increasing day by day. So that we must introduced very advanced Electrical Instruments which having high efficiency and less dissipation of power. The requirement of very advanced Inverter is necessary. Here we are designing a Multi-level Inverter up to the 9-level using IGBT Insulated-gate bipolar transistor by Mat lab which having negligible total harmonic distortion THD thats why it will control the speed of single phase Induction motor which is presently widely used in our daily needs. Also several informative Simulation results verify the authority and truthiness of the proposed Model.

  4. A Grid Connected Transformerless Inverter and its Model Predictive Control Strategy with Leakage Current Elimination Capability

    Directory of Open Access Journals (Sweden)

    J. Fallah Ardashir

    2017-06-01

    Full Text Available This paper proposes a new single phase transformerless Photovoltaic (PV inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.

  5. High speed and high functional inverter power supplies for plasma generation and control, and their performance

    International Nuclear Information System (INIS)

    Uesugi, Yoshihiko; Razzak, Mohammad A.; Kondo, Kenji; Kikuchi, Yusuke; Takamura, Shuichi; Imai, Takahiro; Toyoda, Mitsuhiro

    2003-01-01

    The Rapid development of high power and high speed semiconductor switching devices has led to their various applications in related plasma fields. Especially, a high speed inverter power supply can be used as an RF power source instead of conventional linear amplifiers and a power supply to control the magnetic field in a fusion plasma device. In this paper, RF thermal plasma production and plasma heating experiments are described emphasis placed on using a static induction transistor inverter at a frequency range between 200 kHz and 2.5 MHz as an RF power supply. Efficient thermal plasma production is achieved experimentally by using a flexible and easily operated high power semiconductor inverter power supply. Insulated gate bipolar transistor (IGBT) inverter power supplies driven by a high speed digital signal processor are applied as tokamak joule coil and vertical coil power supplies to control plasma current waveform and plasma equilibrium. Output characteristics, such as the arbitrary bipolar waveform generation of a pulse width modulation (PWM) inverter using digital signal processor (DSP) can be successfully applied to tokamak power supplies for flexible plasma current operation and fast position control of a small tokamak. (author)

  6. From a sociology of mediation to a pragmatics of attachments. An intellectual journey within the CSI revisited

    OpenAIRE

    Hennion, Antoine

    2017-01-01

    Este artículo enfoca sobre un retorno reflexivo en mi propia trayectoria en el CSI. Mi propósito no es fijar la historia sino releerla desde las preocupaciones presentes. Desde su fundación por L. Karpik en 1967, el CSI abogó por tomar seriamente las realidades que estaba investigando (derecho, ciencia y tecnología, negocios, cultura). Bajo el título de un posible “retorno al objeto” en sociología, discuto convergencias y diferencias en el trabajo de campo emprendido, por un lado, sobre la ci...

  7. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Sathyanarayana, E-mail: asharao76@gmail.com; Rao, Asha, E-mail: asharao76@gmail.com [Department of Physics, Mangalore Institute of Technology and Engineering, Moodabidri, Mangalore-574225 (India); Krishnan, Sheeja [Department of Physics, Sri Devi Institute of Technology, Kenjar, Mangalore-574142 (India); Sanjeev, Ganesh [Microtron Centre, Department of Physics, Mangalore University, Mangalagangothri-574199 (India); Suresh, E. P. [Solar Panel Division, ISRO Satellite Centre, Bangalore-560017 (India)

    2014-04-24

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells.

  8. Study of a pure CsI crystal readout by APD for Belle II end cap ECL upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y., E-mail: jin@hep.phys.s.u-tokyo.ac.jp [Department of Physics, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 (Japan); Aihara, H. [Department of Physics, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 (Japan); Borshchev, O.V. [Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393 (Russian Federation); Epifanov, D.A. [Department of Physics, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 (Japan); Ponomarenko, S.A.; Surin, N.M. [Enikolopov Institute of Synthetic Polymeric Materials of the Russian Academy of Sciences, Profsoyuznaya st. 70, Moscow 117393 (Russian Federation)

    2016-07-11

    A scintillation counter consisting of a pure CsI crystal and avalanche photodiodes (Hamamatsu APD S8664-55 and S8664-1010) has been studied for the upgrade of the end cap electromagnetic calorimeter of Belle II detector. An essential increase of the light output was achieved with wavelength shifters based on nanostructured organosilicon luminophores. - Highlights: • A scintillation counter consisting of a pure CsI crystal and avalanche photodiodes has been studied. • The equivalent noise charge and equivalent noise energy of the counter have been measured. • An essential increase of the light output was achieved with wavelength shifters.

  9. 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…

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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...

  15. Surface Passivation Mechanism of Atomic Layer Deposited Al2O3 Films on c-Si Studied by Optical Second-Harmonic Generation

    NARCIS (Netherlands)

    Gielis, J.J.H.; Verlaan, V.; Dingemans, G.; Sanden, van de M.C.M.; Kessels, W.M.M.; Terlinden, N.M.

    2009-01-01

    Recently, it was shown that Al2O3 thin films synthesized by (plasmaassisted) atomic layer deposition (ALD) provide excellent surface passivation of n, p and p+ type c-Si as highly relevant for c-Si photovoltaics. It was found that a large negative fixed charge density (up to 1013 cm-2) in the Al2O3

  16. 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

  17. Study on the effect of deposition rate and concentration of Eu on the fluorescent lifetime of CsI: Tl thin film

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yijun; Guo, Lina [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Liu, Shuang, E-mail: shuangliu@uestc.edu.cn [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Wang, Qianfeng; Zhang, Shangjian; Liu, Yong [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu 610054 (China); Zhong, Zhiyong [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu 610054 (China)

    2017-06-21

    Although there are many new scintillators being developed recently, CsI: Tl is still very efficient among them. The fluorescent lifetime is a very important parameter of CsI: Tl thin film and two series of experiments have been conducted to learn about it. Our experiments, however, have demonstrated that the deposition rate and the codoping of Eu{sup 2+} will significantly influence its fluorescent lifetime. In order to increase the efficiency of the imaging system, we intend to obtain a higher fluorescent lifetime for CsI: Tl thin film by controlling these two conditions. - Highlights: • We used vacuum vapor deposition method to grow the high-quality thin films. • The relationship between the deposition rate and the fluorescent lifetime of CsI: Tl thin film was tested. • Concentration of Eu on fluorescent lifetime of the CsI: Tl thin film was studied.

  18. detectIR: a novel program for detecting perfect and imperfect inverted repeats using complex numbers and vector calculation.

    Science.gov (United States)

    Ye, Congting; Ji, Guoli; Li, Lei; Liang, Chun

    2014-01-01

    Inverted repeats are present in abundance in both prokaryotic and eukaryotic genomes and can form DNA secondary structures--hairpins and cruciforms that are involved in many important biological processes. Bioinformatics tools for efficient and accurate detection of inverted repeats are desirable, because existing tools are often less accurate and time consuming, sometimes incapable of dealing with genome-scale input data. Here, we present a MATLAB-based program called detectIR for the perfect and imperfect inverted repeat detection that utilizes complex numbers and vector calculation and allows genome-scale data inputs. A novel algorithm is adopted in detectIR to convert the conventional sequence string comparison in inverted repeat detection into vector calculation of complex numbers, allowing non-complementary pairs (mismatches) in the pairing stem and a non-palindromic spacer (loop or gaps) in the middle of inverted repeats. Compared with existing popular tools, our program performs with significantly higher accuracy and efficiency. Using genome sequence data from HIV-1, Arabidopsis thaliana, Homo sapiens and Zea mays for comparison, detectIR can find lots of inverted repeats missed by existing tools whose outputs often contain many invalid cases. detectIR is open source and its source code is freely available at: https://sourceforge.net/projects/detectir.

  19. System and method for single-phase, single-stage grid-interactive inverter

    Science.gov (United States)

    Liu, Liming; Li, Hui

    2015-09-01

    The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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

  11. On the c-Si surface passivation mechanism by the negative-charge-dielectric Al2O3

    NARCIS (Netherlands)

    Hoex, B.; Gielis, J.J.H.; Sanden, van de M.C.M.; Kessels, W.M.M.

    2008-01-01

    Al2 O3 is a versatile high- ¿ dielectric that has excellent surface passivation properties on crystalline Si (c-Si), which are of vital importance for devices such as light emitting diodes and high-efficiency solar cells. We demonstrate both experimentally and by simulations that the surface

  12. Charter Schools Indicators: A Report from the Center on Educational Governance University of Southern California. CSI-USC 2010

    Science.gov (United States)

    Center on Educational Governance, 2010

    2010-01-01

    CSI-USC continues to make sense of what the California statewide data system provides. This fourth annual report gauges multiple measures of academic and financial performance, probing well beyond mere test scores. Ratings in familiar green, yellow, and red cover four areas: financial resources and investment, school quality, student performance…

  13. Psychometric Evaluation of a Coping Strategies Inventory Short-Form (CSI-SF in the Jackson Heart Study Cohort

    Directory of Open Access Journals (Sweden)

    Herman Taylor

    2007-12-01

    Full Text Available This study sought to establish the psychometric properties of a Coping Strategies Inventory Short Form (CSISF by examining coping skills in the Jackson Heart Study cohort. We used exploratory and confirmatory factor analysis, Pearson’s correlation, and Cronbach Alpha to examine reliability and validity in the CSI-SF that solicited responses from 5302 African American men and women between the ages of 35 and 84. One item was dropped from the 16-item CSI-SF, making it a 15-item survey. No significant effects were found for age and gender, strengthening the generalizability of the CSI-SF. The internal consistency reliability analysis revealed reliability between alpha = 0.58-0.72 for all of the scales, and all of the fit indices used to examine the CSI-SF provided support for its use as an adequate measure of coping. This study provides empirical support for utilizing this instrument in future efforts to understand the role of coping in moderating health outcomes.

  14. Process Optimization for High Efficiency Heterojunction c-Si Solar Cells Fabrication Using Hot-Wire Chemical Vapor Deposition: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Y.; Yuan, H. C.; Page, M.; Nemeth, W.; Roybal, L.; Wang, Q.

    2012-06-01

    The researchers extensively studied the effects of annealing or thermal history of cell process on the minority carrier lifetimes of FZ n-type c-Si wafers with various i-layer thicknesses from 5 to 60 nm, substrate temperatures from 100 to 350 degrees C, doped layers both p- and n-types, and transparent conducting oxide (TCO).

  15. Atomic-layer deposited Nb2O5 as transparent passivating electron contact for c-Si solar cells

    NARCIS (Netherlands)

    Macco, Bart; Black, Lachlan E.; Melskens, Jimmy; van de Loo, Bas W.H.; Berghuis, Willem Jan H.; Verheijen, Marcel A.; Kessels, Wilhelmus M.M.

    2018-01-01

    Passivating contacts based on metal oxides have proven to enable high energy conversion efficiencies for crystalline silicon (c-Si) solar cells at low processing complexity. In this work, the potential of atomic-layer deposited (ALD) Nb2O5 as novel electron-selective passivating contact is explored

  16. Novel Robust Optimization and Power Allocation of Time Reversal-MIMO-UWB Systems in an Imperfect CSI

    Directory of Open Access Journals (Sweden)

    Sajjad Alizadeh

    2013-03-01

    Full Text Available Time Reversal (TR technique is an attractive solution for a scenario where the transmission system employs low complexity receivers with multiple antennas at both transmitter and receiver sides. The TR technique can be combined with a high data rate MIMO-UWB system as TR-MIMO-UWB system. In spite of TR's good performance in MIMO-UWB systems, it suffers from performance degradation in an imperfect Channel State Information (CSI case. In this paper, at first a robust TR pre-filter is designed together with a MMSE equalizer in TR-MIMO-UWB system where is robust against channel imperfection conditions. We show that the robust pre-filter optimization technique, considerably improves the BER performance of TR-MIMO-UWB system in imperfect CSI, where temporal focusing of the TR technique is kept, especially for high SNR values. Then, in order to improve the system performance more than ever, a power loading scheme is developed by minimizing the average symbol error rate in an imperfect CSI. Numerical and simulation results are presented to confirm the performance advantage attained by the proposed robust optimization and power loading in an imperfect CSI scenario.

  17. Two-way CSI-assisted AF relaying with HPA nonlinearity

    KAUST Repository

    Qi, Jian

    2015-09-11

    In this paper, we investigate half-duplex two-way dual-hop channel state information (CSI)-assisted amplify-andforward (AF) relaying in the presence of high-power amplifier (HPA) nonlinearity at relays. The expression for the end-toend signal-to-noise ratio (SNR) is derived as per the modified system model by taking into account the interference caused by relaying scheme and HPA nonlinearity. The system performance of the considered relaying network is evaluated in terms of average symbol error probability (SEP) in Nakagami-m fading channels, by making use of the moment-generating function (MGF) approach. Numerical results are provided and show the effects of several parameters, such as quadrature amplitude modulation (QAM) order, number of relays, HPA parameters, and Nakagami parameter, on performance. © 2015 IEEE.

  18. Progress in the medicinal chemistry of silicon: C/Si exchange and beyond.

    Science.gov (United States)

    Fujii, Shinya; Hashimoto, Yuichi

    2017-04-01

    Application of silyl functionalities is one of the most promising strategies among various 'elements chemistry' approaches for the development of novel and distinctive drug candidates. Replacement of one or more carbon atoms of various biologically active compounds with silicon (so-called sila-substitution) has been intensively studied for decades, and is often effective for alteration of activity profile and improvement of metabolic profile. In addition to simple C/Si exchange, several novel approaches for utilizing silicon in medicinal chemistry have been suggested in recent years, focusing on the intrinsic differences between silicon and carbon. Sila-substitution offers great potential for enlarging the chemical space of medicinal chemistry, and provides many options for structural development of drug candidates.

  19. CSI Index Of Customer’s Satisfaction Applied In The Area Of Public Transport

    Directory of Open Access Journals (Sweden)

    Poliaková Adela

    2015-06-01

    Full Text Available In Western countries, the new visions are applied in quality control for an integrated public transport system. Public transport puts the customer at the centre of our decision making in achieving customer satisfaction with provided service. Sustainable surveys are kept among customers. A lot of companies are collecting huge databases containing over 30,000 voices of customers, which demonstrates the current satisfaction levels across the public transport service. Customer satisfaction with a provided service is a difficult task. In this service, the quality criteria are not clearly defined, and it is therefore difficult to define customer satisfaction. The paper introduces a possibility of CSI index application in conditions of the Slovak Republic transport area.

  20. CSI Index Of Customer's Satisfaction Applied In The Area Of Public Transport

    Science.gov (United States)

    Poliaková, Adela

    2015-06-01

    In Western countries, the new visions are applied in quality control for an integrated public transport system. Public transport puts the customer at the centre of our decision making in achieving customer satisfaction with provided service. Sustainable surveys are kept among customers. A lot of companies are collecting huge databases containing over 30,000 voices of customers, which demonstrates the current satisfaction levels across the public transport service. Customer satisfaction with a provided service is a difficult task. In this service, the quality criteria are not clearly defined, and it is therefore difficult to define customer satisfaction. The paper introduces a possibility of CSI index application in conditions of the Slovak Republic transport area.