Research on Passivity Based Controller of Three Phase Voltage Source PWM Rectifier
Yin Hongren
2012-09-01
Full Text Available Euler-Lagrange (EL model of voltage source PWM rectifier is set up based on its model in synchronous dq coordinates. Passivity based controller is designed on the basis of passivity and EL model of voltage source PWM rectifier. Three switching function are educed by passivity based controller. A switching function is only realized in engineering consequently. Voltage source PWM rectifier using passivity based controller has many advantages, such as simpler structure, low total harmonic distortion, and good disturbance rejection performance. Passivity based control law is proved feasible by simulink simulation.
A single leg switched PWM method for three-phase H-Bridge Voltage Source Converters
Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig; Rodriguez, Pedro; Teodorescu, Remus
This paper proposes a single leg switched or a hybrid PWM (HPWM) method for three-phase three-level H-Bridge Voltage Source Converters (3L-HB-VSCs). By means of the proposed modulation, a 3L-HB-VSC can generate the same output as a three-level neutral point clamped (3L-NPC) VSC with phase...... disposition (PD) PWM provided that the outputs of 3L-HBVSC are isolated by transformers or connected to open winding machines. Thus, the proposed method is called PD-HPWM. Moreover, it is emphasized that 3L-HB-VSC with HPWM utilizes its switches similar to 3L-NPC-VSC. Compared to 3L-NPC-VSCs, 3L......-HB-VSCs (without neutral point clamping diodes) have simpler, more modular, and more reliable 2L circuit structure. Therefore, this method encourages the use of 3L-HB-VSCs in the applications utilizing transformers such as grid-side converters of multi-MW wind turbines. The proposed PWM method's performance is...
Step-by-Step Design Procedure for a Grid-Connected Three-Phase PWM Voltage Source Converter,
Liserre, Marco; Blaabjerg, Frede; Aquila, Antonio Dell
2004-01-01
The voltage source active rectifier is one of the most interesting solutions to interfacing dc power systems to the grid. Many elements are responsible for the overall system behaviour, such as value of the passive elements, sensors position, analog/digital filters and ac current/dc voltage contr...
S. Manivannan, S. Veerakuma; P. Karuppusamy, A. Nandhakumar
2014-01-01
The Three Phase Voltage Source Inverter supplies invariably required variable voltage and frequency of the adjustable speed drive system. A number of pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply from an inverter. The most widely used PWM scheme for a Three Phase Voltage Source Inverter is carrier based sinusoidal PWM and Space Vector Pulse Width Modulation (SVPWM). There is an increasing trend of using SVPWM, beca...
Three phase voltage source converter current analysis
The proposed rectifier system consists of a three-phase diode bridge circuit as a main power circuit, A C reactors, and an additional circuit, which serves as an active filter with low switching frequencies and forced-commutation circuit for the diodes. These papers describe the operation principle, analysis of the waveforms of input voltage and current, the calculated of A C input current, multiple phase-shifted systems, and the experimental result. Avery conventional method was employed to analyze the input current equation; in that, the ripple output was neglected. The theory developed in this paper was verified twice; by calculation result and experiments. The calculated A C input the simple program using the algorithm of current equations calculated current waveforms presented in this paper. A switching circuit has been added to the diode rectifier, serving as an active filter and a forced-commutation circuit for diodes systems
罗德荣; 姬小豪; 黄晟; 廖武
2014-01-01
Mathematical modeling of voltage source PWM filter is conducted and a predictive power model under two-phase rest frame is established, on this basis an optimal model predictive direct power control (MPDPC) strategy is proposed. In the proposed control strategy the voltage vector in power supply system is taken as the basic control vector and utilizing power directive model and minimum power error principle the formula of objective control voltage vector is obtained, then combining with space vector PWM modulation(SVPWM) the model predictive direct power control is implemented. Meanwhile, considering the step delay in actual control systems a delay compensation scheme is designed. Besides, the repetitive control is led in to optimize the active and reactive power in each sampling cycle. The feasibility of the proposed control method is validated by results of simulation and experiments.%对电压型PWM整流器进行了数学建模，然后在两相静止坐标系下建立了预测功率模型，在此基础上提出了优化的模型预测直接功率控制(model predictive direct power control，MPDPC)策略。该方法用电网电压矢量作为基本控制矢量，利用功率预测模型和功率误差最小原则，得出目标控制电压矢量公式，结合空间矢量脉宽调制实现模型预测功率控制。同时针对实际系统中的一步延迟设计了延时补偿方案。此外，在系统中引入重复控制对每个采样周期系统的有功、无功功率进行优化。仿真和实验验证了表明所提出的方法的可行性。
Abolfazl Halavei Niasar; Ehsan Boloor Kashani
2013-01-01
Induction motors offer many advantages tools, and therefore are becoming very popular industrially and commercially. This paper presents the implementation of Xmega microcontroller based PWM inverter controlled of four-switch three phase voltage source inverter (FSTPI) fed induction motor drive. The reduction of the number of power switches from six to four improves the cost effectiveness, volume-compactness and reliability of the three phase inverters in addition to less complexity of contro...
Zulkifilie Bin Ibrahim
2014-03-01
Full Text Available Pulse width modulation (PWM technique is one of the vital issues for power electronic circuit control. A number of Pulse width modulation (PWM techniques are increasingly applied in many new industrial applications that require superior performance. The most widely applied PWM technique for three-phase voltage source inverters are Sine Pulse Width Modulation (SPWM, Third Harmonic Injection Pulse Width Modulation (THIPWM and Space Vector Pulse Width Modulation (SVPWM. SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD, lower switching frequency and not capable in over modulation region. THIPWM and SVPWM both provide better THD compared to SPWM. SVPWM shows lower THD in over modulation region and in high frequency application compared to THIPWM. These three techniques are discussed, analyzed and compared in terms of modulation index, switching frequency and inverter input voltage in this paper. The modeling and simulation for all PWM techniques have been done by using MATLAB/SIMULINK and Origin 6.1. From the simulation results, SVPWM shows the best performance and meet IEEE 519 standard of current harmonics level.
Ajay Kumar Maurya, Kishore Chahar, Y. K. Chauhan
2013-01-01
This paper presents the analysis of a photovoltaicbases three-phase five level voltage source inverter(VSI) supplying induction motor driven waterpump. The VSI uses a unipolar PWM technique forproducing three phase 5 level voltage output andthis output is used to drive three-phase inductionmotor driving a pump load. Multilevel inverters areused for generating AC voltage from several levelsof DC voltages and enhance the performance of thesystem. The proposed system is used to reduce thefilteri...
An Integrated Inductor For Parallel Interleaved Three-Phase Voltage Source Converters
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus; Kerekes, Tamas; Blaabjerg, Frede
2016-01-01
Three phase Voltage Source Converters (VSCs) are often connected in parallel to realize high current output converter system. The harmonic quality of the resultant switched output voltage can be improved by interleaving the carrier signals of these parallel connected VSCs. As a result, the line...
Shunt PWM advanced var compensators based on voltage source inverters for Facts applications
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.
Three-phase power conversion using soft-switching PWM techniques
Vlatkovic, Vlatko
1994-01-01
This dissertation addresses several key issues related to high-frequency soft-switching PWM three-phase power converters. These are: 1. Analysis, synthesis, and design of three-phase soft-switching PWM power converter topologies, 2. Design of input EMI filters for three-phase converters, and 3. Design of microprocessor controllers for three-phase converters. An analysis of existing soft-switching PWM techniques is performed, and two generalized soft-switching PWM converte...
Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters
Gabriele Grandi; Jelena Loncarski
2013-01-01
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 c...
Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter
Mohd. Arif Khan
2012-03-01
Full Text Available This paper presents discontinuous space vector PWM (DPWM techniques for a seven-phase voltage source inverter (VSI. Space vector model of a seven-phase VSI shows that there exist 128 space vectors with different lengths and maps into fourteen sided polygons. A number of possibilities could arise to implement modulation of inverter legs due to large number of available space voltage vectors. Two strategies are adopted here; one utilising large and two middle sets of space vectors to implement discontinuous space vector PWM. Clamping of legs of inverter to either positive or negative dc bus leads to discontinuity in the switching and consequently offers reduced switching loss modulation strategy. A significant reduction in switching losses can be achieved while employing DPWM in a seven-phase VSI. A generalised method is also proposed to realize the DPWM in a seven-phase VSI. Comparison of continuous and discontinuous PWM is presented in terms of switching current ripple. The experimental set-up is illustrated and the experimental results are presented.
Simulation Study of the Carrier-Based PWM Method in Three- Phase Flying Capacitor Inverters
Adrian Şchiop
2008-01-01
This paper is a simulation study ofmodulation strategies in three-phase flying capacitorinverters. Under investigation are those strategies thatsolve the capacitor voltage balancing problem: phaseshiftPWM method, the saw-tooth rotation PWM methodand carrier redistribution PWM method. The results areshown through simulation.
Impact of PWM strategies on RMS current of the DC-link Voltage Capacitor of a dual-three phase drive
ROUHANA, Najib; DUGUEY, Jean-François; SEMAIL, Eric
2014-01-01
The major drawback of usual dual three-phase AC machines, when supplied by a Voltage Source Inverter (VSI), is the occurrence of extra harmonic currents which circulate in the stator windings causing additional losses and constraints on the power component. This paper compares dedicated Pulse Width Modulation (PWM) strategies used for controlling a dual three phase Permanent Magnet Synchronous machine supplied by a six-leg VSI. Since the application is intended for low-voltage (48V) mild-hybr...
Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi; Eloy-Garcia, Joaquin; Teodorescu, Remus
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...
SYNCHRONOUS PWM CONTROL OF SYMMETRICAL DUAL THREE-PHASE DRIVE IN THE OVERMODULATION ZONE
Oleschuk V.I.; Sizov A.
2013-01-01
The analysis of operation of symmetrical six-phase (dual three-phase) ac drive system (which is a promising solution for the medium-power and high-power applications) with synchronized pulse-width modulation (PWM) during overmodulation has been performed. The induction machine of this system topology has two sets of windings spatially shifted by 60 electrical degrees with isolated neutral points, which are connected with two standard three-phase inverters. Algorithms of synchronized PWM provi...
Integrated inductor for interleaved operation of two parallel three-phase voltage source converters
Gohil, Ghanshyamsinh; Bede, Lorand; Teodorescu, Remus; Kerekes, Tamas; Blaabjerg, Frede
This paper presents an integrated inductor for two parallel interleaved Voltage Source Converters (VSCs). Interleaving of the carrier signals leads to improvement in the harmonic quality of the resultant output voltage and the line current filtering requirements can then be reduced. However, the ...
Control Method Compensating for Unbalanced Three-Phase Voltage Supply in Voltage Source Inverter
Chomát, Miroslav; Schreier, Luděk; Bendl, Jiří
Sydney: The University of Newcastle Australia, 2004, s. 523-527. [Symposium IFAC (International Federation of Automatic Control) on Mechatronic Systems /3./. Sydney (AU), 06.09.2004-08.09.2004] R&D Projects: GA ČR GA102/02/0554 Keywords : voltage source inverter * unbalanced voltage supply * pulse width modulation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Superior decoupled control of active and reactive power for three-phase voltage source converters
RAHBARIMAGHAM, HESAM; AMIRI, ERFAN MAALI; VAHIDI, Behrooz; GHAREHPETIAN, GEVORG BABAMALEK; Abedi, Mehrdad
2015-01-01
This paper presents an active-reactive power control strategy for voltage source converters (VSCs) based on derivation of the direct and quadrature components of the VSC output current. The proposed method utilizes a multivariable proportional-integral controller and provides almost completely decoupled control capability of the active and reactive power with almost full disturbance rejection due to step changes in the power exchanged between the VSC and the grid. It also imposes fast transie...
Three-Phase Voltage Source Inverter with Compensation of Unbalanced Voltage Supply
Chomát, Miroslav; Schreier, Luděk; Bendl, Jiří
Tokyo: Institute of Electrical Engineers of Japan, 2005, s. 2038-2041. ISBN 4-88686-065-6. [International Power Electronic Conference IPEC-Niigata 2005. Toki Messe, Niigata (JP), 04.04.2005-08.04.2005] R&D Projects: GA ČR(CZ) GA102/04/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : unbalanced voltage supply * voltage source inverter * pulse width modulation Subject RIV: JA - Electronic s ; Optoelectronics, Electrical Engineering
Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters
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.
CONTROL TECHNIQUES FOR VARIOUS BIPOLAR PWM STRATEGIES OF THREE PHASE FIVE LEVEL CASCADED INVERTER
C. R. BALAMURUGAN
2015-07-01
Full Text Available This paper presents different types of bipolar Pulse Width Modulation (PWM strategies for the chosen Cascaded MultiLevel Inverter (CMLI. The main purpose of MLI is to use power semiconductor devices of lower voltage ratings to realize high voltage levels at inverter output. Due to their ability to obtain refined output voltage waveforms, reduced Total Harmonic Distortion (THD and reduced EMI problems by reducing the switching dv/dt. In this paper, a three phase CMLI is controlled with Sinusoidal PWM strategy with Phase Disposition PWM (PDPWM, Phase Opposition and Disposition PWM (PODPWM, Alternative Phase Opposition and Disposition PWM (APODPWM, Phase Shift PWM (PSPWM and hybrid modulation strategy and the variation of THD in their outputs are observed by varying the modulation index. Simulations are performed using MATLAB-SIMULINK. It is observed that APODPWM and PSPWM provide output with relatively low distortion. It is also seen that PS, APOD and hybrid PWM are found to perform better since they provide relatively higher fundamental RMS output voltage. From hardware results it is seen that POD PWM provides output with relatively low distortion. It is also observed that PSPWM is found to perform better since it provide relatively higher fundamental RMS output voltage.
Intelligent Optimize Design of LCL Filter for Three-Phase Voltage-Source PWM Rectifier
Sun, Wei; Chen, Zhe; Wu, Xiaojie
2009-01-01
Compared to traditional L filter, a LCL filter is more effective on reducing harmonic distortion at switch frequency. So it is important to choose the LCL filter parameters to achieve good filtering effect. This paper introduces some traditional design methods. Design of a LCL filter by genetic...... algorithm (GA) and particle swam optimization (PSO) are presented in this paper and comparison of the two intelligent optimization. Simulation result and calculate data are provided to prove that intelligent optimization are more effective and simple than traditional methods....
Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement
Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar
2013-01-01
Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provid...
SELVAMUTHUKUMARAN Rajasekar; NATARAJAN Muraly; PERIANAYAGAM Ajay-D-VimalRaj; MAHALINGAM Sudhakaran
2010-01-01
This paper investigates the performanceand comparison of two pulse-width-modulation (PWM)techniques by employing direct current control strategyapplied to three phase shunt hybrid active power filter(SHAPF). The objective of SHAPF is to eliminate linecurrent harmonics and to incur reactive powercompensation. The direct current control strategy isimplemented using Standard PWM (S-PWM) and aModified PWM (M-WM), in order to compensatecurrent harmonic and reactive power generated bydifferent load...
Three-Phase PWM Power Conversion--The Route to Ultra High Power Density and Efficiency
J W Kolar; J Minib(o)ck; T Nussbaumer
2005-01-01
A review of three-phase PWM converter topologies which do show a low complexity/high reliability and high efficiency and power density and are therefore of main interest for a future industrial application is presented.A three-switch/level Boost-type PWM rectifier (VIENNA Rectifier),a Buck+Boost-type PWM rectifier with wide output voltage range and the AC/AC Sparse Matrix Converter concept are discussed in detail and topics to be treated in the course of further research are identified. Finally,it is shown how the aspects being relevant for the realization of highly compact converter systems could be integrated into education in the field.
Abdelkrim Thameur
2015-01-01
Full Text Available This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.
Abdelkrim Thameur; Benamrane Karima; Bezza Badreddine
2015-01-01
This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI) in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC) voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the...
CONTROL TECHNIQUES FOR VARIOUS BIPOLAR PWM STRATEGIES OF THREE PHASE FIVE LEVEL CASCADED INVERTER
C. R. Balamurugan; S. P. NATARAJAN; R. BENSRAJ
2015-01-01
This paper presents different types of bipolar Pulse Width Modulation (PWM) strategies for the chosen Cascaded MultiLevel Inverter (CMLI). The main purpose of MLI is to use power semiconductor devices of lower voltage ratings to realize high voltage levels at inverter output. Due to their ability to obtain refined output voltage waveforms, reduced Total Harmonic Distortion (THD) and reduced EMI problems by reducing the switching dv/dt. In this paper, a three phase CMLI is controlled with S...
Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive
Mohanty Kant Nalin; Muthu Ranganath
2010-01-01
This paper presents PIC microcontroller based PWM inverter controlled four switch three phase inverter (FSTPI) fed Induction Motor drive. The advantage of this inverter that uses of 4 switches instead of conventional 6 switches is lesser switching losses, lower electromagnetic interference (EMI), less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. S...
A New PWM Modifying Technique for Reconstructing Three-phase Currents from DC Bus Current
Aoyagi, Shigehisa; Iwaji, Yoshitaka; Tobari, Kazuaki; Sakamoto, Kiyoshi
Vector control is used to drive a DC brushless motor and generally needs current information. DC bus current detection is often adopted as a low cost method for reconstructing three-phase currents. PWM modifying techniques increase the DC pulse duration, thereby enabling easy detection of the DC bus current. However, these techniques have two problems: reducing a noise frequency and making the reconstructed current waveforms distorted by current ripple. In the techniques, modification signals are added to the three-phase voltage commands; the sum of the signals over a single cycle is zero. The authors examined several PWM modifying techniques from the points of view of noise and current distortion performance. One of the techniques had a good noise performance, and the frequency component of the noise was the same as the carrier frequency (fc). However, the reconstructed current waveforms were distorted. The total harmonic distortion (THD) varied from 1.7% to 4.1%. Another technique had a very poor noise performance, and the frequency component on the noise was one-fourth of fc. The authors developed a new PWM modifying method called “Half Pulse Shift”, which achieves the optimum noise and current distortion performance. The frequency component of the new method was two-thirds of fc, and the current waveforms were not distorted; the THD in the simulations and experiments was 0.5%-1.4% and 3.4%-3.6%, respectively.
Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor
M. A. Latif
2013-04-01
Full Text Available Three phase induction motor has proven to be an extremely reliable electromechanical energy conversion device for over 100 years. The speed control of induction motor is a crying need for the real world industrial applications. However, there are so many options available for the precise speed control of induction motor except by changingthe frequency. Therefore to achieve the goal of speed control of induction motor, there is no alternative of inverters. With the availability of high speed power semiconductor devices, the three phase inverters play the key role for variable speed ac motor drives. In addition to the speed control, the inverter can also provide some unique features, like voltage control, torque control, power factor correction, auto breaking, built in protection system and so forth.In this paper, a three phases PWM inverter using MC3PHAC microcontroller with computer interface is proposed to run a squirrel case induction motor. Some results of the proposed inverter are presented.
Panfilov, Dmitry; Husev, Oleksandr; Blaabjerg, Frede; Zakis, Janis; Khandakji, Kamal
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...
Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive
Mohanty Kant Nalin
2010-01-01
Full Text Available This paper presents PIC microcontroller based PWM inverter controlled four switch three phase inverter (FSTPI fed Induction Motor drive. The advantage of this inverter that uses of 4 switches instead of conventional 6 switches is lesser switching losses, lower electromagnetic interference (EMI, less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using MATLAB SIMULINK and in the experimental work a prototype model is built to verify the simulation results. PIC microcontroller (PIC 16F877A is used to generate the PWM pulses for FSTPI to drive the 0.5 hp 3-phase Induction Motor.
Comparative analysis of SPWM and SVPWM control for three phase inverter
K. Vinoth Kumar; Prawin Angel Michael; Joseph P. John; S.Suresh Kumar
2010-01-01
A voltage source inverter is commonly used to supply a three-phase induction motor with variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation (PWM) technique is employed to obtain the required output voltage in the line side of the inverter. The different methods for PWM generation can be broadly classified into triangle comparison based PWM (TCPWM) and Space Vector based PWM (SVPWM). In TCPWM methods such as sine-triangle PWM, three phase ...
Three phase six-switch PWM buck rectifier with power factor improvement
Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, three phase six-switch PWM buck rectifier is presented which operates at nearly unity power factor and provides variable output voltage. Small size energy storing components are required depending upon switching frequency. MATLAB simulation is performed and modified Sinusoidal Pulse Width Modulation (SPWM) switching technique is used in 3kW prototype converter to demonstrate low input current THD, nearly unity displacement factor, well regulated output voltage and reduced switching losses compared to conventional SPWM.
Cavagnino, Andrea; Boglietti, Aldo; Bojoi, Iustin Radu; Tenconi, Alberto
2008-01-01
A performance analysis of three-phase and dual three-phase (DTP) induction pulsewidth modulation (PWM) inverter-fed motor drives is conducted in this paper. The focus is on the efficiency performance of high-frequency DTP machines compared to their three-phase counterparts in low/medium power applications. For this purpose, a DTP machine, having two sets of stator three-phase windings spatially shifted by 30 electrical degrees (asymmetrical six-phase winding configuration), was tested for bot...
Modi, Manoj Kumar; Venugopal, S.; Narayanan, G.
2013-01-01
The equivalence of triangle-comparison-based pulse width modulation (TCPWM) and space vector based PWM (SVPWM) during linear modulation is well-known. This paper analyses triangle-comparison based PWM techniques (TCPWM) such as sine-triangle PWM (SPWM) and common-mode voltage injection PWM during overmodulation from a space vector point of view. The average voltage vector produced by TCPWM during overmodulation is studied in the stationary (a-b) reference frame. This is compared and contraste...
Doumoto, Takafumi; Akagi, Hirofumi
This paper proposes a small-sized passive EMI filter for the purpose of eliminating high-frequency shaft voltage and ground leakage current from an ac motor. The motor is driven by a general-purpose PWM inverter connected to a three-phase grounded voltage source. The passive EMI filter requires access to the ungrounded neutral point of the motor. This unique circuit configuration makes the common-mode inductor effective in reducing the high-frequency common-mode voltage generated by the PWM inverter with a carrier frequency of 15kHz. As a result, both high-frequency shaft voltage and ground leakage current can be eliminated very efficiently. However, the common-mode inductor may not play any role in reducing the low-frequency common-mode voltage generated by the diode rectifier, so that a low-frequency component still remains in the shaft voltage. Such a low-frequency shaft voltage may not produce any bad effect on motor bearings. The validity and effectiveness of the EMI filter is verified by experimental results obtained from a 200-V 5-kVA laboratory system.
VISHNU MOHAN MISHRA
2012-03-01
Full Text Available The aim of this paper is to present a novel control scheme and designing of reactance parameter of PWM convereterand, find the optimized value of parameters for voltage PI controller for three phase ac/dc PWM converter. Using new trends Genetic algorithms- are discussed, as well.Paper describes the application of Genetic Algorithms for optimization of controller parameters of PWM converter. The behavior of the stability region is plotted with different sampling periods.Genetic Algorithms used for off-line searching Using the MATLAB, the simulation model of the dc- link PWM ac/dc converter is built up. According to the simulation results, it is known that, the presented control strategy is feasible and valid, and the converter can work well under dc motor load condition, and thus the total harmonics distortion (THD can be reduced quickly and effectively. The PWM rectifier operates as a rectifier to supply dc power to its load a dc motor and at the same time, to improve the power factor and to compensate harmonics drawn from non-linear loads connected on the ac line.
Manoj Kumar Modi; S Venugopal; G Narayanan
2013-06-01
The equivalence of triangle-comparison-based pulse width modulation (TCPWM) and space vector based PWM (SVPWM) during linear modulation is well-known. This paper analyses triangle-comparison based PWM techniques (TCPWM) such as sine-triangle PWM (SPWM) and common-mode voltage injection PWM during overmodulation from a space vector point of view. The average voltage vector produced by TCPWM during overmodulation is studied in the stationary (a–b) reference frame. This is compared and contrasted with the average voltage vector corresponding to the well-known standard two-zone algorithm for space vector modulated inverters. It is shown that the two-zone overmodulation algorithm itself can be derived from the variation of average voltage vector with TCPWM. The average voltage vector is further studied in a synchronously revolving (d-q) reference frame. The RMS value of low-order voltage ripple can be estimated, and can be used to compare harmonic distortion due to different PWM methods during overmodulation. The measured values of the total harmonic distortion (THD) in the line currents are presented at various fundamental frequencies. The relative values of measured current THD pertaining to different PWM methods tally with those of analytically evaluated RMS voltage ripple.
An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter
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.
Lar, Ionut Andrei; Radulescu, Mircea; Ritchie, Ewen; Pop, Adrian Augustin
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 w...
C. R. Balamurugan
2012-11-01
Full Text Available This paper presents the comparison of Unipolar Inverted Sine Carrier Pulse Width Modulation (UISCPWM techniques for the Cascaded Multi Level Inverter (CMLI. Due to switch combination redundancies, there are certain degrees of freedom to generate the multilevel AC output voltage. This paper presents the use of Control Freedom Degree (CFD combination. The effectiveness of the pulse width modulation strategies developed using CFD are demonstrated using simulation. The results indicate that the chosen five level inverter triggered by the developed UISC phase shift PWM and UISC variable frequency PWM strategy with sine and stepped wave references and UISC alternate phase opposition disposition PWM strategy with 60 degree reference exhibit reduced harmonics and UISC carrier overlapping PWM provides higher fundamental RMS output voltage for all three chosen references. Simulations are performed using MATLAB-SIMULINK.
Doumoto, Takafumi; Akagi, Hirofumi
This paper proposes a practical approach to suppressing both shaft voltage and leakage current in an ac motor driven by a voltage-source PWM inverter. This approach is characterized by using a neutral line of the ac motor. A common-mode inductor is connected between the inverter and the motor. Moreover, a resistor and a capacitor are connected in series between the motor neutral point and the inverter negative dc bus. This unique circuit configuration makes the common-mode inductor effective in reducing the common-mode voltage appearing at the motor terminals. As a result, both shaft voltage and ground current are significantly suppressed with low cost. Over-voltages at the end of a cable can be suppressed by a normal-mode inductor and a resistor which are connected in parallel. The validity and effectiveness of the new approach are verified by experimental results from a 5-kVA laboratory system.
An Analytical Modelling of Three-Phase Four-Switch PWM Rectifier Under Unbalanced Supply Conditions
Klíma, J.; Škramlík, Jiří; Valouch, Viktor
2007-01-01
Roč. 54, č. 12 (2007), s. 1155-1159. ISSN 1549-7747 R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : modelling * pulsewidth modulation (PWM) * reactive power Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.104, year: 2007
Analytical closed-form solution of three-phase four-switch PWM rectifier
Škramlík, Jiří; Valouch, Viktor; Klíma, J.; Pecha, I.
2010-01-01
Roč. 55, č. 3 (2010), s. 223-235. ISSN 0001-7043 R&D Projects: GA MPO FT-TA5/123 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch PWM rectifier * space vector modulation * closed-form analytical solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Analytical Modeling and Implementation of Three-Phase Four-Switch Space-Vector PWM Converter
Paclt, Zdeněk; Šimek, Petr; Škramlík, Jiří; Valouch, Viktor; Klíma, J.
Prague : Institute of Thermomechanics AS CR, v. v. i., 2008, s. 49-52. ISBN 978-80-87012-13-0. [Symposium Electric Machines and Drives, Power Electronics and Drive Control. Prague (CZ), 30.09.2008-02.10.2008] R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch PWM rectifier * space vector modulation * closed-form analytical solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Modeling and Implementation of Three-Phase Component Minimized PWM Converter
Šimek, Petr; Škramlík, Jiří; Valouch, Viktor; Klíma, J.
Brno : VUT FEKT Brno, 2008, s. 1-8. ISBN 978-80-7204-603-4. [Celostátní konference EPVE 2008. Brno (CZ), 11.11.2008-12.11.2008] R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch PWM rectifier * space vector modulation * closed-form analytical solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Repetitive current control of two-level and interleaved three-phase PWM utility connected converters
Jamil, Mohsin
2012-01-01
This thesis is mainly concerned with investigations into digital repetitive current control of two-level and interleaved utility connected PWM converters. The research is motivated by the relatively poor performance of classical (PI) controllers when the utility voltage harmonic distortion is high. This is due to the low gain, and poor disturbance rejection of the PI controller at the utility harmonic frequencies. Repetitive feedback controllers have the ability to track or rej...
J. CHELLADURAI
2015-04-01
Full Text Available Power quality problems caused by significant increase of non-linear loads initiated intensive research in high power factor converters. Most of the modern power electronic systems like variable speed drives, DC power supplies and battery charging systems uses uncontrolled diode bridge rectifier. The uncontrolled rectifier system injects lot of harmonics in to the AC supply system there by reducing the power factor to less than unity. Single stage PWM rectifier is the novel solution to eliminate the harmonics and to improve the input power factor. In this paper, a scalar controlled PWM rectifier is modeled and the system is compared with the conventional bridge rectifier with and without filter.The major advantages of using this technique are less intensive computational control and sensor less input voltage operation. The PWM rectifier system is investigated using the different carrier and modulating signal. The scalar control technique is used to control the boost rectifier output voltage and input power factor. The performance of the rectifier with different carrier and modulating techniques were compared with respect to the Total Harmonic Distortion (THD in source current. Simulation results demonstrate the effectiveness of the modified modulating signal and triangular carrier signal for effectively reducing the source current THD.
The integrated voltage compensation type active superconducting fault current limiter (SFCL) is composed of three air-core superconducting transformers and a three-phase four-wire PWM converter. In order to realize the current-limiting characteristics of the integrated active SFCL, it is needed to control the three-phase four-wire PWM converter flexibly and reasonably. Thereby, the control strategy for the converter is analyzed in this paper. In dq0 reference frame, the mathematical model of the converter is founded. The double-loop control strategy, consisting of voltage outer loop and current inner loop, is presented. Moreover, the voltage balance control for the split DC link capacitors is also considered. Using MATLAB, the simulation model of the integrated active SFCL is built. According to the simulation results, it is known that, the presented control strategy is feasible and valid, and the converter can work well under unsymmetrical and symmetrical fault conditions, and then the fault current can be limited quickly and effectively.
DUAL THREE-PHASE ADJUSTABLE SPEED DRIVE WITH SYNCHRONIZED SPACE-VECTOR MODULATION
Oleschuk V.I.
2008-04-01
Full Text Available Split-phase symmetrical motor drive on the base of two voltage source inverters, controlled by algorithms of synchronized pulse width modulation (PWM, has been investigated. Simulation results are presented for dual three-phase power conversion systems with continuous, discontinuous and combined versions of synchronized PWM.
DUAL THREE-PHASE ADJUSTABLE SPEED DRIVE WITH SYNCHRONIZED SPACE-VECTOR MODULATION
Oleschuk V.I.; Prudeak R.; Sizov A.S.; Iaroshenco E.M.
2008-01-01
Split-phase symmetrical motor drive on the base of two voltage source inverters, controlled by algorithms of synchronized pulse width modulation (PWM), has been investigated. Simulation results are presented for dual three-phase power conversion systems with continuous, discontinuous and combined versions of synchronized PWM.
Hong-yu Zhu
2013-01-01
Full Text Available Broken rotor bars fault detection in inverter-fed squirrel cage induction motors is still as difficult as the dynamics introduced by the control system or the dynamically changing excitation (stator frequency. This paper introduces a novel fault diagnosis techniques using motor current signature analysis (MCSA to solve the problems. Switching function concept and frequency modulation theory are firstly used to model fault current signal. The competency of the amplitude of the sideband components at frequencies (1±2sfs as indices for broken bars recognition is subsequently studied in the controlled motor via open-loop constant voltage/frequency control method. The proposed techniques are composed of five modules of anti-aliasing signal acquisition, optimal-slip-estimation based on torque-speed characteristic curve of squirrel cage motor with different load types, fault characteristic frequency determination, nonparametric spectrum estimation, and fault identification for achieving MCSA efficiently. Experimental and simulation results obtained on 3 kW three-phase squirrel-cage induction motors show that the model and the proposed techniques are effective and accurate.
Kouchaki, Alireza; Niroumand, Farideh Javidi; Haase, Frerk; Nymand, Morten
This paper presents an analytical method for designing the inductor of three-phase power factor correction converters (PFCs). The complex behavior of the inductor current complicates the inductor design procedure as well as the core loss and copper loss calculations. Therefore, this paper analyze...
Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor
M. A. Latif; M.J. Alam; Rashid, M. A.; Karim, A.; N. H. Ramly; I. Daut
2013-01-01
Three phase induction motor has proven to be an extremely reliable electromechanical energy conversion device for over 100 years. The speed control of induction motor is a crying need for the real world industrial applications. However, there are so many options available for the precise speed control of induction motor except by changingthe frequency. Therefore to achieve the goal of speed control of induction motor, there is no alternative of inverters. With the availability of high speed p...
PWM Technique of Five-Leg Inverter Applying Two-Arm Modulation
Oka, Kazuo; Matsuse, Kouki
This paper presents the simple pulse width modulation (PWM) technique of a five-leg inverter to drive two three-phase AC motors independently. Normal PWM techniques in three-phase voltage source inverter cannot be used for the five-leg inverter with the independent drive. In this paper, two kinds of simple and novel PWM techniques of the five-leg inverter with two three-phase AC motors are introduced. Experimental results are provided to illustrate the validity of the proposed PWM technique.
Spread spectrum in three-phase inverter by an optimised dual randomised PWM technique
Boudjerda, Nasserdine; Boudouda, Aimad; Melit, Mohammed; Nekhoul, Bachir; El Khamlichi Drissi, Khalil; Kerroum, Kamal
2014-03-01
Randomised pulse width modulation (RPWM) technique has become a viable alternative to deterministic pulse width modulation (DPWM). By spreading the power spectrum in a continuous noise, this new technique better complies with electromagnetic compatibility (EMC) requirements for conducted electromagnetic interferences (EMI) and allows reducing the emitted acoustic noise in variable speed drives (VSDs). The most popular RPWM schemes are randomised pulse position modulation (RPPM) and randomised carrier frequency modulation (RCFM). The combination (RCFM-RPPM) or dual RPWM (DRPWM) has also been proposed. In this article, we propose an optimised DRPWM (ODRPWM) for the three-phase inverter. First, the modulating principle is proposed, and then, a mathematical model of power spectral density (PSD) of the output voltage is developed and validated for the three schemes, namely RPPM, RCFM and RCFM-RPPM. PSD analysis shows that the proposed scheme is more effective on spreading PSD. Moreover, this analysis reveals optimal parameters of randomisation for a maximum spread of the PSD. The optimisation problem is then modelled and solved using two powerful non-linear methods.
This paper is concerned with the design and implementation of current control of three-phase PWM rectifier based on predictive control strategy. The proposed predictive current control technique operates with constant switching frequency, using space-vector modulation (SVM). The main goal of the designed current control scheme is to maintain the dc-bus voltage at the required level and to achieve the unity power factor (UPF) operation of the converter. For this purpose, two predictive current control algorithms, in the sense of deadbeat control, are developed for direct controlling input current vector of the converter in the stationary α-β and rotating d-q reference frame, respectively. For both predictive current control algorithms, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of both tracking errors of current vector components at the end of the switching period, is computed and applied during a predefined switching period by means of SVM. The main advantages of the proposed predictive current control are that no need to use hysteresis comparators or PI controllers in current control loops, and constant switching frequency. Finally, the developed predictive current control algorithms were tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance in steady and transient states, and verify the validity of the proposed predictive current control which is compared to other control strategies.
In this paper a new control strategy for voltage-source converters (VSC) is introduced. The proposed strategy consists of a nonlinear feedback controller based on feedback linearization plus a feedforward compensation of the estimated load current. In our proposal an energy function and the direct-axis current are considered as outputs, in order to avoid the internal dynamics. In this way, a full linearization is obtained via nonlinear transformation and feedback. An estimate of the load current is feedforwarded to improve the performance of the whole system and to diminish the capacitor size. This estimation allows to obtain a more rugged and cheaper implementation. The estimate is calculated by using a nonlinear reduced-order observer. The proposal is validated through different tests. These tests include performance in presence of switching frequency, measurement filters delays, parameters uncertainties and disturbances in the input voltage.
Chomát, Miroslav; Schreier, Luděk
2005-01-01
Roč. 152, č. 3 (2005), s. 494-500. ISSN 1350-2352 R&D Projects: GA ČR(CZ) GA102/02/0554 Institutional research plan: CEZ:AV0Z20570509 Keywords : DC-link voltage * unbalanced three - phase voltage Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.587, year: 2005
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....... 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...
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.
The core losses and the lower-order voltage harmonics of four different chorded motors fed from sinusoidal supply and inverter voltage supply were invigilated at no-load condition. All the four motors were tested with 4, 8 and 16 kHz switching frequencies and 30, 40, 50 and 60 Hz modulation frequencies The motor with 120 deg. coil pitch has the least core losses and the lower-order voltage harmonics under sinusoidal and pulse width modulation (PWM) voltage supplies at all switching and modulation frequencies. The drop in the core losses for this motor was 46% and 53% under sinusoidal and PWM voltage supplies, respectively. The motor with 120 deg. coil pitch is recommended to be used under sinusoidal and PWM voltage supplies
Deshmukh, Ram; Moses, A. J.; Anayi, F.
The core losses and the lower-order voltage harmonics of four different chorded motors fed from sinusoidal supply and inverter voltage supply were invigilated at no-load condition. All the four motors were tested with 4, 8 and 16 kHz switching frequencies and 30, 40, 50 and 60 Hz modulation frequencies The motor with 120° coil pitch has the least core losses and the lower-order voltage harmonics under sinusoidal and pulse width modulation (PWM) voltage supplies at all switching and modulation frequencies. The drop in the core losses for this motor was 46% and 53% under sinusoidal and PWM voltage supplies, respectively. The motor with 120° coil pitch is recommended to be used under sinusoidal and PWM voltage supplies.
Klíma, J.; Škramlík, Jiří; Valouch, Viktor
Prague : Czech Technical University, 2007, s. 80-86. ISBN 978-80-01-03807-9. [International Symposium on Electric Machinery /15./. Prague (CZ), 05.09.2007-06.09.2007] Institutional research plan: CEZ:AV0Z20570509 Keywords : PWM rectifier * space-vector modulation * unbalance supply Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Klíma, J.; Škramlík, Jiří; Valouch, Viktor
Sichuan : Sichuan University, 2008, s. 1-4. ISBN 978-1-4244-1706-3. [IEEE International Conference on Industrial Technology (ICIT 2008). Chengdu (CN), 21.04.2008-24.04.2008] R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch PWM rectifier * space vector modulation * unbalance supply Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Inagaki, K. (Toshiba Corp., Tokyo (Japan)); Okuma, S. (Nagoya University, Nagoya (Japan))
1992-06-20
The main circuit configuration and control method were proposed of the high-frequency link DC/AC converter using a three-phase output cycloconverter for UPSs (uninterruptible power supply). The control function approach of the previously proposed PWM controlled cycloconverter was applied to control of the proposed cycloconverter which converts single-phase high-frequency power into three-phase commercial frequency one. The proposed converter could not only charge DC power supplies from a power system but also compensate enough instantaneous reactive power for loads. The circuit configuration was, in particular, effective for such DC power supplies as fuel cell and solar cell which are possible to generate electric power and necessary to be insulated electrically against a power system. The isolated operation and cooperative one of the proposed DC/AC converter were verified by simulation and experiments. 4 refs., 14 figs., 1 tab.
Three-phase Resonant DC-link Converter
Munk-Nielsen, Stig
1997-01-01
The purpose of the project is to develop a three-phase resonant converter suitable for standard speed drives. The motivation for working with resonant converters is found in the problem of the standard converter type used today. In standard converter type Pulse Width Modulated-Voltage Source Inverter, PWM-VSI, the switches are subject to high current and voltage stress during switching, which causes losses. The fast switching of modern switches reduces switching losses. Unfortunately this pro...
This paper proposes direct power control (DPC) for three-phase PWM rectifiers using a new switching table, without line voltage sensors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The main goal of the control system is to maintain the dc-bus voltage at the required level, while input currents drawn from the power supply should be sinusoidal and in phase with respective phase voltages to satisfy the unity power factor (UPF) operation. Conventional PI and a designed fuzzy logic-based controller, in the dc-bus voltage control loop, have been used to provide active power command. A dSPACE based experimental system was developed to verify the validity of the proposed DPC. The steady-state, and dynamic results illustrating the operation and performance of the proposed control scheme are presented. As a result, it was confirmed that the novel DPC is much better than the classical one. Line currents very close to sinusoidal waveforms (THD < 2%) and good regulation of dc-bus voltage are achieved using PI or fuzzy controller. Moreover, fuzzy logic controller gives excellent performance in transient state, a good rejection of impact load disturbance, and a good robustness
Robust Variable Structure Control for Three-phase PWM Converter%三相PWM变换器的鲁棒变结构控制
郭鑫; 任海鹏
2015-01-01
分析了三相脉冲宽度调制(Pulse width modulation, PWM)功率因数校正(Power factor correction, PFC)变换器的工作原理和数学模型。针对现有控制方法在参数不确定及参数变化时性能变差的问题,提出采用鲁棒变结构控制减小系统参数不确定性的影响,同时采用渐缩滑动边界的方法减小了控制量的颤振。仿真及实验结果表明,与传统PI 控制和反馈线性化方法相比,本文方法不仅在标称参数时具有较好的动静态性能,而且在系统参数发生变化时,具有更强的鲁棒性。%In this paper, we analyze the working principle and mathematical model of the three-phase pulse width modulation (PWM) power factor correction (PFC) converter. The performance of conventional control methods will degrade due to parameter uncertainties and parameter variations. To deal with this problem, a robust variable structure control is proposed to alleviate the performance degradation caused by parameter uncertainty;meanwhile, the time-varying boundary layer is employed to decrease the chattering of the control force. Simulation and experimental results show that, compared to traditional PI control and feedback linearization control method, the proposed method not only has nice transient and steady state performances under nominal parameters, but also has better robustness against parameter perturbations.
Design of Three-phase High Power Factor PWM Rectifier%三相高功率因数PWM整流器的设计
孟大鹏; 李国锋; 王志强
2012-01-01
The technique of three-phase power factor correction is widely used in PWM rectifier. Predictive current control strategy applied in three-phase power factor correction technical fields is one of effective control strategies to realize unity power factor, which has solved the phase correction problem of voltage and current in the net-side effectively. The complex power loop is replaced by the simple voltage loop and current loop to simplify the algorithm and save the space of digital signal processor. The voltage loop using PI regnlation could keep the output voltage constant, while the current loop using phase tracking technique could make the rectifier gain higher power factor. Soft-start devices were added behind the inductors to make DC voltage up to steady- state voltage smoothly at the moment of the rectifier device turned on.%目前三相功率因数校正技术广泛应用于PWM整流环节，而预测电流控制则是实现单位功率因数的一种有效控制策略。这种控制方式有效地解决了网侧电压电流相位校正的问题，以简单的电压环和电流环替代原有的复杂的功率环，既简化了算法程序，又节省了数字信号处理器的资源。电压环采用PI调节器，可以稳定调节直流输出电压，电流环采用相位跟踪技术，可以使整流器获得较高的功率因数。此PWM整流器在网侧添加双向可控硅控制的软启动装置，使直流侧输出电压在装置上电瞬间平稳上升至稳态电压。
Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor
Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman
2016-02-01
Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.
Synchronized Scheme of Continuous Space-Vector PWM with the Real-Time Control Algorithms
Oleschuk, V.; Blaabjerg, Frede
2004-01-01
This paper describes in details the basic peculiarities of a new method of feedforward synchronous pulsewidth modulation (PWM) of three-phase voltage source inverters for adjustable speed ac drives. It is applied to a continuous scheme of voltage space vector modulation. The method is based...... on a representation of the pulse patterns as a function of the fundamental and switching frequencies of the drive system. Accurate trigonometric algorithms of vector PWM have been analysed, and also compared with the algebraic ones based on linear approximation of the durations of active switching states from...
Feedforward Synchronised PWM for Adjustable Speed AC Drives with Different Control Modes
Oleschuk, Valentin; Blaabjerg, Frede; Jensen, Flemming Buus
2002-01-01
This paper presents a novel method of direct synchronised pulswidth modulation (PWM) for three-phase voltage source inverters, feeding induction motors with different control regimes. It is based on the universal algorithm with either simplified algebraic or accurate trigonometric control functions......, with vector approached for determination of the pulse patterns, with vector approach for determination of the pulse patterns. Different control modes of the drive system with synchronised PWM, including standard scalar V/F control, and also V2/F = constant and V/F2 = constant control regimes, have been...... analysed in the paper. Simulations give the behaviour of the PWM techniques proposed. Both continuous and discontinuous schemes of synchronised PWM, applied for the corresponding control regime, have been analysed and compared....
Morimoto, Keiki; Doi, Toshimitsu; Manabe, Haruhiko; Ahmed, Tarek; Hiraki, Eiji; Lee, Hyun-Woo; Nakaoka, Mutsuo
This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching PWM inverter linked DC-DC converter, four power switches in the full-bridge arms and DC busline series switch can achieve ZVS at turn-off commutation. By developing the advanced soft-switching PWM high frequency inverter type DC-DC converter, although the conduction power loss of DC busline series power switch increases a little, the total turn-off switching loss of full-bridge high frequency inverter power modules can be sufficiently lowered more and more in the higher frequency range of 60kHz. As a result, when the switching frequency of high frequency inverter power stage using IGBT power modules is designed so as to be more than about 10kHz, the more the switching frequency of inverter increases, the more this high frequency soft-switching DC-DC converter has remarkable advantage as for the power conversion efficiency as compared with the conventional hard-switching PWM inverter DC-DC converter. Its practical effectiveness of high power density and high performance is actually proved for TIG arc welding equipment in industry.
屈克庆; 陈国呈; 孙承波
2005-01-01
A novel software implementation for current polarity detection and current compensation is presented. For a three-phase zero-voltage soft-switching (ZVS) PWM converter based on phase and amplitude control (PAC), when saw-tooth carriers with alternate positive and negative slopes are adopted, the positive or negative slopes are chosen according to the phase current polarity. Since polarity reversal causes current distortion, current at the instant of reversal should be compensated for. Based on the characteristic of unity power factor converter in rectification and regeneration modes, a software implementation for current polarity detection is proposed.Distortion of current zero-crossing caused by using saw-tooth carriers with alternate positive and negative slopes is analyzed, and the relevant compensation method is proposed. Experimental study with a 1.5 kW device shows that phase current has a small harmonic content and power factor is high both in rectification and regeneration modes.
吴翔; 谭国俊; 叶宗彬; 李洪刚
2016-01-01
This paper proposed a programmed pulse width modulation strategy for two-level voltage source inverters based on the on-line programming of the special solutions of the volt-second balance equations with multi-objective satisfactory optimization (MSO-PWM). The global optimum special solutions for the targets that linear modulation range extension, current ripple losses minimization and switching losses minimization were respectively obtained by solving the established mathematic programming model. Meanwhile, the contradiction between different targets was analyzed in nature. The satisfactory optimization with the process of relaxing the satisfying degree of single object was introduced to avoid the insoluble phenomenon caused by the contradiction, thus realizing the three-objective satisfactory optimization. Compared to the existing local optimization pulse width modulation strategies, the MSO-PWM can adjust the importance of single objective flexibly by selecting an appropriate switching loss coefficient limitation according to the preference of the decision maker to satisfy the demand of different fields, which make it universal and flexible. In addition, MSO-PWM can give consideration to other targets when focus on the most important target, thus, it can achieve multi-objective satisfactory optimization. Experimental results show that the proposed strategy is effective and flexible.%提出了一种基于伏秒平衡方程组特解在线规划的新型多目标满意脉宽调制策略(multi-objective satisfactory optimization PWM，MSO-PWM)。首先，针对单个载波周期内线性调制范围扩展、输出电流纹波损耗与开关损耗3个优化目标分别建立了时域数学规划模型，并求解各自的全局最优解，实现了单个目标的全局最优化。通过对3个目标的全局最优解的分析，揭示了不同优化目标之间矛盾的本质原因，通过引入满意优化的思想，以多目标满意取代单目标最优，并
Mechouma Rabiaa
2014-01-01
Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.
THREE-PHASE ACTIVE POWER FILTER CONTROLLER FOR BALANCED AND UNBALANCED NON-LINEAR LOAD
G.NAGESWARA RAO
2010-09-01
Full Text Available The active power filter produces equal but opposite harmonic currents to the point of connection with the nonlinear load. This results in a reduction of the original distortion and correction of the power factor. A threephase insulated gate bipolar transistor based current controlled voltage source inverter with a dc bus capacitor is used as an active filter. The firing pulses to the shunt active filter will be generated by using sine PWM method. The models for three-phase active power filter controller for balanced and unbalanced non-linear load is made and is simulated using Matlab/simulink software.
Paul, R. N.; Arya, L. D.; Verma, H. K.
2012-09-01
In three-phase squirrel-cage ac traction motor, temperature-rise calculation during variable-voltage and variable-frequency starting is of vital importance and has to be predicted and critically examined. Under voltage source inverter supply with PWM, the generation of harmonics by inverter supply reduces the output during starting due to higher harmonic losses, thereby reducing the starting tractive effort in kN on locomotive wheel. Stator and rotor temperature-rises during starting have been determined for average acceleration torque in segmental zone (calculated from variable acceleration) which have been presented in the paper with both copper and aluminium alloy rotor bars.
A Review of Passive Filters for Grid-Connected Voltage Source Converters
Beres, Remus Narcis; Wang, Xiongfei; Blaabjerg, Frede;
2014-01-01
LCL filter is the common interface between the Pulse Width Modulated Voltage Source Converter (PWM VSC) and the utility grid due to high harmonic attenuation capability and reduced size of the passive elements. The present paper investigates the most promising passive damping methods for the LCL ...
Gabriele Grandi
2016-05-01
Full Text Available This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−, and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The maximum and the average values of peak-to-peak current ripple are estimated, and a simple method to correlate the ripple envelope with the ripple rms is proposed and verified. Furthermore, all the results obtained by DPWMs are compared to the centered pulse-width modulation (CPWM, equivalent to the space vector modulation to identify the optimal pulse-width modulation (PWM strategy as a function of the modulation index, taking into account the different average switching frequency. In this way, the PWM technique providing for the minimum output current ripple is identified over the whole modulation range. The analytical developments and the main results are experimentally verified by current ripple measurements with a three-phase PWM inverter prototype supplying an induction motor load.
屈克庆; 陈国呈; 孙承波
2004-01-01
This paper presents a novel current feedforward control strategy for a three-phase pulse-width modulation (PWM) DC voltage-type converter based on phase and amplitude control (PAC).With right-angle triangle relation of phasors and principle of conservation of energy, a phasor adjustment method and the relevant low-frequency mathematical model of the system are analyzed in detail, both in rectification and regeneration modes for the converter, are discussed.For improving the traditional PAC dynamic performance, variable load current is detected indirectly by the change of the DC voltage, which is fed to the control system as an additional control variable to generate modulation index and phase angle.Also, the algorithm is derived and the system principle is introduced.Experimental results from a 3 kw laboratory device are included to demonstrate the effectiveness of the proposed control strategy.
Comparative Study of Multicarrier PWM Techniques for a Modular Multilevel Inverter
Rajan, M S; R. Seyezhai
2014-01-01
This paper presents the simulation of three phase five-level modular multilevel cascade inverter based on double-star chopper-cell (DSCC). The multicarrier PWM techniques such as Phase disposition PWM (PDPWM), Phase opposition disposition PWM (PODPWM), Alternate phase opposition disposition PWM (APODPWM), and Phase shift PWM (PSPWM) is employed and a comparative study is done based on the spectral quality of the load voltage and load current waveforms. Simulation has been carried out for vari...
Three-phase Resonant DC-link Converter
Munk-Nielsen, Stig
The purpose of the project is to develop a three-phase resonant converter suitable for standard speed drives. The motivation for working with resonant converters is found in the problem of the standard converter type used today. In standard converter type Pulse Width Modulated-Voltage Source...... frequency three phase parallel resonant converter is realized....
Space Vector Based Hybrid PWM Techniques for Reduced Current Ripple
Narayanan, G.; Zhao, Di; Krishnamurthy, Harish K; Ayyanar, Rajapandian; Ranganathan, VT
2008-01-01
This paper investigates certain novel switching sequences involving division of active vector time for space vectorbased pulsewidth modulation (PWM) generation for a voltage source inverter. This paper proposes two new sequences, and identifies all possible sequences, which result in the same average switching frequency as conventional space vector PWM (CSVPWM) at a given sampling frequency. This paper brings out amethod for designing hybrid PWMtechniques involving multiple sequences to reduc...
Analytical Method to Calculate the DC Link Current Stress in Voltage Source Converters
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus; Kerekes, Tamas; Blaabjerg, Frede
2014-01-01
The dc-link capacitor is one of the critical components, which influences the lifetime of the whole voltage source converter unit. For reliable design, the operating temperature of the dc-link capacitor should be known, which is primarily determined by the ambient temperature and the rms value of......, especially for the applications with high line current ripple. The effect of the pulsewidth modulation (PWM) scheme on the rms value of the dc-link current is also studied and the analysis for continuous PWM and discontinuous PWM (DPWM) schemes is presented. The proposed analytical method is also verified...... the current flowing through the dc-link capacitor. A simple analytical method to calculate the rms value of the dc-link capacitor current is presented in this paper. The effect of the line current ripple on the rms value of the dc-link capacitor current is considered. This yields accurate results...
Kumar, Binoj AC; Narayanan, G.
2010-01-01
Voltage Source Inverter (VSI) fed induction motors are widely used in variable speed applications. For inverters using fixed switching frequency PWM, the output harmonic spectra are located at a few discrete frequencies. The ac motordrives powered by these inverters cause acoustic noise. This paper proposes a new variable switching frequency pwm technique and compares its performance with constant switching frequency pwm technique. It is shown that the proposed tech...
唐雄民; 朱燕飞
2011-01-01
A predictive direct power control strategy for three-phase pulse width modulation rectifier was presented. Based on instantaneous active and reactive power theory, the rectifier s active and reactive power variations were predicted in the next sampling period and control vector of rectifier was directly calculated. With control vector of rectifier,space vector modulation was used to generate the required switch pulse of con verter in a constant switching frequency. The impact of sampling delay and online calculation delay on the accu racy of active and reactive power was analyzed,and the compensation method was achieved. Simulation results validate the control strategy and compensation method.%提出了一种基于功率预测模型的三相PWM整流器控制策略.控制策略利用瞬时功率理论预测下一个固定周期内电路的有功和无功变化,直接求取整流器交流侧的电压矢量,并采用空间矢量调制方法来保证整流器工作频率的恒定.还对由于采样、实时计算等原因引起的延时对电路有功和无功的影响进行探讨,并给出了补偿方法.仿真结果验证了控制策略和补偿方法的有效性.
Modeling & Simulation of Fuel cell (Choi Model) based 3-Phase Voltage Source Inverter
Gaurav Sachdeva
2011-01-01
In the present work, performance of three phase voltage source inverter, while feeding different power factor loads, has been investigated. Fuel cells models namely Choi model are used in input side as a DC source while dynamic load have been used at the output side. Dynamic load used is induction motor (IM). Performance of IM has been investigated under various loading conditions. ANN based control strategy has been proposed to find the conduction angle of a Three Phase VSI and verified for ...
Kwon, Jun Bum; WANG, XIONGFEI; Bak, Claus Leth; Blaabjerg, Frede
2015-01-01
As the increasing of power electronics based systems, not only the component-based analysis but also a systematic interaction analysis with each other systems are being important. Especially studies about the stability and the harmonics interaction are critical in order to establish the required performance in a power network. However, the traditional small-signal modeling approaches are not enough to represent the complexity of the interaction due to the time varying components of such syste...
Chomát, Miroslav; Schreier, Luděk
Rio de Janeiro : IEEE Service Center, 2003, s. -. ISBN 0-7803-7912-8. [IEEE International Symposium on Industrial Electronics - ISIE 2003. Rio de Janeiro (BR), 09.06.2003-11.06.2003] R&D Projects: GA ČR GA102/02/0554 Institutional research plan: CEZ:AV0Z2057903 Keywords : unbalanced voltage supply * power factor correction * DC-link current pulsations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Compensation of Unbalanced Three-Phase Voltage Supply in Voltage Source Inverter
Chomát, Miroslav; Schreier, Luděk
2003-01-01
Roč. 48, č. 2 (2003), s. 113-128. ISSN 0001-7043 R&D Projects: GA ČR GA102/02/0554 Institutional research plan: CEZ:AV0Z2057903 Keywords : unbalanced voltage supply * power factor correction * DC-link current pulsations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth;
2015-01-01
As the increasing of power electronics based systems, not only the component-based analysis but also a systematic interaction analysis with each other systems are being important. Especially studies about the stability and the harmonics interaction are critical in order to establish the required...... performance in a power network. However, the traditional small-signal modeling approaches are not enough to represent the complexity of the interaction due to the time varying components of such systems. This paper compares the small-signal modeling methods for harmonic analysis of AC - DC converters and...... discusses their advantages and limitations. The Harmonic State Space (HSS) model based on the Linear Time-Periodically varying (LTP) system and the traditional small signal model based on the Linear Time-Invariant (LTI) system are evaluated. The results show that the HSS model presents superior performance...
Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage
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...... PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM in...
Modulation and control of three-phase PWM multilevel converters
Pou Félix, Josep
2002-01-01
La present tesi doctoral estudia els inversors trifàsics multinivell del tipus denominat de díodes de fixació (diode-clamped converters). Aquests convertidors poden generar tres o més nivells de tensió a cada fase de sortida, i normalment s'apliquen a sistemes de gran potència ja que poden treballar amb tensions majors que els inversors clàssics. L'anàlisi es centra fonamentalment en la topologia de tres nivells, tot i que també es realitzen contribucions per a convertidors de més nivells. El...
Hari, Pavan Kumar VSS; Narayanan, G.
2013-01-01
Space-vector-based pulse width modulation (PWM) for a voltage source inverter (VSI) offers flexibility in terms of different switching sequences. Numerical simulation is helpful to assess the performance of a PWM method before actual implementation. A quick-simulation tool to simulate a variety of space-vector-based PWM strategies for a two-level VSI-fed squirrel cage induction motor drive is presented. The simulator is developed using C and Python programming languages, and has a graphica...
Soft Commutated Three-Phase Dc-Dc Converter
Silpa.P.T; Rajeenamol P.T
2014-01-01
High efficient DC-DC Converters find its application in electric power generation, transmission, distribution and Uninterruptable power supplies (UPS). Three phase converter system as compared with single phase converter system increases power density with reduced switching stresses, efficient usage of the transformer magnetic core and smaller filter design as the frequency of the system is higher. Inorder to make use of the above mentioned advantages a ZVS-PWM three- phase current-fed push-p...
Analys av PWM-mönster i Matlab
Milevski, Mikael
2002-01-01
One of ABB Power Systems´s business areas is HVDC (High Voltage Direct Current) technology. HVDC is used for transmissions for both short and long distances. One of Power Systems’s products is called HVDC Light. HVDC Light is a relatively new technology for power transmission, but have before only been used for motor drives applications. The technology is based on VSC (Voltage Source Converter) that uses a technique called PWM (Pulse Width Modulation). There are a lot of PWM patterns that h...
无
2007-01-01
This letter presents a multi-frequency proportional-resonant (MFPR) current controller developed for PWM voltage source converter (VSC) under the unbalanced supply voltage conditions. The delta operator is used in place of the shift operator for the implementation of MFPR by using a low-cost fixed-point DSP. The experimental results with an alternative control strategy validated the feasibility of the proposed MFPR current controller for the PWM VSC during voltage unbalance.
Development of high-voltage PWM power supply for electron beam bombarding furnace
The working principle and operation characteristics of a high-voltage PWM-BUCK DC/DC converter are discussed in this paper, and a practical engineering technical route is proposed to apply the converter to high power accelerating voltage source of electron beam bombarding furnace. Compared with the traditional thyristor phase-shifted high voltage source, the application results show that the suggested power supply has the advantages of lower current harmonic, higher power factor and higher operation efficiency. (authors)
Analysis of Input and Output Ripples of PWM AC Choppers
Pekik Argo Dahono
2008-11-01
Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.
Performance analysis of samarium cobalt P.M. synchronous motor fed from PWM inverters
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
Analysis and Minimization of Output Current Ripple of Multiphase Carrier-Based PWM Inverters
Pekik Argo Dahono
2010-01-01
Analysis and minimization of output current ripple of multiphase carrier-based PWM inverters are presented in this paper. Analytical expression of rms value of output current ripple of multiphase PWM inverters as a function of the reference signal is first derived. Based on this expression, it is shown that a pure sinusoidal signal is the optimum reference signal that results in minimum output current ripple. Different to three-phase PWM inverters, injection of harmonics into the sinusoidal r...
High performance direct instantaneous power control of PWM rectifiers
This paper presents a new direct instantaneous power control (DPC) strategy for active rectifiers. In this novel scheme the PWM modulator has been utilized instead of the hysteresis comparators and switching table. The required converter voltage in each sampling period is directly calculated based on the reference and measured values of powers, system parameters, and the measured voltage of the AC source through simple equations which are wisely compensated for variations of the grid voltage during a sampling period. Then, the PWM generator generates the switching pulses for the voltage source converter. It is shown that the proposed DPC-PWM exhibits several features, such as a simple algorithm, constant switching frequency, robust to sampling frequency changes, robust to inductance values mismatch, and particularly it provides low sampling frequency. Extensive simulation and experimental results have proven the excellent performance and verify the validity and effectiveness of the proposed instantaneous power control scheme.
Generalized SVPWM Algorithm for Two Legged Three Phase Multilevel Inverter
Devisree Sasi; Jisha Kuruvilla P; Anish Gopinath
2013-01-01
This paper establishes the inherent fractal structure in the space vector representation of two legged three phase multilevel inverters. The established fractal structure is utilized to propose a generalized algorithm for space vector PWM generation for two legged multilevel inverters. The voltage space vectors of higher level inverters can be generated from the voltage space vectors of equivalent 2-level inverter. The proposed algorithm can be easily extended to n-level inverters without any...
Indirect Vector Control of Three Phase Induction Motor using PSIM
Nagulapati Kiran
2014-01-01
This paper presents the implementation of indirect vector control of three phase Induction Motor using Hysteresis Band PWM current control and Synchronous Current Control in PSIM environment. In any machine drive system, current control directly influences both flux and torque developed directly. In Hysteresis current control method, actual current tracks the command current within a hysteresis band. There is no difficulty in current control tracking when CEMF is low, but at higher speeds, cu...
N. Belhaouchet
2008-03-01
Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.
A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller
Ahmet ALTINTAŞ
2009-01-01
A lot of topologies of pulse-width modulated (PWM)-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with abi...
Qu, Hao; Yang, Xijun; Guo, Yougui;
2014-01-01
Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC...... as well as its modulation algorithms is widely used as the fundamental part of large scale PEC’s, having a long list of applications. In the paper, as first, on the basis of the discontinuous pulse-width modulation (DPWM) of three-phase VSC, a new DPWM of single-phase VSR is presented in virtue of...... zero-sequence component injection, in order to reduce power loss and increased overall efficiency. And then by reconstructing the other two phase input voltages and currents, the transformation from stationary frame (abc) to rotating frame (dq frame) is designed. Finally, a PI regulator based...
A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller
Ahmet ALTINTAŞ
2009-04-01
Full Text Available A lot of topologies of pulse-width modulated (PWM-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with ability of generating fewer harmonics. In the proposed control method, both the traditional AC voltage controllers and the PWM-AC controllers are combined; and smaller THD values are obtained. Thus, the harmonic pollution in the power system will be reduced; and consequently, the power quality will be increased. For this purpose, computer simulations are performed in order to investigate the proposed controller performance. The obtained results are compared with the conventional PWM-AC controller.
Optimal condition of memristance enhancement circuit using external voltage source
Hiroya Tanaka
2014-05-01
Full Text Available Memristor provides nonlinear response in the current-voltage characteristic and the memristance is modulated using an external voltage source. We point out by solving nonlinear equations that an optimal condition of the external voltage source exists for maximizing the memristance in such modulation scheme. We introduce a linear function to describe the nonlinear time response and derive an important design guideline; a constant ratio of the frequency to the amplitude of the external voltage source maximizes the memristance. The analysis completely accounts for the memristance behavior.
V.Arun#1 , B.Shanthi
2013-01-01
This paper presents multicarrier PWM strategies for three phase diode clamped seven level Z-source inverter. Multilevel inverters posses the advantage of reduced harmonics,high power capability and high voltage level. Impedance network in the diode clamped multilevel inverter circuit will perform boost operation. This paper focuses on multicarriersinusoidal pulse width modulation (MCSPWM) strategy for the three phase seven level Z-source diode clamped inverter. Performance parameters of three...
Power Loss Calculation and Thermal Modelling for a Three Phase Inverter Drive System
Zhou, Z.; M. S. Khanniche; P. Igic; S. M. Towers; P. A. Mawby
2005-01-01
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 accur...
A low cost rapid prototype platform for a three phase PFC rectifier application
Haase, Frerk; Kouchaki, Alireza; Nymand, Morten
2015-01-01
In this paper the design and development of a low cost rapid prototype platform for a Three Phase PFC rectifier application is presented. The active rectifier consists of a SiC-MOSFET based PWM converter and a low cost rapid prototype platform for simulating and implementing the digital control...
Three-Phase Grid-Connected of Photovoltaic Generator Using Nonlinear Control
Yahya, A.; El Fadil, H.; Guerrero, Josep M.;
2014-01-01
This paper proposes a nonlinear control methodology for three phase grid connected of PV generator. It consists of a PV arrays; a voltage source inverter, a grid filter and an electric grid. The controller objectives are threefold: i) ensuring the Maximum power point tracking (MPPT) in the side o...
Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi;
2011-01-01
the VSIs were based on the stationary reference frame. A hierarchical control for the paralleled VSI system was developed based on three levels. The primary control includes the droop method and the virtual impedance loops, in order to share active and reactive power. The secondary control restores...... the frequency and amplitude deviations produced by the primary control. And the tertiary control regulates the power flow between the grid and the microgrid. Also, a synchronization algorithm is presented in order to connect the microgrid to the grid. The evaluation of the hierarchical control is......-grid interactivity, and to manage power flows between the main grid and the VSIs....
A Review of Passive Power Filters for Three-Phase Grid-Connected Voltage-Source Converters
Beres, Remus Narcis; Wang, Xiongfei; Liserre, Marco;
2016-01-01
In order to reduce size and cost, high-order passive filters are generally preferred in power converters to cancel out high frequency harmonics caused by pulse width modulation. However, the filter resonance peaks may require the use of passive dampers to stabilize the interactions between the lo...
Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand;
2010-01-01
This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on the measurements, it is shown that the spread effect of the discrete components from the motor current spectra is very effective independent of the modulation...
Three-phase Photovoltaic Systems
Kerekes, Tamas; Sera, Dezso; Máthé, Lászlo
2015-01-01
grid through a three-phase power electronic converter are now well on the way to becoming a major player in the power system in many countries. Therefore, this article gives an overview of photovoltaic systems with a focus on three-phase applications, presenting these both from a hardware point of view...
Three phase downhole separator process
Cognata, Louis John
2008-06-24
Three Phase Downhole Separator Process (TPDSP) is a process which results in the separation of all three phases, (1) oil, (2) gas, and (3) water, at the downhole location in the well bore, water disposal injection downhole, and oil and gas production uphole.
Transistorized PWM inverter-induction motor drive system
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.
Power Loss Calculation and Thermal Modelling for a Three Phase Inverter Drive System
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.
Nongrounded Common-Mode Equivalent Circuit for Brushless DC Motor Driven by PWM Inverter
Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo
This paper describes nongrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was small, the phenomenon that polarity of the common mode voltage and shaft voltage reversed was observed. In order to model this phenomenon, the bridge type equivalent circuit is proposed. It is verified with the calculation and experiment that shaft voltage values and polarity are accurately calculated with the proposed equivalent circuit.
Mathematical analysis of PWM processes
Ainslie-Malik, Gregory R.
2013-01-01
Pulse width modulation (PWM) inverters convert a direct current (DC) power supply to an alternating current (AC) supply by means of high frequency switching between two DC sources. Undesirable high-frequency components are generated in the frequency spectra of the voltages and currents of PWM inverters. The high-frequency components are ultimately removed from the input and output waveforms by filters. PWM inverters are used in a wide variety of electrical devices, ranging from microwave oven...
Gheraia, H.; Berkouk, E. M.; Manesse, G.
2001-08-01
In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction.
Gheraia, H.; Berkouk, E.M. [ENP, Alger (Algeria). Lab. de Commande des Processus; Manesse, G. [CNAM-Paris (France). Lab. d' Electricite Industrielle
2001-08-01
In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction. (orig.)
Robust Fuzzy-Second Order Sliding Mode based Direct Power Control for Voltage Source Converter
D. Kairous
2015-08-01
Full Text Available This paper focuses on a second order sliding mode based direct power controller (SOSM-DPC of a three-phase grid-connected voltage source converter (VSC. The proposed control scheme combined with fuzzy logic aims at regulating the DC-link voltage of the converter and precisely tracking arbitrary power references, in order to easily control the system’s power factor. Therefore measures are proposed to reduce the chattering effects inherent to sliding-mode control (SMC. Simulations performed under Matlab/Simulink validate the feasibility of the designed Fuzzy-SOSM. Simulation results on a 1kVA grid-connected VSC under normal and faulted grid voltage conditions demonstrate good performance of the proposed control law in terms of robustness, stability and precision.
Syed Sabir Hussain Bukhari
2016-03-01
Full Text Available Numerous industrial applications involve loads that are very sensitive to electrical supply instabilities. These instances involve various types of voltage imbalances as well as more serious disturbances such as symmetrical and asymmetrical faults. This paper proposes a cost-effective voltage imbalance and asymmetrical fault correction solution for the three phase sensitive loads utilizing an industry-standard current regulated voltage source inverter by connecting it in parallel to the grid mains powering to the sensitive load. The inverter regulates the current for the load and never permits it to go beyond a prescribed value under any type of asymmetrical fault condition, which ensures high power regulating and conditioning capacities. Experimental results are obtained from a small laboratory size prototype to validate the operation of the proposed technique.
A battery-based, low-noise voltage source
Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang
2010-06-01
A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of ±15 and ±5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7×10-7 over 6.5 h and a noise level equal or smaller than 30 nV/√Hz is achieved.
EMI in Induction Motor Drive Fed from IGCT Voltage Source
Bartoš, Stanislav; Jehlička, Vladimír; Škramlík, Jiří; Valouch, Viktor
Cambridge, MA: Electromagnetic s Academy, 2007, s. 93-97. ISBN 978-1-934142-02-8. [Progress In Electromagnetic s Research Symposium 2007. Prague (CZ), 27.08.2007-30.08.2007] R&D Projects: GA ČR GA102/06/0112 Institutional research plan: CEZ:AV0Z20570509 Keywords : electromagnetic interference (EMI) * induction motor drive * IGCT voltage source inverter Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Marcelino, M.A.; Silva, G.B.S.; Grandinetti, F.J. [Universidade Estadual Paulista (UNESP), Guaratingueta, SP (Brazil). Fac. de Engenharia; Universidade de Taubate (UNITAU), SP (Brazil)], Emails: abud@feg.unesp.br, gabonini@yahoo.com.br, grandinetti@unitau.br
2009-07-01
This paper presents a technique for speed control three-phase induction motor using the pulse width modulation (PWM), in open loop while maintaining the tension for constant frequency. The technique is adapted from a thesis entitled 'Control of the three-phase induction motor, using discrete PWM generation, optimized and synchronized', where studies are presented aimed at their application in home appliances, to eliminate mechanical parts, replaced by low cost electronic control, thus having a significant reduction in power consumption. Initially the experiment was done with the Intel 80C31 micro controller. In this paper, the PWM modulation is implemented using a PIC micro controller, and the speed control kept a low profile, based on tables, synchronized with transitions and reduced generation of harmonics in the network. Confirmations were made using the same process of building tables, but takes advantage of the program of a RISC device.
Three-phase Photovoltaic Systems
Kerekes, Tamas; Sera, Dezso; Máthé, Lászlo
2015-01-01
Photovoltaic technology has experienced unprecedented growth in the last two decades, transforming from mainly off-grid niche generation to a major renewable energy technology, reaching approximately 180 GW of capacity worldwide at the end of 2014. Large photovoltaic power plants interfacing the...... grid through a three-phase power electronic converter are now well on the way to becoming a major player in the power system in many countries. Therefore, this article gives an overview of photovoltaic systems with a focus on three-phase applications, presenting these both from a hardware point of view......, detailing the different photovoltaic inverter structures and topologies as well as discussing the different control layers within a grid-connected photovoltaic plant. Modulation schemes for various photovoltaic inverter topologies, grid synchronization, current control, active and reactive power control...
Analysis and Minimization of Output Current Ripple of Multiphase Carrier-Based PWM Inverters
Pekik Argo Dahono
2010-05-01
Full Text Available Analysis and minimization of output current ripple of multiphase carrier-based PWM inverters are presented in this paper. Analytical expression of rms value of output current ripple of multiphase PWM inverters as a function of the reference signal is first derived. Based on this expression, it is shown that a pure sinusoidal signal is the optimum reference signal that results in minimum output current ripple. Different to three-phase PWM inverters, injection of harmonics into the sinusoidal reference signal is neither necessary nor useful. The rms values of output current ripple of 5-, 7-, and 9-phase PWM inverters under various reference signals are compared. Experimental results are included to show the validity of the analysis method.
Measurements of power loss distribution in a typical stator core under PWM voltage excitation
The pulse width modulated (PWM) inverter is widely used to feed small induction motors for variable speed and torque control. When a laminated stator core is energised in this way additional iron losses occur due to localised distorted flux. Flux density and power loss distribution under PWM and sinusoidal voltage excitations were measured in a typical induction motor stator core lamination at 1.3 T, 50 Hz by using a computer-aided magnetising system to set up flux distribution as would occur in a practical three-phase stator core. The iron loss increased 15-20% under PWM excitation. The loss increase under PWM excitation in the stator core laminations was 3% lower than in Epstein strips of the same electrical steel under the same conditions showing an effect of the magnetic circuit geometry
The Application of FPGA in PWM Controlled Resonant Converter for an Ozone Generator
Mochammad Facta
2013-07-01
Full Text Available Pulse Width Modulation (PWM is a very common technique used in many different applications. The Conventional method its generation is the heart of the inverter system. This paper present methodology to generate Sinusoidal PWM (SPWM signal for three-phase inverter based on EP20K200EFC484-2x Altera Field Programmable Gate Array (FPGA. Designing a PWM inverter drive using FPGA has several advantages, such as: it's quick, very modifiable, and very suitable for prototyping. In this paper, the PWM signal is used control switching action conducted by MOSFET as part of power electronics devices in resonant power converter which has 24 volt DC input voltage. As the result, by using resonant oscillation controlled by FPGA the high sinusoidal voltage until 1.0 kV peak-to peak has been generated in the load side.
Voltage harmonic variation in three-phase induction motors with different coil pitches
A pulse-width modulation (PWM) inverter feeding four different chorded three-phase induction motors was tested for low-order odd harmonic voltage component and efficiency at different loads. Total harmonic distortion (THD) due to 3rd, 5th and 9th harmonics was less in a motor with 160o coil pitch. Particular harmonic order for each coil pitch was suppressed and the efficiency of a 120o coil pitch motor was increased by 7.5%
F. J. De la Hidalga-W
2013-01-01
Full Text Available This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can beobtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and ametal (semitransparent gate oxide semiconductor capacitor (MOS-C.The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductorsubstrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification ofthe sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive andnegative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional tothe light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating rangeof this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors couldbe useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contactoptical position sensing for nulling and centering measurements.
Shunt active filter algorithms for a three phase system fed to adjustable speed drive
Sujatha.CH; Sravanthi.Kusam; Dr. K.Chandra shek
2011-01-01
This paper presents the simulation of Shunt Active Power filter by using two different control schemes, Indirect current control technique and Synchronous detection technique by using ANN. These two control techniques are working under both balanced and unbalanced three phase voltage source conditions and it is feeding to aadjustable speed drive the torque speed characteristics of a motor is presented. Indirect current control technique is implemented under dynamic load condition and load bal...
New Space Vector Selection Scheme for VSI Supplied Dual Three-Phase Induction Machine
MILICEVIC, D.; KATIC, V.; CORBA, Z.; GRECONICI, M.
2013-01-01
This paper presents a novel space vector selection scheme applicable for the control of dual three-phase induction motor drives supplied from a six-phase voltage source inverter (VSI). The vector selection method is based on the vector space decomposition technique (VSD). Unique vector selection pattern simplifies problems related to complicated implementation of standard VSD in commercially available digital signals processors (DSP). The proposed vector selection scheme is verified throu...
Component-Minimized Buck-Boost Voltage Source Inverters
Gao, F.; Loh, P.C.; Blaabjerg, Frede;
2007-01-01
order to form a distinct neutral potential in the corresponding voltage boost circuitry for correct B4 inverter operation, necessary modifications are derived step by step. The resulted dc networks with symmetrical placement of passive components allow complete charging and equal energy distribution...... 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...
Diode-Assisted Buck-Boost Voltage-Source Inverters
Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;
2009-01-01
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...
New algorithm to detect voltage disturbances in three phases alternative current systems
Benslimane, T.; Chetate, B. [University of Boumerdes (Algeria)
2006-07-01
In this paper is presented a new algorithm based on logical functions to detect different disturbances in alternative voltage in electrical power networks such as over-voltage, under-voltage, unbalanced voltage, short circuit besides the safe operating condition. This algorithm is based on RMS values of three phases voltages as input values to detection system that is basically based on logical functions. This system is applied on three phase electrical power network of sinusoidal voltage. It can also be applied on PWM voltage that must be filtered to get its fundamental RMS value. Simulation program was developed in Matlab/Simulinksoftware. Simulation results are presented. (orig.)
New Space Vector Selection Scheme for VSI Supplied Dual Three-Phase Induction Machine
MILICEVIC, D.
2013-02-01
Full Text Available This paper presents a novel space vector selection scheme applicable for the control of dual three-phase induction motor drives supplied from a six-phase voltage source inverter (VSI. The vector selection method is based on the vector space decomposition technique (VSD. Unique vector selection pattern simplifies problems related to complicated implementation of standard VSD in commercially available digital signals processors (DSP. The proposed vector selection scheme is verified through a theoretical analysis, computer simulations and practical experimental results conducted on a dual three-phase test rig prototype with control algorithm implemented in Texas Instrument?s TMS320F2808 DSP.
High-Speed Fuses in IGBT based Voltage Source Converters
Iov, Florin; Blaabjerg, Frede; Rasmussen, Henrik
2005-01-01
The demand for protection of power electronic applications has during the last couple of years increased regarding the high-power IGBT modules. Even with an active protection, a high power IGBT still has a risk of exhibiting a violent rupture in the case of a fault if IGBT fuses do not protect it....... By introducing fuses into voltage source converters a better protection of IGBTs can be achieved. This paper is a complete overview of a research project carried out in cooperation by Aalborg University, Denmark and Cooper Bussmann International. This paper discusses three main issues regarding the...... IGBT fuse protection. First, the problem of adding inductance in the DC-link circuit is treated, second a short discussion of the protection of the IGBT module is done, and finally, the impact of the high frequency loading on the current carrying capability of the fuses is presented....
Four-switch three-phase space-vector PWM AC-DC converter
Klíma, J.; Škramlík, Jiří; Valouch, Viktor
2008-01-01
Roč. 95, č. 4 (2008), s. 383-397. ISSN 0020-7217 Institutional research plan: CEZ:AV0Z20570509 Keywords : AC-DC converter * space-vector pulsewidth modulation * rectifier Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.567, year: 2008
C. R. Balamurugan; S. P. NATARAJAN; R. BENSRAJ
2012-01-01
This paper presents the comparison of Unipolar Inverted Sine Carrier Pulse Width Modulation (UISCPWM) techniques for the Cascaded Multi Level Inverter (CMLI). Due to switch combination redundancies, there are certain degrees of freedom to generate the multilevel AC output voltage. This paper presents the use of Control Freedom Degree (CFD) combination. The effectiveness of the pulse width modulation strategies developed using CFD are demonstrated using simulation. The results indicate that th...
Software Phase Lock Loops Applied in Three-Phase PWM Rectifier
Šimek, Petr; Škramlík, Jiří; Valouch, Viktor; Bejvl, Martin
Košice : Technical University of Košice, 2011, s. 227-232. ISBN 978-80-553-0734-3. [International Conference on Electrical Drives and Power Electronics - EDPE 11 /17./. Stará Lesná, The High Tatras (SK), 28.10.2011-30.10.2011] R&D Projects: GA MPO(CZ) FR-TI1/330 Institutional research plan: CEZ:AV0Z20570509 Keywords : phase lock loop * unsymmetrical voltage system * harmonics Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
PWM nonlinearity reduction in microstepping unit firmware
Krumnikl, Michal; Olivka, Petr
2012-01-01
Pulse Width Modulation (PWM) is a popular method for controlling analogue circuits with digital output of a microcontroller. This paper is focused on practical issues of using PWM in precise positioning systems. PWM is easy to grasp intuitively, but due to the motor characteristics, is not as easy to implement as one would expect. There is a distortion or nonlinear gain between the reference and real output voltage in the PWM system. In this paper, we will present a pure software sol...
Mitigation of Lower Order Harmonics with Filtered Svpwm In Multiphase Voltage Source Inverters
K. Uday Kiran
2014-08-01
Full Text Available Multi-phase machines and drives is a topic of growing relevance in recent years, and it presents many challenging issues that still need further research. This is the case of multi-phase space vector pulse width modulation (SVPWM, which shows not only more space vectors than the standard three-phase case, but also new subspaces where the space vectors are mapped. In the digital implementation, multiphase reference voltages are sampled and fed into the digital modulator to produce gating signals at a constant clock rate f. This means a finite pulse-width resolution because the gating state transition can only occur at some specific time instants depending on frequency. This results in a deviation of produced phase voltages from the desired phase voltages, i.e., increasing harmonic distortion especially for a small modulation index signal. In the present paper a filtered space-vector pulse-width modulation (SVPWM considering finite pulse-width resolution is proposed to produce a switching sequence with reduced baseband harmonics for multiphase voltage source inverters (VSI. This is achieved by incorporating a pseudo feedback loop regarding weighted voltage difference between desired and produced phase voltages.
OPTIMAL PWM BASED ON REAL—TIME SOLUTION WITH NEURAL NETWORK
ShenZhongting; YanYangguang
2002-01-01
A novel concept of neural network based control in pulse-width modulation(PWM)voltage source inverters is presented.On the one hand,the optimal switching an-gles are obtained in real time by the neural network based controller；on the other hand,the output voltage is ad-justed to fit the expected value by neural network when input voltage or loads change.The structure of neural network is simple and easy to be realized by DSP hard-ware system.No large memory used for the existing opti-mal PWM schemes is required in the system.Theoreticalanlysis of the proposed so-called sparse neural network is provided,and the stability of the system is proved.Un-der the control of neural network the error of output volt-age descends sharply,and the system outputs ac voltage with high precision.
A novel PWM scheme to eliminate the diode freewheeling In the Inactive phase in BLDC motor
WEI Kun; HU Chang-sheng; ZHANG Zhong-chao
2006-01-01
The brushless DC motor (BLDCM) with trapezoidal electromotive force (back-EMF) waveform is used widely.In principle,when the motor runs in the 120°conduction mode,two of the three phases are active while the other phase is inactive at all times.However,a ripple current occurs in the inactive phase due to the diode freewheeling during the non-commutation period in the traditional pulse width modulation (PWM) methods,which aggravates the torque ripples.A new PWM method is proposed in this paper to eliminate the diode freewheeling during the non-commutation period in the inactive phase.As a result,the torque ripple is suppressed using the proposed method.The simulation and experimental results are demonstrated to verify the validity of the proposed PWM method.
Three-phase power supply, output 60v and 100a, with unit power factor and low RFI level
João Batista Vieira Júnior
2003-01-01
Full Text Available This paper presents a three-phase rectifier, unit power factor, non-dissipative commutation in DC-DC converter and synchronized control in frequency, working with 89% of global efficiency and low level do RFI. The proposed structure allows the operation with high switching frequency. The output voltage is controlled by PWM with a constant frequency. The operation principle, theoretical analysis from DC converter, relevant equations, current balance control technique and experimental results, are shown in this paper.
Gabriele Grandi; Jelena Loncarski; Milan Srndovic
2016-01-01
This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM) strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−), and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The...
Resonant Demagnetization PWM Forward Converter
BİLGİN, Bülent
2003-01-01
In this paper, a new approach to demagnetization process of a PWM forward converter (FC) is proposed. According to this approach, the demagnetization winding and diode of a conventional FC are removed, and an external capacitor is added in parallel with the secondary diode. This replacement changes the linear demagnetization process of a conventional FC into a resonant demagnetization process. The theoretical performance results of the proposed resonant demagnetization forward conve...
Studying Three-Phase Supply in School
Singhal, Amit Kumar; Arun, P.
2009-01-01
The power distributions of nearly all major countries have accepted three-phase distribution as a standard. With increasing power requirements of instrumentation today even a small physics laboratory requires a three-phase supply. While physics students are given an introduction to this in passing, no experimental work is done with three-phase…
Three-Phase Power Factor Controller
Nola, F. J.
1982-01-01
Three-Phase Power-Factor Controller develops a control signal for each motor winding. As motor loading decreases, rms value of applied voltage is decreased by feedback-control circuit. Power consumption is therefore lower than in unregulated operation. Controller employs phase detector for each of three phases of delta-connected induction motor. Phase-difference sum is basis for control.
Blaabjerg, Frede; Chiarantoni, Ernesto; Aquila, Antonio Dell; Liserre, Marco; Vergura, Silvano
2004-01-01
Three-phase active rectifiers based on the voltage source converter topology can successfully replace traditional thyristor based rectifiers or diode bridge plus chopper in interfacing dc-systems to the grid. However, if the application in which they are employed has a high safety issue or if there......, to the grid side stiffness and to the parameters of the controller has never been detailed considered. In this paper the experimental results of an LCL-filter-based three-phase active rectifier are analysed with the circuit theory approach. A ?virtual circuit? is synthesized in role of the digital...
Direct Space Vector PWM Strategy for Matrix Converters with Reduced Number of Switching Transitions
Tadano, Yugo; Hamada, Shizunori; Urushibata, Shota; Nomura, Masakatsu; Sato, Yukihiko; Ishida, Muneaki
This paper proposes a novel “Direct Space Vector PWM (Direct SVPWM)” strategy based on the direct AC/AC conversion approach for three-phase to three-phase matrix converters. This method allows the sine input and sine output waveforms as a major premise, and gives top priority to the improvement of the output control performance in motor drive applications, for instance, provides maximum riding comfort for an elevator, etc. Output voltage harmonics, switching losses, and common-mode voltage can be reduced across the entire voltage region. In addition, the switching count can be reduced even further by fully utilizing the output current detection value. Direct space vectors are first defined, and the selection method of space vectors is described. Next, the PWM duty calculation technique is explained. Finally, the validity of the proposed method is proven from the comparison with the conventional virtual indirect method based on the experimental and analysis results.
Three-phase multilevel inverter configuration for open-winding high power application
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....../IGBT) per phase and two capacitors with neutral point. Hence, introduces the additional voltage levels in each phase of the VSI. Further, this paper developed a modified single carrier five-level modulation (MSCFM) scheme in such way to overcome the complexity of standard space vector modulations, ready...... 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...
Kouchaki, Alireza; Nymand, Morten
2015-01-01
This paper studies the inductor design for three-wire and four-wire power factor correction converter (PFC). Designing the efficient inductor for this converter (regardless of connecting the midpoint to the ground) requires a comprehensive knowledge of the inductor current and voltage behavior. T......W PFC experimental setup. The experimental results which are performed for three-wire and four-wire PFC show a good match with the analyses....
Chomát, Miroslav; Schreier, Luděk
Piscataway, NJ : IEEE Service Center, 2003, s. 869-875. ISBN 0-7803-7818-0. [IEEE International Electric Machines and Drives Conference(IEMDC). Madison, Wisconsin (US), 01.06.2003-04.06.2003] R&D Projects: GA ČR GA102/02/0554 Institutional research plan: CEZ:AV0Z2057903 Keywords : unbalanced voltage supply * control method for DC link voltage ripple cancellation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
We have performed comparative studies of Space Vector Pulse Width Modulation (SVPWM) and Sinusoidal Pulse Width Modulation (SPWM) techniques utilizing MATLAB tools. During these investigations, we carried out intensive simulations, comprehensively analyzed the obtained results and compared the harmonic density, power factor (PF), and switching losses of SVPWM and SPWM. It has been observed during investigations that if the switching frequency is high then losses due to harmonics are negligible, thus based on obtained results we suggested that the SVPWM technique is a more reliable solution. Because SVPWM utilizes DC bus voltage more efficiently, generates less Total Harmonic Distortion (THD) and has higher output quality it provides flexible control of output voltage and output frequency for Variable Speed Drive (VSD)
Electrochemistry at three-phase electrodes
Gulaboski, Rubin
2005-01-01
Three-phase electrodes are seen as a powerful tool for the determination of thermodynamic and kinetic parameters of ion transfer across biomimetic membranes. In this lecture, their application and the phenomena occuring at them are described and discussed.
Selection of Carrier Waveforms for PWM Inverter
陈国呈; 屈克庆; 许春雨; 孙承波
2003-01-01
In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.
Active control of flying capacitor currents in multilevel voltage-source inverters
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
Investigation of Harmonic Characteristics in Printer due to Different Types of Voltage Source
C. Risnidar
2012-01-01
Full Text Available This paper discusses about harmonic characteristics due to different types of voltage sources. Usually, the voltage source is sinusoidal. But in actual condition the load that receives voltage sources through the elements where the output voltage of element as input to the load is not pure sinusoidal, for example voltage source at Power of Common Coupling (PCC between transformer and linear load and nonlinear load. This research has been done with Schhafner Power Quality Analyzer and PM300 Power Quality Analyzer, was focused to all harmonic characteristics as power, voltage, current, power factor (p.f., Harmonic Distortion, and harmonic energy losses cost. The load is printer because the printer is one of electronic device causes harmonics. The voltage sources in this research are sine wave, triangle wave and harmonic order combinations of 3rd, 5th and 9th. Why this research discuses voltage source for Harmonic order 3rd, 5th and 9th and don not combination of 3rd, 5th and 7th, because the combination 3rd, 5th and 9th is more complicated then combination of 3rd, 5th and 7th.
Rasoul Shalchi Alishah
2015-06-01
Full Text Available In recent, several numbers of multilevel inverter structures have been introduced that the numbers of circuit devices have been reduced. This paper introduces a new structure for multilevel inverter which can be used in high-power applications. The proposed topology is based on cascaded connection of basic units. This topology consists of minimum number of circuit components such as IGBT, gate driver circuit and antiparallel diode. For proposed topology, two methods are presented for determination of dc voltage sources values. Multi-carrier PWM method for 25-level proposed topology is used. Verification of the analytical results is done using MATLAB simulation.
Scalar Controlled Boost PWM Rectifier for Micro Wind Energy Systems
J. Chelladurai
2015-05-01
Full Text Available Uses of Permanent Magnet Synchronous Generators (PMSG are increasing in variable speed micro-Wind Energy Conversion Systems (WECS. In stand-alone or grid-connected Micro-WECS, extraction of maximum power is vital. To extract maximum power output and to obtain a constant DC bus voltage from variable magnitude and variable frequency voltage output of PMSG and generally a two stage scheme namely i conventional diode bridge rectifier and ii DC-DC Boost/Buck/Buck-Boost converters are used. In this study, a single stage Scalar Controlled PWM (SCPWM Boost Rectifier is proposed in order to minimize the current harmonics and to improve the power factor on source side. The modeling and simulation of PMSG based wind generator and SCPWM Boost rectifier was developed in MATLAB. The harmonic content in the input current waveform of the proposed SCPWM rectifier is compared with the conventional three-phase bridge rectifier. The Simulation results show the effectiveness of the PWM Boost rectifier in terms of effective utilization of source, improved efficiency and harmonic mitigation for PMSG based Wind Generator. Simulation results demonstrate the effectiveness of the proposed system in reducing the current and voltage THD on source side.
PWM Inverter control and the application thereof within electric vehicles
Geppert, Steven
1982-01-01
An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).
罗江虎; 马家庆; 高鹏; 赵勇
2012-01-01
本文基于电压型超导电磁储能系统（SuperconductingMagnetEnergyStorage，简称SMES）的基本结构和工作原理，结合脉冲宽度调制（PulseWidthModulation，简称PWM）整流器的应用，建立了三相电压型PWM整流器控制的超导电磁储能系统的数学模型．设计了具有前馈解耦控制的PWM整流器双闭环控制系统，并运用Matlab／Simulink仿真分析软件对基于PWM整流器的超导电磁储能双闭环控制系统进行了仿真研究．仿真结果表明PWM整流器双闭环控制策略应用于SMES电压型SMES功率控制器比直接电流控制等传统的控制策略反应速度更快，向电网注入谐波电流更小，有利于提高了电网的稳定性．%Based on the principle of Superconducting Magnet Energy Storage （SMES） and the usage of the rectifier with control mode of Pulse Width Modulation （PWM）, a kind of mathematical model, in which a SMES is controlled by a three-phase voltage source PWM rectifier, is established and a PWM rectifier double close＆loop control system with the control mode of fee＆forward decoupling is designed. Simulation results using Matlab/Simulink software reveal that such a system has some advantages such as quicker response and higher stability compared with conventional system.
Evaluation of Modulation Schemes for Three-Phase to Three-Phase Matrix Converters
Helle, Lars; Larsen, Kim B.; Joergensen, Allan Holm;
2004-01-01
This paper presents a method for evaluating different modulation schemes employed with three-phase to three-phase matrix converters. The evaluation method addresses three important modulator characteristics: the output waveform quality, the input waveform quality and the switching losses associated...
PWM Rectifier Control Comparison for Aerospace Applications
R. Todd, K. Liu, Y. Lau
2014-01-01
High-voltage DC-bus power quality is examined when the power network is supplied by a PWM rectifier controlled using different DC-bus voltage regulation schemes. Three controllers are compared, a voltage oriented control and two model predictive control schemes, predictive current fixed frequency and predictive direct power control. A set of PWM rectifier simulation models illustrate the performance of the controllers; a switched model, an ideal averaged-value model and an enhanced averaged-v...
Three-phase Brushless DC Motor Control
Fang, Xinwei
2012-01-01
With the increasing demand of using electric power and unpleasant of using brush motor; the usage of Three-phase Brushless Motor has been significantly developed in industry. However, with market-standard motor driver, there are many inconveniences for small institutions or companies in either application developments or education purposes. For instance, the size and the price of driver. Therefore, the object of this thesis was design modular sections (Software program, PCB driver and PCB con...
Methods, systems and apparatus for adjusting duty cycle of pulse width modulated (PWM) waveforms
Gallegos-Lopez, Gabriel; Kinoshita, Michael H; Ransom, Ray M; Perisic, Milun
2013-05-21
Embodiments of the present invention relate to methods, systems and apparatus for controlling operation of a multi-phase machine in a vector controlled motor drive system when the multi-phase machine operates in an overmodulation region. The disclosed embodiments provide a mechanism for adjusting a duty cycle of PWM waveforms so that the correct phase voltage command signals are applied at the angle transitions. This can reduce variations/errors in the phase voltage command signals applied to the multi-phase machine so that phase current may be properly regulated thus reducing current/torque oscillation, which can in turn improve machine efficiency and performance, as well as utilization of the DC voltage source.
Sliding mode Control using 3D-SVM for Three-phase Four-Leg Shunt Active Filter
Bouzidi Mansour
2013-02-01
Full Text Available This paper proposes a sliding mode control strategy for a three-phase shunt active power filter. The SAPF consists of four-leg voltage source inverter bridge. The SAPF ensures full compensation for harmonic phase currents, harmonic neutral current, reactive power compensation and unbalanced nonlinear load currents. The modulation task can be carried out with three dimensional space vector modulation, which operate under a constant switching frequency. The simulation results show that the performance of the four-leg SAPF with the proposed control algorithm – compared with PI controller - is found considerably effective and adequate to compensate harmonics, reactive power, neutral current and balance load currents.
A Three-Phase Dual-Input Matrix Converter for Grid Integration of Two AC Type Energy Resources
Liu, Xiong; Wang, Peng; Chiang Loh, Poh;
2013-01-01
-switch voltage source converter replaced by a nine-switch configuration. With the additional three switches, the proposed DIMC can provide six in put terminals, which make it possible to integrate two independent ac sources into a single grid-tied power electronics interface. The proposed converter has input......This paper proposes a novel dual-input matrix converter (DIMC) to integrate two three-phase ac type energy resources to a power grid. The proposed matrix converter is developed based on the traditional indirect matrix converter under reverse power flow operation mode, but with its six...
High performance predictive current control of a three phase VSI: An experimental assessment
Vikas Kumar; Prerna Gaur; A P Mittal
2014-12-01
Delay has a significant role to play in the implementation of the predictive current control scheme as large amount of calculations are involved. Compensating delay in the predictive current controller design can lead to an improved load current total harmonic distortion (THD) and also an increased switching frequency. Minimization of switching frequency while maintaining the lower value of load current THD requires multiple objective optimization which is achieved by optimizing a single objective function, constructed using weighting factors as a linear combination of individual objective function. The effect of weighting factor on the switching frequency minimization and the current tracking error with delay compensation for the two level voltage source inverter (VSI) are investigated in this paper. The outcomes of the predictive current control using an optimized weighting factor which is calculated using branch and bound algorithm with the delay compensation are compared with the PWM based current control scheme. The experimental tests are conducted on a 2.2 kW VSI to verify the simulation observations.
An Impedance-Based Stability Analysis Method for Paralleled Voltage Source Converters
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
This paper analyses the stability of paralleled voltage source converters in AC distributed power systems. An impedance-based stability analysis method is presented based on the Nyquist criterion for multiloop system. Instead of deriving the impedance ratio as usual, the system stability is asses...
High-frequency, three-phase current controller implementation in an FPGA
Hartmann, M.; Round, S. D.; Kolar, J. W.
2008-07-01
Three phase rectifiers with switching frequencies of 500 kHz or more require high speed current controllers. At such high switching frequencies analog controllers as well as high speed digital signal processing (DSP) systems have limited performance. In this paper, two high speed current controller implementations using two different field-programmable gate arrays (FPGA) - one for switching frequencies up to 1 MHz and one for switching frequencies beyond 1 MHz - are presented to overcome this performance limitation. Starting with the digital system design all the blocks of the signal chain, containing analog-to-digital (A/D) interface, digital controller implementation using HW-multipliers and implementation of a novel high speed, high resolution pulse width modulation (PWM) are discussed and compared. Final measurements verify the performance of the controllers. (author)
A vector modulated three-phase four-quadrant rectifier - Application to a dc motor drive
Jussila, Matti; Salo, Mika; Kaehkoenen, Lauri; Tuusa, Heikki
2004-07-01
This paper introduces a theory for a space vector modulation of a three-phase four-quadrant PWM rectifier (FQR). The presented vector modulation method is simple to realize with a microcontroller and it replaces the conventional modulation methods based on the analog technology. The FQR may be used to supply directly a dc load, e.g. a dc machine. The vector modulated FQR is tested in simulations supplying a 4.5 kW dc motor. The simulations show the benefits of the vector modulated FQR against thyristor converters: the supply currents are sinusoidal and the displacement power factor of the supply can be controlled. Furthermore the load current is smooth. (author)
Three phase full wave dc motor decoder
Studer, P. A. (Inventor)
1977-01-01
A three phase decoder for dc motors is disclosed which employs an extremely simple six transistor circuit to derive six properly phased output signals for fullwave operation of dc motors. Six decoding transistors are coupled at their base-emitter junctions across a resistor network arranged in a delta configuration. Each point of the delta configuration is coupled to one of three position sensors which sense the rotational position of the motor. A second embodiment of the invention is disclosed in which photo-optical isolators are used in place of the decoding transistors.
Three phase superconducting armature: Windings and cryostat
The existence of superconducting wires with reduced losses under AC magnetic fields allows to design AC Machines using superconducting coils for both field and armature windings. A superconduction armature needs new materials and new concepts for the windings and the cryostat: Glass fiber reinforced epoxy structure; Non impregnated superconducting windings; Low losses horizontal cryostat. The paper presents a cryostat designed to receive a three phase superconducting winding as to form, with a superconducting field winding rotor, a 20 kVa synchronous machine. Construction and preliminary test on the cryostat and the windings are reported
Self oscillating PWM modulators, a topological comparison
Poulsen, Søren; Andersen, Michael Andreas E.
2004-01-01
High precision control of the output voltage or current of a switch mode converter with fast response is required for a number of applications. Dependent on the type of application, the desired precision and transient response can be difficult, if not impossible, to achieve with standard PWM...... control caused by limitations in dynamic capabilities which often limits fast tracking of a reference signal, or fast settling during load steps due to too small achievable control loop bandwidth. Achievable open loop bandwidth for standard voltage and current mode PWM modulators is typical in the fs/10...... equal to fs which makes this type of modulators an excellent choice for a wide range of applications. Self oscillating PWM modulators can be made in a number of ways, either as voltage or current mode modulators, and the self oscillating behavior can be achieved either by using hysteresis control or by...
Chandra Babu Paduchuri
2014-01-01
Full Text Available This paper proposes the instantaneous p-q theory based fuzzy logic controller (FLC for multi converter unified power quality conditioner (MC-UPQC to mitigate power quality issues in two feeders three-phase four-wire distribution systems. The proposed system is extended system of the existing one feeder three-phase four-wire distribution system, which is operated with UPQC. This system is employed with three voltage source converters, which are connected commonly to two feeder distribution systems. The performance of this proposed system used to compensate voltage sag, neutral current mitigation and compensation of voltage and current harmonics under linear and nonlinear load conditions. The neutral current flowing in series transformers is zero in the implementation of the proposed system. The simulation performance analysis is carried out using MATLAB.
B. Santhosh Kumar
2014-02-01
Full Text Available This paper presents a novel structure for a three- phase four-wire (3P4W distribution system utilizing unified power quality conditioner (UPQC. The 3P4W system is realized from a three-phase three-wire system where the neutral of series transformer used in series part UPQC is considered as the fourth wire for the 3P4W system. A new control strategy to balance the unbalanced load currents is also presented in this paper. The neutral current that may flow toward transformer neutral point is compensated by using a four-leg voltage source inverter topology for shunt part. Thus, the series transformer neutral will be at virtual zero potential during all operating conditions. The simulation results based on MATLAB/Simulink are presented to show the effectiveness of the proposed UPQC-based 3P4W distribution system.
Ying Jiang; Jianguo Li; Sanbo Pan; Xi Zhang; Peng Hu; Haiyan Zhang
2013-01-01
In three-phase photovoltaic (PV) system, three-phase filter inductors are important part for the output electrical power quality. The comparison analyses of three-phase discrete filter inductors and two kinds of three-phase integrated filter inductors in three-phase PV inverter are proposed. Firstly, the three-phase PV inverter operation with discrete filter inductors is analyzed, and the design of discrete filter inductors is given; then operation of the three-phase PV inverter with three-ph...
Three-phase partitioning of hydrolyzed levan.
Coimbra, Cynthia Gisele de Oliveira; Lopes, Carlos Edison; Calazans, Glícia Maria Torres
2010-06-01
During the fructose and polymerization to synthesize levan, smaller fructooligosaccharide (FOS) molecules are produced. FOS can also be obtained by levan hydrolysis. Three-phase partitioning (TPP) is a separation technique that has been used for polysaccharide precipitation and gathers t-butanol and ammonium sulphate to exclude the polymer from the aqueous solution. In this work TPP was tested to separate levan and FOS from aqueous solution. The FOS used was obtained from Zymomonas mobilis levan acid hydrolysis and fractionation with ethanol. The yield of low TPP fractions was higher than those obtained from the native levan. The F-90 exhibited a higher yield than other fractions. However, when applying the TPP technique to lightest fraction not precipitated by ethanol at 90% (F>90), the intermediate phase was not possible to be visualize. These results have potential application because they show that by using the levan TPP separation it is possible to separate low-molecular weight sugar. PMID:20163956
The Investigation of Sinusoidal Single Phase Voltage Source Inverter Output Filter
Andrius Platakis
2011-08-01
Full Text Available The results of output filter investigation of single phase sine voltage source inverter (VSI are presented. The operating principle, construction and a most widely used topology of single phase voltage source inverter is discussed. The results obtained using modeling and experimental investigation are presented. The Total Harmonic Distortion of the inverter output voltage and maximal current of the output capacitor were analyzed using Matlab Simulink software. The 1 kW inverter prototype was built for experimental investigation. The inverter switches are realized using IGBT transistors. The toroidal iron powder core with distributed air gap was used as the core of the inductor. The experimental investigation of inductor core losses and maximal current of output filter capacitor were performed.Article in Lithuanian
PWM Switching Strategy for Torque Ripple Minimization in BLDC Motor
Salah, Wael A.; Ishak, Dahaman; Hammadi, Khaleel J.
2011-05-01
This paper describes a new PWM switching strategy to minimize the torque ripples in BLDC motor which is based on sensored rotor position control. The scheme has been implemented using a PIC microcontroller to generate a modified Pulse Width Modulation (PWM) signals for driving power inverter bridge. The modified PWM signals are successfully applied to the next up-coming phase current such that its current rise is slightly delayed during the commutation instant. Experimental results show that the current waveforms of the modified PWM are smoother than that in conventional PWM technique. Hence, the output torque exhibits lower ripple contents.
Cingoski, Vlatko; Yamashita, Hideo
1994-01-01
To optimize the production of high-efficiency induction skull melting furnace, we analyzed magnetic flux density, eddy current and electromagnetic flux density, eddy current and electromagnetic force distributions using 3-D edge- based finite element method excited from a voltage source. Changing the number of copper rods and, therefore the distance between them, we analyzed both the intensity and direction of the electromagnetic forces and the amount of power consumed by the molten alloy and...
Blahník, Vojtĕch; Peroutka, Zdenĕk; Talla, Jakub
2014-03-01
This paper introduces the advanced control of single-phase voltage-source active rectifier. This control provide direct control of trolley-wire current and active damping of low-frequency disturbances at the converter ac side. Our proposed control strategy combines PR controller with feed-forward model and low-frequency harmonic compensator based on resonant controllers. Achieved experimental results show excellent converter behavior, where converter is fed by strongly distorted supply voltage.
A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources
Shen, Hui; Qiu, Jinhao; Ji, Hongli; Zhu, Kongjun; Balsi, Marco; Giorgio, Ivan; Dell'Isola, Francesco
2010-01-01
In the paper, a vibration damping system powered by harvested energy with implementation of the so-called SSDV (synchronized switch damping on voltage source) technique is designed and investigated. In the semi-passive approach, the piezoelectric element is intermittently switched from open-circuit to specific impedance synchronously with the structural vibration. Due to this switching procedure, a phase difference appears between the strain induced by vibration and the resulting voltage, thu...
Variable speed wind turbine generator system with current controlled voltage source inverter
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.
Variable speed wind turbine generator system with current controlled voltage source inverter
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.
Discrete/PWM Ballast-Resistor Controller
King, Roger J.
1994-01-01
Circuit offers low switching loss and automatic compensation for failure of ballast resistor. Discrete/PWM ballast-resistor controller improved shunt voltage-regulator circuit designed to supply power from high-resistance source to low-impedance bus. Provides both coarse discrete voltage levels (by switching of ballast resistors) and continuous fine control of voltage via pulse-width modulation.
Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1 MΩ at 2 MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (Rs) and an external sample. To maintain high SNR, Rs is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz in
Stability analysis and design of the improved droop controller on a voltage source inverter
Calabria, Mauro; Schumacher, Walter; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez; Zhao, Xin
This paper studies the dynamics of a droop-controlled voltage source inverter connected to a stiff grid and addresses the use of the improved droop controller in order to enhance the dynamic behavior of the system. The small-signal stability of the inverter is studied in depth considering...... variations on its droop parameters, providing a general understanding on the functioning of such system. Finally, three methods to tune the dynamic droop gain are introduced and compared, providing analytical, simulation, and experimental results....
NingYi Dai; Chi-Seng Lam; WenChen Zhang
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 fundame...
Passivity-based design of robust passive damping for LCL-filtered voltage source converters
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
Passive damping is proven as a robust stabilizing technique for LCL-filtered voltage source converters. However, conventional design methods of passive dampers are based on the passive components only, while the inherent damping effect of time delay in the digital control system is overlooked. In...... this paper, a frequency-domain passivity-based design approach is proposed, where the passive dampers are designed to eliminate the negative real part of the converter output admittance with closed-loop current control, rather than shaping the LCL-filter itself. Thus, the influence of time delay in the...
Zhu, Jiebei; Guerrero, Josep M.; Hung, William; Booth, Campbell D.; Adam, Grain P.
2014-01-01
A generic Inertia Emulation Controller (INEC) scheme for Multi-Terminal Voltage-Source-Converter based HVDC (VSC-MTDC) systems is proposed and presented in this paper. The proposed INEC can be incorporated in any Grid-side Voltage-Source-Converter (GVSC) station, allowing the MTDC terminal to contribute an inertial response to connected AC systems during system disturbances, in a fashion similar to synchronous generators. The DC link capacitors within the MTDC are utilised by the INEC scheme ...
Evolutionary Computing Based Area Integration PWM Technique for Multilevel Inverters
S. Jeevananthan
2007-01-01
The existing multilevel carrier-based pulse width modulation (PWM) strategies have no special provisions to offer quality output, besides lower order harmonics are introduced in the spectrum, especially at low switching frequencies. This paper proposes a novel multilevel PWM strategy to corner the advantages of low frequency switching and reduced total harmonic distortion (THD). The basic idea of the proposed area integration PWM (AIPWM) method is that the area of the required sinusoidal (fun...
Single-phase to three-phase power conversion interface
Wu, Jinn-Chang; Wang, Yung-Shan; Jou, Hurng-Liahng; Lu, Wei-Tso
2016-07-01
This study proposes a single-phase to three-phase power conversion interface which converts the power from a single-phase utility to three-phase power for a three-phase load. The proposed single-phase to three-phase power conversion interface comprises a bridge-type switch set, a set of three-phase inductors, a transformer set and a set of three-phase capacitors. A current-mode control controls the switching of bridge-type switch set, to generate a set of nonzero-sequence (NZS) currents and a set of zero-sequence (ZS) currents. The transformer set is used to decouple the NZS currents and the ZS currents. The NZS currents are used to generate a high-quality three-phase voltage that supplies power to a three-phase load. The ZS currents flow to the single-phase utility so that the utility current is sinusoidal and in phase with the utility voltage. Accordingly, only a bridge-type switch set is used in the single-phase to three-phase power conversion interface to simply the power circuit. A prototype is developed and tested to verify the performance of the proposed single-phase to three-phase power conversion interface.
Saito, Y.; Tsunehiro, Y.; Yamamura, N. [Nagoya Inst. of Tech. (Japan)
1996-02-20
In respect of the construction of motor as the driving source of electric vehicle, there are two means as inverter-driving induction motors and DC brushless motors. Both of said means have the merits and demerits respectively as DC brushless motor has the excellent driving efficiency in low speed region and the advantage to deal with the trouble of inverter by the brake of power generation while the problems thereof are the filed-weakening control like induction motors is difficult in the practical use and a position sensor is necessary. In this paper, the electric vehicle are used as the object of the research for studying the construction and controlling method of brushless motor without position sensor, the control of the constant output in high speed region, and the starting as well as braking methods of the motor. Using current-source PWM inverter is the characteristic of this means. It is indicated by the comparative investigation with respect to the operating characteristics between the present means and the system using voltage-source inverter to the same synchronous machine that for the latter system the filter at the output side is indispensable and the values of the operating characteristics, efficiency, etc., in the brushless control are lower than those of the present means. 7 refs., 9 figs., 1 tab.
System For Characterizing Three-Phase Brushless dc Motors
Howard, David E.; Smith, Dennis A.
1996-01-01
System of electronic hardware and software developed to automate measurements and calculations needed to characterize electromechanical performances of three-phase brushless dc motors, associated shaft-angle sensors needed for commutation, and associated brushless tachometers. System quickly takes measurements on all three phases of motor, tachometer, and shaft-angle sensor simultaneously and processes measurements into performance data. Also useful in development and testing of motors with not only three phases but also two, four, or more phases.
Apparatus and method for heat-run test on high-power PWM converters with low energy expenditure
J S Siva Prasad; G Narayanan
2013-06-01
Before installation, a voltage source converter is usually subjected to heat-run test to verify its thermal design and performance under load. For heat-run test, the converter needs to be operated at rated voltage and rated current for a substantial length of time. Hence, such tests consume huge amount of energy in case of high-power converters. Also, the capacities of the source and loads available in the research and development (R & D) centre or the production facility could be inadequate to conduct such tests. This paper proposes a method to conduct heat-run tests on highpower, pulse width modulated (PWM) converters with low energy consumption. The experimental set-up consists of the converter under test and another converter (of similar or higher rating), both connected in parallel on the ac side and open on the dc side. Vector-control or synchronous reference frame control is employed to control the converters such that one draws certain amount of reactive power and the other supplies the same; only the system losses are drawn from the mains. The performance of the controller is validated through simulation and experiments. Experimental results, pertaining to heat-run tests on a high-power PWM converter, are presented at power levels of 25 kVA to 150 kVA.
Simulation of Five Phase Voltage Source Inverter with Different Excitation for Star Connected Load
M.A Inayathullaah
2014-07-01
Full Text Available In order to reduce the torque ripple and harmonics for smooth operation of the machine and to reduce the amount of heat generated the motor has to be supplied with multi phase supply greater than three phase supply. Selection of even number of phases should be avoided, because it decreases the performance of the motor as poles coincide with each other. So, Five Phase Supply is preferred. A five phase five leg 10 switch inverter fed five phase star connected load operating with five different excitation is simulated and compared with that of three phase conventional inverter.
Influence of current limitation on voltage stability with voltage sourced converter HVDC
Zeni, Lorenzo; Jóhannsson, Hjörtur; Hansen, Anca Daniela; Sørensen, Poul Ejnar; Hesselbæk, Bo; Kjær, Philip C.
2013-01-01
A first study of voltage stability with relevant amount of Voltage Sourced Converter based High Voltage Direct Current (VSC-HVDC) transmission is presented, with particular focus on the converters’ behaviour when reaching their rated current. The detrimental effect of entering the current...... limitation on the Power-Voltage (PV) curves at a load bus is exemplified on a three-bus system, proposing a method to model the converters in current limiting mode through ideal current sources. The influence of the current magnitude and angle on the reduced stability margin is analysed and results show that......, when the current limit is reached, despite the detrimental effect brought about by an increased equivalent transmission impedance, the loss of stability margin can be minimised by proper control of the converter....
Voltage source ac-to-dc converters for high-power transmitters
Cormier, R.
1990-01-01
This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
the passive capacitor current through a high-pass filter, which indirectly, furnishes two superior features. They are the mitigation of phase lag experienced by a conventional damper and the avoidance of instability caused by the negative resistance inserted unintentionally. Moreover, with the virtual......Active damping and harmonic compensation are two common challenges faced by LCL-filtered voltage source converters. To manage them holistically, this paper begins by proposing a virtual RC damper in parallel with the passive filter capacitor. The virtual damper is actively inserted by feeding back...... RC damper, the frequency region, within which the harmonic compensation is effective, can be extended beyond the gain crossover frequency. This is of interest to some high-performance applications, but has presently not been achieved by existing schemes. Performance of the proposed scheme has been...
Llopis, Francisco
2013-01-01
The circuit presented in this paper aims at providing three 40 Vpp 50Hz AC voltages sources with 120-degree phase separation between them. This is a fully analogue circuit that uses standard, low-cost electronic components without resorting to a microcontroller as previously proposed by Shirvasar et al [1]. This circuit may serve as a basis for a low-voltage 3P-AC power supply that students may safely use to realize experiments, i.e. about the principles and applications of three-phase AC power lines, without the risk of electric shocks.
Pires, Dulce F. [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal); Pires, V. Fernao [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal)]|[LabSEI - Laboratorio de Sistemas Electricos Industriais, Setubal (Portugal); Martins, J.F. [CTS, Faculdade de Ciencias e Tecnologia/UNL, Lisboa (Portugal); Pires, A.J. [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal)]|[LabSEI - Laboratorio de Sistemas Electricos Industriais, Setubal (Portugal)]|[CTS, Faculdade de Ciencias e Tecnologia/UNL, Lisboa (Portugal)
2009-04-15
This paper focuses on the detection of a rotor cage fault in a three-phase PWM feed induction motor. In inverter-fed machines there are some difficulties for the detection of a rotor cage fault. These difficulties are due to the fault signature that will be contained in the currents or voltages applied to the machine. In this way, a new approach based on the current and a virtual flux is proposed. The use of the virtual flux allows the improving of the signal to noise ratio. This approach also allows the identification of a rotor cage fault independently of the type of control used in the ac drive. The theoretical principle of this method is discussed. Simulation and experimental results are presented in order to show the effectiveness of the proposed approach. (author)
Bogimi Sirisha
2012-03-01
Full Text Available In this paper, a three-phase two leg neutral point clamped (NPC converter is presented for power factor correction and dc-link voltage regulation. The adopted converter has simpler circuit configuration and less number of power switches compared to three-level PWM converter. In this circuit configuration, only eight power switches and four clamping diodes with voltage stress of half the dc bus voltage are used. A simplified space vector pulse width modulation scheme (SVPWM is also adopted to track the line current commands. A reference voltage vector is generated on the ac terminal for drawing the sinusoidal line currents with unity power factor. This algorithm reduces the time required to calculate the switching time durations of voltage vectors. The simulation results have been presented to verify the validity and effectiveness of the proposed control strategy.
Three phase stratified sampling with ratio method of estimation
Bijoy Kumar Pradhan
2014-01-01
In this paper a three phase sampling is proposed to estimate the population mean of character by a three phase stratified ratio estimator and some numerical results are presented to illustrate efficiency of the proposed procedure against possible alternative ones and from the expected cost optimum sample sizes on first, second and third phases are also calculated.
7 CFR 3403.4 - Three-phase program.
2010-01-01
... 7 Agriculture 15 2010-01-01 2010-01-01 false Three-phase program. 3403.4 Section 3403.4... Program Description § 3403.4 Three-phase program. The Small Business Innovation Research Grants Program is carried out in three separate phases described in this section. The first two phases are designed...
Single-Phase Optimal Odd PWM Problem
Kujan, Petr; Hromčík, M.; Šebek, M.
Piscataway : IEEE, 2008, s. 371-378. ISBN 978-1-4244-1767-4; ISBN 978-1-4244-1766-7. [The 34th Annual Conference of the IEEEE Industrial Electronics Society. Orlando (US), 10.12.2008-13.12.2008] R&D Projects: GA MŠk(CZ) 1M0567; GA ČR(CZ) GA102/08/0186 Grant ostatní: GA MŠk(CZ) LA300 Institutional research plan: CEZ:AV0Z10750506 Keywords : Optimal PWM problem * selected harmonics elimination * Newton identities Subject RIV: BC - Control Systems Theory
Push-Pull Converter Fed Three-Phase Inverter for Residential and Motor Load
Samuel Rajesh Babu
2015-06-01
Full Text Available The proposed paper is an new approach for power conditioning of a PV (photo-voltaic cell array. The main objective is to investigate an approach to provide and improve the delivered electric energy by means of power conditioning structures with the use of alternative renewable resources (ARRs for remote rural residential or industrial non-linear loads. This approach employs a series-combined connected boost and buck boost DC-DC converter for power conditioning of the dc voltage provided by a photo-voltaic array. The input voltage to the combined converters is 100 V provided from two series connected PV cells, which is converted and increased to 200 V at the dc output voltage. Series-combined connected boost and buck-boost DC-DC converters operate alternatively. This helps to reduce the input ripple current and provide the required 400 Vdc on a sinusoidal PWM three-phase inverter. Analysis of the two series-combined DC-DC converters is presented along with simulation results. Simulations of the series-combined DC-DC converters are presented with an output DC voltage of 200 V and a maximum output load of Po = 600 W.
The pulse width modulated (PWM) inverter power supplies have been used increasingly to drive many electromagnetic devices for various purposes. When typical magnetic cores are energized by such voltage waveforms, additional iron losses occur due to distorted flux waveform. Most of these losses are due to an increase in frequency dependent losses. It should be noted that core geometry may also affect total power loss increase under PWM voltage excitation. This is because of a different magnetization process with respect to sinusoidal excitation. The effects of geometrical factors on magnetic properties of wound toroidal cores made of 3% grain oriented electrical steel were investigated. The results indicated that geometrical factors affect an iron loss increase under PWM voltage excitation as well as under sinusoidal excitation. The aspect ratio is particularly important in this regard
An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.
Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam
2013-11-01
This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. PMID:23916869
Three-phase relative permeability of Berea sandstone
Oak, M.J.; Baker, L.E. (Amoco Production Co., Tulsa, OK (US)); Thomas, C.C. (Amoco Corp., Naperville Research Center, IL (US))
1990-08-01
Reservoir engineering calculations frequently require consideration of coexisting oil, water, and gas phases. Such three-phase flow occurs when oil is displaced by simultaneous gas/water flow as in CO{sub 2}, water-alternating-gas flooding, steam-flooding, or other enhanced recovery processes. For this reason, reservoir simulators generally include three-phase relative permeability prediction methods. This paper presents two- and three-phase relative permeabilities measured on a water-wet fired Berea sandstone core with a fully automated steady-state method to investigate prediction methods experimentally.
Design and Implementation of Three Phase Unbalanced Voltage Motor Controller
M. A. A. Mashud
2013-09-01
Full Text Available A state-of-the-art-technology was used to design the unbalanced three phase motor controller. The fluctuation of line voltage has been questioned in recent times due to the use of heavy powered machine with three phases. This paper is focused on deriving a control scheme to drive a three phase motor that could be used in industry or households. The very simple circuitry has been employed in this design. To do this, extensive MATLAB analysis and PSpice software was conducted in order to optimize the control system and finally the results are practically verified.
Characteristics and application of three-phase extraction systems
A literature review dealing with three-phase extraction systems has been given. A classification of three-phase systems and their physicochemical characteristics have been presented. Mechanisms and reasons of the liquid third phase separation have been discussed. Studies on the partition of elements (V, Cd, REE and others) and organic compounds between three equilibrated phases in extraction systems of various types have been presented. Literature data concerning the application of three-phase extraction systems to separation, isolation and concentration of elements prior to their determination by various methods have been reviewed. 181 refs., 5 tabs
Design and Implementation of Three Phase Unbalanced Voltage Motor Controller
Mashud, M. A. A.; S. C. Barman; M. R. A. Bhuiyan; Md. Serajul Islam
2013-01-01
A state-of-the-art-technology was used to design the unbalanced three phase motor controller. The fluctuation of line voltage has been questioned in recent times due to the use of heavy powered machine with three phases. This paper is focused on deriving a control scheme to drive a three phase motor that could be used in industry or households. The very simple circuitry has been employed in this design. To do this, extensive MATLAB analysis and PSpice software was conducted in order to optimi...
A New Generalized Discontinuous-PWM Strategy for Active Power Filters
Asiminoaei, Lucian; Rodriguez, Pedro; Blaabjerg, Frede
2007-01-01
Classical discontinuous pulse width modulations (DPWM's) may not be efficiently applied in active power filters, because it is hard to predict the peak values of the inverter current, and consequently it is difficult to calculate the position of the clamped interval, that minimizes the switching...... losses in any operating point. This paper proposes a new discontinuous pulse width modulation strategy applied to shunt active power filters. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines instantaneously the optimum clamped...... is described, analyzed and validated on a three-phase voltage source inverter, rated at 7 kVA, 400 V, controlled as an active power filter....
Blaabjerg, Frede; Asiminoaei, Lucian; Malinowski, M.;
2008-01-01
switching losses in any operating point. This paper proposes a new DPWM strategy for shunt APFs. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines the optimum clamped duration for each phase, in terms of switching power losses. It......The classical discontinuous pulsewidth modulations (DPWMs) cannot be efficiently applied in active power filters (APFs) because it is difficult to predict the peak values of the inverter current. Consequently, it is difficult to calculate the optimal position of the clamped interval to minimize the...... achieves a clamped voltage pattern, with variable lengths depending on the magnitude of the inverter current. This property reduces the current stress and minimizes the inverter switching losses. The proposed modulation strategy is described, analyzed, and validated on a three-phase voltage source inverter...
Juhi Choudhary*
2014-12-01
Full Text Available In this paper, the four-leg voltage source converter (VSC with capacitor in its parallel, was functioned as a distribution static compensator (DSTATCOM. In three-phase four-wire distribution system, DSTATCOM was proposed for obtaining load balancing, harmonic current reduction and voltage regulation. The proposed technology was based on synchronous reference frame (SRF Theory. This theory was used for generating a reference current or gate pulse for VSC of DSTATCOM. Performance analysis of DSTATCOM under linear non linear loads was carried out and the Simulink results were shown. The analysis was carried out in MATLAB environment using Simulink and SimPowerSystem toolbox. The proposed SRF based DSTATCOM model was seen to be very effective to enhance the power quality of a three phase four wire distribution system.
Numerical Iterative Methods Solving three-phase Multilevel Voltage Converter
Kujan, Petr
Vol. IEEE CACSC CFP10CAC-CDR. Yokohama: IEEE, 2010, s. 1801-1806. ISBN 978-1-4244-5355-9. [The 10th IEEE International Symposium on Computer - Aided Control System Design . Yokohama, Kanagawa (JP), 08.09.2010-10.09.2010] R&D Projects: GA MŠk(CZ) 1M0567 Grant ostatní: GA ČR(CZ) GPP103/10/P323 Institutional research plan: CEZ:AV0Z10750506 Keywords : multilevel converter * numerical methods * optimal PWM * selective harmonic elimination Subject RIV: BC - Control Systems Theory
Accurate Parameter Estimation for Unbalanced Three-Phase System
Yuan Chen; Hing Cheung So
2014-01-01
Smart grid is an intelligent power generation and control console in modern electricity networks, where the unbalanced three-phase power system is the commonly used model. Here, parameter estimation for this system is addressed. After converting the three-phase waveforms into a pair of orthogonal signals via the α β-transformation, the nonlinear least squares (NLS) estimator is developed for accurately finding the frequency, phase, and voltage parameters. The estimator is realized by the Newt...
Testing of three-phase equipment under voltage sags
Rolan Blanco, Alejandro; Córcoles, F.; Pedra, J.; Monjo, L.; Bogarra, S.
2015-01-01
This paper provides insight into the testing of three-phase equipment exposed to voltage sags caused by faults. The voltage sag recovers at the fault-current zeros, leading to a `discrete' voltage recovery, that is, the fault is cleared in different steps. In the literature, the most widespread classification divides `discrete' sags into 14 types. The authors study shows that it is generally sufficient to consider only five sag types for three-phase equipment, here called `time-invariant (TI)...
Analyse van de Spotspray van een PWM-spuitdop
Groot, T.T.; Velde, Van de, E.; Stallinga, H.; Nieuwenhuizen, A.T.; Holterman, H.J.; Zande, van der, W.J.
2014-01-01
Sensor gestuurde spuitsystemen waarmee door middel van een sensor kwantitatief een aantasting of hoeveelheid onkruid (biomassa) in het veld gemeten kan worden vragen om spuitsystemen met een variabele dosering. Eén methode om dat te realiseren is met een Pulse Width Modulation (PWM) techniek het debiet van de spuitdop te variëren. Dit PWM-systeem bestaat uit een dophouder met daarin een klep die tijdens de bespuiting met een hoge frequentie (PWM-cyclus) open en dicht wordt gezet. Met deze deb...
O.Chandra sekha
2014-07-01
Full Text Available This paper presents the regulation of the voltage and frequency of a stand-alone fixed-pitch wind energy conversion system (WECS based on a self-excited squirrel-cage induction machine. A shunt connected voltage source inverter (VSI and a controllable dump load are used for regulation purposes. A battery bank is included in the dc side of the VSI so that it can absorb and inject active power thus increasing the efficiency and availability of the system. A control scheme for the VSI with self-governing control of real and reactive power allows the state of charge of the batteries to be kept in a safe range while maximizing the voltage regulating capabilities of the VSI. The characteristics of the wind turbine, selfexcited generator, and the ratings of the VSI are considered in order to find out the load range for which voltage and frequency can be regulated for a given wind speed range. The possibility of the proposed system is verified by MATLAB/SIMULINK. simulations.
Nonlinear control of voltage source converters in AC-DC power system.
Dash, P K; Nayak, N
2014-07-01
This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. PMID:24906895
Effect of embedded voltage source converter on power system oscillation damping
R; DUNN
2010-01-01
This paper presents the damping torque analysis of power system oscillation stability as affected by the dynamic and control functions of an embedded voltage source converter(VSC).The objective of the study is to explain why and how the dynamic and basic control functions of the embedded VSC,ac and dc voltage regulation,provide damping to power system oscillations.The most important conclusion obtained in the paper is that both the dynamics and the dc voltage control of the VSC contribute a variable damping torque,which can be positive or negative,at different levels of system load conditions.More positive damping torque can be provided by the VSC at a heavier load condition.There exists a point of system load condition where the VSC provides no damping torque to power system oscillation hence dose not impose any influence on power system oscillation stability.The VSC studied in the paper can be the power-electronics-based interface of various FACTS(flexible ac transmission systems) devices,energy storage systems and renewable power generation units,although the focus of the discussion presented in this paper is the effect of the dynamics and basic control functions of the VSC themselves on power system oscillation damping.To demonstrate the analytical conclusions obtained in the paper,results of eigenvalue computation and nonlinear simulation of an example power system with STATCOM(static synchronous compensator) are given.
NingYi Dai
2014-01-01
Full Text Available 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.
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. PMID:25177725
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
This paper addresses the interaction between harmonic resonant controllers and active damping of LCL resonance in voltage source converters. A virtual series R-C damper in parallel with the filter capacitor is proposed with the capacitor current feedback loop. The phase lag resulting from the dig...
Improved Passive-Damped LCL Filter to Enhance Stability in Grid-Connected Voltage-Source Converters
Beres, Remus Narcis; Wang, Xiongfei; Blaabjerg, Frede;
2015-01-01
This paper proposes an improved passive-damped LCL filter to be used as interface between the grid-connected voltage-source converters and the utility grid. The proposed filter replaces the LCL filter capacitor with a traditional C-type filter with the resonant circuit tuned in such a way that sw...
Harmonic Filtering Performance of a Hybrid Active Filter for a Three-Phase 12-Pulse Diode Rectifier
Isozaki, Kohei; Akagi, Hirofumi
This paper describes a hybrid active filter for harmonic-current compensation of a three-phase 12-pulse diode rectifier used as the front end of a medium-voltage motor drive system. This hybrid filter is characterized by the direct series connection of a simple LC filter and a small-rated active filter. This circuit configuration brings low cost, small size, and light weight to the hybrid filter. The authors design, construct, and test a three-phase experimental system rated at 400V and 15kW, which is a downscaled model of the medium-voltage motor drive system. In this experiment, the LC filter is tuned to the 11th harmonic frequency, and the active filter is based on a three-level diode-clamped PWM converter with a dc capacitor voltage as low as 28V. This hybrid filter is connected on either the first or fourth winding of a line-frequency transformer with a first Δ-winding voltage of 400V in the primary, and a second Δ-winding voltage of 220V, a third Y-winding voltage of 220V, and a fourth Δ-winding voltage of 400V in the secondary. Experimental results show that the hybrid filter performs satisfactory filtering in a range from the no-load to full-load conditions.
An Investigation on the Performance of Random PWM Controlled Converters
R. Jadeja
2015-12-01
Full Text Available This paper provides an insight on various random pulse width modulation techniques and their effect on spreading the harmonic spectrum for various applications like drives, hybrid electric vehicles and renewable energy sources, for two level as well as three level inverter. Acoustic noise reduction, electromagnetic interference conducted and torque ripple are obvious advantages of random pulse width modulation (PWM. PWM converters with multilevel topology can meet with global quality standards for power supplies. The random PWM technique provides additional advantages. Among others, it may be implemented to achieve switching loss equalization in power switches for cascaded H-Bridge multilevel inverters. This paper provides in depth understanding for different random PWM techniques and their applications.
Simulation of Five Phase Voltage Source Inverter with Different Excitation for Star Connected Load
M. A. Inayathullaah; Dr. R. Anita
2014-01-01
In order to reduce the torque ripple and harmonics for smooth operation of the machine and to reduce the amount of heat generated the motor has to be supplied with multi phase supply greater than three phase supply. Selection of even number of phases should be avoided, because it decreases the performance of the motor as poles coincide with each other. So, Five Phase Supply is preferred. A five phase five leg 10 switch inverter fed five phase star connected load operating with five different ...
An Investigation on the Performance of Random PWM Controlled Converters
Jadeja, R.; Ved, A.; S. Chauhan
2015-01-01
This paper provides an insight on various random pulse width modulation techniques and their effect on spreading the harmonic spectrum for various applications like drives, hybrid electric vehicles and renewable energy sources, for two level as well as three level inverter. Acoustic noise reduction, electromagnetic interference conducted and torque ripple are obvious advantages of random pulse width modulation (PWM). PWM converters with multilevel topology can meet with global quality standar...
A Composite PWM Control Strategy for Boost Converter
Qingfeng, Liu; Zhaoxia, Leng; Jinkun, Sun; Huamin, Wang
In order to improve the control performance of boost converter with large signal disturbance, a composite PWM control strategy for boost converter operating in continuous condition mode (CCM) was proposed in this paper. The parasitical loss of Boost converter was analyzed and a loss compensation strategy was adopted to design feed-forward tracker for converter. The composite PWM controller consisted of the tracker and PID controller. Simulation and experiment results validated the validity of the control strategy presented in this paper.
VFT PHASE VOLTAGE MEASUREMENT IN THREE-PHASE ENCLOSED GIS
邹建华; 岳子丁; 李洋
2002-01-01
The measuring of VFT phase voltage in three-phase enclosed GIS is more complex and difficult than in single-phase ones. There are 3 capacitive sensors in the measuring system, the outputs of which are with a linear relation to the three phase voltages. This linear relation is presented with a factorial matrix. Because each capacitive sensor is coupled with the electric field of three phases (A, B, and C), the electric coupling coefficients are introduced. In order to determine the matrix of electric coupling coefficients, the numerical calculation method can be used. From the discussion on two types of three-phase enclosed GIS bus, i.e. standard arrangement and biased arrangement, the dominant electric coupling coefficients are named, which can be simply and approximately calculated by an analytic expression. Finally, as an example, the waveforms of VFT phase voltage generated on a three-phase enclosed GIS bus model are displayed. When a capacitive sensor is located at the 'shortest point' of phase A (or B, or C), the VFT phase voltage VA (or VB, or VC) can almost be measured by that capacitive sensor alone.
Three-phase multilevel solar inverter for motor drive system
Bhasagare, Mayuresh P.
This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.
Harmonic three-phase circular inclusions in finite elasticity
Wang, Xu; Schiavone, Peter
2015-09-01
We study the exterior stress field in a three-phase circular inclusion which is bonded to the surrounding matrix through an intermediate interphase layer. All three phases belong to a particular class of compressible hyperelastic materials of harmonic type. We focus on the design of a harmonic elastic inclusion which by definition, does not disturb the sum of the normal stresses in the surrounding matrix. We show that in order to make the coated inclusion harmonic, certain inequalities concerning the material and geometric parameters of the three-phase composite must first be satisfied. The corresponding remote loading parameters can then be uniquely determined while keeping the associated phase angles arbitrary. Our results allow for both uniform and non-uniform remote loading. We show that the stress field inside the inclusion is uniform when the remote loading is uniform.
Hagiwara, Makoto; Nishimura, Kazutoshi; Akagi, Hirofumi
This paper presents a medium-voltage motor drive with a three-phase modular multilevel PWM inverter and focuses on its control method and operating performance. This motor drive is particularly suitable for fans, blowers, pumps, and compressors, in which the load torque is proportional to the square of the rotating speed. Particular attention is paid to the dc-capacitor voltage fluctuation of each chopper-cell because it may affect the voltage rating of the power switching devices used. This paper describes the theoretical equations related to the amount of the voltage fluctuation. A downscaled model rated at 400V and 15kW is designed and built to confirm the validity and effectiveness of the nine-level (17-level in line-to-line) PWM inverter that is intended for use in medium-voltage motor drives to achieve energy savings.
Losses in armoured three-phase submarine cables
Ebdrup, Thomas; Silva, Filipe Miguel Faria da; Bak, Claus Leth;
2014-01-01
The number of offshore wind farms will keep increasing in the future as a part of the shift towards a CO2 free energy production. The energy harvested from the wind farm must be brought to shore, which is often done by using a three-phase armoured submarine power cable. The use of an armour...... increases the losses in armoured cables compared to unarmoured cables. In this paper a thorough state of the art analysis is conducted on armour losses in three-phase armoured submarine power cables. The analysis shows that the IEC 60287-1-1 standard overestimates the armour losses which lead to the...
Effect and surfactants on three-phase fluidized bed hydrodynamics
Experiments were conducted to discern the relationship between three-phase fluidized bed hydrodynamics and surfactant solution characteristics. The standard characteristic, equilibrium surface tension, is inadequate. A novel method for surface tension evaluation, a dynamic maximum bubble pressure technique, was found to differentiate the 12 different solutions studied. The surfactant solutions were categorized based upon a combination of the terminal bubble rise velocity reduction, the equilibrium surface tension, and the new bubble tension values. These surfactant solution categories were correlated with experimentally observed three-phase fluidized bed and bubble column hydrodynamic behavior. Specifically, empirical correlations for gas holdup are presented
Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo
This paper describes an ungrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was is small, the reversal of the polarities of the common-mode voltage and shaft voltage is observed. In order to model this reversal, a bridge-type equivalent circuit is proposed. On the basis of calculations and experiment, it is found the values and polarity of the shaft voltage can be are accurately determined with the proposed equivalent circuit. Furthermore, the capacitance value of the insulated rotor required to make the shaft voltage equal to or less than the dielectric breakdown voltage of the bearing grease is obtained.
Comparison of phase-shifted and level-shifted PWM in the modular multilevel converter
Darus, Rosheila; Konstantinou, Georgios; Pou Félix, Josep; Ceballos Recio, Salvador; Agelidis, Vassilios
2014-01-01
This paper reports a comparison study of different carrier-based PWM techniques applied to the modular multilevel converter. Phase-disposition PWM (PD-PWM) and phase-shifted pulse-width modulation (PS-PWM) with non-interleaving and interleaving are considered in this study. In PS-PWM, two cases are evaluated. In the first case, the particular SMs that have to be activated/deactivated are defined by a voltage balancing algorithm, which is the same one implemented in PD-PWM. In addition, an alg...
A high-quality multi-level voltage source inverter suitable for high power/high voltage applications
In this paper new magnitudes for D C side capacitors' voltages of a multi level voltage source inv enter are presented. Using these magnitudes of D C side capacitors voltage allow generation of Σ3k steps of A C output voltage by cascade connection of only N single-phase full bridge inverter. This subject has resulted in almost sinusoidal output voltage wave form. Approximated equal area pulse amplitude modulation technique is used to calculate the duration of each step of voltage, which has resulted in reduction of complexity of control circuit. A simple closed-loop controller is developed for controlling the voltage of D C side capacitors. Harmonic analysis and capacitor calculations are presented, too. Simulation results have been used to verify the overall operation of the proposed multi level voltage source inverter in feeding a R-L load with a stepped sinusoidal wave form
The Distance Learner Competencies: A Three-Phased Empirical Approach
Hong, Seongyoun; Jung, Insung
2011-01-01
This study identifies a set of competencies displayed in the successful distance learner. It employed a three-phased approach. Phase I, conducted to develop an initial list of competencies, comprised Behavioral Event Interviews with nine successful distance learners. In Phase II, these competencies were reviewed, elaborated and categorized by…
Periodic Operation of Three-Phase Catalytic Reactors
Silveston, P.T.; Hanika, Jiří
2005-01-01
Roč. 82, č. 6 (2005), s. 1105-1142. ISSN 0008-4034 Institutional research plan: CEZ:AV0Z4072921 Keywords : three-phase reactors * trickle bed * periodic operation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.574, year: 2005
Lattice Boltzmann modeling of three-phase incompressible flows
Liang, H.; Shi, B. C.; Chai, Z. H.
2016-01-01
In this paper, based on multicomponent phase-field theory we intend to develop an efficient lattice Boltzmann (LB) model for simulating three-phase incompressible flows. In this model, two LB equations are used to capture the interfaces among three different fluids, and another LB equation is adopted to solve the flow field, where a new distribution function for the forcing term is delicately designed. Different from previous multiphase LB models, the interfacial force is not used in the computation of fluid velocity, which is more reasonable from the perspective of the multiscale analysis. As a result, the computation of fluid velocity can be much simpler. Through the Chapman-Enskog analysis, it is shown that the present model can recover exactly the physical formulations for the three-phase system. Numerical simulations of extensive examples including two circular interfaces, ternary spinodal decomposition, spreading of a liquid lens, and Kelvin-Helmholtz instability are conducted to test the model. It is found that the present model can capture accurate interfaces among three different fluids, which is attributed to its algebraical and dynamical consistency properties with the two-component model. Furthermore, the numerical results of three-phase flows agree well with the theoretical results or some available data, which demonstrates that the present LB model is a reliable and efficient method for simulating three-phase flow problems.
Three-Phase Unbalanced Load Flow Tool for Distribution Networks
Demirok, Erhan; Kjær, Søren Bækhøj; Sera, Dezso; Teodorescu, Remus
2012-01-01
This work develops a three-phase unbalanced load flow tool tailored for radial distribution networks based on Matlab®. The tool can be used to assess steady-state voltage variations, thermal limits of grid components and power losses in radial MV-LV networks with photovoltaic (PV) generators where...
Lattice Boltzmann modeling of three-phase incompressible flows.
Liang, H; Shi, B C; Chai, Z H
2016-01-01
In this paper, based on multicomponent phase-field theory we intend to develop an efficient lattice Boltzmann (LB) model for simulating three-phase incompressible flows. In this model, two LB equations are used to capture the interfaces among three different fluids, and another LB equation is adopted to solve the flow field, where a new distribution function for the forcing term is delicately designed. Different from previous multiphase LB models, the interfacial force is not used in the computation of fluid velocity, which is more reasonable from the perspective of the multiscale analysis. As a result, the computation of fluid velocity can be much simpler. Through the Chapman-Enskog analysis, it is shown that the present model can recover exactly the physical formulations for the three-phase system. Numerical simulations of extensive examples including two circular interfaces, ternary spinodal decomposition, spreading of a liquid lens, and Kelvin-Helmholtz instability are conducted to test the model. It is found that the present model can capture accurate interfaces among three different fluids, which is attributed to its algebraical and dynamical consistency properties with the two-component model. Furthermore, the numerical results of three-phase flows agree well with the theoretical results or some available data, which demonstrates that the present LB model is a reliable and efficient method for simulating three-phase flow problems. PMID:26871191
A cascaded three-phase symmetrical multistage voltage multiplier
Iqbal, Shahid [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia); Singh, G K [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia); Besar, R [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia); Muhammad, G [Faculty of Information Science and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)
2006-10-15
A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM.
Controlling An Inverter-Driven Three-Phase Motor
Dolland, C.
1984-01-01
Control system for three-phase permanent-magnet motor driven by linecommutated inverter uses signals generated by integrating back emf of each phase of motor. High-pass filter network eliminates low-frequency components from control loop while maintaining desired power factor.
A cascaded three-phase symmetrical multistage voltage multiplier
A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM
EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier
R. Dolecek
2008-12-01
Full Text Available Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.
Backstepping controller of five-level three-phase inverter
Majdoul R.
2014-01-01
Full Text Available Multilevel converters are becoming increasingly used in many industrial applications due to the many advantages that they offer. The improvements in the output signal quality, lower Total Harmonic Distortion (THD and many other properties make multilevel converters very attractive for connecting photovoltaic generators to medium voltage grid directly or to be used in a local power supply. In this paper, we focus on the implementation of a three-phase five-level diode clamped inverter and design of a performing nonlinear controller using the Backstepping approach. The control objective is to generate, at the system output, sinusoidal three-phase voltages with amplitude and frequency fixed by the reference signal independently of load variations. The performance study of the multilevel inverter and the designed controller are made by simulations in Matlab/Simulink environment.
Differential Protection for Arbitrary Three-Phase Power Transformers
Gajic, Zoran
2008-01-01
This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in the protective relaying standards and practices currently applied. The first part of the thes...
Peripheral cholangiocarcinoma : three-phase helical CT appearance
To analyze the enhancement patterns and morphology of peripheral cholangiocar-cinomas (CCs), as seen on three-phase helical CT. Three-phase helical CT scans of 25 cases of 24 patients with pathologically-proven CCs were retrospectively reviewed. After intravenous administration of contrast media, scans of the hepatic arterial phase (HAP) were obtained at 30 seconds, of the portal venous phase (PVP) at 70 seconds, and of the delayed phase (DP) at 3 minutes. Linear, dense, marginal enhancement was seen in 17 CCs (68%), mainly on HAP images (64%) while thick, band-like, peripheral enhancement was seen in 18 (72%), on either PVP (52%) or DP (44%). Internal enhancement was observed in 23 CCs (92%) on PVP (68%) and/or DP (88%), and 19 CCs (76%) among them showed incomplete enhancement of stippled and/or septated patterns. Most (76%) were seen throughout all three phases to be hypoattenuating, as compared to the surrounding parenchyma. On HAP, wedge-shaped parenchymal enhancement was demonstrated at the periphery of 19 CCs (76%) suggesting impaired portal flow. Associated morphologic findings were satellate nodules (n=15, 60%), lymphadenopathy (n=14, 56%), focal dilatation of intrahepatic ducts around the tumor (44%), umbilication of the liver surface (50%), and clonorchiasis (44%). On three-phase helical CT, peripheral cholangiocarcinoma showed linear marginal enhancement on HAP, thick peripheral enhancement on PVP and/or DP, stippled and septated enhancing foci on DP, and peritumoral wedge enhancement on HAP. Associated findings such as satellite nodules, focal dilatation of the intrahepatic ducts, umbilication of the tumor, and clonorchiasis were helpful
Three-phase model of a chiral quark bag
Three-phase modification of the model of hybrid chiral quark bag is suggested. Along with the phase of asymptotically free current quarks and completely achromatic meson phase the model contains an intermediate phase including massive quark components. Self-consistent solution of model equations with account of contribution from the Dirac sea is found for (1+1)-dimensional case. The dependence of bag characteristics on theory parameters is investigated in analytical and numerical forms
Faults Classification Scheme for Three Phase Induction Motor
Mohammed Obaid Mustafa; George Nikolakopoulos; Thomas Gustafsson
2014-01-01
In every kind of industrial application, the operation of fault detection and diagnosis for induction motors is of paramount importance. Fault diagnosis and detection led to minimize the downtime and improves its reliability and availability of the systems. In this article, a fault classification algorithm based on a robust linear discrimination scheme, for the case of a squirrelâ€“cage three phase induction motor, will be presented. The suggested scheme is based on a novel feature extraction...
Analysis and Design of a Three-Phase PLL Structure
Reza Sedaghati
2014-01-01
A phase-locked loop is really a feedback system combining a voltage controlled oscillator (VCO) and a phase comparator so connected that the oscillator maintains a continuing phase angle in accordance with a reference signal. To be able to synchronize two power generation systems with equal frequencies; synchronism must occur while voltages' phase angles of the systems will be the same. Phase angle of a three-phase system is set via phase locked loops. If three input phases are balanced, then...
Three Phase High Power Quality Two- Stage Boost Rectifier
P.NAMMALVAR; S. ANNAPOORANI
2012-01-01
Three-phase two-stage boost rectifier with sinusoidal input current are presented and a novel topology with two active power devices is proposed. These contain a capacitor for pumping action in DC circuit. This gives twostage boost operation to obtain higher DC output voltage. The rectifier can be operated in the switch mode forpumping action and for forcing the input current to follow its sinusoidal reference independent of the working conditions. The results of the proposed rectifier are co...
Incompressible smoothed particle hydrodynamics simulation of three phase flows
Tofighi, Nima; Yıldız, Mehmet; Yildiz, Mehmet
2013-01-01
In this study, a new surface tension formulation for modeling incompressible, immiscible three phase fluid flows in the context of incompressible smoothed particle hydrodynamics (ISPH) in two dimensions has been proposed. Continuum surface force model is employed while physical surface tension coefficients are expressed as the sum of phase specific surface tension coefficients. In order to illustrate the effectiveness of the proposed method, a liquid lens test case has been simulated and resu...
Three-phase coexistence in colloidal rod-plate mixtures
Woolston, Phillip; Van Duijneveldt, Jeroen S
2015-01-01
Aqueous suspensions of clay particles, such as montmorillonite (MMT) platelets and sepiolite (Sep) rods, tend to form gels at concentrations around 1 vol %. For Sep rods, adsorbing sodium polyacrylate to the surface allows for an isotropic-nematic phase separation to be seen instead. Here, MMT is added to such Sep suspensions, resulting in a complex phase behavior. Across a range of clay concentrations, separation into three phases is observed: a lower, nematic phase dominated by Sep rods, a ...
Backstepping controller of five-level three-phase inverter
Majdoul R.; Abouloifa A.; Abdelmounim E.; Aboulfatah M.; Touati A.; Moutabir A.
2014-01-01
Multilevel converters are becoming increasingly used in many industrial applications due to the many advantages that they offer. The improvements in the output signal quality, lower Total Harmonic Distortion (THD) and many other properties make multilevel converters very attractive for connecting photovoltaic generators to medium voltage grid directly or to be used in a local power supply. In this paper, we focus on the implementation of a three-phase five-level diode clamped inverter and des...
A Novel SVPWM Technology Used in PWM Rectifiers of WPGS
Zhang Junli
2013-04-01
Full Text Available In order to achieve the transformation of electrical energy in Variable Speed Constant Frequency (VSCF Wind Power Generation System (WPGS, a novel Space Vector Pulse Width Modulation (SVPWM pulse trigger technology applied in high efficient PWM rectifier is proposed. Rectifier is an important part of WPGS and its performance affects the harmonic content and power factor of the power energy delivered to the grid. In order to improve the performance of PWM rectifier, a novel SVPWM pulse generator technology is proposed. Compared with other kinds of PWM pulse generator systems, Space Vector Pulse Width Modulation (SVPWM has many advantages such as clear physical concept, simple algorithm, suitable for digital implementation, high voltage utilization, low harmonic content, low switches losses and simple hardware circuit.
Neural network based PWM AC chopper fed induction motor drive
Venkatesan Jamuna
2009-01-01
Full Text Available In this paper, a new Simulink model for a neural network controlled PWM AC chopper fed single phase induction motor is proposed. Closed loop speed control is achieved using a neural network controller. To maintain a constant fluid flow with a variation in pressure head, drives like fan and pump are operated with closed loop speed control. The need to improve the quality and reliability of the drive circuit has increased because of the growing demand for improving the performance of motor drives. With the increased availability of MOSFET's and IGBT's, PWM converters can be used efficiently in low and medium power applications. From the simulation studies, it is seen that the PWM AC chopper has a better harmonic spectrum and lesser copper loss than the Phase controlled AC chopper. It is observed that the drive system with the proposed model produces better dynamic performance, reduced overshoot and fast transient response. .
Realise of PWM-generating based on FPGA
The power supply digital controllers of Shanghai Synchrotron Radiation Facility(SSRF) make use of the PWM (pulse width modulation) wave as the feedback to the power-electrical devices, so as to obtain constant current of high accuracy and stability. The design of PWM wave generation structure in FPGA is good for a compact controller,and the reduction of the usage of Integrated Circuits (ICs) decreases the interference from the noise among the ICs, hence better performance of the controller. In addition, FPGA can be programmed circularly at any time,so as to optimize the structure design and make a maximum use of the advantage of FPGA. As a part of transplanting the complete function of the DSP (digital signal processor/processing), realizing the generation of PWM wave in FPGA is feasible. In this paper, we report progress in this regard at SSRF. (authors)
Synchronization of the distributed PWM carrier waves for modular multilevel converters
Burlacu, Paul Dan; Mathe, Laszlo; Teodorescu, Remus
drift between the PWM outputs of each sub-module increasing the total harmonic distortion of the output voltage. This paper presents a solution to synchronize the PWM outputs of the MMC submodules using EtherCAT communication protocol focusing on phase shifted PWM modulation technique....
Three-dimensional numerical simulations of three-phase flows
Pavlidis, Dimitrios; Xie, Zhizhua; Salinas, Pablo; Pain, Chris; Matar, Omar
2015-11-01
The objective of this study is to investigate the fluid dynamics of three-dimensional three-phase flow problems, such as droplet impact on a gas-liquid interface and bubble rising through a liquid-liquid interface. An adaptive unstructured mesh modelling framework is employed here to study three-phase flow problems, which can modify and adapt unstructured meshes to better represent the underlying physics of multiphase problems and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid' type method for the interface capturing based on a compressive control volume advection method and second-order finite element methods, and a force-balanced algorithm for the surface tension implementation, minimising the spurious velocities often found in such flow simulations. The surface tension coefficient decomposition method has been employed to deal with surface tension pairing between different phases via a compositional approach. Numerical examples of some benchmark tests and the dynamics of three-phase flows are presented to demonstrate the ability of this method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.
Three-phase flow of submarine gas hydrate pipe transport
李立; 徐海良; 杨放琼
2015-01-01
In the hydraulic transporting process of cutter-suction mining natural gas hydrate, when the temperature−pressure equilibrium of gas hydrate is broken, gas hydrates dissociate into gas. As a result, solid−liquid two-phase flow (hydrate and water) transforms into gas−solid−liquid three-phase flow (methane, hydrate and water) inside the pipeline. The Euler model and CFD-PBM model were used to simulate gas−solid−liquid three-phase flow. Numerical simulation results show that the gas and solid phase gradually accumulate to the center of the pipe. Flow velocity decreases from center to boundary of the pipe along the radial direction. Comparison of numerical simulation results of two models reveals that the flow state simulated by CFD-PBM model is more uniform than that simulated by Euler model, and the main behavior of the bubble is small bubbles coalescence to large one. Comparison of numerical simulation and experimental investigation shows that the values of flow velocity and gas fraction in CFD-PBM model agree with experimental data better than those in Euler model. The proposed PBM model provides a more accurate and effective way to estimate three-phase flow state of transporting gas hydrate within the submarine pipeline.
Analysis of Capacitive Parasitism in PWM Inverter-Fed Motor
无
2001-01-01
The effects of parasitic capacitance in induction motor system are unnoticed when it is fed from the AC line. but they are obvious when supplied directly from a PWM inverter. Consequently. many parasitic problems occur, such as motor-to-earth leakage current, bearing current, incoming line current distortion and uneven distribution of electrical stresses along the winding. On the ba sis of the uniform transmission line principle, a complete equivalent circuit of the PWM inverter-fed motor system is presented, based on which all the capacitive parasitic problems mentioned above are analyzed and simulated by means of PSPICE. All the results are consistent with the existing ones.
Inexpensive discrete PSD controller with PWM power output
Krejcar, Ondřej; Frischer, Robert
2011-01-01
Większość kontrolerów przemysłowych to urządzenia dość drogie, chociaż wykorzystuje sie w nich często tylko bazowe funkcje kontrolera. Dość często zachodzi potrzeba ustalenia sygnału PWM (Modulacja szerokości impulsu). Dlatego w pracy przedstawiono cyfrowy kontroler PSD z uproszczoną konstrukcją umożliwiający uzyskiwanie sygnału PWM. Otrzymano bardzo prosty kontroler o niewielkiej powierzchni.
FPGA baserad PWM-styrning av BLDC-motorer
Johansson, Andreas
2003-01-01
This thesis work contains a litterature study about electrical motors in general and how PWM-patterns for brushless DC-motors can be made. A suitable method has been implemented as a simulation model in VHDL. A simulation model of a brushless DC-motor which describes the phasecurrents, torque and angular velocity has also been made. The motor model made simulations easier for the complete PWM-system. The design was synthesised and tested with a prototypeboard including a SPARTAN II FPGA. In ...
Dielectric-barrier discharges (DBDs) in atmospheric pressure air have been studied by using a power-frequency voltage source. In this paper the electrical characteristics of DBDs using glass and alumina dielectrics have been investigated experimentally. According to the Lissajous figures of voltage-charges, it is discovered that the discharge power for an alumina dielectric is much higher than that for a glass dielectric at the same applied voltage. Also, the voltage-current curves of the glass and alumina dielectrics confirm the fact that the dielectric barriers behave like semiconducting materials at certain applied voltages. (low temperature plasma)
P.Narasimhulu
2014-09-01
Full Text Available A reduced rating voltage-source converter with a zig-zag transformer as a distribution static compensator is proposed for power-quality improvement in the three-phase four-wire distribution system. The source voltages in the distribution systems are also experiencing power quality problems, such as harmonics, unbalance, flicker, sag, swell, etc. The distribution static compensator (DSTATCOM is proposed for compensating power quality problems in the current, and the dynamic voltage restorer (DVR is used for mitigating the power quality problems in the voltage. The zig-zag transformer is used for the neutral current compensation. Distribution systems are facing severe power-quality (PQ problems, such as poor voltage regulation, high reactive power and harmonics current burden, load unbalancing, excessive neutral current, etc. The zig-zag transformer is used for providing a path to the zero-sequence current. The DSTATCOM is used to improve the quality of power to the non linear loads. By using both zig-zag transformer and DSTATCOM in the distribution system the rating of the voltage source converter can be reduced. Hence it can be also called reduced rating device. The performance of the DSTATCOM is validated through extensive simulations using MATLAB software with its Simulink and power system block set toolboxes.
Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions
无
2007-01-01
This paper presents a unified positive- and negative-sequence dual-dq dynamic model of wind-turbine driven doublyfed induction generator (DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back (BTB) PWM voltage source converter (VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency, and the two proposed control targets for the rotor-side converter are alternatively achieved, which, as a result, improve the fault-ride through (FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid- and rotor-side converters included is designed. Finally, simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.
Contrast enhancement patterns of hepatic masses using three phase spiral
To compare the contrast enhancement patterns of hepatocellular carcinomas(HCCs), hemangiomas, and metastases on three-phase images with spiral CT for differential diagnosis. Three-phase spiral CT scan was performed in 73 patients with hepatic masses. CT scanning was performed with a table speed of 10 mm/sec, section thickness of 10 mm, and a reconstruction interval of 5 mm. 100-150mL of contrast medium was injected intravenously with an automatic injector at a rate of 2-3 mL/sec. CT scans were obtained at 30, 70 and 180 seconds after the start of contrast material injection. The enhancement patterns of 136 lesions in 53 patients with HCCs were as follows : 47 lesions(35%) were totally high and 55(40%) were mixed in the early phase deparlesions(22%) were mixed and 66(49%) were totally low in the portal phase ; and 105 lesions(78%) were totally low in the delayed phase. In hemangiomas of 23 lesions in 15 patients, 7 lesions(30%) were peripherally high and 11(48%) were totally low in the arterial phase ; 4 lesion(17%) were totally high and 12(53%) were peripherally high in the portal phase ; 10 lesions (42%) were totally high and 4(18%) were peripherally high in the delayed phase. In metastatic liver malignancies of 42 lesions in 5 patients, 13 lesions(31%) were peripherally high and 22(52%) were totally low in the arterial phase ; 32 lesions(77%) were totally low in the portal phase, and 35(83%) were totally low in the delayed phase. Three-phase spiral CT scanning is a useful diagnostic method in the differential diagnosis of hepatic masses including HCCs, hemangiomas, and hepatic metastases
Three-Phase High-Power and Zero-Current-Switching OBC for Plug-In Electric Vehicles
Cheng-Shan Wang
2015-06-01
Full Text Available In this paper, an interleaved high-power zero-current-switching (ZCS onboard charger (OBC based on the three-phase single-switch buck rectifier is proposed for application to plug-in electric vehicles (EVs. The multi-resonant structure is used to achieve high efficiency and high power density, which are necessary to reduce the volume and weight of the OBC. This study focuses on the border conditions of ZCS converting with a battery load, which means the variation ranges of the output voltage and current are very large. Furthermore, a novel hybrid control method combining pulse frequency modulation (PFM and pulse width modulation (PWM together is presented to ensure a driving frequency higher than 10 kHz, and this will reduce the unexpected inner resonant power flow and decrease the total harmonic distortion (THD of the input current under a light load at the end of the charging process. Finally, a prototype is established, and experiments are carried out. According to the experimental results, the conversion efficiency is higher than 93.5%, the THD about 4.3% and power factor (PF 0.98 under the maximum power output condition. Besides, a three-stage charging process is also carried out the experimental platform.
Mary Kaye; Chris Diduch; Qing-rong ZENG; Idris Gadoura; Liu-chen ZHANG
2011-01-01
Voltage space vector pulse-width modulation(SVPWM) has been widely applied to control current in threephase vohage source inverters (VSI).However,as a voltage type modulator,SVPWM has certain drawbacks compared with current type modulators for grid-connected applications.For a grid-connected VSI,the performance of existing current controllers based on SVPWM is compromised by grid harmonics,control delay and system nonlinearities such as switching dead time.Moreover,unlike current type PWM,SVPWM does not inherently have over-current protection.A novel SVPWM-based current controller is proposed for three-phase grid-connected VSIs for small wind turbine applications.To overcome the drawbacks of SVPWM,a grid harmonic compensation method is proposed along with compensation for control delays.Both simulation and experimental results have established excellent steady-state response and fast dynamic response of the current controller.In addition,the DSP-based control system has both improved real-time control performance and fast response for over-current protection.
Evaluation of Three-Phase Transformerless Photovoltaic Inverter Topologies
Kerekes, Tamas; Liserre, Marco; Teodorescu, Remus;
2009-01-01
This paper analyzes and compares three transformerless photovoltaic inverter topologies for three-phase grid connection with the main focus on the safety issues that result from the lack of galvanic isolation. A common-mode model, valid at frequencies lower than 50 kHz, is adopted to study the...... crucial influence. Finally, a comparison of the selected topologies is carried out, based on the adopted modulation, connection of the neutral and its inductance, effects of unbalance conditions, component ratings, output voltage levels, and filter size....
Three-phase electric drive with modified electronic smoothing inductor
Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole
2010-01-01
This paper presents a three-phase electric drive with a modified electronic smoothing inductor (MESI) having reduced size of passive components. The classical electronic smoothing inductor (ESI) is able to control a diode bridge output current and also reduce not only mains current harmonics but...... series with DC-link capacitor. This increases power factor (PF) and reduces the total harmonic distortions (THDs) in current at mains. Input currents of the diode bridge which usually show high peak amplitudes are converted into a 120° rectangular shape which ideally results in a total PF of 0.955 and...
Mechanical properties of three-phase polyamide 6 nanocomposites
Gendre, Laura; Abhyankar, Hrushikesh; Njuguna, James; Ermini, Valentina
2013-01-01
This work focus on the mechanical properties of three-phase nanocomposites using multiscale reinforcements. The influence of the nano-fillers content, as well as the temperature were studied. Polyamide-6 reinforced with short glass fibre 30 wt.% and with an addition of nanoclay (montmorillonite) and/or nanosilica (SiO2) were tested in order to characterise their tensile properties at room temperature and at 65oC just above the polyamide 6 glass transition temperature. SEM analysis were conduc...
Performance characteristics of three-phase induction motors
Wood, M. E.
1977-01-01
An investigation into the characteristics of three phase, 400 Hz, induction motors of the general type used on aircraft and spacecraft is summarized. Results of laboratory tests are presented and compared with results from a computer program. Representative motors were both tested and simulated under nominal conditions as well as off nominal conditions of temperature, frequency, voltage magnitude, and voltage balance. Good correlation was achieved between simulated and laboratory results. The primary purpose of the program was to verify the simulation accuracy of the computer program, which in turn will be used as an analytical tool to support the shuttle orbiter.
A DSP controlled one-to-three phase matrix converter
Dubovsky, J.; Dobrucly, B; Tabacek, R.; Havrila, R. [Department of Electric Traction and Energetics Faculty of Electrical Engineering, University of Zilina (Slovakia)
1997-12-31
This paper deals with the theoretical analysis computer simulation and experimental results of IM fed by a one-to-three phase matrix converter which offers a unique solution for single phase electric traction applications. The proposed drive in comparison with currently used conventional drives reduces the number of power switching elements of the converter, which increases drives dependability and brings lower investment in power electronics used in drive. Further advantage is that the converter is controlled with nearly unity power factor which cuts down the operational expenses and offers higher overall performance of the drive. (orig.) 6 refs.
A Single Phase to Three Phase PFC Half-Bridge Converter Using BLDC Drive with SPWM Technique.
Srinu Duvvada
2014-07-01
Full Text Available In this paper, a buck half-bridge DC-DC converter is used as a single-stage power factor correction (PFC converter for feeding a voltage source inverter (VSI based permanent magnet brushless DC motor (BLDC drive. The front end of this PFC converter is a diode bridge rectifier (DBR fed from single-phase AC mains. The BLDC is used to drive a compressor load of an air conditioner through a three-phase VSI fed from a controlled DC link voltage. The speed of the compressor is controlled to achieve energy conservation using a concept of the voltage control at DC link proportional to the desired speed of the BLDC. Therefore the VSI is operated only as an electronic commutator of the BLDC. The stator current of the BLDC during step change of reference speed is controlled by a rate limiter for the reference voltage at DC link. The proposed BLDC drive with voltage control based PFC converter is designed, modeled and its performance is simulated in Matlab-Simulink environment for an air conditioner compressor driven through a 1.5 kW, 1500 rpm BLDC motor. The evaluation results of the proposed speed control scheme are presented to demonstrate an improved efficiency of the proposed drive system with PFC feature in wide range of the speed and an input AC voltage.
Tsengenes, Georgios; Adamidis, Georgios [Department of Electrical Engineering and Computer Engineering, Democritus University of Thrace, University Campus Kimmeria, 67100 Xanthi (Greece)
2011-01-15
In this paper, a photovoltaic (PV) system, with maximum power point tracking (MPPT), connected to a three phase grid is presented. The connection of photovoltaic system on the grid takes place in one stage using voltage source inverter (VSI). For a better utilization of the photovoltaic system, the control strategy applied is based on p-q theory. According to this strategy during sunlight the system sends active power to the grid and at the same time compensates the reactive power of the load. In case there is no sunlight (during the night for instance), the inverter only compensates the reactive power of the load. In this paper the use of p-q theory to supply the grid with active power and compensate the reactive power of the load is investigated. The advantage of this control strategy is that the photovoltaic system is operated the whole day. Furthermore, the p-q theory uses simple algebraic calculations without demanding the use of PLL to synchronize the inverter with the grid. (author)
Control Strategy of PWM Rectifiers Connected to Unbalanced Grids
Bejvl, Martin; Švec, J.; Tlustý, J.; Valouch, V.
-, č. 11 (2013). ISSN 2172-038X. [International Conference on Renewable Energies and Power Quality (ICREPQ´13). Bilbao, 20.03.2013-22.03.2013] Institutional support: RVO:61388998 Keywords : electric power system * PWM rectifier * dc voltage ripple Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Spectra of Grid Current Generated by High Power PWM Rectifiers
Šimek, Petr; Škramlík, Jiří; Tlustý, J.; Valouch, Viktor
Ponta Delgada - Azores: APDEE, 2011, s. 1-4. ISBN 978-972-8822-23-1. [Portuguese- Spanish Conference on Electrical Engineering - XII CLEEE /12./. Ponta Delgada - Azores (PT), 30.06.2011-02.07.2011] Institutional research plan: CEZ:AV0Z20570509 Keywords : PWM rectifier * current spectra * FCC inverter Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Stator insulation systems for medium voltage PWM drives fed motors
This paper presents the partial results of a research project that studied the impact of medium voltage PWM ASD (adjustable speed drives) on motor stator insulation system. The findings from this study/ investigation have aided designers to improve the robustness of the insulation system used for ASD-fed motors, based on accelerated laboratory tests. (author)
Compensation on Hall effect sensor of PWM switching control
In this paper, it mainly investigates the relationship between switching frequency and measured currents of Hall effect sensor. How to effectively measure the current waveforms to improve the PWM switching control performance is the main subject of concern. A compensation circuit is designed to enlarge the operational range of Hall effect sensor, and the measurement error can be reduced without additional temperature sensor
Simple PWM modulator topology with excellent dynamic behavior
Poulsen, Søren; Andersen, Michael Andreas E.
This paper proposes a new PWM modulator topology. The modulator is used in switch mode audio power amplifiers, but the topology can be used in a wide range of applications. Due to excellent transient behavior, the modulator is very suited for VRMs or other types of DC-DC or DC-AC applications....
Spread Spectrum Modulation by Using Asymmetric-Carrier Random PWM
Mathe, Laszlo; Lungeanu, Florin; Sera, Dezso; Rasmussen, Peter Omand; Pedersen, John Kim
2012-01-01
This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on simulations and experimental measurements, it is shown that the spread effect of the discrete components from the motor current spectra and acoustic spectra is...
A new Zero-Voltage-Transition PWM switching cell
Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics
1997-12-31
In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.
A new Zero-Current-Transition PWM switching cell
Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics
1997-12-31
In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.
Okedu, Kenneth Eloghene; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji
Recent wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage is recovered. However, fixed speed wind turbine generator system using induction generator (IG) has the stability problem similar to the step-out phenomenon of a synchronous generator. On the other hand, doubly fed induction generator (DFIG) can control its real and reactive powers independently while being operated in variable speed mode. This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs, without incorporating additional FACTS devices. A new current controlled voltage source converter (CC-VSC) scheme is proposed to control the converters of DFIG and the performance is verified by comparing the results with those of voltage controlled voltage source converter (VC-VSC) scheme. Another salient feature of this study is to reduce the number of proportionate integral (PI) controllers used in the rotor side converter without degrading dynamic and transient performances. Moreover, DC-link protection scheme during grid fault can be omitted in the proposed scheme which reduces overall cost of the system. Extensive simulation analyses by using PSCAD/EMTDC are carried out to clarify the effectiveness of the proposed CC-VSC based control scheme of DFIGs.
Han, Yang; Luo, Mingyu; Chen, Changqing;
2016-01-01
The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of the phase-locked loops (PLLs), which is of vital significance for the grid-integration and stable operation of power electronic converters to the electric power systems. However, the open-loop ba...
Three-phase scintigraphy in the Sudeck syndrome
Koppers, B.
1982-11-01
37 patients with clinically and radiologically proved reflex sympathetic dystrophy syndrome were scintigraphied by sup(99)mTc-MDP (three-phase scintigraphy). In 87% of the examinations (all three-phases) an increased tracer accumulation in the region of the affected limb could be seen scintigraphically. The majority of the positive results (92% resp. 87%) were found in the intervall phase (phase II) and the late phase (phase III) of the scintigraphic examinations. - We recommend a staging of the increase of the tracer accumulation when examing the reflex sympathetic dystrophy syndrome. This staging doesn't significantly correlate with the familiar clinical and radiological stagings. However it may be useful when assessing the course of the syndrome. - Increased tracer accumulations could be observed in the case of clinically, radiologically and scintigraphically manifest reflex sympathetic dystrophy syndrome in the region of the foot, frequently in the ipsilateral knee region, rarely in the ipsilateral hip joint region, although clinically the syndrome could not be observed in these regions.
A fuzzy controlled three-phase centrifuge for waste separation
The three-phase centrifuge technology discussed in this paper was developed by Neal Miller, president of Centech, Inc. The three-phase centrifuge is an excellent device for cleaning up oil field and refinery wastes which are typically composed of hydrocarbons, water, and solids. The technology is unique. It turns the waste into salable oil, reusable water, and landfill-able solids. No secondary waste is produced. The problem is that only the inventor can set up and run the equipment well enough to provide an optimal cleanup. Demand for this device has far exceeded a one man operation. There is now a need for several centrifuges to be operated at different locations at the same time. This has produced a demand for an intelligent control system, one that could replace a highly skilled operator, or at least supplement the skills of a less experienced operator. The control problem is ideally suited to fuzzy logic, since the centrifuge is a highly complicated machine operated entirely by the skill and experience of the operator. A fuzzy control system was designed for and used with the centrifuge
Boosted PWM open loop control of hydraulic proportional valves
This paper presents an innovative open loop control technique for direct single stage hydraulic proportional valves whose response rate is significantly higher than that obtained by standard open loop control techniques, even comparable to more costly commercial closed loop systems. Different from standard open loop techniques, which provide the coil with a constant current proportional to the target position, the control strategy proposed in this paper employs the peak and hold (P and H) technique, widely used in Diesel engine modern supply systems, to boost the duty cycle value of the pulse width modulation (PWM) signal for a short time, namely during the spool displacement, while maintaining a lower duty cycle for holding the spool in the required opening position. The developed 'boosted PWM' technique only requires a low cost microcontroller, such as a peripheral interface controller (PIC) equipped with a metal oxide semiconductor (MOS) power driver. The PWM parameters are calibrated as a function of the spool displacement so as to maximize the response rate without introducing overshoots: the collected data are stored in the PIC. Different valve opening procedures with step response have been compared to demonstrate the merits of the proposed boosted PWM technique. No overshoots have been registered. Moreover, the proposed method is characterized by a significantly higher response rate with respect to a standard open loop control, which approximately has the same cost. Similar experimental tests show that the proposed boosted PWM technique has a response rate even higher than that provided by the more costly commercial closed loop system mounted on the valve, and it produces no overshoots
Research on Space Vector PWM Strategy of Matrix Converter%矩阵变换器空间矢量PWM策略的研究
何红颜
2011-01-01
On the basis of analyzing the mathematical model of three-phase to three-phase matrix converter, the equivalent structure of matrix converter is given based on the virtual rectifier and inverter. The space vector PWM arithmetic of matrix converter is proposed based on the conventional space vector PWM. The simulation model of matrix converter is built under MATLAB and simulation results are showed. The results verify that the proposed space vector strategy is right and realizable.%在分析三相-三相矩阵变换器数学模型的基础上,给出了基于虚拟整流器和逆变器的矩阵变换器的等效结构.在此基础上提出了基于常用空间矢量PWM策略的矩阵变换器的空间矢量PWM算法,并在MATLAB仿真环境下建立了矩阵变换器的仿真模型,给出了仿真实验结果.实验结果证实了所提出的空间矢量PWM策略正确性和可实现性.
Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System
Santiago, Walter
2004-01-01
NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.
Phase detector for three-phase power factor controller
Nola, F. J. (Inventor)
1984-01-01
A phase detector for the three phase power factor controller (PFC) is described. The phase detector for each phase includes an operational amplifier which senses the current phase angle for that phase by sensing the voltage across the phase thyristor. Common mode rejection is achieved by providing positive feedback between the input and output of the voltage sensing operational amplifier. this feedback preferably comprises a resistor connected between the output and input of the operational amplifier. The novelty of the invention resides in providing positive feedback such that switching of the operational amplifier is synchronized with switching of the voltage across the thyristor. The invention provides a solution to problems associated with high common mode voltage and enables use of lower cost components than would be required by other approaches.
Three-phase radionuclide bone imaging in sports medicine
Three-phase radionuclide bone (TPB) imaging was performed on 238 patients with sports-related injuries. A wide variety of lesions was encountered, but the most frequent lesions seen were stress fractures of the lower part of the leg at the junction of the middle and distal thirds of the posterior tibial cortex (42 of 79 lesions). There were no differences in the type, location, or distribution of lesions between males and females or between competitive and noncompetitive athletes. In 110 cases, bone stress lesions were often diagnosed when radiographs were normal, whereas subacute or chronic soft-tissue abnormalities had few specific scintigraphic features. TPB imaging provides significant early diagnostic information about bone stress lesions. Normal examination results (53 cases) exclude underlying osseous pathologic conditions
Transient three-phase three-component flow. Pt. 3
A mathematical model of a transient three-dimensional three-phase three-component flow described by three-velocity fields in porous body is presented. A combination of separated mass and energy equations together with mixture momentum equations for the flow is used. The mixture equations are used in diffusion form with the assumption that the diffusion velocity can be calculated from empirical correlations. An analytical coupling between the governing equations is developed for calculation of the pressure field. The system is discretized semiimplicitly in 3D-cylindrical space and different solution methods for the algebraic problem are presented. Finally, numerical examples and comparisons with experimental data demonstrate that the method presented is a powerful tool for numerical multiphase flow simulation. (orig.)
Mucormycosis and bone scintillography of three phases. Case description
The purpose of presenting this work, besides the interest that shows the mucormycosis pathology not so frequent, it is to carry out a clinical correlation photographic with the imagenology, particularly with the bone scintillography. In the Nuclear Medicine Service it is carried out bone scintillography of three phases previous endovenous administration of 30 mCi (1110 MBq) of 99m Tc-MDP. The images are obtained with a gamma camera model Elscint APEX SPX, first each 2 seconds during the first minute, then early image to the 5 minutes and finally the late ones to the 3 hs. The bone scintillography in the phases 2 and 3 detects bigger radioactive density in left hemi side, with increment of the osteoblast activity mainly in the medial border and the floor of the orbit, in the malar bone and a little more tenuous in the superior maxillary. (Author)
Advanced nonlinear control of three phase series active power filter
Abouelmahjoub Y.
2014-01-01
Full Text Available The problem of controlling three-phase series active power filter (TPSAPF is addressed in this paper in presence of the perturbations in the voltages of the electrical supply network. The control objective of the TPSAPF is twofold: (i compensation of all voltage perturbations (voltage harmonics, voltage unbalance and voltage sags, (ii regulation of the DC bus voltage of the inverter. A controller formed by two nonlinear regulators is designed, using the Backstepping technique, to provide the above compensation. The regulation of the DC bus voltage of the inverter is ensured by the use of a diode bridge rectifier which its output is in parallel with the DC bus capacitor. The Analysis of controller performances is illustrated by numerical simulation in Matlab/Simulink environment.
Three Phase High Power Quality Two- Stage Boost Rectifier
P.NAMMALVAR
2012-04-01
Full Text Available Three-phase two-stage boost rectifier with sinusoidal input current are presented and a novel topology with two active power devices is proposed. These contain a capacitor for pumping action in DC circuit. This gives twostage boost operation to obtain higher DC output voltage. The rectifier can be operated in the switch mode forpumping action and for forcing the input current to follow its sinusoidal reference independent of the working conditions. The results of the proposed rectifier are compared with those of the rectifier with a single active power device. The simulation result gives the better output DC voltage regulation under open loop condition. The simulated results prove that the proposed rectifier has the expected performance.
Three-Phase Coexistence in Colloidal Rod-Plate Mixtures.
Woolston, Phillip; van Duijneveldt, Jeroen S
2015-09-01
Aqueous suspensions of clay particles, such as montmorillonite (MMT) platelets and sepiolite (Sep) rods, tend to form gels at concentrations around 1 vol %. For Sep rods, adsorbing sodium polyacrylate to the surface allows for an isotropic-nematic phase separation to be seen instead. Here, MMT is added to such Sep suspensions, resulting in a complex phase behavior. Across a range of clay concentrations, separation into three phases is observed: a lower, nematic phase dominated by Sep rods, a MMT-rich middle layer, which is weakly birefringent and probably a gel, and a dilute top phase. Analysis of phase volumes suggests that the middle layer may contain as much as 6 vol % MMT. PMID:26262770
Optimal anisotropic three-phase conducting composites: Plane problem
Cherkaev, Andrej
2010-01-01
The paper establishes tight lower bound for effective conductivity tensor $K_*$ of two-dimensional three-phase conducting anisotropic composites and defines optimal microstructures. It is assumed that three materials are mixed with fixed volume fractions and that the conductivity of one of the materials is infinite. The bound expands the Hashin-Shtrikman and Translation bounds to multiphase structures, it is derived using the technique of {\\em localized polyconvexity} that is a combination of Translation method and additional inequalities on the fields in the materials; similar technique was used by Nesi (1995) and Cherkaev (2009) for isotropic multiphase composites. This paper expands the bounds to the anisotropic composites. The lower bound of conductivity (G-closure) is a piece-wise analytic function of eigenvalues of $K_*$, that depends only on conductivities of components and their volume fractions. Also, we find optimal microstructures that realize the bounds, developing the technique suggested earlier ...
Three Phase Bone Scintigraphy in Active and Inactive Osteomyelitis
To Appreciate the value of bone scintigraphy in determination of the bony infection, we performed three phase bone scintigraphy in 34 cases of osteomyelitis of extremities prospectively. They were clinically inactive in 11 and active in 23 cases. We confirmed the active osteomyelitis by operation or aspiration within one week after scintigraphy. Perfusion, blood pool and delayed images were analyzed respectively and compared with the plain roentgenograms. All 23 active lesions showed diffusely increased perfusion in affected limbs. The areas of the increased activities on blood pool images were larger than or similar to those on delayed images in 17 cases (73.9%) with active osteomyelitis and smaller in 6 cases (26.1%). 5 of the latter 6 cases showed definite soft tissue activities on blood pool images. In inactive cases bone scintigrams were completely normal in 4 cases. Two of those were normal on plain films and remaining two showed mild focal bony sclerosis. Among 7 inactive lesions, perfusion was normal in 2 cases, diffusely increased in 4 cases and diffusely decreased in 1 case. 6 of these 7 cases showed increased activities both on blood pool and delayed images and the areas of increased activities on blood pool images didn't exceed those on delayed images. Bony sclerosis was noted on plain films in those 7 inactive lesions and the extent of the sclerosis correlated well to delayed images. Large blood pool activity was characteristics of active osteomyelitis. Normal three phase bone scintigram may indicate the time to terminate the treatment, but increased activity on perfusion and blood pool scans is not absolute indication of active lesion if the extent of the lesion on the blood pool image is smaller than that on delayed image and if no definite soft tissue activity is noted on perfusion and blood pool images in clinically inactive patient.
Cellular automata approach to three-phase traffic theory
The cellular automata (CA) approach to traffic modelling is extended to allow for spatially homogeneous steady state solutions that cover a two-dimensional region in the flow-density plane. Hence these models fulfil a basic postulate of a three-phase traffic theory proposed by Kerner. This is achieved by a synchronization distance, within which a vehicle always tries to adjust its speed to that of the vehicle in front. In the CA models presented, the modelling of the free and safe speeds, the slow-to-start rules as well as some contributions to noise are based on the ideas of the Nagel-Schreckenberg-type modelling. It is shown that the proposed CA models can be very transparent and still reproduce the two main types of congested patterns (the general pattern and the synchronized flow pattern) as well as their dependence on the flows near an on-ramp, in qualitative agreement with the recently developed continuum version of the three-phase traffic theory (Kerner B S and Klenov S L 2002 J. Phys. A: Math. Gen. 35 L31 ). These features are qualitatively different from those in previously considered CA traffic models. The probability of the breakdown phenomenon (i.e. of the phase transition from free flow to synchronized flow) as function of the flow rate to the on-ramp and of the flow rate on the road upstream of the on-ramp is investigated. The capacity drops at the on-ramp which occur due to the formation of different congested patterns are calculated
Teodorescu, Remus; Blaabjerg, Frede
2004-01-01
decoupling for three-phase converters can be alleviated. Additionally, selective harmonic compensation is also possible with PR controllers. Suggested control-diagrams for three-phase grid converters and active filters are also presented. A practical application of PR current control for a photovoltaic (PV......This paper is describing the recently introduced proportional-resonant (PR) controllers and their suitability for grid-connected converters current control. It is shown that the known shortcomings associated with PI controllers like steady - state error for single-phase converters and the need of......) inverter is also described....
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
Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2016-01-01
adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps to mitigate phase lag caused by time delays found in a digitally controlled system. The mitigation of......This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent to...... phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus a...
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
This paper investigates the active damping of LCL-filter resonance within single-loop grid current control of grid-connected voltage source converters. First, the basic analysis in the continuous s-domain reveals that the grid-current-feedback active damping forms a virtual impedance across the...... grid-side inductor, and the use of a high-pass filter with a negative sign shapes the virtual impedance by an RL damper paralleled by a negative inductance. It is further found that such a negative virtual inductance plays a critical role in mitigating the phase lag caused by the time delay in a...... digital control system. The instability induced by the negative virtual resistance, which is commonly experienced in the feedback-type active damping, can thus be avoided. A systematic design method of the highpass filter is also proposed by the help of root locus analysis in the discrete z-domain. Lastly...
The testing and optimization of high-voltage source Cockcroft-Walton generator for latex vulcanization has been done. The optimization began with oscillator of Cockcroft-Walton generator, in the initial testing (using isolation of N2 + CO2 gas with pressure of 4 bar to isolate the Cockcroft-Walton circuit) capable of generating voltages up to 167 kV. In the initial testing, the primary coil of high-frequency transformator was damaged and repairment has been done. After the repairment of high-frequency transformator, continued with the testing using isolation of N2 + CO2 gas, the oscillator of Cockcroft-Walton generator and the high-voltage multiplier are work properly capable of generating voltages up to 200 kV. Next activity is to replace one of the diode circuit which is broken because of discharge and replace the high-frequency transformator with the newer design, the new high-frequency transformator using a whole of ferrite core, previously using ferri t core compiled from bars of inhomogeneous ferrite. Next activity is reliability testing of high-voltage source (using SF6 gas) by varying the output frequency of power oscillator which is done by varying the frequency, the maximum frequency of 24 kHz generating voltages 200 kV, beam current 50 µA and outgassing occurred in the vacuum system. After the repairment on the vacuum system, the next activity is the test to produce beam current, and obtained output voltage of 203 kV and beam current of 550 µA. (author)
Dimensional similitude and the hydrodynamics of three- phase fluidized beds
Safoniuk, Michael
It is proposed that scaling of three-phase fluidized bed hydrodynamics can be carried out based on geometric similarity and matching of a set of five dimensionless groups: (i)the M-group, M = g.Δρ.μ L4/(ρL2.σ 3); (ii)an Eötvös number, Eo = g.Δρ.d p2/σ (iii)the liquid Reynolds number, Re L = ρL.dp.UL/μ L; (iv)a density ratio, βd = ρp/ρ L; and (v)a superficial velocity ratio, βu = U g/UL. These were varied in an experimental study where four dimensionless hydrodynamic parameters were measured: (i)gas hold-up, ɛ g; (ii)bed expansion ratio, βbe (iii)the ratio of mean bubble diameter to particle diameter, db/dp ; and (iv)the ratio of mean bubble rise velocity to gas superficial velocity, Ub/Ug. This approach was validated experimentally by matching the dimensionless operating conditions from a kerosene-nitrogen-ceramic three-phase system with those in an aqueous magnesium sulphate solution-air-aluminum particle fluidized bed. There was good agreement between the gas hold-ups and bed expansion ratios in the two systems. A pilot-plant scale cold-flow co-current upwards-flowing three-phase fluidized bed column of inside diameter 292 mm was built and operated using three different liquids (tap water, an aqueous 44 mass % glycerol solution, and an aqueous 60 mass % glycerol solution), air, and cylindrical aluminum particles of diameter 4 mm and length 10 mm. The fluids and solids were carefully selected to result in dimensionless group values in the range of those of an industrial hydroprocessor. Specially built conductivity probes and pressure transducers were used to measure the hydrodynamic properties for different gas and liquid superficial velocities. Special attention was required to provide for drift and calibration when recording and analyzing data from the conductivity probes. Gas hold-ups were in the range of 5 to 20% by volume and were correlated as a function of liquid-phase Reynolds number and superficial velocity ratio. The gas hold-ups were a
Apparent permeability of electrical steel under PWM magnetisation
In recent years much attention has been paid to material performance under pulse width modulation (PWM) excitation conditions, which is of increasing importance to motor applications particularly in energy efficient variable speed drive systems. It is well known that in general, losses increase significantly with reducing modulation index, the increase depending on parameters such as silicon contents, thickness and grain size. The effect of the PWM waveform on permeability has attracted little attention until now. So in this paper its influence on the permeability of electrical steel is analysed and characterised. A prediction approach based on the permeability under sine wave excitation and total harmonic distortion is introduced which results in errors below 10% for non-electrical steel at 1.5 T
CLOSED LOOP SPEED CONTROL OF DC MOTOR USING PWM
Mangesh J Nemade
2015-01-01
In This work reveals the digital closed loop control system for speed control of DC motor using PWM technique. In present days the power semiconductor devices have co mpletely revolutionized the control of drives especially in the area of control usage of thyristors IGBT’s power MOSFET etc., was increased. The digital circuit can be interfaced to microcontroller. So that the speed can be controlled by Microcontroller there by making speed control of DC motor even more easil...
Power electronic converters PWM strategies and current control techniques
Monmasson, Eric
2013-01-01
A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.
Solving the optimal PWM problem for odd symmetry waveforms
Kujan, Petr; Hromčík, Martin; Šebek, Michael
Laxenburg: IFAC, 2008, s. 8672-8677. ISBN 978-3-902661-00-5. [The 17th IFAC World Congress. Seoul (KR), 06.07.2008-11.07.2008] R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10750506 Keywords : Polynomial methods * optimal PWM * selected harmonics elimination * Newton identities * Pade approximation * orthogonal polynomials * composite power sums Subject RIV: BC - Control Systems Theory
Acoustic noise radiated by PWM-controlled induction machine drives
Lo, W.C.; Chan, C.C.; Zhu, Z Q; Xu, L.; Howe, D.; Chau, K. T.
2000-01-01
This paper investigates the acoustic noise radiated from two nominally identical induction motors when fed from sinusoidal, and asymmetric regular sampling subharmonic and space-vector pulsewidth modulation (PWM) converters. The theory for analyzing the noise spectrum is developed further to account for the interaction between the motor and the drive. It is shown that manufacturing tolerances can result in significant differences in the noise level emitted from nominally identical motors, and...
Algorithms of space vector PWM in overmodulation area
Tomas Glasberger; Zdenek Peroutka
2006-01-01
The aim of this paper is the comparison and evaluation of different space vector PWM (SVPWM) strategies enabling the continuous transition from the linear modulation to the six-step mode. One of the important factors to be explored is the frequency analysis of the motor quantities in order to be able to evaluate the possible impact of the drive on the traction mains – specifically the impact on the railway signaling.
Application of digital PWM technology in current transducers
With the development of DSP technology and mature use of PID technology,, a new program for DC or AC signal measurement is proposed. Combined with the DSP chip timer module and PID algorithm, PWM signals are generated to control the feedback circuit for the compensation current. Finally the measured current value can be obtained according to the ampere-turns compensation current and the measured current. Studies have shown that this technology enables new current transducers have high stability. (authors)
Asymmetric Switching For A PWM H-Bridge Power Circuit
Wong, See-Pok
1995-01-01
Only two of four switches interrupt substantial current. An asymmetric timing scheme improves design and operation of pulse-width-modulation (PWM) H-bridge switch-and-transformer circuit. Circuit part of dc-to-dc converter or dc-to-ac inverter; in either case, output current or voltage regulated by adjusting times of opening and closing of semiconductor switches 1 through 4 to adjust durations of current pulses in primary winding of transformer.
Soft Switched Space Vector PWM Control Of Asynchronous Motor
Burak Akin; M. Hadi Sarul
2016-01-01
In this study, the parallel-resonance DC link inverter (PRDCLI) topology is chosen and detailed simulation analysis of that circuit is given. It is observed that all the semiconductors in the circuit turn on and turn off under approximately zero voltage switching (ZVS) or zero current switching (ZCS) and no additional voltage stress occurred on the main switch. The proposed soft switched inverter system has % 95.3 total efficiency with space vector PWM control.
Investigation of PWM-controlled MOSFET with inductive load
Ljunggren, Tobias
2002-01-01
This report is the basis for a Bachelor of Science thesis in engineering done at Volvo Powertrain in Gothenburg. The problem consisted of investigating a circuit with a PWM-controlled MOSFET driving a DC-motor. The problem was to investigate what caused the circuit to break the transistor. Finally an improvement of the circuit is designed making the MOSFET withstand the stressful conditions exposed to. An overall description of the problems with switching an inductive load using a MOSFET as...
Sk Moin Ahmed
2013-07-01
Full Text Available This paper presents pulse width modulation technique for a direct ac-ac converter. The converter has seven-phase input supply and three-phase output. The input supply may be obtained from a seven-phase wind energy generation system with variable output voltage magnitude and frequency. The output of the proposed converter topology may be fed to the three-phase stiff grid system. Thus the requirement of the modulation of the ac-ac converter is to produce fixed voltage and fixed frequency output while the input can be variable. Additionally the output voltage gain should be high. Simple carrier-based PWM technique is suggested and harmonic injection scheme is proposed to enhance the output voltage magnitude. The output voltage reaches 90% of the input supply voltage with the proposed technique. An additional control block is used to stabilize the output voltage and frequency of the converter. Simulation results are shown in the paper for the verification of the proposed scheme.
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.
Dynamics of IGBT based PWM Converter A Case Study
Vijay Shukla
2012-04-01
Full Text Available Optimizing the efficiency and dynamics of power converters is a critical tradeoff in power electronics. The increase of switching frequency can improve the dynamics of power converters, but theefficiency may be degraded as well as the switching losses. As power semiconductor devices like diodes, MOSFETS, IGBTs, Thyristors, BJTs have their own characterstics and dynamic responses. It is desired toanalyze and observe the dynamics of different semiconductor devices before they actually employed in the model. Inclusion of different PWM techniques help in the removal of power line interferences like harmonic losses, unwanted ripples, chopped frequencies, spikes. In this paper, we have studied and analyzed the dynamics of IGBT based PWM converter with subjected to different conditions like transient state, steady state feeding the RLC load. Snubber circuits are used to reduce the switching losses. The IGBT based PWM converter reflects the better dynamics with improved efficiency and reduced harmonics as compared to some other power semiconductor devices when FFT is performed and subjected to standard parameterized RLC load understeady state and transient analysis.
Controlling DC Motor using Microcontroller (PIC16F72) with PWM
Shruti Shrivastava1 , Jageshwar Rawat2 , Amit Agrawal3
2012-01-01
Motion control plays a vital role in industrial atomization. Different types of motors AC, DC, SERVO or stepper are used depending upon the application; of these DC motors are widely used because of easier controlling. Among the different control methods for DC motor armature voltage control method using pulse width modulation (PWM) is best one. We can realize the PWM using H-bridge built with IGBT switches or transistors. To generate PWM signals we use PIC16F7...
Controlling DC Motor using Microcontroller (PIC16F72 with PWM
Shruti Shrivastava, Jageshwar Rawat, Amit Agrawal
2012-12-01
Full Text Available Motion control plays a vital role in industrial atomization. Different types of motors AC, DC, SERVO or stepper are used depending upon the application; of these DC motors are widely used because of easier controlling. Among the different control methods for DC motor armature voltage control method using pulse width modulation (PWM is best one. We can realize the PWM using H-bridge built with IGBT switches or transistors. Togenerate PWM signals we use PIC16F72 microcontroller.
Analysis and Simulation of a High Performance Quasi Resonant PWM Inverter for Solar Power Generation
Yun-Parn Lee; Yu-Huang Lin; Yu-Lun Lin
2016-01-01
A quasi resonant pulse width modulation (PWM) inverter is used in a solar power system to convert the solar panel and battery charger’s direct current (DC) output to alternating current (AC). Although much has been published about DC to AC PWM inverters, none of the previous work has shown modeling and simulation results for DC to AC inverters. In this study, we suggest a new topology for a quasi resonant PWM inverter. Experimental results are also presented.
Design of Space Vector-Based Hybrid PWM Techniques for Reduced Current Ripple
Krishnamurthy, H.; Narayanan, G.; Ayyanar, R; Ranganathan, VT
2003-01-01
Switching sequence used by conventional space vector PWM (CSVPWM) involves equal division of zero vector time between the two zero states in every subcycle. The sequences employed by bus-clamping PWM involve use of only one zero state in a subcycle. This paper deals with two sequences, which use only one zero state and involve division of active vector time within a subcycle. A novel hybrid PWM technique, employing these two sequences in conjunction with the conventional sequence, is proposed...
Huang, Shaojun; Mathe, Laszlo; Teodorescu, Remus
proper switching instances needed for the resampling modulation technique. The software implementation of the proposed phase shifted PWM (PS-PWM) method, and its application in a distributed control system for MMC, are fully discussed in this paper. Simulation and experiment results show that the...... proposed solution can realize the resampled uniform PWM and provide high effective sampling frequency and low time delay, which is critical for the distributed control of MMC....
Space Vector PWM Control of Dual Inverter Fed Open-End Winding Induction Motor Drive
Shivakumar, EG; Gopakumar, K.; Sinha, SK; Pittet, Andrei; Ranganathan, VT
2001-01-01
A space vector PWM technique is developed based on the combination of space vectors from dual inverters feeding the induction motor from both ends (open-end winding without neutral point). A total of 64 voltage space vector combinations are available for PWM voltage control of the inverter fed machine with open-end winding. A space phasor based PWM scheme is proposed with minimum number of switching in a cycle per inverter coupled with equal number of switching for each inverter.
pth Moment Exponential Stability of Stochastic PWM Feedback Systems with Time-Varying Delays
Zhang, Zhong; Ye, Lixia
2012-01-01
This paper further studies the pth moment exponential stability of stochastic pulse-width-modulated (PWM) feedback systems with distributed time-varying delays. We establish several globally exponential stability criteria for such PWM feedback systems by using Lyapunov-Krasovskii functional and then present an upper bound of the parameter of PWM when the system is stable and such system has stronger anti-interference performance than the system without time-varying delays. Furthermore, we pre...
Zhao, Di; Narayanan, G.; Ayyanar, Raja
2004-01-01
This paper analyzes the switching loss characteristics of sequences involving division of active state duration in space vector based PWM. This analysis, together with the THD performance of the different sequences, reported recently, is used to design new hybrid PWM techniques for induction motor drives, which result in simultaneous reduction in both THD as well as inverter switching losses. Experimental results are presented to demonstrate the feasibility and advantages of the proposed PWM ...
$p$ th Moment Exponential Stability of Stochastic PWM Feedback Systems with Time-Varying Delays
Zhong Zhang; Lixia Ye
2012-01-01
This paper further studies the $p$ th moment exponential stability of stochastic pulse-width-modulated (PWM) feedback systems with distributed time-varying delays. We establish several globally exponential stability criteria for such PWM feedback systems by using Lyapunov-Krasovskii functional and then present an upper bound of the parameter of PWM when the system is stable and such system has stronger anti-interference performance than the system without time-varying delays. Furthermore, we ...
Synthesis of Voltages of Multiple Uniform PWM, Generated by Trapezoidal and Sinusoidal Functions
A. Ctryzhniou
2014-09-01
Full Text Available The problem of synthesis and qualitative estimation of the harmonic composition of voltages of multiple uniform PWM pulses generated by trapezoidal and sinusoidal functions is considered. Analytical expressions for PWM pulses parameters ai and ti have been received and they can be used for program-based generation of multiple uniform PWM, determination of n-harmonic magnitude in pulse-width regulation and AC motor operation simulation.
Distortion-Free 1-Bit PWM Coding for Digital Audio Signals
John Mourjopoulos; Andreas Floros
2007-01-01
Although uniformly sampled pulse width modulation (UPWM) represents a very efficient digital audio coding scheme for digital-to-analog conversion and full-digital amplification, it suffers from strong harmonic distortions, as opposed to benign non-harmonic artifacts present in analog PWM (naturally sampled PWM, NPWM). Complete elimination of these distortions usually requires excessive oversampling of the source PCM audio signal, which results to impractical realizations of digital PWM syste...
Prediction of power losses in silicon iron sheets under PWM voltage supply
The behavior of iron losses in silicon iron steels submitted to a PWM voltage is studied. The influence of modulation parameters (the depth of modulation and the number of eliminated harmonics) is clarified. In particular, the idea of an equivalent alternating pulse voltage that gives the same iron losses as the PWM voltage is established. An estimation formula for iron losses under the PWM voltage is developed based on the loss separation model and the voltage form factor. ((orig.))
Deterministic approach to microscopic three-phase traffic theory
Kerner, B S; Kerner, Boris S.; Klenov, Sergey L.
2005-01-01
A deterministic approach to three-phase traffic theory is presented. Two different deterministic microscopic traffic flow models are introduced. In an acceleration time delay model (ATD-model), different time delays in driver acceleration associated with driver behavior in various local driving situations are explicitly incorporated into the model. Vehicle acceleration depends on local traffic situation, i.e., whether a driver is within the free flow, or synchronized flow, or else wide moving jam traffic phase. In a speed adaptation model (SA-model), driver time delays are simulated as a model effect: Rather than driver acceleration, vehicle speed adaptation occurs with different time delays depending on one of the three traffic phases in which the vehicle is in. It is found that the ATD- and SA-models show spatiotemporal congested traffic patterns that are adequate with empirical results. It is shown that in accordance with empirical results in the ATD- and SA-models the onset of congestion in free flow at a...
Three-phase inverter for small high speed motors
McCormick, John A.; Valenzuela, Javier A.
1991-07-01
A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.
Self-biased magnetoelectric response in three-phase laminates
Yang, Su-Chul; Park, Chee-Sung; Cho, Kyung-Hoon; Priya, Shashank
2010-11-01
This study reports the experimental observation and analysis of self-biased magnetoelectric (ME) effect in three-phase laminates. The 2-2 L-T mode laminates were fabricated by attaching nickel (Ni) plates and ME particulate composite plates having 3-0 connectivity with 0.948Na0.5K0.5NbO3-0.052LiSbO3 (NKNLS) matrix and Ni0.8Zn0.2Fe2O4 (NZF) dispersant. The presence of two types of ferromagnetic materials, Ni and NZF, results in built-in magnetic bias due to difference in their magnetic susceptibilities and coercivity. This built-in bias (Hbias) provides finite ME effect at zero applied magnetic dc field. The ME response of bending mode trilayer laminate NKNLS-NZF/Ni/NKNLS-NZF in off-resonance and on-resonance conditions was shown to be mathematical combination of the trilayers with configuration NKNLS-NZF/Ni/NKNLS-NZF and NKNLS/Ni/NKNLS representing contributions from magnetic interaction and bending strain.
Three-phase inverter for small high speed motors
Mccormick, John A.; Valenzuela, Javier A.
1991-01-01
A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.
High-Frequency Link Inverter for Fuel Cells Based on Multiple-Carrier PWM （to continue）
无
2004-01-01
C. Operation of a PWM Cycloconverter The concepts in Section Ⅱ-B, present a progression of solutions to known design difficulties. To incorporate these benefits and eliminate the redundant conversion step shown in Fig. 6, we propose the PWM cycloconverter shown in Fig. 7. It will be shown in Section Ⅲ. that the conventional PWM inverter can be unified through a multiple-carrier PWM framework. The control concept introduced is extended to demonstrate that multiple-carrier PWM methods lead to HF link inverters that are nearly as simple to control as conventional PWM inverters.
Effects of 60Co γ-rays on PWM and LPS induced lymphocytes
The relationship between lymphocytes induced by PWM and LPS was investigated by means of 3H-TdR and 14C-UR incorporation. The study showed that in votro, PWM-induced cells were able to promote the stimulating effect of LPS to B lymphocyte. The stimulating effect of PWM-induced cells was obviously weakened after PWM cells being irradiated with γ-rays. When PWM-induced cells and LPS-induced cells were incubated together, with one kind of cells exposed to 60Co γ-rays, incorporation value of 3H-TdR became much smaller and the synergetic function disappeared, especially, when PWM-induced cells were irradiated. For patients suffering from carcinoma of nasopharynx, when treated with 60Co γ-rays, the incorporation value in LPS-induced cells approached normal level, while the incorporation value in PWM-induced cells reduced significantly and the stimulating effect of PWM-induced cells on LPS-induced cells became much weaker. The fact described above demonstrated that PWM-induced cells have the function of T-helper cells and play a more important role in the synergy than LPS induced cells
PWM-based PPM format for dimming control in visible light communication system
Jang, Hyung-Joon; Choi, Joon-Ho; Ghassemlooy, Zabih; Lee, Chung Ghiu
2012-01-01
We report simulation results of pulse width modulation (PWM)-based pulse position modulation (PPM) signal format for visible light communication systems. For simultaneous operation of data transmission and dimming control, PPM data format is added to PWM dimming control signal. To show dimming control, the PWM duty ratio is changed from 40 % to 80 % during PPM data transmission. The PWM frame rate is set to 1 kHz to avoid flickering in human eyes. The PPM data rate is set to 20 kb/s. The wave...
Dale, Elisabeth Iren; Skauge, Arne
2008-01-01
The effect of including a three-phase representation of the flow parameters and capillary pressure has been investigated using a black oil simulator. The simulation approaches include the complexity of three-phase flow, relative permeability hysteresis, dynamic phase trapping functions and capillary pressure. A WAG simulation case was used to study the effect of three-phase flow parameters and capillary pressure on the size of the three-phase zone, breakthrough time of the inje...
A novel three-phase UPS system with a single-phase resonant HF link
Darwish, MK
2006-01-01
This paper presents a new three-phase uninterruptible power supply (UPS) system based on a single-phase resonant high frequency (HF) link and a single-phase transformer. The three-phase output voltage is constructed and regulated from a three-phase cycloconverter fed from the constant amplitude, constant frequency link voltage. The generation of a novel switching stategy for the three-phase cycloconverter is presented. The simulation of the proposed system is carried out and verified with exp...
三相ZVS逆变器磁链轨迹%Locus of Flux Linkage for Three-Phase ZVS Inverter
陈国呈; 许春雨; 孙承波; 屈克庆; Taniguchi Katsunori
2005-01-01
ZVS(zero voltage switching) PWM(pulse width modulation) inverters have attracted much attention recently. The basic idea is to use ZVS circuit as the main circuit of inverter resonance at the beginning of every carrier period so that each power device can commutate when voltage of the main circuit' s DC bus line is zero. To ensure the resonant circuit to operate properly, sawtooth with alternate slope (positive or negative) is used as carrier. But the time of zero voltage vectors with such PWM pattern is greatly different from traditional hard-switching PWM pattern. This paper discusses the locus of flux linkage under soft-switching PWM pattern by using space voltage vector. It is pointed out that, under the hard-switching PWM pattern, speed of flux linkage is adjusted by zero space voltage vector. When soft-switching PWM pattern is used, however, effective time of space voltage vector varies considerably, sometimes even without zero space voltage vector. Therefore non-zero space voltage vector has been used to make the speed of flux linkage locus equal to that of hard-switching PWM pattern. The cause of current distortion in soft-switching PWM inverters is also discussed. Based on the flux linkage locus circle, corresponding compensation methods are proposed. Experimental results show that the described method can effectively improve output current waveform of inverter.
30 CFR 77.901 - Protection of low- and medium-voltage three-phase circuits.
2010-07-01
... Protection of low- and medium-voltage three-phase circuits. (a) Low- and medium-voltage circuits supplying power to portable or mobile three-phase alternating equipment shall contain: (1) Either a direct or.... (c) Low- and medium-voltage circuits supplying power to three-phase alternating current...
ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS
In this project, an Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column was developed. The approach used an Eulerian analysis of liquid flows in the bubble column, and made use of the Lagrangian trajectory analysis for the bubbles and particle motions. The bubble-bubble and particle-particle collisions are included the model. The model predictions are compared with the experimental data and good agreement was found An experimental setup for studying two-dimensional bubble columns was developed. The multiphase flow conditions in the bubble column were measured using optical image processing and Particle Image Velocimetry techniques (PIV). A simple shear flow device for bubble motion in a constant shear flow field was also developed. The flow conditions in simple shear flow device were studied using PIV method. Concentration and velocity of particles of different sizes near a wall in a duct flow was also measured. The technique of Phase-Doppler anemometry was used in these studies. An Eulerian volume of fluid (VOF) computational model for the flow condition in the two-dimensional bubble column was also developed. The liquid and bubble motions were analyzed and the results were compared with observed flow patterns in the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were also analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures were also studied. The simulation results were compared with the experimental data and discussed A thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion was developed. The balance laws were obtained and the constitutive laws established
Three Phase Upward Flow in a Vertical Pipe
Many specialized technologies need to be developed to deal with the mobilization, retrieval, transport and reliable delivery of large amounts of toxic and radioactive waste to pretreatment facilities. At these facilities the waste is prepared for long term, unsupervised storage. At Hanford as well as other DOE nuclear sites, there are many underground storage tanks that are holding many millions of gallons of toxic and radioactive waste. A class of these storage tanks can utilize pneumatic conveying for the retrieval of scarified solids that are occasionally laced with sticky sludge, followed by slurry transport to pretreatment facilities. The formation of a thin liquid film that travels upwards along the internal wall of a vertical retrieval pipe may prevent those particles that are laced with the sticky sludge from adhering to it and eventually causing instability and blockage. In this paper we develop an approach to the design of a three-phase gas-solid-liquid flow system that could transport scarified solid particles, including sticky particles, pneumatically through a vertical pipe. A liquid film is introduced and maintained along the pipe's inner wall to act as a lubricant that ensure that sticky particles will continue to be transported without permanently adhering to the pipe wall. The system's operating conditions are within the boundaries of the annular dispersed region on a typical flow pattern map of vertical flow of a gas-liquid mixture. High gas superficial velocities combined with low liquid superficial velocities, conditions that satisfy the requirement and geometry of our proposed system, characterize such a region
ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS
Goodarz Ahmadi
2004-10-01
In this project, an Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column was developed. The approach used an Eulerian analysis of liquid flows in the bubble column, and made use of the Lagrangian trajectory analysis for the bubbles and particle motions. The bubble-bubble and particle-particle collisions are included the model. The model predictions are compared with the experimental data and good agreement was found An experimental setup for studying two-dimensional bubble columns was developed. The multiphase flow conditions in the bubble column were measured using optical image processing and Particle Image Velocimetry techniques (PIV). A simple shear flow device for bubble motion in a constant shear flow field was also developed. The flow conditions in simple shear flow device were studied using PIV method. Concentration and velocity of particles of different sizes near a wall in a duct flow was also measured. The technique of Phase-Doppler anemometry was used in these studies. An Eulerian volume of fluid (VOF) computational model for the flow condition in the two-dimensional bubble column was also developed. The liquid and bubble motions were analyzed and the results were compared with observed flow patterns in the experimental setup. Solid-fluid mixture flows in ducts and passages at different angle of orientations were also analyzed. The model predictions were compared with the experimental data and good agreement was found. Gravity chute flows of solid-liquid mixtures were also studied. The simulation results were compared with the experimental data and discussed A thermodynamically consistent model for multiphase slurry flows with and without chemical reaction in a state of turbulent motion was developed. The balance laws were obtained and the constitutive laws established.
Three phases of the Pacific Islands Project (1995-2010).
Watters, David A K; Ewing, Hamish; McCaig, Eddie
2012-05-01
The Pacific Islands Project (PIP), funded by AusAid and managed by the Royal Australasian College of Surgeons (RACS), has progressed through three phases from 1995 to 2010. During this time, it has sent over 520 teams to 11 Pacific Island Countries, providing over 60,000 consultations and some 16,000 procedures. In addition to this delivery of specialist medical and surgical services that were not previously available in-country, the project has contributed as a partner in capacity building with the Fiji School of Medicine and Ministries of Health of the individual nations. By 2011, Fiji School of Medicine, which began postgraduate specialist training in 1998, had awarded 51 doctors a diploma in surgery (1 year), 20 of whom had completed their Masters in Medicine (4 years). PIP was independently evaluated on completion of every phase, including the bridging Phase III (2006-2010). The project delivered on its design, to deliver services, and also helped build capacity. The relationship established with the RACS throughout the project allowed Pacific Island graduates to access the Rowan Nicks scholarship, and the majority of MMed graduates received International Travel Grants to attend the Annual Scientific Meeting. PIP has been a highly successful partnership in delivering and building specialist medical services. Although AusAid contributed some $20 million over 16 years, the value added from pro bono contributions by Specialist Teams, Specialty Coordinators and the Project Directors amounted to an equivalent amount. With the emergence of Pacific Island-trained specialists, PIP is ready to move into a new phase where the agendas are set, monitored and managed within the Pacific, and RACS fulfils the role of a service provider. A critical mass of Pacific Island surgeons has been trained, so that sub-specialization will be an option for the general surgeons of the larger island nations. PMID:22507204
OPTIMAL PWM BASED ON REAL-TIME SOLUTION WITH NEURAL NETWORK%神经网络在逆变器控制中的应用
沈忠亭; 严仰光
2002-01-01
针对传统的基于最优消谐波理论的逆变器,应用了一种全新的神经网络控制器.当系统工作时,由在线神经网络实时调节逆变器输出电压的大小;同时各功率管的开关角由另一个神经网络通过对最优PWM最优开关角的拟合,直接计算出来.整个控制系统具有结构简单、反应灵敏、调压精确、输出电能质量高且全数字化的特点.%A novel concept of neural network based control in pulse-width modulation (PWM) voltage source inverters is presented. On the one hand, the optimal switching angles are obtained in real time by the neural network based controller; on the other hand, the output voltage is adjusted to fit the expected value by neural network when input voltage or loads change. The structure of neural network is simple and easy to be realized by DSP hardware system. No large memory used for the existing optimal PWM schemes is required in the system. Theoretical analysis of the proposed so-called sparse neural network is provided, and the stability of the system is proved. Under the control of neural network the error of output voltage descends sharply, and the system outputs ac voltage with high precision.
Wu Cao
2015-02-01
Full Text Available Compared with the three-phase, two-split-capacitor active power filter (3P2C-APF, the three-phase, four-leg active power filter (3P4L-APF has been widely used in three-phase, four-wire grid utility for power quality control due to its numerous advantages, such as higher current output capability, particularly in phase N, lower current and easier voltage control on the DC-side. However, designing the grid-connecting interface, which is between the voltage source converter (VSC and grid utility, is rather difficult due to the higher requirement for current ripple filtering in phase N, cross-coupling in four phases and lack of relevant design methodology and specification. In this paper, a four-branch LCL-type (4B-LCL grid-connecting interface is proposed for 3P4L-APF, which features better current ripple filtering performance without decreasing the current output capability in all phases. First, this paper describes the mathematical models of 4B-LCL in the fully-complex-vector form from the zero and non-zero sequence perspective, resulting in two independent and uniform equivalent circuits without cross coupling terms. Then, the 4B-LCL parameter design method based on the most comprehensive performance index is proposed, including three main stages as the specification: performance index requirement determination, fulfillment of that requirement, and verification. Finally, the validity and effectiveness of the proposed design are proven by the simulated and experimental results of a 3P4L-APF with 4B-LCL.
Datta, Aniket; Narayanan, G.
2016-05-01
Insulated gate bipolar transistor (IGBT) based voltage source converters use copper plates with insulating sheets in between them (sandwich bus-bar arrangement) for connecting the different device terminals in the power circuit. In such converters, the parasitic inductances in the power circuit are crucial as they cause overvoltage spikes across the device. Also, the parasitics affect the current sharing between IGBTs when they are connected in parallel in high power converters. The conduction path through plates and fasteners in the bus-bar assembly is three-dimensional and quite complex, making analytical evaluation of the stray inductance quite challenging. The first objective here is to present a simple experimental setup and experimental procedure, which are convenient for power electronic engineers, to measure the bus-bar inductance. The next objective is to carry out experimental studies on the inductances offered by different components and sub-assemblies in a bus-bar assembly. This includes evaluation of inductances of the different conduction paths in typical bus-bar plates. The third objective is to experimentally evaluate the parasitic inductances in the bus-bar assembly of a commercial 250 kVA high power converter. Each leg of this converter consists of two 300 A/1200 V IGBTs connected in parallel. The effective inductance seen by the individual device modules are determined experimentally.
Suul, Jon Are
2012-03-15
Three-Phase Voltage Source Converters (VSCs) are finding widespread applications in grid integrated power conversion systems. The control systems of such VSCs are in an increasing number of these applications required to operate during voltage disturbances and unbalanced conditions. Control systems designed for grid side voltagesensor-less operation are at the same time becoming attractive due to the continuous drive for cost reduction and increased reliability of VSCs, but are not commonly applied for operation during unbalanced conditions. Methods for voltage-sensor-less grid synchronization and control of VSCs under unbalanced grid voltage conditions will therefore be the main focus of this Thesis. Estimation methods based on the concept of Virtual Flux, considering the integral of the converter voltage in analogy to the flux of an electric machine, are among the simplest and most well known techniques for achieving voltage-sensor-less grid synchronization. Most of the established techniques for Virtual Flux estimation are, however, either sensitive to grid frequency variations or they are not easily adaptable for operation under unbalanced grid voltage conditions. This Thesis addresses both these issues by proposing a simple approach for Virtual Flux estimation by utilizing a frequency-adaptive filter based on a Second Order Generalized Integrator (SOGI). The proposed approach can be used to achieve on-line frequency-adaptive varieties of conventional strategies for Virtual Flux estimation. The main advantage is, however, that the SOGI-based Virtual Flux estimation can be arranged in a structure that achieves inherent symmetrical component sequence separation under unbalanced conditions. The proposed method for Virtual Flux estimation can be used as a general basis for voltage-sensor-less grid synchronization and control during unbalanced conditions. In this Thesis, the estimated Virtual Flux signals are used to develop a flexible strategy for control of active
Novel Resonant Pole Voltage Source Inverter for Brushless DC Motor%新型无刷直流电动机专用谐振极逆变器研究
贺虎成; 杜京义; 刘卫国
2009-01-01
无刷直流电动机通常采用硬开关逆变器驱动.硬开关逆变器的系统效率较低,散热器的体积和重量较大,限制了无刷直流电动机驱动系统功率密度和性能的进一步提升.针对硬开关逆变器问题,提出了一种无刷直流电动机驱动系统专用的谐振极软开关电压源逆变器.通过在传统硬开关逆变器三个输出端和直流母线之间添加辅助谐振单元,实现了逆变桥主开关器件的PWM软开关动作.谐振控制开关零电流开关条件开通,零电压开关条件关断.对提出的新型谐振极逆变器进行了数学分析和仿真研究;仿真结果验证了电路结构和理论分析的正确性与可行性.%The brushless DC motor (BLDCM) has high torque, compact size, and high efficiency.Therefore, BLDCM is widely used in computers, household and industrial products, and automobiles.It is usually driven by a hard-switching PWM inverter, which has low switching frequency, high switc-hing loss, high EMI and acoustic noise, etc. To improve performance in brushless DC motor system,proposed a novel resonant pole voltage-source-inverter (VSI) for BLDCM. Realized soft switching oper-ation of switch devices in inverter by adding auxiliary remnant unit from three output ends to DC link.Auxiliary resonant switch was turned on under zero current switching (ZCS) and turned off under zero voltage switching (ZVS). Mathematic analysis and simulation were performed for novel inverter, and the simulation results were consistent with the theoretical analysis.
Development of a PWM precision spraying controller for unmanned aerial vehicles
This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidan...
Synchronized PWM Scheme for Dual Inverter-Fed Drives with Zero Common-Mode Voltages
Oleschuk, Valentin; Blaabjerg, Frede; Chen, Zhe; Stankovic, Alexander M.
2005-01-01
Abstract - Novel method of direct synchronized pulsewidth modulation is applied for control of a dual inverter-fed opened winding induction motor drive with zero common-mode voltages. New strategy and algorithms of synchronized PWM provide symmetry of the phase voltage of the system during the...... the proposed synchronized PWM scheme....
Effect of 60Co γ-rays on PWM and LPS induced lymphocytes
The relationship between lymphocytes induced by PWM (pokeweed mitogen) and LPS (lipopolysaccharide) was investigated by means of 3H-TdR incorporation. The study showed that, in vitro, PWM-induced cells were able to promote the stimulating effect of LPS to B lymphocytes. The stimulating effect of PWM-induced cells was obviously weakened after PWM cells being irradiated with γ-rays. When PWM-induced cells and LPS-induced cells were incubated together, with one kind of cells exposed to 60Co γ-ray, incorporation value of 3H-TdR became much smaller and the synergetic function disappeared, especially, when PWM-induced cells were irradiated. For patients suffering from carcinoma of nasopharynx, while treated with 60Co γ-rays, the incorporation value in LPS-induced cells approached normal level, meanwhile, the incorporation value in PEM-induced cells reduced significantly and the stimulating effect of PWM-induced cells on LPS-induced cells became much weaker. The facts described above demonstrated that PWM-induced cells have the function of T-helper cells and play more important role in the synergy than LPS-induced cells
Influence of PWM Modes on Commutation Torque Ripples in Sensorless Brushless DC Motor Control System
ZHANGXiang－jun; CHENBo－shi; 等
2001-01-01
This paper introduces four PWM modes used in the sensorless brushless DC motor control system,analyzes their different influences on the commutation torque ripple in detail,and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC( BLDC) motors,Simulation and experimental results show that the selection is correct and practical.
Md. Aziz Ul Huq; Md Abul. Bashar; Farruk Ahmed
2013-01-01
The speed of a three-phase induction motor can be varied within a wide range other than its rated value if its input parameters (frequency, voltages) are varied properly. For industrial, mainly in knitting and some other sophisticated use of three-phase induction motor, precise and accurate control of the speed of the motor is necessary. The present three-phase inverter is so designed that its input parameters can be easily varied through proper software program and computer inter...
High flexibility and low cost digital implementation for modern PWM strategies
Mathe, Laszlo; Sera, Dezso; Kerekes, Tamas; Crisafulli, Vittorio
2011-01-01
In this paper a new low cost technique for PWM strategy implementation is presented. The proposed technique does not require dedicated hardware PWM units, thus offering higher flexibility of use. Furthermore, the aforementioned method eases the digital implementation of modern modulation methods...... like AZSPWM, NSPWM, or ACRPWM. By using a conventional PWM unit from a microcontroller, these modern modulation techniques are often difficult, or even impossible, to implement. The proposed method can be used to implement PWM strategies even for those microcontrollers which are not equipped with...... hardware PWM unit. The experimental results show that this new technique is suitable to replace traditional implementation methods with minimum computational overhead, with the benefit of high flexibility, lower cost and faster code development....
Instantaneous Power Compensation in Three-Phase Systems by Using p-q-r Theory
Kim, Hyosung; Blaabjerg, Frede; Bak-Jensen, Birgitte;
2002-01-01
Three linearly independent instantaneous powers have been defined in the time domain in three-phase four-wire systems with the use of p-q-r theory. Any three-phase circuit can be transformed into three single-phase circuits by the p-q-r transformation Thus the instantaneous powers in any three......-phase systems can be analysed as the same way of instantaneous power in single-phase systems.This paper analyses the instantaneous powers spectrally in the frequency domain for single-phase systems and three-phase systems. Each instantaneous power in three-phase systems has its own spectral pattern that is...... characterized by the spectral distribution of the system voltages and currents. The instantaneous power in single-phase systems has its own spectral pattern different from that of three-phase systems.From the spectral analysis of the instantaneous powers, powers are newly defined in the frequency domain. The...
PWM ZCS DC Motor Drive and DC Power Supply
Bardia Montazeri
2011-01-01
Full Text Available Following the extension and increase in capacity of power electronic elements, many convertors with special applications have been designed. Convertors such as rectifiers, AC and DC power supplies, AC and DC drivers and so on. At present, optimization of these convertors, decreasing loss and bringing down the electromagnetic interference are desired. In this paper, a DC to DC convertor for controlling the speed of DC motor is designed and one prototype is presented in which switching losses is close to zero and it has a very low electromagnetic interference. In this convertor, the switches turn on and turn off approximately with zero current. The speed of motor is controlled by PWM. This plan includes advantages of PWM and resonant convertors.The disadvantages, such as ; high switching losses and changing switching frequency for controlling output were removed. As switching frequency has a direct relation with switching losses, when losses decreased, it is possible to increase the frequency, then volume and weight of passive filter elements can be decreased. Besides, by decreasing the losses , the need of heatsink , which is the heavy and voluminous elements of convertors, can be removed.
An Improved Switching Period Optimization Space Vector PWM Strategy
Guoqiang Chen
2014-01-01
Full Text Available In order to improve the performance of space vector PWM (pulse width modulation, the optimization is widely used. The switching period optimization space vector PWM can reduce both total harmonic distortion and spectrum peaks, so it has important application prospects and has been widely discussed among several types of optimization strategies. Aiming at the characteristic of uncontrollable switching frequency, the study proposes an improved optimization method that can be used in both steady and non-steady states. The method uses a time window with adaptive width to control the average switching period and divides the value range of reference voltage vectors into two kinds of regions: R and Q based on period coefficients. Switching periods are dependent in the same time window, while independent in different windows. The total extra time between specified periods and optimal periods in region R can be made full use of in region Q. A simulation platform was built in software MATLAB/Simulink. The simulation result verifies excellent performance on harmonic distortion and amplitude peak reduction. The improved strategy has widespread applications in electric vehicles, industry automation and drives, household appliances and so on.
Research on a New Control Strategy of Three Phase Inverter for Unbalanced Loads
Liu, Chunxi; Weiming Ma; Hu, Wenhua
2010-01-01
One of the very important functions of three-phase inverter is to maintain the symmetric three-phase output voltage when the three-phase loads are unbalanced. Although the traditional symmetrical component decomposing and superimpose theory can keep the voltage balance through compensating the positive-, negative- and zero-sequence components of the output voltage of inverter, however, this method is time-consuming and not suitable for control. Aiming at high power medium frequency inverter s...
Generalisation of Helmholtz-Thevenin theorem to three-phase electrical circuits
Gheorghe MIHAI
2009-01-01
The scope of this paper is to determine the generalized form for equivalent tension generator theorem (Helmholtz-Thevenin theorem) for three-phase electrical circuit. Any complicated electrical power systems we can reduce depending on any three-phase electrical consumer to a three-phase electrical generator that has certain internal impedance. Starting with this assumption, we have demonstrated the way to obtain the electromotive voltages for an equivalent generator and its internal impedances.
Overview of three-phase inverter topologies for distributed generation purposes
Meersman, Bart; Renders, Bert; Degroote, Lieven; Vandoorn, Tine; Kooning, Jeroen De; Vandevelde, Lieven
2010-01-01
The increasing presence of single-phase distributed generators and unbalanced loads in the electric power system may lead to unbalance of the three phase voltages, resulting in increased losses and heating. Distribution network operators are seeking to install larger DG units (viz. $>5$kVA in Belgium) by means of three-phase connections instead of single-phase to reduce voltage unbalance. There are several possible topologies to connect the DG units to the three-phase distribution network. Th...
Control of a Three Phase Induction Motor using Single Phase Supply
G. R. Sreehitha, A. Krishna Teja, Kondenti. P. Prasad Rao
2012-01-01
In Industrial applications, two forms of electrical energy are used: Direct Current (DC) and Alternating Current (AC). Usually constant voltage, constant frequency Single-Phase or Three-Phase AC is readily available. However, for different applications different forms, magnitudes and/or frequencies are required. This paper proposes how the Three-Phase inductive load is run by a Single-Phase supply by using Cycloconverter and a Scott-T connected Transformer. The controlling of a ThreePhase Ind...
Vector Control of Three-Phase Induction Motor with Two Stator Phases Open-Circuit
Seyed Hesam Asgari; Mohammad Jannati; Tole Sutikno; Nik Rumzi Nik Idris
2015-01-01
Variable frequency drives are used to provide reliable dynamic systems and significant reduction in usage of energy and costs of the induction motors. Modeling and control of faulty or an unbalanced three-phase induction motor is obviously different from healthy three-phase induction motor. Using conventional vector control techniques such as Field-Oriented Control (FOC) for faulty three-phase induction motor, results in a significant torque and speed oscillation. This research presented a no...
Efficiency analysis on a two-level three-phase quasi-soft-switching inverter
Geng, Pan; Wu, Weimin; Huang, Min; Blaabjerg, Frede
non-conventional inverters with special shoot-through state is introduced and illustrated through the analysis on a special two-level three-phase quasi-soft-switching inverter. Efficiency comparison between the classical two-stage two-level three-phase inverter and the two-level three-phase quasi......-soft-switching inverter is carried out. A 10 kW/380 V prototype is constructed to verify the analysis. The experimental results show that the efficiency of the new inverter is higher than that of the traditional two-stage two- level three-phase inverter....
Implementation and Analytical Model of Three-Phase Four-Switch Power Factor Corrector
Klíma, J.; Škramlík, Jiří; Valouch, Viktor
Sevilla: EA4EPQ, 2007, s. 1-4. ISBN 978-84-611-4707-6. [International Conference on Renewable Energies and Power Quality - ICREPQ 07. Sevilla (ES), 28.03.2007-30.03.2007] R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : SV PWM * four-switch converter * AD-DC power converters Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Three-Phase Four-Switch PFC and Its Analytical Model
Klíma, J.; Škramlík, Jiří; Valouch, Viktor
Setúbal : Escola Superior de Tecnologia - IEEE, 2007, s. 66-71. ISBN 1-4244-0895-4. [International Conference on Power Engineering, Energy and Electrical Drives. Setúbal (PT), 12.04.2007-14.04.2007] R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch converter * space-vector PWM * closed-form solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Control Strategies for Trap Filter Interfaced Three-Phase Grid Connected Converters
Min, Huang
spectrum analysis. A basic parameters design for high order filters is proposed and also the stability issued of LLCL filter-based grid-connected inverter with grid current control is analyzed. Chapter 3 investigates the impedance-based active damping methods investigation for voltage source converter with...... damping in order to stabilize the whole system with resonance issue. LC trap filter application for current source converters to reduce the size of the filter and get a higher power factor....
Analysis of Dc/Dc converters with PWM and sliding mode controls
Static and dynamic performances of D C/D C converters with PWM and sliding mode controllers are investigated. To improve the performance of the PWM controller, a linear compensator is proposed and used. For sliding controller, important parameters such as sliding coefficients and filter time constant are carefully computed and used. Finally, a D C/D C buck converter with PWM and sliding controller is designed, modeled and constructed. Theoretical and experimental results are compared and the distinguished features and limitations of each control technique are presented
Soft-switching PWM full-bridge converters topologies, control, and design
Ruan, Xinbo
2014-01-01
Soft-switching PWM full-bridge converters have been widely used in medium-to-high power dc-dc conversions for topological simplicity, easy control and high efficiency. Early works on soft-switching PWM full-bridge converter by many researchers included various topologies and modulation strategies. However, these works were scattered, and the relationship among these topologies and modulation strategies had not been revealed. This book intends to describe systematically the soft-switching techniques for pulse-width modulation (PWM) full-bridge converters, including the topologies, control and
Three-Phase and Six-Phase AC at the Lab Bench
Caplan, George M.
2009-01-01
Utility companies generate three-phase electric power, which consists of three sinusoidal voltages with phase angles of 0 degrees, 120 degrees, and 240 degrees. The ac generators described in most introductory textbooks are single-phase generators, so physics students are not likely to learn about three-phase power. I have developed a simple way…
Three-Phase Modulated Pole Machine Topologies Utilizing Mutual Flux Paths
Washington, Jamie G.; Atkinson, Glynn J.; Baker, Nick J.; Jack, Alan G.; Mecrow, Barrie C.; Jensen, Bogi Bech; Pennander, Lars-Olov; Nord, Göran L.; Sjöberg, Lars
2012-01-01
This paper discusses three-phase topologies for modulated pole machines (MPMs). The authors introduce a new threephase topology, which takes advantage of mutual flux paths; this is analyzed using 3-D finite-element methods and compared to a three-phase topology using three single-phase units stac...
A modified two-level three-phase quasi-soft-switching inverter
Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede;
2014-01-01
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 in...
Robustness of Three-Phase Contactless Power Transfer System for Horizontal Displacement
Matsumoto, Hirokazu; Neba, Yasuhiko; Ishizaka, Kouichi; Itoh, Ryozo
This paper presents a model of a three-phase contactless power transfer system with short gap between the primary and secondary armatures. The model of the system is derived from typical equivalent circuit equations of a three-phase induction motor. On the basis of this model, robustness of the system for the horizontal displacement between the primary and secondary armatures is proved.
A new PWM based control method for forced commutated cycloconverters
Highlights: ► A new control method is proposed for three-phase to single-phase cycloconverters from balanced and unbalanced input voltages. ► The proposed method has no limitation on frequency conversion and is independent of the load. ► In proposed method, the low order harmonics are not generated in the input and output quantities. ► The proposed method can be easily extended to three-phase to n-phase cycloconverters. ► We demonstrate real experimental results of the power converter. - Abstract: In this paper, a new control method is proposed for three-phase to single-phase cycloconverters for synthesizing the desired output voltage from balanced and unbalanced input voltages. The theoretical analysis of the proposed control method is given for both of the conventional topologies of three-phase to single-phase cycloconverters. Using the proposed control method, the maximum output/input voltage transfer ratios are 0.5 and 1.5 for conventional cycloconverters that consist of three and six bidirectional switches, respectively. The proposed control method has no limitation on frequency conversion and is independent of the load. In other words, using the proposed control method, the three-phase to single-phase cycloconverter can operate as a generalized transformer. Using the proposed control method, the low order harmonics are not generated in the input and output quantities. As a result, the size of the required filters is decreased. The proposed control method can be easily extended to three-phase to n-phase cycloconverters based on the same principle of the operation. The simulation and experimental results verify the operation and performance of the proposed control method.
A PWM transistor inverter for an ac electric vehicle drive
Slicker, J. M.
1981-01-01
A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.
Single Phase Bidirectional PWM Converter for Microgrid System
C.Kalavalli
2013-06-01
Full Text Available Smart grid is a newly flourishing research area because of its viable applications and expected to address the drawback of existing grid. Microgrids are the part of the Smart grid and they are designed to supply electricity for a small community such as residential areas, universities or industrial sites. Power electronics plays a vital role for connecting the renewable energy sources to Microgrid system. This paper deals the Microgrid connected single phase Bidirectional PWM converter which operates in Rectification and Inverting mode. This converter helps to connect renewable energy sources to loads as well as excess power are given to power grid. Double Loop PID control technique is used for controlling the converter for both modes. The designed Converter is simulated in MATLAB/Simulink software and results are verified using the Hardware.
M Vijayakumar; S Vijayan
2014-08-01
This paper proposes a Photovoltaic (PV)-based three-phase four-wire Series Hybrid Active Power Filter (SHAPF), it comprises of a Series Active Power Filter (SAPF) and an LC shunt passive filter. The proposed system eliminates both the current and voltage harmonics and compensates reactive power, neutral current and voltage interruption. A SAPF demands a source of energy for compensating the voltage sag/swell. This system found a new topology for SHAPF which utilizes the PV with DC–DC boost converter as a source of DC power for the series active filter. The compensation current reference evaluation is based on the twin formulation of the vectorial theory of electrical power theorem with Fuzzy Logic Controller (FLC). The PV array/battery managed DC–DC boost converter is employed to step up the voltage to meet the DC bus voltage requirement of the three-leg Voltage Source Inverter (VSI). The foremost benefit of the proposed system is that, it will provide uninterrupted compensation for the whole day. This system utilizes the renewable energy; accordingly saves the energy and provides the uninterruptable power supply to critical/sensitive load, through the PV array/battery bank during both day time and night time. An experimental model was established and results were obtained, which indicated the capability of the proposed control scheme.
Stator insulation systems for medium voltage PWM drives fed motors
Gao, G.; Chen, W. [TECO-Westinghouse Motor Co., Round Rock, TX (United States)
2005-07-01
Adjustable speed drives (ASD) are commonly used in power electronics and control systems. It is estimated that more than 15 per cent of medium voltage motors are currently fed by such drives worldwide. A research project was conducted to examine the influence of medium voltage pulse width modulated (PWM) ASD on motor stator insulation systems. The findings, based on accelerated laboratory tests, have helped designers to improve the capabilities of the insulation system used for ASD-fed motors. Repetitive, high magnitude voltage spikes with fast rise time create significant stress on insulation systems. Gradual deterioration and premature failure of the motor insulation can result from surge voltages which generate surface discharges between phase windings/end windings, or partial discharges between stator turns. However, there is no industrial standard to evaluate motor insulation life under ASD-cable-motor conditions. Several material manufacturers have developed their own version of corona resistant material. However, the insulation life of ASD-fed motors does not depend solely on the raw materials. Rather, it depends on the complete insulation system, including the stator manufacturing process. In order to address this problem, TECO-Westinghouse Motor Company has developed special design criteria and manufacturing practices in order to reduce winding insulation temperature and to compensate for the additional heat generated by high frequency contents in the PWM voltage waveform. A patent pending new cooling system should reduce winding temperature by 15 to 20 degrees C. This paper presented design considerations for turn insulation, groundwall insulation, and a voltage stress grading system. A new thermal class H insulation system was also described. 6 refs., 2 tabs., 5 figs.
PWM Switching Frequency Effects on Eddy Current Sensors for Magnetically Suspended Flywheel Systems
Jansen, Ralph; Lebron, Ramon; Dever, Timothy P.; Birchenough, Arthur G.
2003-01-01
A flywheel magnetic bearing (MB) pulse width modulated power amplifier (PWM) configuration is selected to minimize noise generated by the PWMs in the flywheel position sensor system. Two types of noise are addressed: beat frequency noise caused by variations in PWM switching frequencies, and demodulation noise caused by demodulation of high order harmonics of the switching voltage into the MB control band. Beat frequency noise is eliminated by synchronizing the PWM switch frequencies, and demodulation noise is minimized by selection of a switching frequency which does not have harmonics at the carrier frequency of the sensor. The recommended MB PWM system has five synchronized PWMs switching at a non-integer harmonic of the sensor carrier.
Experiment Research on Fine Regulation of Wheel Cylinder Pressure Using PWM Technology
SI Hai; LIU Zhao-du; CUI Hai-feng; WANG Bin
2008-01-01
A test bench of ABS/ASR integrated hydraulic system is developed by using pulse-width modulation (PWM) technology. The effective duty ratio range of ABS outlet valve has been tested in PWM control. With 50Hz carrier wave frequency, the tests are performed to determine the correspondence between duty ratio and the wheel cylinder pressure variation. The duty ratio range of ABS outlet valve in PWM control is determined and an experimental model of pressure reduction velocity (PRV) of wheel cylinder using PWM control is established. By comparison and test of the experimental model and realization of controlling the duty ratio of ABS outlet valves, the fine regulation of wheel cylinder PRV is realized in the working of ABS/ASR braking regulation, which is important and valuable to the improvement of the ABS/ASR controlling effect.
A digital input class-D audio amplifier with sixth-order PWM
A digital input class-D audio amplifier with a sixth-order pulse-width modulation (PWM) modulator is presented. This modulator moves the PWM generator into the closed sigma—delta modulator loop. The noise and distortions generated at the PWM generator module are suppressed by the high gain of the forward loop of the sigma—delta modulator. Therefore, at the output of the modulator, a very clean PWM signal is acquired for driving the power stage of the class-D amplifier. A sixth-order modulator is designed to balance the performance and the system clock speed. Fabricated in standard 0.18 μm CMOS technology, this class-D amplifier achieves 110 dB dynamic range, 100 dB signal-to-noise rate, and 0.0056% total harmonic distortion plus noise. (semiconductor integrated circuits)
A Time-Delay Suppression Technique for Digital PWM Control Circuit
Ishizuka, Yoichi
2010-01-01
This paper describes a digital PWM controller IC without A/D converters. The analog timing converter (ATC) is proposed for output voltage sensing. In this system, analog circuit are realized with an comparator and an D/A converter.
Stator Interturn Fault Detection in Permanent-Magnet Machines Using PWM Ripple Current Measurement
Sen, B.; Wang, J.
2016-01-01
This paper proposes a novel method of interturn fault detection based on measurement of pulsewidth modulation (PWM) ripple current. The method uses the ripple current generated by the switching inverter as a means to detect interturn fault. High-frequency (HF) impedance behavior of healthy and faulted windings is analyzed and modeled, and ripple current signature due to interturn faults is quantified. A simple analog circuit is designed to extract the PWM ripple current via a bandpass (BP) fi...
Electrical Discharge Machining Flyback Converter using UC3842 Current Mode PWM Controller
Nazriah Mahmud
2014-10-01
Full Text Available This paper presents a current mode Pulse Width Modulation (PWM controlled Flyback converter using UC3842 for Electrical Discharge Machining current generator control circuit. Circuit simplicity and high efficiency can be achieved by a Flyback converter with current mode PWM controller. The behaviors of the system's operation is analyzed and discussed by varying the load resistance. Matlab sofware is used to simulate the Flyback converter where a prototype has been built and tested to verify it's performance.
A COMPUTER-AIDED UNIFIED APPROACH TO MODELING PWM AND RESONANT CONVERTERS
无
2005-01-01
This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/(parallel) resonant switching converters based on pulse-waveform integral approach. As an example, PWM and quasi-resonant converters are used to discuss the principle of the approach. The results are compared with those in the relative literatures. Computer aided analysis are made to confirm the correctness.
Method for Calculating Performance of Three-Phase Line-Start Permanent-Magnet Synchronous Motor
Takegami, Tsuneo; Tsuboi, Kazuo; Hirotsuka, Isao; Nakamura, Masanori
A three-phase line-start permanent-magnet synchronous motor (three-phase LSPMM) is expected to operate with ultrahigh efficiency because it can start as an induction motor and can then operate as a permanent-magnet synchronous motor. In a previous study, we developed a practical analytical theory for a three-phase LSPMM on the basis of a tensor analysis. Then, we developed (1) a method for calculating the asynchronous starting characteristics and synchronous operating characteristics of the three-phase LSPMM on the basis of the developed analytical theory and (2) a method for determining the constants of the three-phase LSPMM. Herein, we report the results of a comparison between the calculated and measured asynchronous starting characteristics and synchronous operating characteristics of a test three-phase LSPMM. The comparison results show that the developed calculation method is highly efficient and that the results obtained by using it are sufficiently precise, and therefore, the method is suitable for practical use. Furthermore, we propose a method for improving the starting performance of the three-phase LSPMM, on the basis of simulations performed using the calculation method.
Mathematical Modeling and Fault Tolerance Control for a Three-Phase Soft-Switching Mode Rectifier
Kuei-Hsiang Chao; Chin-Tsang Hsieh
2013-01-01
This study primarily focuses on the design of an intelligent three-phase soft-switching mode rectifier (SSMR). Firstly, the small-signal dynamic model of a single-phase SSMR is derived together with the design of its controller. Then, the developed single-phase SSMR is connected to form an intelligent three-phase SSMR. When any of the phase modules in the proposed intelligent three-phase SSMR experiences a fault, it can continue to supply power automatically under reduced load capacity while ...
Design of materials with extreme thermal expansion using a three-phase topology optimization method
Sigmund, Ole; Torquato, S.
1997-01-01
Composites with extremal or unusual thermal expansion coefficients are designed using a three-phase topology optimization method. The composites are made of two different material phases and a void phase. The topology optimization method consists in finding the distribution of material phases that......-called Vigdergauz microstructures that realize the bounds. For three phases, the optimal microstructures are also compared with new rigorous bounds and again it is shown that the method yields designed materials with thermoelastic properties that are close to the bounds. The three-phase design method is illustrated...
GENERALIZED (COMPOSITE) SPACE VECTOR FOR A FLAT THREE-PHASE LINEARLY INDEPENDENT SYSTEM OF SIGNALS
Fedorenko, A.; Lazovskiy, Ed
2011-01-01
In the article the authors specify concept of composite vector for flat three-phase system of signals and give relators connecting instantaneous data of phase signals to coordinates of generalized vector in 3-D rectangular and cylindrical coordinate system.
A reverse mode of three-phase asynchronous motors with hexaphase windings
V.D. Lushchyk; S.Yu. Polezin
2014-01-01
A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.
Vector Control of Three-Phase Induction Motor with Two Stator Phases Open-Circuit
Seyed Hesam Asgari
2015-06-01
Full Text Available Variable frequency drives are used to provide reliable dynamic systems and significant reduction in usage of energy and costs of the induction motors. Modeling and control of faulty or an unbalanced three-phase induction motor is obviously different from healthy three-phase induction motor. Using conventional vector control techniques such as Field-Oriented Control (FOC for faulty three-phase induction motor, results in a significant torque and speed oscillation. This research presented a novel method for vector control of three-phase induction motor under fault condition (two-phase open circuit fault. The proposed method for vector control of faulty machine is based on rotor FOC method. A comparison between conventional and modified controller shows that the modified controller has been significantly reduced the torque and speed oscillations.
ELECTROMAGNETIC CALCULATION OF THREE-PHASE ASYNCHRONOUS MOTORS WITH A SIX-PHASE WINDING
S.Yu. Polezіn; Kiryanov, V. V.; V.D. Lushchyk
2013-01-01
Features of electromagnetic computation of three-phase asynchronous motors with a six-phase winding in the stator are described. Experimental data on a conveyor motor with two six-phase windings are given.
ELECTROMAGNETIC CALCULATION OF THREE-PHASE ASYNCHRONOUS MOTORS WITH A SIX-PHASE WINDING
S.Yu. Polezіn
2013-02-01
Full Text Available Features of electromagnetic computation of three-phase asynchronous motors with a six-phase winding in the stator are described. Experimental data on a conveyor motor with two six-phase windings are given.
A reverse mode of three-phase asynchronous motors with hexaphase windings
V.D. Lushchyk
2014-04-01
Full Text Available A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.
Kanchan, RS; Baiju, MR; Mohapatra, KK; Ouseph, PP; Gopakumar, K.
2005-01-01
A pulse width modulation (PWM) scheme for multilevel inverters is proposed. The proposed PWM scheme generates the inverter leg switching times, from the sampled reference phase voltage amplitudes and centres the switching times for the middle vectors, in a sampling interval, as in the case of conventional space vector PWM (SVPWM). The SVPWM scheme, presented for multilevel inverters, can also work in the overmodulation range, using only the sampled amplitudes of reference phase voltages. The ...
Busquets Monge, Sergio; Ruderman, Alex
2010-01-01
This paper presents four carrier-based PWM strategies for diode-clamped converters of any number of levels and any number of legs (phases). These carrier-based PWM strategies guarantee the dc-link capacitor voltage balance in every switching cycle without the need of additional hardware and with low dc-link capacitance values for any modulation index and load, provided that the sum of leg currents equals zero. The performance of the presented carrier-based PWM strategies,...
Direct torque control for dual three-phase induction motor drives
Farina, Francesco; PROFUMO Francesco; Griva, Giovanni Battista; TENCONI Alberto; Bojoi, Iustin Radu
2005-01-01
A direct torque control (DTC) strategy for dual three-phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees. The DTC strategy is based on a predictive algorithm and is implemented in a synchronous reference frame aligned with the machine stator flux vector. The advantages of the discussed control strategy are constant inverter switching frequency, good transient and steady-state per...
Comparison of three-phase modulation with two-phase and four-phase modulation
Pierce, J. R.
1980-01-01
For a constant added noise density at high signal-to-noise ratios and for the same error rate, three-phase PSK requires about 0.75 dB less energy per bit than two-phase or four-phase PSK. However, at very low signal-to-noise ratios, three-phase PSK requires about 0.74 dB more energy per bit of channel capacity than two-phase or four-phase PSK.
A Fully Equivalent Global Pressure Formulation for Three-Phase Compressible Flow
Chavent, Guy
2008-01-01
We introduce a new global pressure formulation for immiscible three-phase compressible flows in porous media which is fully equivalent to the original equations, unlike the one introduced in \\cite{CJ86}. In this formulation, the total volumetric flow of the three fluids and the global pressure follow a classical Darcy law, which simplifies the resolution of the pressure equation. However, this global pressure formulation exists only for Total Differential (TD) three-phase data, which depend o...
An Improved Model Describing Mass Transfer In Three-Phase Fluidized Beds
Asfour, Abdel Fattah A.
1990-01-01
A model for describing mass transfer in three-phase fluidized beds has been developed and tested using experimental data. The presence of two distinguishable mass transfer zones in three-phase fluidized beds led to the idea of interfacing a plug flow model (PFM) with an axial dispersion model (ADM) at the separation boundary between these zones to yield the proposed model. The model reported here has been valildated at a wide range of operating conditions and proved to perform better th...
Surface Effect on Three Phase Lines of Low-Ohmic Furnaces
Pavel Novak
2004-01-01
The article another option of using numerical method of elementary conductors in surface effect three-phase supply linesfor low-ohmic furnaces. Impedance asymmetry of three-phase supply lines of different conductor profiles and various spaceconfigurations is analysed following to the author`s article published in this journal (Vol. 2/2003, No. 2, pg. 42). Options of reducingunfavourable effect of so called live and dead phase and their utilization in design and construction of mentioned lines...
Towards assessing online uncertainty for three-phase flow metering in the oil and gas industry
Henry, M. P.; M. S. Tombs; Zhou, F. B.
2014-01-01
A new three-phase (oil/water/gas) flow metering system has been developed for use in the oil and gas industries, based on Coriolis mass flow metering. To obtain certification for use in the Russian oil and gas industries, trials have taken place at the UK and Russian national flow laboratories, NEL in Glasgow and VNIIR in Kazan, respectively. The metrology of three-phase flow is complex, and the uncertainty of each measurement varies dynamically with the operating point, as ...
MODELING OF SYMMETRIC THREE-PHASE ASYNCHRONOUS ELECTRIC MOTOR IN ASYMMETRIC CONNECTION TO NETWORK
V. I. Lukovnikov
2016-01-01
Full Text Available The paper shows how to solve the problem concerning reveal of changes in mathematical models and electric parameters of symmetric three-phase short-circuited asynchronous electric motors in case of their connection to single- or two-phase network in comparison with their connection to three-phase network. The uniform methodological approach permitting to generalize the known data and receive new results is offered in the paper.
Turki Y. Abdalla; Haroution Antranik Hairik; Adel M. Dakhil
2010-01-01
This paper presents a method for improving the speed profile of a three phase induction motor in direct torque control (DTC) drive system using a proposed fuzzy logic based speed controller. A complete simulation of the conventional DTC and closed-loop for speed control of three phase induction motor was tested using well known Matlab/Simulink software package. The speed control of the induction motor is done by using the conventional proportional integral (PI) cont...
MODELING OF SYMMETRIC THREE-PHASE ASYNCHRONOUS ELECTRIC MOTOR IN ASYMMETRIC CONNECTION TO NETWORK
V. I. Lukovnikov; I. A. Rudchenko; A. V. Тurenkova
2016-01-01
The paper shows how to solve the problem concerning reveal of changes in mathematical models and electric parameters of symmetric three-phase short-circuited asynchronous electric motors in case of their connection to single- or two-phase network in comparison with their connection to three-phase network. The uniform methodological approach permitting to generalize the known data and receive new results is offered in the paper.
Fuzzy Logic Closed Loop Control of 5 level MLI Driven Three phase Induction motor
Mulukutla Venkata Subramanyam; P.V.N. Prasad; G.Poornachandra Rao
2013-01-01
This paper deals about fuzzy logic control of closed loop controlled five level Multi Level Inverter (MLI) driven three phase induction motor. Three phase Induction motor is most widely used drive in Industries, so needs proper control of speed. Induction motor is fed from five level multilevel inverter which is controlled by fuzzy logic. The closed loop consists of two loops. First inner loop is current loop and second outer loop is speed loop. The torque is varied at different times and cor...
Dynamic D-Q Axis Modeling Of Three-Phase Asynchronous Machine Using Matlab
SHAKUNTLA BOORA, S.K AGARWAL, K.S SANDHU
2013-01-01
Abstract:This paper presents a dynamic d-q axis model of three- phase asynchronous motor in synchronously rotating frame. The systems of differential equations representing the dynamic state behaviours of the machine as developed are implemented in MATLAB/SIMULINK. The effects of the stepped sequence of mechanical loading on the motor output variables namely: three-phase stator currents (ia, ib and ic), electromechanical torque and rotor speed, d-q stator and rotor currents (iqs, ids, iqr and...
Ufa Ruslan A.
2014-01-01
Full Text Available The motivation of the presented research is based on the needs for development of new methods and tools for adequate simulation of Flexible Alternating Current Transmission System (FACTS devices and High Voltage Direct Current Transmission (HVDC system as part of real electric power systems (EPS. For that, a hybrid approach for advanced simulation of the FACTS and HVDC based on Voltage Source is proposed. The presented simulation results of the developed hybrid model of VSC confirm the achievement of the desired properties of the model and the effectiveness of the proposed solutions.
The analysis of magnesium oxide hydration in three-phase reaction system
In order to investigate the magnesium oxide hydration process in gas–liquid–solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid–solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH)2 precipitation, Mg(OH)2 peeling off from MgO particle and leaving behind fresh MgO surface. - Graphical abstract: There was existence of a peeling-off process in the gas–liquid–solid (three-phase) MgO hydration system. - Highlights: • Magnesium oxide hydration in gas–liquid–solid system was investigated. • The experimental data in three-phase system could be fitted well by two models. • The morphology analysis suggested that there was existence of a peel-off process
Three-Phase Capillary Pressure, Hysteresis and Trapping in a Porous Glass-Bead Column
Andersson, L.; Schlüter, S.; Li, T.; Brown, K. I.; Helland, J. O.; Wildenschild, D.
2015-12-01
Enhanced oil recovery (EOR) strategies employing water-alternate-gas (WAG) injections may improve oil mobility and production recovery. WAG injections for EOR create regions in the reservoir with simultaneous flow of oil, water and air dominated by capillary and gravity forces. As a result of the dynamics in the transition zones, the invading fluid may snap off compartments of the displaced fluid which could then be trapped in the pore space, contributing to the hysteresis of the three-phase capillary pressure curves. Three-phase capillary pressure curves are needed to model the three-phase transition zone movements in the reservoir. In reservoir simulation models, the common practice has been to implement three-phase capillary pressure curves based on two-phase gas-oil and oil-water capillary pressure data. However, experimental and modelling studies of three-phase fluid distributions at the pore scale have shown that this procedure is not always valid; three-phase capillary pressure curves exhibit hysteresis and depend on the saturation history of the three phases which cannot be derived from two-phase capillary pressure curves. We have developed three-phase experiments that provide capillary pressures and 3D-image data of fluid distributions in the entire saturation space of oil, water and air in water-wet porous glass-bead columns; a time-consuming and technically challenging exercise. The 3D data with a resolution of 6.38 μm were derived from high-resolution synchrotron x-ray computed micro-tomography (CMT), collected at the GSECARS beam line 13-BM-D at the Advanced Photon Source, Argonne National Laboratory. In particular, we discuss how three-phase pore-scale mechanisms, such as oil layer existence and multiple displacement events, affect the mobility and trapping of oil in the porous medium. We also show that wettability-alterations of the porous medium in contact with the three-phase fluid system and exposure to x-rays can be avoided by using iodine
曾祥君; 胡京莹; 王媛媛; 熊婷婷
2014-01-01
配电网三相对地参数不平衡会产生三相不平衡电压，一般采用投切电容器或电抗器补偿三相不平衡参数，抑制不平衡电压，但该方法补偿的精度和速度有限，难以彻底而迅速地实现三相不平衡过电压抑制。因此，在前期发明的柔性接地技术(专利201110006701.2)基础上，提出配电网三相不平衡过电压抑制新方法。通过PWM有源逆变向配电网注入零序电流补偿三相对地不平衡电流，实现对零序电压的控制，从而抑制三相不平衡过电压。仿真分析结果表明，所提方法可有效抑制三相不平衡过电压，能够将中性点位移电压限制为零。%Unbalanced three-phase parameters to ground can result in the three-phase unbalanced voltage in distribution networks. Generally switched capacitors and reactors are applied in the compensation of three-phase unbalanced parameters to limit the unbalanced voltage. Whereas, the compensation method has limited precision and speed, it is difficult to satisfy the requirement of the three-phase unbalanced voltage suppressing thoroughly and rapidly. In order to improve it, a new method based on the invention patent of flexible grounding technique (Patent number 201110006701.2) was presented in this paper. The three-phase unbalanced current to ground was compensated by the injecting zero sequence current to distribution network through pulse width modulation (PWM) inverter. The zero sequence voltage was controlled and the three-phase unbalanced overvoltage was thus suppressed. Simulation results showed that the proposed method limited the unbalanced overvoltage effectively, and the neutral displacement voltage could be limited to zero.
A new method for the experimental determination of three-phase relative permeabilities
Petroleum reservoirs under primary, secondary or tertiary recovery processes usually experience simultaneous flow of three fluids phases (oil, water and gas). Reports on some mathematical models for calculating three-phase relative permeability are available in the Literature. Nevertheless, many of these models were designed based on certain experimental conditions and reservoir rocks and fluids. Therefore, special care has to be taken when applying them to specific reservoirs. At the laboratory level, three-phase relative permeability can be calculated using experimental unsteady-state or steady state methodologies. This paper proposes an unsteady-state methodology to evaluate three-phase relative permeability using the equipment available at the petrophysical analysis Laboratory of the Instituto Colombiano del Petroleo (ICP) of Ecopetrol S.A. Improvements to the equipment were effected in order to achieve accuracy in the unsteady-state measurement of three-phase relative permeability. The target of improvements was directed toward to the attainment of two objectives:1) the modification of the equipment to obtain more reliable experimental data and 2) the appropriate interpretation of the data obtained. Special attention was given to the differential pressure and uncertainty measurement in the determination of fluid saturation in the rock samples. Three experiments for three-phase relative permeability were conducted using a sample A and reservoir rock from the Colombian Foothills. Fluid tests included the utilization of synthetic brine, mineral oil, reservoir crude oil and nitrogen. Two runs were conducted at the laboratory conditions while one run was conducted at reservoir conditions. Experimental results of these tests were compared using 16 mathematical models of three-phase relative permeability. For the three-phase relative permeability to oil, the best correlations between experimental data and tests using Blunt, Hustad Hasen, and Baker's models were
郭艳清; 冯占伟; 袁天驰
2015-01-01
In the voltage type PWM AC/DC/AC conversion , the DC side energy-storage filtering capacitor′s parame-ter selection is one of the key factors for stable operation of the converter .In view of the certain inaccuracy in the DC capacitor′s selection , this paper analyzed the principle of the DC side capacitor′s charge and discharge when the AC/DC/AC conversion circuit in steady state , and studied the voltage relationship between the DC side and the AC side of the converter .A mathematical model between capacitor ripple voltage and three-phase power supply voltage deviation is established .Thus, the capacitance parameter selection method based on the three-phase power supply voltage devi-ation is proposed .This paper respectively gives the appropriate analysis and calculations of filter capacitance when three phase and single phase uncontrolled rectifier circuit provides dc power .And through simulation and experimental verification of the DC filter capacitor energy storage method verifies the validity of arguments .%在电压型PWM AC／DC／AC变换中，直流侧储能滤波电容参数的选取是变换器稳定运行的关键因素之一。针对目前直流侧电容选取存在一定的不精确性，分析了AC／DC／AC变换电路稳态时直流电容充放电的原理，对变换器交直流侧电压的关系进行研究，建立了电容纹波电压与三相供电电压偏差之间的数学模型，提出了基于三相供电电压偏差选取直流侧电容参数的方法。分别对单相和三相不可控整流电路提供直流电源时直流侧电容C的合理选取给出了相应的分析和计算，并通过仿真和试验验证了直流储能滤波电容参数确定方法的有效性。
Investigation of the effects of PWM parameters on ionic polymer metal composite actuators
The effects of the PWM excitation signal parameters, such as frequency and magnitude, on the Nafion-based ionic polymer metal composite (IPMC) actuator response were found out. The first set of experiments was designed to observe the actuator response when the actuators were biased with constant DC voltages. These experimental results were exploited to build an experimental data based dynamic model. The model and these results were also used as references to evaluate the experimental results in the proceeding experiments. The second set of experiments was designed to observe the actuator response when the DC square wave signals at different frequencies (0 to 1000 Hz) were applied. The third set of experiments was designed to observe the actuator response when the PWM signals at different magnitudes (6, 8 and 10 V) were applied. It is observed that back relaxation reduces with increasing frequency, but after a certain frequency value, it remains approximately constant. It is seen that the input output relationship of the actuators are linear only for a range of PWM signal magnitudes. The observations in both the PWM frequency and the magnitude experiments indicated that the performance of the Nafion-based IPMC actuator could be improved by selecting a magnitude of PWM signals between 6–8 Volts and by selecting a frequency between 400–1000 Hz. (paper)
Investigation of the effects of PWM parameters on ionic polymer metal composite actuators
Cem Yılmaz, Ozgun; Cetin, Levent; Oguz Gurses, Baris; Sen, İbrahim; Ozdemir, Okan; Sarıkanat, Mehmet; Seki, Yoldas; Sever, Kutlay; Akar, Emine; Mermer, Omer
2014-09-01
The effects of the PWM excitation signal parameters, such as frequency and magnitude, on the Nafion-based ionic polymer metal composite (IPMC) actuator response were found out. The first set of experiments was designed to observe the actuator response when the actuators were biased with constant DC voltages. These experimental results were exploited to build an experimental data based dynamic model. The model and these results were also used as references to evaluate the experimental results in the proceeding experiments. The second set of experiments was designed to observe the actuator response when the DC square wave signals at different frequencies (0 to 1000 Hz) were applied. The third set of experiments was designed to observe the actuator response when the PWM signals at different magnitudes (6, 8 and 10 V) were applied. It is observed that back relaxation reduces with increasing frequency, but after a certain frequency value, it remains approximately constant. It is seen that the input output relationship of the actuators are linear only for a range of PWM signal magnitudes. The observations in both the PWM frequency and the magnitude experiments indicated that the performance of the Nafion-based IPMC actuator could be improved by selecting a magnitude of PWM signals between 6-8 Volts and by selecting a frequency between 400-1000 Hz.
Compositional modeling of three-phase flow with gravity using higher-order finite element methods
Moortgat, Joachim
2011-05-11
A wide range of applications in subsurface flow involve water, a nonaqueous phase liquid (NAPL) or oil, and a gas phase, such as air or CO2. The numerical simulation of such processes is computationally challenging and requires accurate compositional modeling of three-phase flow in porous media. In this work, we simulate for the first time three-phase compositional flow using higher-order finite element methods. Gravity poses complications in modeling multiphase processes because it drives countercurrent flow among phases. To resolve this issue, we propose a new method for the upwinding of three-phase mobilities. Numerical examples, related to enhanced oil recovery and carbon sequestration, are presented to illustrate the capabilities of the proposed algorithm. We pay special attention to challenges associated with gravitational instabilities and take into account compressibility and various phase behavior effects, including swelling, viscosity changes, and vaporization. We find that the proposed higher-order method can capture sharp solution discontinuities, yielding accurate predictions of phase boundaries arising in computational three-phase flow. This work sets the stage for a broad extension of the higher-order methods for numerical simulation of three-phase flow for complex geometries and processes.
2010-07-01
... portable or mobile three-phase alternating current equipment; circuit breakers. 77.900 Section 77.900... mobile three-phase alternating current equipment; circuit breakers. Low- and medium-voltage circuits supplying power to portable or mobile three-phase alternating current equipment shall be protected...
Chaotic Recurrence Analysis of Oil-Gas-Water Three-phase Flow in Vertical Upward Pipe
Ling-Fu Kong
2011-01-01
Full Text Available In this study, the conductance fluctuating signals of oil/gas/water were analyzed by using nonlinear chaotic recurrence, were obtained four kinds of recurrence quantification indicator, recurrence rate, determinism, average length of diagonal segment, entropy which got the transition law of the oil/gas/water three-phase flow patterns in vertical upward pipe. Specific process was: Firstly the C-C algorithm was used to determine phase space embedding dimension and time delay of nonlinear time series, then the method of using the time series data generated by the Lorenz equation to verify the sensitivity of recurrence quantification analysis was presented, finally the chaotic recurrence analysis method was used to identify three-phase flow patterns. The results show that: the texture of chaotic recurrence plot can reflect the oil/gas/water three-phase flow pattern evolution, the recurrence quantification indicator with the phase flow are more sensitive.
Phase field modeling and simulation of three-phase flow on solid surfaces
Zhang, Qian; Wang, Xiao-Ping
2016-08-01
Phase field models are widely used to describe the two-phase system. The evolution of the phase field variables is usually driven by the gradient flow of a total free energy functional. The generalization of the approach to an N phase (N ≥ 3) system requires some extra consistency conditions on the free energy functional in order for the model to give physically relevant results. A projection approach is proposed for the derivation of a consistent free energy functional for the three-phase Cahn-Hilliard equations. The system is then coupled with the Navier-Stokes equations to describe the three-phase flow on solid surfaces with moving contact line. An energy stable scheme is developed for the three-phase flow system. The discrete energy law of the numerical scheme is proved which ensures the stability of the scheme. We also show some numerical results for the dynamics of triple junctions and four phase contact lines.
Kolla, Sri R; Altman, Shawn D
2007-04-01
This paper presents results from the implementation and testing of a PC based monitoring and fault identification scheme for a three-phase induction motor using artificial neural networks (ANNs). To accomplish the task, a hardware system is designed and built to acquire three-phase voltages and currents from a 1/3 HP squirrel-cage, three-phase induction motor. A software program is written to read the voltages and currents, which are first used to train a feed-forward neural network structure using the JavaNNS program. The trained network is placed in a LabVIEW based program formula node that monitors the voltages and currents online and displays the fault conditions and turns the motor off. The complete system is successfully tested in real time by creating different faults on the motor. PMID:17336306
AC Motor Drive Fed by Renewable Energy Sources with PWM
J. Pavalam
2014-01-01
Full Text Available In this fast aproaching nature of technology the ned of Electricity becomes a mandatory in developing technology. The ned of Electricity increases the power demand where the power demand met by the conventional sources of energy has some disadvantage of polution, this disadvantage can be decreased by the use of the Renewable energy sources like Fuel Cel and available solar energy. When a FUEL cel produces AC power, basicaly two stages are required for conversion first a bosting stage and second is inversion stage. In this paper the Bost inverter topology is achieved where in the conventional methods the normal DC - AC power conversion method is used where as in this paper the PWM based DC - AC inverter has ben used which is useful in reducing the harmonics in the output of the Inverter. The voltage controled output is produced in the bost inverter the curent controled output is taken from dc-dc bidirectional converter. The Fuel cel canot be relied as a whole so a Solar PV module is conected acros the Load so while the Sunlight days the PV arays generate power and in the night time the Fuel cel is used to generate power for the load. Since, the Fuel cel and PV arays can generate power in Partial load they are prefered than any other sources. When the output from the Solar PV aray is low or when the sunlight available is not eficient in generating the power a automatic switch over is provided in the junction betwen the Solar PV aray and Fuel cel so that whenever it hapens the switch automaticaly switch over to another source. The simulation results are presented to confirm the operational feature of the proposed system.
The effect of saturation path on three-phase relative permeability
Kianinejad, Amir; Chen, Xiongyu; DiCarlo, David A.
2015-11-01
Simulation and fluid flow prediction of many petroleum-enhanced oil recovery methods as well as environmental processes such as carbon dioxide (CO2) geological storage or underground water resources remediation requires accurate modeling and determination of relative permeability under different saturation histories. Based on this critical need, several three-phase relative permeability models were developed to predict relative permeability; however, for practical purposes most of them require a variety of parameters introducing undesired complexity to the models. In this work, we attempt to find out if there is a simpler way to express this functionality. To do so, we experimentally measure three-phase, water/oil/gas, relative permeability in a 1 m long water-wet sand pack, under several saturation flow paths to cover the entire three-phase saturation space. We obtain the in situ saturations along the sand pack using a CT scanner and then determine the relative permeabilities of liquid phases directly from the measured in situ saturations using an unsteady state method. The measured data show that at a specific saturation, the oil relative permeability varies significantly (up to two orders of magnitude), depending on the path through saturation space. The three-phase relative permeability data are modeled using standard relative permeability models, Corey-type, and Saturation Weighted Interpolation (SWI). Our measured data suggest that three-phase oil relative permeability in water-wet media is only a function of its own saturation if the residual oil saturation is treated as a function of two saturations. We determine that residual saturation is the key parameter in modeling three-phase relative permeability (effect of saturation history).
High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit
C. P. Sai Kiran
2014-10-01
Full Text Available This thesis presents High frequency Soft Switching DC-DC boost Converter. The circuit consists of a general Boost Converter with an additional resonant circuit which has a switch, inductor, capacitor and a diode.In general Boost Converter circuits have snubber circuits where switching losses are dissipated in external passive resistors; which is known as hard switching. As the switching frequency of PWM converters is increased its switching losses and conduction losses also increases. This restricts the use of PWM technique. New Zero Voltage Transition-Zero Current Transition (ZVT-ZCT PWM converter equipped with the snubber provides the most desirable features of both ZVT and ZCT converters presented previously. Moreover all semiconductors devices operate with soft switching and hence losses are reduced.
A deadbeat control method for a PWM converter applied to a superconducting magnet
Current-type pulse-width-modulated (PWM) converter is regarded as one of the candidates for the superconducting magnet power supplies in next generation tokamak devices. However, this type PWM converter has a problem of the transient oscillation of the reactor current and capacitor voltage in an AC-side harmonic filter, which occurs owing to the LC resonance of the filter when the reference of the DC output current is changed rapidly. In this paper, the new PWM control method based on the deadbeat control theory is proposed to suppress the transient oscillation. The converter employing this method can control the reactor current and capacitor voltage in one sampling period under ideal conditions. In addition, the effect of dead time on the control is discussed. The performance of the newly proposed method is demonstrated through numerical circuit simulation
EVALUATION OF VARIOUS UNIPOLAR MULTICARRIER PWM STRATEGIES FOR FIVE LEVEL FLYING CAPACITOR INVERTER
B. SHANTHI
2012-06-01
Full Text Available This paper presents the comparison of unipolar multicarrier Pulse Width Modulation (PWM techniques for the Flying Capacitor Multi Level Inverter (FCMLI. Due to switch combination redundancies, there are certain degrees of freedom to generate the five level AC output voltage. This paper presents the use of Control Freedom Degree (CFD combination. The effectiveness of the PWM strategies developed using CFD are demonstrated by simulation and experimentation. The results indicate that the multilevel inverter triggered by the developed USHPWM strategy exhibits reduced harmonics. PWM strategies developed are implemented in real time using dSPACE/Real Time Interface (RTI. The simulation and experimental output closely match with each other validating the strategies presented.
Voltage unbalance mitigation in LV networks using three-phase PV systems
Garcia Bajo, Cristina; Hashemi Toghroljerdi, Seyedmostafa; Bækhøj Kjær, Søren;
2015-01-01
In this paper a new method is proposed to mitigate voltage unbalance caused by single-phase solar inverters in low voltage (LV) networks. The method is based on uneven reactive power absorption and injection by three-phase solar inverters. Independent control of each phase is performed to achieve...... this uneven injection. The average values of phase voltages at the connection points of the photovoltaic (PV) inverters are used as the references for the balancing algorithm. Voltage unbalance mitigation is achieved by use of this method in different scenarios with variable three-phase and single...
TORQUE ANALYSIS OF THREE-PHASE INDUCTION MOTOR UNDER VOLTAGE UNBALANCE USING 2D FEM
ALI EBADI,
2011-02-01
Full Text Available Because of various techno-economic benefits, three-phase induction motors are used extensively in industry, commercial and residential applications and most of them are connected to electric power distribution system directly, thus they will be affected by voltage quality problems. An important voltage quality problem in power systems is voltage unbalance. Therefore, it is very important to studyperformance of these motors under unbalanced voltages. In this paper, Two-Dimensional Finite Element Method is employed to analyze the performance of a three-phase squirrel cage induction motor undervoltage unbalance, focusing on electromagnetic torque.
Numerical investigation of three-phase flows using incompressible smoothed particle hydrodynamics
Zainali, Amir; Tofighi, Nima; Yıldız, Mehmet; YILDIZ, Mehmet
2011-01-01
An ISPH method for the simulation of three-phase °ows is presented in this article. The proposed method is investigated through the simulation of a droplet located at the interface of two immiscible °uids as well as diamond droplet deformation. The extendibility of the proposed surface tension formulations for three-phase fows to two-phase fows is also investigated. It is observed that the results obtained from the numerical simulations are in good agreement with the analytical ones.
A Smart Current Modulation Scheme for Harmonic Reduction in Three- Phase Motor Drive Applications
Davari, Pooya; Zare, Firuz; Blaabjerg, Frede
2015-01-01
Electric motor-driven systems consume considerable amount of the global electricity. Majority of three-phase motor drives are equipped with conventional diode rectifier and passive harmonic mitigation, being witnessed as the main source in generating input current harmonics. While many active...... harmonic mitigation methods have been developed over the years, the total cost and complexity has become the main obstacle in employing prior-art methods for motor drive systems. This paper presents a novel current modulation method based on the electronic inductor concept for three-phase ac-dc systems to...
Uncertainty Assessment of Interpolation-Based Three Phase Relative Permeability Models
Ranaee, Ehsan; Giovanni, Porta; Monica, Riva; Alberto, Guadagnini
2013-04-01
A major element affecting uncertainty associated with prediction of three-phase flow in reservoirs is the parameterization of relative permeability. The latter are typically obtained through interpolation of two phase relative permeability data because of intrinsic difficulties related to direct measurements. Here, we discuss and analyze the saturation history dependency of water, oil and gas relative permeabilities and distinguish key features of three- and two- phase flow configurations. We start by investigating the advantages and limitations of several methodologies available in the literature and widely adopted in three-phase flow simulation. This analysis is performed by comparing model outcomes against experimental data published in the literature. The results provided by considering Corey-type equations as input to the aforesaid models is compared against the use of linear interpolation of two-phase measurements from oil-water and oil-gas environment. Our results show that available models typically fail to reproduce the set of experimental results ever the full range of saturations. This analysis suggests that not only saturation history but also wettability, residual oil and trapping behavior of oil during drainage and imbibition are key elements distinguishing between the physics of two- and three-phase settings. These effects should be taken in account to predict three-phase relative permeability. We then propose an alternative formulation to compute oil relative permability under three-phase conditions. Our model takes into account (i) the dependence of three-phase oil relative permeability on the saturation path, and (ii) the effect of wettability observed for three-phase systems. The model is based on a sigmoid-type interpolation of the oil relative permeability-saturation data in a two-phase oil-water system. Three-phase oil relative permeability is then computed through an additional interpolation between the oil-water effective sigmoid curve and
Stator Winding Fault Diagnosis Of Three-Phase Induction Motor By Park’s Vector Approach
S.M.SHASHIDHARA, DR. P.S.RAJU
2013-01-01
Through this paper issue of on-line detection of short winding fault in three-phase induction motors is presented, and a technique, based on the computer-aided monitoring of the stator current Park’s Vector, is proposed. The park's vector model is realized by employing Virtual instrumentation. The Virtual Instrumentation is acquired by programming in Lab-view software. Laboratory analysis was performed on a 0.5 hp three phase induction motor. The motor was originally evaluated under optimum c...
Juvenile Dermatomyositis Diagnosed by 99mTc-HDP Three-phase Bone Scintigraphy
Juvenile dermatomyositis is a common inflammatory muscle disease of childhood, characterized by weakness in proximal muscles and specific skin rash. In case of juvenile dermatomyositis without characteristic clinical features, non-invasive imaging tools such as 99mTc-HDP three-phase bone scan are very helpful in diagnostic workup of myopathies. We report a case of 13-year old female with juvenile dermatomyositis, in which 99mTc-HDP three-phase bone scan was useful in diagnosis and assessing therapy response
Selection of Carrier Waveforms for PWM Inverter%PWM逆变器载波方式的选择
陈国呈; 屈克庆; 许春雨; 孙承波
2003-01-01
In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described indetail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the out-put frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switchingPWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization ofthe DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current wave-form. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonance-trigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.
Genetic estimation of iron losses in strip wound toroidal cores under PWM flux conditions
Recently estimation of iron losses in electrical steels have become very significant for the manufacture of well-designed magnetic devices that are to be subjected to electronically generated voltage excitations such as pulse width-modulated (PWM) voltage excitation. In this study, iron loss components were estimated by means of the genetic algorithms method and electrical steel manufacturers' data. The results were compared with those obtained by a widely used classical method. The comparison has shown that the genetic algorithms method improved loss estimation with respect to the classical method under both sinusoidal and PWM flux conditions
Performance Comparison of Phase Shifted PWM and Sorting Method for Modular Multilevel Converters
Haddioui, Marcos Rejas; Máthé, Lászlo; Burlacu, Paul Dan; Pereira, Heverton A.; Sangwongwanich, Ariya; Bongiorno, Massimo; Teodorescu, Remus
Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to modularity, scalability, low losses and low filtering requirement. Carrier-based (PWM) and carrier-less (nearest level control) modulation can be applied. By using advanced sorting methods focusing on...... keeping the capacitor voltage ripple under some limit, unnecessary switching events are eliminated leading to reduced switching losses. This paper presents a comparison between the steady-state performances in terms of output voltage THD and equivalent switching frequency of the Phase Shifted Carrier PWM...
Soft Switching Full-Bridge PWM DC/DC Converter Using Secondary Snubber
Jaroslav Dudrik
2009-05-01
Full Text Available A novel full-bridge PWM DC/DCconverter with controlled secondary side rectifier usingsecondary snubber is presented in this paper.Limitation of the circulating current as well as softswitching for all power switches of the inverter isachieved for full load range from no-load to shortcircuit by using controlled rectifier and snubber on thesecondary side. Phase shift PWM control strategy isused for the converter. The principle of operation isexplained and analyzed and the experimental resultson a 1kW, 50 kHz laboratory model of the converterare presented.
Xiao, Lei; Huang, Shoudao; Lu, Kaiyuan
2013-01-01
Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load. In this...... study, a new proportional-integral-resonant (PI-RES) controller-based, space vector modulated direct power control topology is proposed to suppress the dc-bus voltage ripple and in the same time, controlling effectively the instantaneous power of the VSC. A special ac reactive power reference component...... is introduced in the controller, which is necessary in order to reduce the dc-bus voltage ripple and active power harmonics at the same time. The proposed control topology is implemented in the lab. Simulation and experimental results are provided to validate its performance and the analysis...
Design of PWM Siginal Generator of the Active Power Filter Based on FPGA%基于FPGA的有源电力滤波器PWM信号发生器的设计
段月霞; 郭振华
2011-01-01
Focus on the high requirements of active power filter（APF） on the control of the IGBT trigger pulse signal,the PWM signal mechanism is analyzed.And a fully digital three-phase PWM signal generator is designed based on Quartus II,which can realize the comparing between the pulse width signal modulated and triangular wave signal.After processed by the dead-generator signal,the pulse width signal produces six-way PWM pulse signal.Signal modulated circuit can control the state of IGBT,if it should be on or off.It can get the aim of harmonic suppression,reactive current compensation.At last the program of dead zone generator is introduced.In the simulation experiments,the results are confirmed correctly and feasibly.%针对有源电力滤波器（APF）对IGBT触发脉冲信号控制的较高要求,分析了PWM信号产生机理,基于QuartusII软件设计了一种全数字三相PWM信号发生器,给定脉宽信号经过调理与数字三角波信号比较,经过宽度可调的死区发生器信号处理后,产生六路PWM脉冲信号,经驱动保护信号调理电路控制相关IGBT的导通,达到抑制谐波、补偿无功电流的目的。给出了死区发生器程序。通过仿真实验,结果证实了设计的正确性和可行性。
Garza Macias, Anibal [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1988-12-31
In the Mexico`s Gulf Coast and in the North East part of the country there are severe pollution problems on the electric distribution power systems insulators. To solve this problem, in specialized laboratories are reproduced the pollution conditions for their quantitative and qualitative analyses. In general terms, for this purpose special voltage transformers have been used that, for being imported, are very expensive; furthermore there is no defined selection criterion that allows the voltage source to supply the current recommended by the IEC (International Electrotechnical Commission). In this article, a proposal is presented to select a transformer that fulfills the IEC requirements. This equipment, because of its acquisition easiness and economy, permits that any teaching or research institution have a voltage source that allows the experimentation of the pollution phenomena at a minimum cost. [Espanol] En la costa del Golfo de Mexico y en el noroeste del pais hay severos problemas de contaminacion en los aisladores de los sistemas electricos de distribucion. Para solucionar este problema, se reproducen, en laboratorios especializados, las condiciones de contaminacion para su analisis cualitativo y cuantitativo. En general, con este proposito se han utilizado transformadores especiales de voltaje que por ser de importacion son muy costosos; ademas, no existe un criterio definido de seleccion que permita suministrar a la fuente de voltaje la corriente recomendada por el IEC (International Electrotechnical Commission). En este articulo se presenta una propuesta para seleccionar un transformador que cumpla con los requerimientos del IEC. Esta, por su facilidad de adquisicion y economia, permite que cualquier institucion docente o de investigacion cuente con una fuente de voltaje que permita la experimentacion de los fenomenos contaminantes con un costo minimo.
郑先成; 黄沈; 张晓斌
2013-01-01
The PWM rectifier is an important power converter in an aircraft′s variable frequency power system , and it is necessary to explore the relationship between the output impedance of the PWM rectifier and the stability of the DC loop of the variable frequency power system .This paper establishes the mathematical model of a three-phase boost PWM rectifier and the open/closed loop output impedance expressions .With theoretical calculation and simu-lation, we analyze the various factors that affect the output impedance of the PWM rectifier , such as the frequency of power supply source , load, input inductance , output capacitor and control bandwidth , thus obtaining a method for enhancing the output characteristics of the PWM rectifier .The simulation results and their analysis show prelimi-narily that:(1) within the control bandwidth , the output impedance of the PWM characteristic is determined mainly by control parameters;(2) outside of the control bandwidth , it is determined mainly by source-free devices such as output capacitor , whereas the frequency of power supply source and input inductance affect little on the output im -pedance .The exploration results are useful for optimizing the PWM rectifier design and analyzing the stability of the DC loop of the rectifier with a DC/DC converter or the controller of a motor .%PWM整流器是飞机变频电力系统中重要的功率变换设备，研究其输出阻抗特性与飞机变频电力系统直流环稳定性的关系具有重要意义。针对三相升压型PWM整流器，建立开环/闭环输出阻抗表达式，通过理论计算分析和仿真测试，研究了影响PWM整流器输出阻抗的参数，如供电电源频率、负载、输入电感、输出电容和控制带宽，由此得出改善整流器输出特性的方法。仿真结果表明，在控制带宽内，整流器输出阻抗主要决定于控制参数，在控制带宽外，输出阻抗主要决定于直流侧电容等无源器件，而
Improved control strategy for the three-phase grid-connected inverter
Yao, Zhilei; Xiao, Lan; Guerrero, Josep M.
2015-01-01
An improved control strategy for the three-phase grid-connected inverter with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d- and q-axis grid currents will be interacted, and then the waveform quality of the grid current will be poorer. As...
Dual-modality wire-mesh sensor for the visualization of three-phase flows
Three-phase gas–liquid–liquid flows are very common in petroleum extraction, production, and transport. In this work a dual-modality measuring technique is introduced which may be well applied for three-phase flow visualization. The measuring principle is based on simultaneous excitation with two distinct frequencies to interrogate each crossing point of a mesh sensor, which in turn are linked to conductive and capacitive parts of fluid impedance. The developed system can operate eight transmitter and eight receiver electrodes at a frame repetition frequency up to 781 Hz. The system has been evaluated by measuring reference components. The overall measurement uncertainty was 8.4%, which considering the fast repetition frequency of measurements is suitable for flow investigation. Furthermore, a model-based method to fuse the data from the dual-modality wire-mesh sensor and to obtain individual phase fraction of gas–oil–water flow is introduced. Here a parametrized model is fitted to the measured conductivity and permittivity distributions enabling one to obtain phase fraction from measured data. The method has been applied and tested to the acquired data from a mesh sensor in static and dynamic three-phase mixtures of gas, oil, and water. Fused images and quantitative values show good agreement with reference values. The newly developed dual-modality wire-mesh sensor has the potential to investigate three-phase flows to a good degree of detail, being a valuable tool to investigate such flows. (paper)
Three-phase inductive-coupled structures for contactless PHEV charging system
Lee, Jia-You; Shen, Hung-Yu; Li, Cheng-Bin
2016-07-01
In this article, a new-type three-phase inductive-coupled structure is proposed for the contactless plug-in hybrid electric vehicle (PHEV) charging system regarding with SAE J-1773. Four possible three-phase core structures are presented and subsequently investigated by the finite element analysis. To study the correlation between the core geometric parameter and the coupling coefficient, the magnetic equivalent circuit model of each structure is also established. In accordance with the simulation results, the low reluctance and the sharing of flux path in the core material are achieved by the proposed inductive-coupled structure with an arc-shape and three-phase symmetrical core material. It results in a compensation of the magnetic flux between each phase and a continuous flow of the output power in the inductive-coupled structure. Higher coupling coefficient between inductive-coupled structures is achieved. A comparison of coupling coefficient, mutual inductance, and self-inductance between theoretical and measured results is also performed to verify the proposed model. A 1 kW laboratory scale prototype of the contactless PHEV charging system with the proposed arc-shape three-phase inductive-coupled structure is implemented and tested. An overall system efficiency of 88% is measured when two series lithium iron phosphate battery packs of 25.6 V/8.4 Ah are charged.
Dual-modality wire-mesh sensor for the visualization of three-phase flows
dos Santos, E. N.; Vendruscolo, T. P.; Morales, R. E. M.; Schleicher, E.; Hampel, U.; Da Silva, M. J.
2015-10-01
Three-phase gas-liquid-liquid flows are very common in petroleum extraction, production, and transport. In this work a dual-modality measuring technique is introduced which may be well applied for three-phase flow visualization. The measuring principle is based on simultaneous excitation with two distinct frequencies to interrogate each crossing point of a mesh sensor, which in turn are linked to conductive and capacitive parts of fluid impedance. The developed system can operate eight transmitter and eight receiver electrodes at a frame repetition frequency up to 781 Hz. The system has been evaluated by measuring reference components. The overall measurement uncertainty was 8.4%, which considering the fast repetition frequency of measurements is suitable for flow investigation. Furthermore, a model-based method to fuse the data from the dual-modality wire-mesh sensor and to obtain individual phase fraction of gas-oil-water flow is introduced. Here a parametrized model is fitted to the measured conductivity and permittivity distributions enabling one to obtain phase fraction from measured data. The method has been applied and tested to the acquired data from a mesh sensor in static and dynamic three-phase mixtures of gas, oil, and water. Fused images and quantitative values show good agreement with reference values. The newly developed dual-modality wire-mesh sensor has the potential to investigate three-phase flows to a good degree of detail, being a valuable tool to investigate such flows.
High accuracy interface characterization of three phase material systems in three dimensions
Jørgensen, Peter Stanley; Hansen, Karin Vels; Larsen, Rasmus; Bowen, Jacob R.
2010-01-01
tomography schemes such as focused ion beam serial sectioning or micro-computed tomography. We present a high accuracy method of calculating two phase surface areas and triple phase length of triple phase systems from subvoxel accuracy segmentations of constituent phases. The method performs a three phase...
A parametric study on unbalanced three phase islanded microgrids with inverter interfaced units
Sanseverino, Eleonora Riva; Quang, Ninh Nguyen; Zizzo, Gaetano; Di Silvestre, Maria Luisa; Guerrero, Josep M.
In this paper, the solution of the power flow for unbalanced three phase microgrids systems is proposed. The study aims at the integration of inverter interfaced units using the control law used for primary voltage and frequency regulation, so as to take into account possible small variations of...
Modular Plug’n’Play Control Architectures for Three-phase Inverters in UPS Applications
Zhang, Chi; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez; Seniger, Carsten
2016-01-01
In this paper a control strategy for the parallel operation of three-phase inverters in a modular online uninterruptable power supply (UPS) system is proposed. The UPS system is composed of a number of DC/ACs with LC filter connected to the same AC critical bus and an AC/DC that forms the DC bus...
Bezrukih, A.; Meister, R; Lubnin, M.; Gotovko, S.
2010-01-01
This paper is devoted to the high-effective process of surfacing by the indirect three-phase arc with covered electrodes. The share of the parent metal in the surfaced one does not exceed 10 % which is infeasible for one-arc surfacing.
Energy Saving in Three-Phase Diode Rectifiers using Adjustable Switching Frequency Modulation Scheme
Davari, Pooya; Yang, Yongheng; Zare, Firuz; Blaabjerg, Frede
2016-01-01
This paper proposes an adjustable switching frequency modulation scheme in order to improve energy efficiency of three-phase diode rectifiers operating at partial loading. In the proposed solution, the switching frequency automatically gets adjusted with the loading conditions, and thus maintains...
Molecular Modeling of Three Phase Contact for Static and Dynamic Contact Angle Phenomena
Malani, Ateeque; Amat, Miguel; Raghavanpillai, Anilkumar; Wysong, Ernest; Rutledge, Gregory
2012-02-01
Interfacial phenomena arise in a number of industrially important situations, such as repellency of liquids on surfaces, condensation, etc. In designing materials for such applications, the key component is their wetting behavior, which is characterized by three-phase static and dynamic contact angle phenomena. Molecular modeling has the potential to provide basic insight into the detailed picture of the three-phase contact line resolved on the sub-nanometer scale which is essential for the success of these materials. We have proposed a computational strategy to study three-phase contact phenomena, where buoyancy of a solid rod or particle is studied in a planar liquid film. The contact angle is readily evaluated by measuring the position of solid and liquid interfaces. As proof of concept, the methodology has been validated extensively using a simple Lennard-Jones (LJ) fluid in contact with an LJ surface. In the dynamic contact angle analysis, the evolution of contact angle as a function of force applied to the rod or particle is characterized by the pinning and slipping of the three phase contact line. Ultimately, complete wetting or de-wetting is observed, allowing molecular level characterization of the contact angle hysteresis.
Computer Simulation of a Three-phase Brushless Self-Excited Synchronous Generator
Cingoski, Vlatko; Mikami, Mitsuru; Yamashita, Hideo
1999-01-01
Computer simulation of the operating characteristics of a three-phase brushless synchronous generator with self-excited is presented. A voltage driven nonlinear time-periodic FEA is utilized to compute accurately the magnetic field distribution and the induced voltage and currents simultaneously.
The analysis of magnesium oxide hydration in three-phase reaction system
Tang, Xiaojia; Guo, Lin; Chen, Chen; Liu, Quan; Li, Tie; Zhu, Yimin
2014-05-01
In order to investigate the magnesium oxide hydration process in gas-liquid-solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid-solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH)2 precipitation, Mg(OH)2 peeling off from MgO particle and leaving behind fresh MgO surface.
Leakage Current Elimination of Four-Leg Inverter for Transformerless Three-Phase PV Systems
Guo, Xiaoqiang; He, Ran; Jian, Jiamin;
2016-01-01
Eliminating the leakage current is one of the most important issues for transformerless three phase photovoltaic (PV) systems. In this paper, the leakage current elimination of a three-phase four-leg PV inverter is investigated. With the common mode loop model established, the generation mechanis....... Finally the different modulation methods are implemented and tested on the TMS320F28335 DSP +XC3S400 FPGA digital control platform. The experimental results verify the effectiveness of the proposed solution.......Eliminating the leakage current is one of the most important issues for transformerless three phase photovoltaic (PV) systems. In this paper, the leakage current elimination of a three-phase four-leg PV inverter is investigated. With the common mode loop model established, the generation mechanism...... of the leakage current is clearly identified. Different typical carrier-based modulation methods and their corresponding common mode voltages are discussed. A new modulation strategy with Boolean logic function is proposed to achieve the constant common mode voltage for the leakage current reduction...
Analysis of a Three Phase Induction Motor Directly from Maxwell's Equations
Bhattacharjee, Shayak
2011-01-01
The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This allows us to estimate the torque developed by a motor without knowing the details of its circuitry.
何秀琼; 黄昆; 于品华; 张超; 谢铿; 李鹏飞; 王娟; 安震涛; 刘会洲
2012-01-01
Abstract A new mixer-settler-mixer three chamber integrated extractor is proposed in this work for liquid-liquid- liquid three phase countercurrent and continuous extraction. Experiments revealed the influences of the structural design of the three-liquid-phase extractor and some key operational parameters on three-phase partition of two phenolic isomers, p-nitrophenol （p-NP） and o-nitrophenol （o-NP）. The model three-liquid-phase extraction system used here is nonane （organic top-plaase）-polyethylene glycol （PEG 20UU） （polymer mlddle-phase）-（NH4）2SO4 aqueous solution （aqueous bottom-phase）. It is indicated that agitating speed and retention time in three-phase mixer are key parameters to extraction fraction of nitrophenol. Dispersion band behavior is related to agitating intensity, and its occurrence does not affect the extraction fraction of target compounds. The present work highlights the possibility of a feasible approach of scaling up of the proposed three-phase extraction apparatus for future in- dustrial-aimed applications.
Three-phase diode rectifiers with low harmonics current injection methods
Pejovic, Predrag
2007-01-01
Presents results of numerous research papers in the area of current injection based rectifiers. This book discusses the principles of current injection, followed by an analysis of various magnetic current injection devices. It concludes with a chapter where the results are generalized to three-phase full-bridge thyristor rectifiers.
A predictive control algorithm for an active three-phase power filter
R.V. Vlasenko; Bialobrzeski, O. V.
2014-01-01
The paper deals with grid connection circuits for active filters, structures of active power filter control systems, and methods based on full capacity components determination. The existing structures of active power filter control and control algorithm adjustment for valve commutation loss reduction are analyzed. A predictive control algorithm for an active three-phase power filter is introduced.
Teaching Qualitative Research for Human Services Students: A Three-Phase Model
Goussinsky, Ruhama; Reshef, Arie; Yanay-Ventura, Galit; Yassour-Borochowitz, Dalit
2011-01-01
Qualitative research is an inherent part of the human services profession, since it emphasizes the great and multifaceted complexity characterizing human experience and the sociocultural context in which humans act. In the department of human services at Emek Yezreel College, Israel, we have developed a three-phase model to ensure a relatively…
THREE-PHASE ENERGY SUPPLY SYSTEMS SIMULATION FOR THE TOTAL POWER LOSSES COMPONENTS ASSESSMENT
D.V. Tugay
2016-09-01
Full Text Available Purpose. The goal is to optimize a structure of Matlab-model of the three-phase energy supply system with power active filter. The mathematical model that describes the energy supply system modes of operation which contains additional losses is proposed. Methodology. We have applied concepts of the electrical circuits theory, mathematical modeling elements based on linear algebra and vector calculus, mathematical simulation in Matlab package. Results. We have developed two models of three-phase energy supply system. The first one is based on a vector representation, and the second one on the matrix representation of energy processes. Using these models we have solved the problem of maintaining unchanged the average useful power for 279 cases of energy supply system modes of operation. Originality. We have developed methods of mathematical analysis of a three-phase energy supply systems with polyharmonic voltages and currents in the symmetric and asymmetric modes. Practical value. We have created Matlab-model of a three-phase energy supply system with automated calculation of a correction factor. It allows reducing more than one order the time for energy processes elucidation in multiphase systems.
Novel, Four-Switch, Z-Source Three-Phase Inverter
Antal, Robert; Muntean, Nicolae; Boldea, Ion;
2010-01-01
) 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......3011 digital signal processor....
Mathe, Laszlo; Cornean, Horia; Sera, Dezso;
2011-01-01
transfer ratio. The difference between most of the proposed modulation methods like sine-triangular, SVM, and 120 - 60 - 30 Discontinuous PWM consists in the redistribution of the time-length applied for the zero voltage vectors during a fundamental frequency period. This paper presents a unified...
Sensorless Position Measurement Based on PWM Eddy Current Variation for Switched Reluctance Motor
Laurent, Philippe; Multon, Bernard; Hoang, Emmanuel; Gabsi, Mohamed
1995-01-01
This paper proposes a new method for indirect sensing of the rotor position in a switched reluctance motor. The method operates with the rotor eddy current losses produced by the PWM converter switching, regardless of magnetic saturation. Experimental results concerning sensivity and performances are schown in a 6/4 30W 3000rpm SRM.
Performance analysis of SHE-PWM using Fourier Series and Newton-Raphson analysis
Lada, M. Y.; Khiar, M. S. A.; Ghani, S. A.; Nawawi, M. R. M.; Nor, A. S. M.; Yuen, J. G. M.
2015-05-01
The performance of inverter has become a vital role in contributing effective power system nowadays. However the major issue that will reduce the inverter performance is the harmonic distortions that contribute to power losses. Thus, there are a variety of controls techniques have been implemented for inverters switching such as square wave, SHE-PWM, unipolar and bipolar. The square wave type inverter produces output voltage in square shape which has simple logic control and power switches. Next, unipolar and bipolar techniques are using comparator to compare the reference voltage waveform with the triangular waveform. The difference between unipolar and bipolar is there are two reference signals which are compared with the triangular waveform for unipolar switching. On the other hand, bipolar switching compares triangular waveform with a reference signal. Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is another control technique for inverters. This research propose SHE-PWM as a low switching frequency strategy that uses Fourier Series and Newton-Raphson analysis to calculate the switching angles for elimination of harmonic distortion. Fourier Series is used to determine the amplitude of any odd harmonic in the output signal whereas Newton-Raphson is used to solve the equation for finding switching angles. As a result, SHE-PWM can select the low frequency harmonic components need to be eliminated and reduce the harmonic distortion. It also prevents the harmonic distortion that sensitive to the inverter performance
Prediction of 2-level PWM inverter efficiency using MATLAB/Simulink
Kim, Yoon-Ho; Kim, Seong-Je
2015-10-01
This article proposes a direct approach for the prediction of inverter efficiency using MATLAB/Simulink, instead of an indirect loss calculation approach based on analytical models. In analytical approach, efficiency is obtained by calculating individual losses separately, such as switching losses, conduction losses and harmonic losses using analytical models. However, this approach requires accurate analytical models and complicated calculations, due to the variation in the switching frequency, switching transient and modulation techniques. In the proposed approach, the actual waveform of the inverter system is directly generated using MATLAB/Simulink. The instantaneous voltage and current waveform including switching transients are generated. Thus, the proposed approach is very simple and convenient for efficiency prediction. The proposed approach also works for any system parameters or control methods, such as various pulse-width modulation (PWM) techniques, different switching frequencies, switching devices and load types. The proposed approach can be adopted for the efficiency prediction of any switching strategies and any types of inverters such as neutral-point-clamped (NPC) inverters, H bridge inverters and H5 topology, since the topologies are modelled as circuits in the MATLAB/Simulink program and no analytical model is required for the proposed approach. Furthermore, the proposed approach can provide operation techniques and conditions such as PWM techniques and switching frequency that offer high efficiency. In this article, inverter performance is evaluated for various PWM techniques and switching frequencies. The PWM technique and switching frequency that offer high efficiency is obtained. Finally, the proposed approach is verified by experimental results.
Development and Tests of PWM Amplifier for Driving the Piezoelectric Elements
Matiulko, J; Przygoda, K
2010-01-01
The paper describes the design and research work carried out to prepare the prototype of pulse amplifier. The work was aimed to describe main operational parameters of PWM amplifiers enabling using them to control the piezoelectric actuators used for active compensation of Lorentz force detuning of superconducting cavities.
The PWM auto-control circuit of neutron tube atmospheric pressure
Ion source atmospheric pressure auto-control circuit for C/O logging neutron generator is introduced. The pulse circuit of ion source adopts zero-voltage quasi-resonant switch technique and the heating circuit for replenisher adopts PWM converter
The comparison of radiosensitivity of human lymphocytes stimulated with PHA Con A and PWM
The transformation, DNA strand breaks and its repair ability in human peripheral blood lymphocytes stimulated with PHA, Con A and PWM were respectively assessed following exposure to 60Co gamma rays by 3H-thymidine uptake and hydroxylapatite chromatography. It was showed the transformation of lymphocytes stimulated with PHA, Con A and PWM were suppressed by gamma rays and the dose-effect curves were biphase within the range of 0∼8 Gy. The lymphocytes stimulated with PWM was the most resistant to gamma rays. The extent of DNA strand breaks in lymphocytes induced by gamma rays was linearly related to the dose within the range of 0∼30 Gy and was identical in three kinds of lymphocytes. After post-irradiation incubation of 37 deg C, the DNA strand breaks could be repaired incompletely and after maxium repair the strand breaks were observed again. The repair ratio of strand breaks in the lymphocytes stimulated with PWM was the highest in the cells with three mitogens. The results showed that the difference of radiation effect on the transformation is probably related to the repair ability of DNA strand breaks
Led spectral and power characteristics under hybrid PWM/AM dimming strategy
Beczkowski, Szymon; Munk-Nielsen, Stig
2010-01-01
In order to dim LEDs the pulse width modulation (PWM) or amplitude modulation (AM) dimming scheme is typically used. Previous studies show that these dimming schemes can have opposite effects on diodes peak wavelength shift. An experimental study was conducted to test the behavior of InGaN diodes...
Analytical Modelling of Periodical PWM Converter Fed R-L Load
Klíma, J.; Schreier, Luděk
Orlando, Florida : International Institute of Informatics and Systemics, 2003, s. 406-411. ISBN 980-6560-01-9. [World Multiconference on Systemics, Cybernetics and Informatics - SCI 2003 /7./. Orlando, Florida (US), 27.07.2003-30.07.2003] Institutional research plan: CEZ:AV0Z2057903 Keywords : analytical model * periodical PWM * Laplace transform Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Active and reactive power control of a current-source PWM-rectifier using space vectors
Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics
1997-12-31
In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.
HAMEDANI, P.
2016-08-01
Full Text Available Multicarrier based PWM switching patterns are commonly utilized to control Cascaded H-bridge (CHB inverters. The main contribution of this paper is to comprehensively investigate the effect of various multicarrier based PWM techniques on harmonic content of the CHB multilevel inverter. In order to achieve this, both of the CHB output voltage and the input current at power grid side have been taken into account. In this work, various PWM modulations such as level shifted (LS, phase shifted (PS, hybrid, and rotative-LS (R-LS have been studied through both simulation and implementation of an experimental setup. By extracting the frequency spectrum and calculation of THD and WTHD indices, a quantitative comparative study of various multicarrier PWM techniques has been carried out. According to the results, the R-LS-PWM methods (i.e. R-PD, and two new proposed R-POD and R-APOD reduce the harmonic distortion of the input current while keeping the obvious advantage of LS-PWM modulation such as lower harmonic distortion of the output voltage. Specially, the proposed R-APOD-PWM modulation offers these preferable privileges at odd frequency ratio values.
Parallel Interleaved VSCs: Influence of the PWM Scheme on the Design of the Coupled Inductor
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Maheshwari, Ram Krishan;
2014-01-01
The line current ripple and the size of the dc-link capacitor can be reduced by interleaving the carriers of the parallel connected Voltage Source Converters (VSCs). However, the interleaving of the carriers gives rise to the circulating current between the VSCs, and it should be suppressed. To...
Gohil, Ghanshyamsinh Vijaysinh; Maheshwari, Ram Krishan; Bede, Lorand;
2015-01-01
Parallel voltage-source converters (VSCs) require an inductive filter to suppress the circulating current. The size of this filter can be minimized by reducing either the maximum value of the flux linkage or the core losses. This paper presents a modified discontinuous pulsewidth modulation (DPWM...
Turki Y. Abdalla
2010-12-01
Full Text Available This paper presents a method for improving the speed profile of a three phase induction motor in direct torque control (DTC drive system using a proposed fuzzy logic based speed controller. A complete simulation of the conventional DTC and closed-loop for speed control of three phase induction motor was tested using well known Matlab/Simulink software package. The speed control of the induction motor is done by using the conventional proportional integral (PI controller and the proposed fuzzy logic based controller. The proposed fuzzy logic controller has a nature of (PI to determine the torque reference for the motor. The dynamic response has been clearly tested for both conventional and the proposed fuzzy logic based speed controllers. The simulation results showed a better dynamic performance of the induction motor when using the proposed fuzzy logic based speed controller compared with the conventional type with a fixed (PI controller.
Ibagon, Ingrid; Bier, Markus; Dietrich, S
2016-06-22
The three-phase contact line formed by the intersection of a liquid-vapor interface of an electrolyte solution with a charged planar substrate is studied in terms of classical density functional theory applied to a lattice model. The influence of the substrate charge density and of the ionic strength of the solution on the intrinsic structure of the three-phase contact line and on the corresponding line tension is analyzed. We find a negative line tension for all values of the surface charge density and of the ionic strength considered. The strength of the line tension decreases upon decreasing the contact angle via varying either the temperature or the substrate charge density. PMID:27116050
Modeling and control of three phase rectifier with electronic smoothing inductor
Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole;
2011-01-01
This paper presents a simple, direct method for deriving the approximate, small-signal, average model and control strategy for three-phase diode bridge rectifier operating with electronic smoothing technique. Electronic smoothing inductor (ESI) performs the function of an inductor that has...... controlled variable impedance. This increases power factor (PF) and reduces total harmonic distortions (THDs) in mains current. The ESI based rectifier enables compact and cost effective design of three phase electric drive as size of passive components is reduced significantly. In order to carry out...... stability and voltage regulation studies, the average, small-signal, dynamic model and control strategy of the ESI is developed and validated by simulation and laboratory measurements....
Analysis of three-phase power-supply systems using computer-aided design programs
A major concern of every designer of large, three-phase power-supply systems is the protection of system components from overvoltage transients. At present, three computer-aided circuit design programs are available in the Magnetic Fusion Energy (MFE) National Computer Center that can be used to analyze three-phase power systems: MINI SCEPTRE, SPICE I, and SPICE II. These programs have been used at Lawrence Livermore Laboratory (LLL) to analyze the operation of a 200-kV dc, 20-A acceleration power supply for the High Voltage Test Stand. Various overvoltage conditions are simulated and the effectiveness of system protective devices is observed. The simulated overvoltage conditions include such things as circuit breaker openings, pulsed loading, and commutation voltage surges in the rectifiers. These examples are used to illustrate the use of the computer-aided, circuit-design programs discussed in this paper