Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation
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MILOUD, Y.
2010-08-01
Full Text Available This paper proposes the space vector pulse width modulation (SVPWM control scheme for three-phase voltage source PWM rectifier. The control system based on SVPWM includes two PI controllers which are used to regulate the AC currents and DC-link voltage. The proposed control can stabilize the minimum of the systems storage function at the desired equilibrium point determined by unity power factor and sinusoidal current on the AC side, and constant output voltage on the DC side. So the stable state performance and robustness against the load?s disturbance of PWM rectifiers are both improved. The simulation result shows feasibility of this strategy.
Research on Passivity Based Controller of Three Phase Voltage Source PWM Rectifier
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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.
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
International Nuclear Information System (INIS)
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
Directory of Open Access Journals (Sweden)
S. Manivannan, S. Veerakuma
2014-01-01
Full Text Available 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, because of their easier digital realization and better DC bus utilization. The study of SVPWM technique reveals that this technique utilizes DC bus voltage more efficiently and generates less harmonic distortion when compared with sinusoidal PWM techniques. The SVPWM technique has become one of the important PWM technique for Three Phase Voltage Source Inverter for the control of AC induction motor, Brushless DC motor, Switched Reluctance motor and Permanent Magnet Synchronous motor. In this paper having collection of different schemes in SVPWM. Specifically various schemes are Center aligned two level SVPWM, Level shifted multi-carrier concepts based SVPWM, and Third order harmonic injection based modulated reference waveform generation and comparison in SVPWM. This paper having simulation results of all the three schemes of SVPWM by using MATLAB/SIMULINK software. The performance of Three Phase Voltage Source Inverter fed induction motor drive based on various SVPWM schemes are analyzed by various reference parameters like DC bus utilization, Total harmonic distortion (THD, switching stress and efficiency. As a result of these analysis this paper recommends which scheme is more suitable for variable voltage and various frequency drives. The simulation results are provided to validate the proposed model approaches.
Miller, Stephanie Katherine Teixeira
Of all the alternative and renewable energy sources, wind power is the fastest growing alternative energy source with a total worldwide capacity of over 93 GW as of the end of 2007. However, making wind energy a sustainable and reliable source of electricity doesn't come without its set of challenges. As the wind turbines increase in size and turbine technology moves towards off-shore wind farms and direct drive transmission, the need for a reliable and efficient power electronics interface to convert the variable-frequency variable-magnitude output of the wind turbine's generator into the fixed-frequency fixed-magnitude voltage of the utility grid is critical. This dissertation investigates a power electronics interface envisioned to operate with an induction generator-based variable-speed wind turbine. The research conclusions and the interface itself are applicable to a variety of applications, including uninterruptible power supplies, industrial drives, and power quality applications, among others. The three-phase PWM rectifiers with ac-side bidirectional switches are proposed as the rectification stage of the power electronics interface. Modulation strategies are proposed for the rectifiers and the operation of the rectifiers in conjunction with an induction generator is demonstrated. The viability of using these rectifiers in place of the standard three-phase voltage-source converter is analyzed by comparing losses and common-mode voltage generation of the two topologies. Parallel three-phase voltage-source converter modules operated in an interleaved fashion are proposed for the inversion stage of the power electronics interface. The interleaved three-phase voltage-source converters are analyzed by deriving analytical models for the common-mode voltage, ac phase current, and dc-link current to reveal their spectra and the harmonic cancellation effects of interleaving. The practical problem of low frequency circulating current in parallel voltage-source converters is also analyzed. The low frequency circulating current characteristics of abc, dq, and nonlinear average current control are determined and experimental results for the nonlinear average current control are presented.
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...
A Comprehensive Study of Modulation Strategies for Three Phase Low Cost PWM Converter
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S. BHATTACHARYA
2011-07-01
Full Text Available A three phase voltage source converter using six power switches is a very important structure with wide variety of applications involving sophisticated ac drives, active power filters and power supplies etc. PWM voltage source inverters are also being incorporated in grid connected distributed power generating units to provide secure and reliable power to the utility grid. Due to the popularity of three-phase PWM converters there have been efforts in reducing the component count in these power electronic converters as a cost effective substitute. These researches led to the development of four-switch converter topology. The four switches present in thepower circuit can be controlled in various ways to deliver the desired characteristics of sinusoidal source current, ability to deliver unity or even leading power factor, bidirectional power flow. To obtain such characteristics of the converter, various control techniques have been envisaged and implemented. The other PWM strategies have their own advantages and disadvantages. In this paper a study of the various control methods applied to four-switch PWM converter is presented are presented along with their performancecomparison.
Control and Modeling of Shaft Generator with PWM Voltage Source Inverter for ship
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Sathish Kumar T
2012-07-01
Full Text Available This papers deals with well – based mathematicalmodeling of variable speed alternator (Shaft Generator withPWM voltage source inverter used in ship. Detailed knowledge ofelectromagnetic characteristics of shaft generator is necessary fordesign complex ship's power system. Such knowledge isobtainable only by numerical simulations. The dynamic behaviorof shaft generators, SPWM voltage source inverter and theircontrollers during load variations are also discussed with the helpof MATLAB/SIMULINK. Elimination of harmonic contentsusing sinusoidal pulse width modulation also discussed here.
Reduced Snubber Circuit Elements For Pwm Voltage Source Inverter
Saied, Basil M.
2002-01-01
This paper presents the description and simulation of a new proposed arrangement of RLD/RCD snubber circuit used with pulse width modulated voltage source inverter. The new arrangement allows minimizing the number of active elements of RCD with 50%. This will help the designer to reduce the size of the system. SPICE programming package is used as principal simulation tool. A detailed simulation given that includes the sever effects of snubber diode reverse recovery current, as well as, the ef...
Shunt PWM advanced var compensators based on voltage source inverters for Facts applications
Energy Technology Data Exchange (ETDEWEB)
Barbosa, Pedro G.; Misaka, Isamu; Watanabe, Edson H. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia
1994-12-31
Increased attention has been given to improving power system operation. This paper presents modeling, analysis and design of reactive shunt power compensators based on PWM-Voltage Source Inverters (Pulse Width Modulation -Voltage Source Inverters). (Pulse Width Modulation - Voltage Source Inverters). The control algorithm is based on new concepts of instantaneous active and reactive power theory. The objective is to show that with a small capacitor in the side of a 3-phase PWM-VSI it is possible to synthesize a variable reactive (capacitive or inductive) device. Design procedures and experimental results are presented. The feasibility of this method was verified by digital simulations and measurements on a small scale model. (author) 9 refs., 12 figs.
Current Tracking Control of Voltage Source PWM Inverters Using Adaptive Digital Signal Processing
Fukuda, Shoji; Furukawa, Yuya
An active filter (AF) is required to have a high control capability of tracking a time-varying current reference. However, a steady-state current error always exists if a conventional proportional and integral (PI) regulator is used because the current reference varies in time. This paper proposes the application of adaptive digital signal processing (ADSP) to the current control of voltage source PWM inverters. ADSP does not require any additional hardware. It can automatically minimize the mean square-error. Since the processing time available by a computer is limited, ADSP cannot eliminate higher order harmonics but can eliminate lower order harmonics such as 5th to 17th. Experimental results demonstrate that ADSP is useful for improving the reference tracking performance of voltage source inverters.
A Novel PWM Scheme for a Three-Level Voltage Source Inverter Fed Induction Motor
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J. Amarnath
2009-03-01
Full Text Available This paper presents a space vector PWM scheme for a three level GTO voltage source inverter fed induction motor. This SVPWM method provides high safety voltages with less harmonic components compared to two level structures and reduces the switching losses by limiting the switching to the two thirds of the pulse duty cycle. The principle of SVPWM method and voltage vector selection procedure for two level and three level inverters are described in detail. The theoretical study was numerically simulated and high power and high voltage three-level GTO inverters applied to induction motors drives.
Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter
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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
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Adrian ?chiop
2008-05-01
Full Text Available 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.
Simulation Study of the Carrier-Based PWM Method in Three- Phase Flying Capacitor Inverters
Adrian ?chiop
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.
An Integrated Inductor For Parallel Interleaved Three-Phase Voltage Source Converters
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand
2015-01-01
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 current filtering requirement can be reduced. However, an additional inductive filter is required to suppress the circulating current. The integrated inductive component, which combines the functionality of the line filter inductor and the circulating current inductor is presented in this paper. An analysis of the flux density distribution in the integrated inductor is presented and design procedure is described. The analysis has been also verified by performing finite element analysis. The advantage offered by the use of the integrated inductor is demonstrated by comparing its volume with the volume of the state-of-the-art filtering solution. The performance of the integrated inductor is also verified by the experimental measurements.
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Ajay Kumar Maurya, Kishore Chahar, Y. K. Chauhan
2013-03-01
Full Text Available 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 thefiltering requirements and reduce the amplitude ofall harmonics at the output of the inverter. ThePower quality improves by reducing the harmonicslevel. The complete simulation model is simulatedin MATLAB/SIMULINK and validates thetheoretical considerations
Sunil Kumar Chaudhary; Z.A. Jaffery
2012-01-01
The authors present the design, simulation and analysis of a single phase voltage source inverter using soft switching techniques. The performance of the inverter has been compared in terms of harmonic contents present in output voltage and current. The research works for a PWM inverter along with a LLCC filter has been investigated. This paper also investigated the performance of the same inverter with a feedback controller with a closed loop feedback path to maintain rated output voltage. T...
Control Method Compensating for Unbalanced Three-Phase Voltage Supply in Voltage Source Inverter.
Czech Academy of Sciences Publication Activity Database
Chomát, Miroslav; Schreier, Lud?k; Bendl, Ji?í
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 ?R GA102/02/0554 Keywords : voltage source inverter * unbalanced voltage supply * pulse width modulation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
B. Muralidhara,; Ramachandran, A.; A. Srinivasan,; M. Channa Reddy
2010-01-01
This paper presents the space vector definitions for the flux, current and the voltage in a three phase system. In this paper, a Space Vector PWM signal generation for a conventional 3-phase inverter by comparing the reference phase voltages with the reference voltage vector is presented. The sector in which the tip of the reference vector lies is found out and the proposed Space Vector-PWM (SVPWM) method generates the inverter leg switching times, from the sampled reference phase voltage amp...
DEFF Research Database (Denmark)
Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi; Teodorescu, Remus
2011-01-01
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 three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models of 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 vir...
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe
2012-01-01
The virtual output impedance loop is known as an effective way to enhance the load sharing stability and quality of droop-controlled parallel inverters. This paper proposes an improved design of virtual output impedance loop for parallel three-phase voltage source inverters. In the approach, a virtual output impedance loop based on the decomposition of inverter output current is developed, where the positive- and negative-sequence virtual impedances are synthesized separately. Thus, the negative...
DEFF Research Database (Denmark)
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 mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two levels. The primary control includes the ...
CONTROL TECHNIQUES FOR VARIOUS BIPOLAR PWM STRATEGIES OF THREE PHASE FIVE LEVEL CASCADED INVERTER
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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.
Three-Phase Voltage Source Inverter with Compensation of Unbalanced Voltage Supply.
Czech Academy of Sciences Publication Activity Database
Chomát, Miroslav; Schreier, Lud?k; Bendl, Ji?í
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 ?R(CZ) GA102/04/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : unbalanced voltage supply * voltage source inverter * pulse width modulation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Directory of Open Access Journals (Sweden)
Sunil Kumar Chaudhary
2012-10-01
Full Text Available The authors present the design, simulation and analysis of a single phase voltage source inverter using soft switching techniques. The performance of the inverter has been compared in terms of harmonic contents present in output voltage and current. The research works for a PWM inverter along with a LLCC filter has been investigated. This paper also investigated the performance of the same inverter with a feedback controller with a closed loop feedback path to maintain rated output voltage. This work is helpful for the inverter used in application where high quality ac wave is prime requirement
A Review of Passive Power Filters for Three-Phase Grid Connected Voltage-Source Converters
DEFF Research Database (Denmark)
Beres, Remus Narcis; Wang, Xiongfei; Liserre, Marco; Blaabjerg, Frede; Bak, Claus Leth
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 load...... the utility grid are reviewed, and evaluated in terms of damping capability, stored energy in the passive components and power loss in the damping circuit. Additionally, the influences of different switching frequencies of power converters on the passive filter design are also discussed in the range...... and source impedances. Furthermore, the stabilizing effect is more difficult to be guaranteed for cost-optimized filters, which are characterized by low inductance and high capacitance passive components. In this paper, several passive filter topologies used to interface voltage source converters with...
Integrated inductor for interleaved operation of two parallel three-phase voltage source converters
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh; Bede, Lorand
2015-01-01
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 instantaneous potential difference, caused by the interleaved carriers, may drive large circulating current between the parallel VSCs and an additional inductor is often placed in the circulating current path to suppress the current to an acceptable limit. Integration of both line filter inductor and circulating current filter inductor is proposed. The flux in the magnetic structure is analyzed and the values of the line filter inductance and circulating current filter inductance are derived. Steady-state and the transient performance of the system has been verified by means of simulation and experimental results.
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 intel...
A Novel Three-Phase UPS Inverter Driven by Error-Tracking-Mode PWM Scheme
Ohshima, Masaaki; Nakamura, Fuminori; Tamai, Shinzo; Yamamoto, Yuushin; Yoshida, Kouichi
With prevalence of information technology into our modern society and advance of automation technology in modern production process, the UPS market is assumed to make sustainable expansion. Error-Tracking-Mode PWM scheme offers novel constantly-sampled current-regulated switching algorithm to voltage-source power converters. This paper proposes a UPS in which Error-Tracking-Mode PWM scheme is applied to the current minor loop. The upper voltage control loop (ac-AVR) is developed afresh, that makes best of the PWM attributes. The equivalent output impedance of the UPS is derived theoretically for not only small signal but also large signal operation, that value can be arbitrarily specified by the ac-AVR parameters. A 3 kVA experimental setup was designed and fabricated, which has demonstrated the theoretical characteristics satisfactorily. The paper discusses the experimental results in detail. The authors believe that the paper presents a clue to realize independent and autonomic operation of dispersed PWM converters.
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Zhongjiu Zheng
2011-08-01
Full Text Available The paper describes a microcomputer control system, which uses the floating-point digital signal processor TMS320LF2407 from Texas Instruments, for three-phase PWM rectifier. Â It could effectively eliminate harmonic distortion of line currents and provides power factor correction. Moreover, it can be save electrical energy and reduction of production cost. In the control system, the predictive current control in two-dimensional (Î±-Î² stationary frame, makes the input current following the phase voltage in phase to get unity power factor; and space vector pulse wide modulation (SVPWM generates the modulation wave. Finally, the three-phase PWM rectifier using the proposed control system is designed in Simulink/Matlab and executed in laboratory prototype, and the results are provided to verify the proposed control system in the end of the paper.
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B. Muralidhara,
2010-10-01
Full Text Available This paper presents the space vector definitions for the flux, current and the voltage in a three phase system. In this paper, a Space Vector PWM signal generation for a conventional 3-phase inverter by comparing the reference phase voltages with the reference voltage vector is presented. The sector in which the tip of the reference vector lies is found out and the proposed Space Vector-PWM (SVPWM method generates the inverter leg switching times, from the sampled reference phase voltage amplitudes in a sampling interval. Here Vdc is the conventional three phase inverter DC link voltage. To generate gating signals PIC Î¼- controller is used in addition to the interface circuit. The present work explains the gating signal generation and implementation by SVPWM using Î¼- controller.
Converter-flux-based current control of voltage source PWM rectifiers - analysis and implementation
Energy Technology Data Exchange (ETDEWEB)
Poellaenen, R.
2003-07-01
Pulsewidth-modulated (PWM) rectifier technology is increasingly used in industrial applications like variable-speed motor drives, since it offers several desired features such as sinusoidal input currents, controllable power factor, bidirectional power flow and high quality DC output voltage. To achieve these features, however, an effective control system with fast and accurate current and DC voltage responses is required. From various control strategies proposed to meet these control objectives, in most cases the commonly known principle of the synchronous-frame current vector control along with some space-vector PWM scheme have been applied. Recently, however, new control approaches analogous to the well-established direct torque control (DTC) method for electrical machines have also emerged to implement a high-performance PWM rectifier. In this thesis the concepts of classical synchronous-frame current control and DTC-based PWM rectifier control are combined and a new converter-flux-based current control (CFCC) scheme is introduced. To achieve sufficient dynamic performance and to ensure a stable operation, the proposed control system is thoroughly analysed and simple rules for the controller design are suggested. Special attention is paid to the estimation of the converter flux, which is the key element of converter-flux-based control. Discrete-time implementation is also discussed. Line-voltage-sensorless reactive reactive power control methods for the L- and LCL-type line filters are presented. For the L-filter an open-loop control law for the d-axis current reference is proposed. In the case of the LCL-filter the combined open-loop control and feedback control is proposed. The influence of the erroneous filter parameter estimates on the accuracy of the developed control schemes is also discussed. A new zero vector selection rule for suppressing the zero-sequence current in parallel-connected PWM rectifiers is proposed. With this method a truly standalone and independent control of the converter units is allowed and traditional transformer isolation and synchronised-control-based solutions are avoided. The implementation requires only one additional current sensor. The proposed schemes are evaluated by the simulations and laboratory experiments. A satisfactory performance and good agreement between the theory and practice are demonstrated. (orig.)
Research on Three-phase Voltage Type PWM Rectifier System Based on SVPWM Control
Haoran Shi; Wei Xu; Chenghua Fu; Yao Yang
2013-01-01
The fundamental principle of SVPWM is introduced in this study. The design on the structure of three-phase voltage type PWM rectifier system based on SVPWM control was also discussed. Then we calculate the DC capacitor and AC side inductance. The computer simulation tool MATLAB/Simulink is taken and the result is shown in the end. The result indicates that the design of such platform is feasible.
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...
DEFF Research Database (Denmark)
Vasquez, Juan Carlos; Guerrero, Josep M.
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 mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two 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. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control architecture.
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M.S.Priyadarshini
2015-02-01
Full Text Available The performance analysis of three phase three wire voltage source inverter based unified power quality conditioner (UPQC with a control configuration is implemented in this paper. UPQC is utilized for power quality improvement at distribution level. The operation of UPQC combines the operations of series component Dynamic Voltage Restorer (DVR and shunt component Distribution Static Compensator (DSTATCOM together. The series component of the UPQC inserts voltage so as to maintain the voltage at the point of common coupling balanced and free of distortion. Simultaneously, the shunt component of the UPQC injects current into the system such that the currents entering the bus to which the UPQC is connected are balanced sinusoids. Both these objectives must be met irrespective of unbalance or distortion in either source or load sides. When UPQC is used in a power distribution system, the series and shunt active filters of the UPQC are made to operate in an effective and efficient unified manner. The control strategy should be able to reduce the negative effects of the variations in distorted supply voltage and the nonlinear load current. The control signals, generated by the various functional modules of the control design circuit Discrete Proportional IntegralController. Phase Locked Loop and Discrete Pulse Width Modulation Generator, will be the switching schemes for the series and shunt active filters of the UPQC to provide simultaneous shunt and series compensation in a power distribution system. The validation of performance analysis of three phase three wire voltage source inverter based unified power quality conditioner is verified through simulation inMatlab.
Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive
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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.
Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor
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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.
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...
A Fuzzy-Logic-Based Controller for Three-Phase PWM Rectifier With Unity Power Factor Operation
A. Bouafia; F. Krim
2008-01-01
In this paper, direct power control (DPC) of three-phase PWM rectifiers based on fuzzy logic controller is presented, without line voltage sensors. The control technique is built upon the ideas of the well known direct torque control (DTC) for induction motors. 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 proposed fuzzy logic controller...
Indian Academy of Sciences (India)
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 (aâ€“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.
DEFF Research Database (Denmark)
Lar, Ionut Andrei; Radulescu, Mircea; Ritchie, Ewen; Pop, Adrian Augustin
2012-01-01
A comparison between two current control methods of grid side inverter, PI current control and Robust Forward control is made. PI control is implemented in d-q synchronous frame while Forward is implemented in abc stationary frames.The report contains both simulations and experimental test wich were made at a reduced scale ( 2.2 kW). The constant power test showed that both method have good results which can respect existing grid codes. The constant power test showed that both method have good r...
Directory of Open Access Journals (Sweden)
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.
An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Xiaobo Dou
2015-07-01
Full Text Available Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary frame to suppress the transient fluctuations and the total harmonic distortion (THD of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load. The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.
BENSLIMANE, Tarak; ABDELKRIM, Thameur
2012-01-01
OPEN SWITCH FAULTS DETECTION AND LOCALIZATION ALGORITHM FOR THREE PHASE SHUNT ACTIVE POWER FILTER BASED ON TWO LEVEL VOLTAGE SOURCE INVERTER IN MAIN POWER SUPPLY CONSTANT AND VARIABLE FREQUENCY CONDITIONS
A Fuzzy-Logic-Based Controller for Three-Phase PWM Rectifier With Unity Power Factor Operation
Directory of Open Access Journals (Sweden)
A. Bouafia
2008-03-01
Full Text Available In this paper, direct power control (DPC of three-phase PWM rectifiers based on fuzzy logic controller is presented, without line voltage sensors. The control technique is built upon the ideas of the well known direct torque control (DTC for induction motors. 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 proposed fuzzy logic controller presents the advantage to be based on linguistic description and does not require a mathematical model of the system. The controller ensures a good regulation of the output voltage, and guarantees the power factor close to one. The simulation results show that the designed fuzzy controller has a good dynamic behavior, a good rejection of impact load disturbance, and is very robust.
Analytical Modeling and Implementation of Three-Phase Four-Switch Space-Vector PWM Converter.
Czech Academy of Sciences Publication Activity Database
Paclt, Zden?k; Šimek, Petr; Škramlík, Ji?í; 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 ?R 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
Directory of Open Access Journals (Sweden)
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.
Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor
Latif, M. A.; Alam, M. J.; 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...
DEFF Research Database (Denmark)
Kouchaki, Alireza; Niroumand, Farideh Javidi; Haase, Frerk; Nymand, Morten
2015-01-01
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 analyzes the inductor voltage/current for sinusoidal pulse width modulation technique. Accordingly, the maximum current ripple as a function of the dc link voltage is derived and the minimum required inductance...
DEFF Research Database (Denmark)
Kouchaki, Alireza; Niroumand, Farideh Javidi
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 analyzes the inductor voltage/current for sinusoidal pulse width modulation technique. Accordingly, the maximum current ripple as a function of the dc link voltage is derived and the minimum required inductance value is calculated. To explain the copper and the core losses in the inductor, the single-phase equivalent circuit is used to provide the inductor current harmonic spectrum. Therefore, using the harmonic spectrum, the low and high frequency copper losses are calculated. The high frequency minor B-H loops in one switching cycle are also analyzed. Then, the loss map provided by the measurement setup is used to calculate the core loss in the PFC application. To investigate the impact of the dc link voltage level, two inductors for different dc voltage levels are designed and the results are compared.
International Nuclear Information System (INIS)
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 ?-? 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.
Energy Technology Data Exchange (ETDEWEB)
Bouafia, Abdelouahab, E-mail: bouafia_aou@yahoo.f [Laboratoire d' Electronique de Puissance et Commande Industrielle (LEPCI), Universite de Setif, Departement d' electronique, Route de Bejaia, Setif (Algeria); Gaubert, Jean-Paul, E-mail: Jean.Paul.Gaubert@univ-poitiers.f [Laboratoire d' Automatique et d' Informatique Industrielle (LAII), ESIP, Universite de Poitiers (France); Krim, Fateh, E-mail: krim_f@ieee.or [Laboratoire d' Electronique de Puissance et Commande Industrielle (LEPCI), Universite de Setif, Departement d' electronique, Route de Bejaia, Setif (Algeria)
2010-12-15
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 {alpha}-{beta} 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.
Comparative analysis of SPWM and SVPWM control for three phase inverter
Directory of Open Access Journals (Sweden)
K. Vinoth Kumar
2010-07-01
Full Text Available 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 reference modulating signals are compared against a common triangular carrier to generate the PWM signals for the three phases. In SVPWM methods, a revolving reference voltage vector is provided as voltage reference instead of three phase modulating waves. The magnitude and frequency of the fundamental component in the line side are controlled by the magnitude and frequency, respectively, of the reference vector. The highest possible peak phase fundamental is very less in sine triangle PWM when compared with space vector PWM. Space Vector Modulation (SVM technique has become the important PWM technique for three phase voltage source inverters for the control of AC Induction, Brushless DC, Switched Reluctance and Permanent Magnet Synchronous Motors. The study of space vector modulation technique reveals that space vector modulation technique utilizes DC bus voltage more efficiently and generates less harmonic distortion when compared with Sinusoidal PWM (SPWM technique. In this paper first a model for Space vector PWM is made and simulated using MATLAB/SIMULINK software and its performance is compared with Sinusoidal PWM. The simulation study reveals that Space vector PWM utilizes DC bus voltage more effectively and generates less THD when compared with sine PWM.
DEFF Research Database (Denmark)
Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede; Ojo, Joseph Olorunfemi; Wheeler, Patrick William
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...
DEFF Research Database (Denmark)
Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede; Ojo, Joseph Olorunfemi; Wheeler, Patrick William
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 synch...
International Nuclear Information System (INIS)
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.
Energy Technology Data Exchange (ETDEWEB)
Deshmukh, Ram; Moses, A.J. [Wolfson Centre for Magnetics, Cardiff School of Engineering, Queens Building, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); Anayi, F. [Wolfson Centre for Magnetics, Cardiff School of Engineering, Queens Building, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom)], E-mail: spefja@cardiff.ac.uk
2008-10-15
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.
International Nuclear Information System (INIS)
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 120Â° 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 120Â° coil pitch is recommended to be used under sinusoidal and PWM voltage supplies.
DEFF Research Database (Denmark)
Padmanaban, Sanjeevikumar; Grandi, Gabriele
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 results are provided in this paper, which confirms a good agreement with theoretical development.
Czech Academy of Sciences Publication Activity Database
Klíma, J.; Škramlík, Ji?í; 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
Czech Academy of Sciences Publication Activity Database
Klíma, J.; Škramlík, Ji?í; 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 ?R IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch PWM rectifier * space vector modulation * unbalance supply Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Directory of Open Access Journals (Sweden)
M. E. Oliveira Filho
2010-10-01
Full Text Available Com o avanço da tecnologia dos dispositivos semicondutores de potência os inversores de frequência atuam de forma importante em toda indústria. O inversor de frequência convencional contém elementos armazenadores de energia no seu elo de corrente contínua. Estes elementos armazenadores de energia são capacitores eletrolíticos e possibilitam manter a tensão do elo de corrente contínua constante. Entretanto, quanto maior sua capacitância maior é a distorção da corrente de entrada. Com a substituição do banco de capacitores eletrolíticos por um capacitor de filme, diminui-se a distorção nas correntes de entrada, porém distorções indesejadas aparecem na tensão do elo de corrente contínua e também nas correntes de saída. Estas distorções são compostas por componentes harmônicas de baixas frequências. O conversor em matriz trifásico-trifásico por sua vez, possibilita a transferência direta de energia da entrada (rede diretamente para a saída (carga sem a necessidade de elementos armazenadores de energia como acontece no inversor de frequência. Entretando o desbalanceamento das tensões da entrada afetam diretamente a forma de onda das tensões da saída. Dessa maneira, este trabalho propõe um método de controle de corrente do conversor em matriz e do inversor de frequência sem banco de capacitores do elo de corrente contínua com objetivo de compensar o desbalanceamento das tensões de saída do conversor em matriz e compensar também as componentes harmônicas de baixa frequência que aparecem nas correntes de saída do inversor de frequência. O método proposto utiliza um controlador do tipo PI e modulação por vetores espaciais para que a frequência de acionamento das chaves dos conversores seja constante.Voltage source three-phase inverter plays an important role in modern industry. The conventional voltage source inverter has a large electrolytic capacitor as energy store element in order to keep the DC-link voltage constant. However, a large electrolytic capacitor increases the input current distortion. Replacing the large electrolytic capacitor by a small film capacitor, the input current quality is improved but the DC-link voltage and the output currents are distorted by low order harmonic components. The three phase to three phase matrix converter performs electric energy direct transfer from the input to the output with sinusoidal input current although the distortion and the unbalance of the input voltages affects directly the output of the matrix converter. This paper proposes a load current control method to the matrix converter and also to the voltage source inverter in absence of the dc-link capacitor in order to compensate the distortion caused by low order harmonics components in the output currents. The proposed load current control scheme employs just one PI controller and since that the space vector modulation is used in this control, the switching frequency of the converter is kept constant. Theorical foundation, simulations results and experimental results are presented.
Scientific Electronic Library Online (English)
M. E., Oliveira Filho; A. J., Sguarezi Filho; J. R., Gazoli; E., Ruppert Filho.
2010-10-01
Full Text Available Com o avanço da tecnologia dos dispositivos semicondutores de potência os inversores de frequência atuam de forma importante em toda indústria. O inversor de frequência convencional contém elementos armazenadores de energia no seu elo de corrente contínua. Estes elementos armazenadores de energia sã [...] o capacitores eletrolíticos e possibilitam manter a tensão do elo de corrente contínua constante. Entretanto, quanto maior sua capacitância maior é a distorção da corrente de entrada. Com a substituição do banco de capacitores eletrolíticos por um capacitor de filme, diminui-se a distorção nas correntes de entrada, porém distorções indesejadas aparecem na tensão do elo de corrente contínua e também nas correntes de saída. Estas distorções são compostas por componentes harmônicas de baixas frequências. O conversor em matriz trifásico-trifásico por sua vez, possibilita a transferência direta de energia da entrada (rede) diretamente para a saída (carga) sem a necessidade de elementos armazenadores de energia como acontece no inversor de frequência. Entretando o desbalanceamento das tensões da entrada afetam diretamente a forma de onda das tensões da saída. Dessa maneira, este trabalho propõe um método de controle de corrente do conversor em matriz e do inversor de frequência sem banco de capacitores do elo de corrente contínua com objetivo de compensar o desbalanceamento das tensões de saída do conversor em matriz e compensar também as componentes harmônicas de baixa frequência que aparecem nas correntes de saída do inversor de frequência. O método proposto utiliza um controlador do tipo PI e modulação por vetores espaciais para que a frequência de acionamento das chaves dos conversores seja constante. Abstract in english Voltage source three-phase inverter plays an important role in modern industry. The conventional voltage source inverter has a large electrolytic capacitor as energy store element in order to keep the DC-link voltage constant. However, a large electrolytic capacitor increases the input current disto [...] rtion. Replacing the large electrolytic capacitor by a small film capacitor, the input current quality is improved but the DC-link voltage and the output currents are distorted by low order harmonic components. The three phase to three phase matrix converter performs electric energy direct transfer from the input to the output with sinusoidal input current although the distortion and the unbalance of the input voltages affects directly the output of the matrix converter. This paper proposes a load current control method to the matrix converter and also to the voltage source inverter in absence of the dc-link capacitor in order to compensate the distortion caused by low order harmonics components in the output currents. The proposed load current control scheme employs just one PI controller and since that the space vector modulation is used in this control, the switching frequency of the converter is kept constant. Theorical foundation, simulations results and experimental results are presented.
Optimum space vector PWM algorithm for three-level inverter
Directory of Open Access Journals (Sweden)
B. Urmila
2011-09-01
Full Text Available A Three - Level Voltage Source Inverter is used increasingly to supply a variable frequency and variable voltage for variable speed applications. A suitable pulse width modulation (PWM technique is employed to obtain the required output voltage at the line side of the inverter. This paper studies popular multi-level topology, Diode Clamped or Neutral Point Clamped for three-level. Two methods of Sine-triangle (SPWM and two methods of Space Vector Pulse Width Modulation (SVPWM are employed to generate the modulation wave. These modulation waves are compared against a triangular carrier to generate the PWM signals for the three phases. In SVPWM methods, a revolving reference voltage vector is provided as voltage reference instead of three phase modulating waves used in SPWM. The magnitude and frequency of the fundamental component in the line side are controlled by the magnitude and frequency, respectively, of the reference vector. Space Vector Modulation Technique has become the important PWM technique for three phase Voltage Source Inverters because of its increased dc bus utilization and reduced harmonic distortion compared to SPWM. The four PWM methods are simulated in MATLAB/SIMULINK software and are compared for THD and Capacitor Balance. Programs are carried out using Embedded Editor functions and matlab editor functions. The simulation study reveals that Space vector PWM utilizes dc bus voltage more effectively, generates less THD and improved capacitor balance when compared to sine PWM.
International Nuclear Information System (INIS)
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
Energy Technology Data Exchange (ETDEWEB)
Bouafia, Abdelouahab; Krim, Fateh [Laboratoire d' Electronique de Puissance et Commande Industrielle (LEPCI), Universite de Setif, Departement d' electronique, Route de Bejaia, Setif (Algeria); Gaubert, Jean-Paul [Laboratoire d' Automatique et d' Informatique Industrielle (LAII), ESIP, Universite de Poitiers (France)
2009-01-15
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. (author)
Three-phase Resonant DC-link Converter
DEFF Research Database (Denmark)
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 proced...
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...
Minimization of Harmonics in PWM Inverters Based on Genetic Algorithms
B. Justus Rabi
2006-01-01
This study describes a new approach based on genetic algorithm to suppress the current harmonic contents in output of an inverter. A genetic algorithm is applied to optimize a pulse width modulation (PWM) inverter, which can not only spread harmonic energy but also reduce harmonic distortion. A feasible test is implemented by building a proto type three phase voltage source inverter which is designed and controlled on the basis of proposed considerations. It is verified from a practical point...
THREE-PHASE ACTIVE POWER FILTER CONTROLLER FOR BALANCED AND UNBALANCED NON-LINEAR LOAD
G NAGESWARA RAO; Dr.K. CHANDRA SEKHAR,; Sangameswara Raju, Dr.P.
2010-01-01
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...
DEFF Research Database (Denmark)
Blaabjerg, Frede; Aquila, A. Dell?; Liserre, Marco; Teodorescu, Remus; Vacca, F.; Vergura, S.
2004-01-01
A systematic approach to study dc/ac and ac/dc converters without the use of synchronous transformation is proposed. The use of a frequency-shift technique allows a straightforward analysis of single-phase and three-phase systems. The study of dc/ac and of ac/dc converters is reported to the study of dc/dc converters via a 50 Hz frequency-shift. The input admittance is calculated and measured for two study examples (a three-phase active rectifier and a single-phase photovoltaic inverter). These ...
Space Vector PWM Implementation for Z-Source Inverter
Directory of Open Access Journals (Sweden)
K Veera Reddy
2014-06-01
Full Text Available Space Vector Modulation (SVM Technique has become the most popular and important PWM technique for three phase Voltage Source Inverters. Z-Source Inverters have the ability to boost the dc link voltage, thus increasing the output ac voltage beyond the values reached by conventional inverters. The enhanced ratio from ac output voltage to dc link voltage is possible due to an impedance network connected between the dc power supply and the main converter. This paper presents implementation of Space Vector Modulation technique for Two Level Z Source Inverter using MATLAB.
Directory of Open Access Journals (Sweden)
Mechouma Rabiaa
2014-01-01
Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.
Directory of Open Access Journals (Sweden)
Rudolf Ribeiro Riehl
2012-04-01
Full Text Available A proposta deste trabalho é apresentar uma nova metodologia para determinação experimental das capacitancias parasitas do motor de indução trifásico de rotor em gaiola. As capacitancias parasitas fazem parte do circuito equivalente do motor para estudos de interferência eletromagnética causada no motor de indução em modo comum quando ele for acionado por inversor controlado por modulação por largura de pulsos (MLP. Os procedimentos propostos para o desenvolvimento deste novo método consistem em: a determinação dos parâmetros do circuito equivalente do motor de indução trifásico, em regime permanente, através de ensaio em laboratório; b estabelecer configurações de ligações entre o inversor MLP e o motor para medições das grandezas de interesse que são as seguintes: tensões de modo comum e de eixo, correntes de fuga e de eixo, através de circuito de medição desenvolvido para este fim; c calcular os valores das capacitancias parasitas entre estator e carcaça do motor; estator e rotor; rotor e carcaça e de rolamento utilizando a expressão matemática da definição de capacitancia; d utilizar o software Pspice para simular o sistema motor de indução trifásico, alimentado por inversor MLP, com os circuitos equivalentes em baixas e altas frequências; e obter as formas de onda características do fenômeno de modo comum.Three-phase induction motors present stray capacitances. The aim of this paper is to present a new methodology to experimentally determine these capacitances and also evaluates the effects of electromagnetic interference on the motors in common mode. The proposed procedures to the development of this new methodology consists in: a identification of the motor equivalent electrical circuit parameters through characteristic tests performed in the laboratory; b to set up configurations between PWM inverter and the motor for voltage and current measurements: common mode and shaft voltages, leakage and shaft (bearing currents by using a dedicated measuring circuit; c to calculate the parasitic capacitance values between stator and frame, stator and rotor, rotor and frame and bearings of the motor using the capacitance characteristic equation; d use the dedicated software Pspice to simulate the system composed by the three-phase induction motor fed by PWM inverter with the equivalent electrical circuit parameters; e to determine the characteristic waveforms involved in the common mode phenomenon.
Scientific Electronic Library Online (English)
Rudolf Ribeiro, Riehl; Ernesto, Ruppert.
2012-04-01
Full Text Available A proposta deste trabalho é apresentar uma nova metodologia para determinação experimental das capacitancias parasitas do motor de indução trifásico de rotor em gaiola. As capacitancias parasitas fazem parte do circuito equivalente do motor para estudos de interferência eletromagnética causada no mo [...] tor de indução em modo comum quando ele for acionado por inversor controlado por modulação por largura de pulsos (MLP). Os procedimentos propostos para o desenvolvimento deste novo método consistem em: a) determinação dos parâmetros do circuito equivalente do motor de indução trifásico, em regime permanente, através de ensaio em laboratório; b) estabelecer configurações de ligações entre o inversor MLP e o motor para medições das grandezas de interesse que são as seguintes: tensões de modo comum e de eixo, correntes de fuga e de eixo, através de circuito de medição desenvolvido para este fim; c) calcular os valores das capacitancias parasitas entre estator e carcaça do motor; estator e rotor; rotor e carcaça e de rolamento utilizando a expressão matemática da definição de capacitancia; d) utilizar o software Pspice para simular o sistema motor de indução trifásico, alimentado por inversor MLP, com os circuitos equivalentes em baixas e altas frequências; e) obter as formas de onda características do fenômeno de modo comum. Abstract in english Three-phase induction motors present stray capacitances. The aim of this paper is to present a new methodology to experimentally determine these capacitances and also evaluates the effects of electromagnetic interference on the motors in common mode. The proposed procedures to the development of thi [...] s new methodology consists in: a) identification of the motor equivalent electrical circuit parameters through characteristic tests performed in the laboratory; b) to set up configurations between PWM inverter and the motor for voltage and current measurements: common mode and shaft voltages, leakage and shaft (bearing) currents by using a dedicated measuring circuit; c) to calculate the parasitic capacitance values between stator and frame, stator and rotor, rotor and frame and bearings of the motor using the capacitance characteristic equation; d) use the dedicated software Pspice to simulate the system composed by the three-phase induction motor fed by PWM inverter with the equivalent electrical circuit parameters; e) to determine the characteristic waveforms involved in the common mode phenomenon.
THREE-PHASE ACTIVE POWER FILTER CONTROLLER FOR BALANCED AND UNBALANCED NON-LINEAR LOAD
Directory of Open Access Journals (Sweden)
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.
Three-phase Resonant DC-link Converter
DEFF Research Database (Denmark)
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 procedure increased dv/dt and the size of the input/output filters of the PWM-SVI must be increased. The high speed of the switches cannot be fully utilizied. By using a parallel resonant converter the switching happens at low or zero voltage which reduses switch losses. The dv/dt is controlled by the resonant circuit, and it is therefore reduced significantly. The perspective using a resonant converter is high switching frequency combined with a high converter efficiency and low dv/dt. In the first report several resonant converters are investigated to find a resonant converter that can complete with the standard PWM-VSI converter. Four converters were selected for the theoretical analysis, and the converters are simulated. An evaluation of the resonant converters is made, and one converter is selected for the realization. In the second report the realization of the selected resonant converter is described. This includes analysis, design and test of the converter. A new control principle, using no additional power electric components is eliminating the high voltage peaks associated with the resonant circuit. The resonant link voltage peaks are limited below 2.1 times the DC link voltages. A new principle eliminating former resonant converter stability problems are proposed, implemented and tested. A resonant converter efficiency of 97 [%] was measured. The low dv/dt of the converter makes it possible to drive long cables without filtering. A successful test with a 300 [m] long cable and an induction machine load was carried out. It is concluded that a stable, high efficiency and high switching frequency three phase parallel resonant converter is realized.
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...
DEFF Research Database (Denmark)
Mathe, Laszlo; Cornean, Horia; Sera, Dezso; Rasmussen, Peter Omand; Pedersen, John Kim
2011-01-01
Pulse width modulation (PWM) is a key element of a voltage source inverter, inverter which is widely used for electric motor control and electric energy conversion. Several PWM methods have been proposed in the literature, focusing on performance, ease of implementation, and maximization of the 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 ...
P. Avirajamanjula; P. Palanivel
2015-01-01
A direct Selective current harmonic elimination pulse width modulation technique is proposed for induction motor drive fed from voltage source inverter. The developed adaptive filtering algorithm for the selective current harmonic elimination in a three phase Voltage Source Inverter is a direct method to improve the line current quality of the Voltage Source Inverter base drive at any load condition. The self-adaptive algorithm employed has the capability of managing the time varying nature o...
Investigation of FPGA Based PWM Control Technique for AC Motors
Valantina Stephen; Padma Suresh
2013-01-01
This paper proposes a Random Frequency PWM synchronized for a three phase inverter implemented with use of FPGA and applied to a 1-hp induction motor drive system for the reduction of harmonics and improvement of fundamental peak voltage. For providing alternating output voltage with a specific magnitude and frequency to industrial applications, three-phase inverter is preferred. The gating signals to the inverter are produced by means of Random Frequency PWM to significantly reduce harmonic...
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 ...
Directory of Open Access Journals (Sweden)
S. Elangovan
2014-07-01
Full Text Available The main aim of this study is to control a multivariable coupled system by choosing sliding mode switching function. A Sliding mode control approach is developed to control a three phase three wire voltage source inverter operating as a shunt active power filter. Hence, no need to divide the system model developed in the synchronous ‘dq’ reference frame into two separate loops. Furthermore, the proposed control strategy allows a better stability and robustness over a wide range of operation. When sine PWM is used for generation of pulses for the switches, a variable switching nature is exhibited. The pulses for the active filter are fed by a Space Vector Modulation in order to have a constant switching of converter switches. But, the conventional space vector modulation, if implemented practically, needs a complicated algorithm which uses the trigonometric functions such as arctan, Sine and Cosine functions which in turn needs look up tables to store the pre-calculated trigonometric values. In this study, a very simplified algorithm is proposed for generating Space vector modulated pulse for all six switches without the use of look up tables and only by sensing the voltages and currents of the voltage source inverter acting as shunt active filter. The simulation using PSIM and MATLAB software verifies the results very well.
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei
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 for the AC-DC converters with a low ratio of switching to the fundamental frequency, and it provides an effective way to reveal the harmonic interaction and stability analysis for the future power electronics based power systems.
DEFF Research Database (Denmark)
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 systems....
Control to Three-phase Inverter by Sliding Mode
Mouhamadou Thiam; Gustave Sow; Dorothé Azilinon; Lamine Thiaw; Salif S. Fall; Momar Kassé; Alphousseyni Ndiaye
2014-01-01
In this study, it is treated the modeling and the ordering of a three-phase inverter. The studied system is a load supplied with a three-phase inverter by means of a transformer. The ordering of the inverter is with PWM (pulse-width modulation/pulse-width Modulation) and its regulation is made by the sliding method. This method is presented in this document with its various laws. The simulation of the unit is made and the results presented.
Analysis of Input and Output Ripples of PWM AC Choppers
Directory of Open Access Journals (Sweden)
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.
Cascaded Nine Level Inverter Using Pulse Width Modulation And Hybrid PWM
Directory of Open Access Journals (Sweden)
Rohini Sharma
2014-05-01
Full Text Available The multilevel voltage source converters typically synthesize the staircase voltage wave from several levels of dc voltage sources. This paper presents a PWM modulation and hybrid modulation using cascaded topology which allows one to achieve high-quality output voltages and input currents and also outstanding availability due to their intrinsic component redundancy. The simulation results reveal that method can effectively eliminate harmonics in the output waveform of the inverter, and also low THD (Total Harmonics Distortion.
Voltage Source Converters with Energy Storage Capability
Xie, Hailian
2006-01-01
This project deals with voltage source converters with energy storage capability. The main objective is to study the possible benefits of energy storage to a power system with a VSC as the interface between them. First of all, a converter control system is proposed for a two level VSC. In the conventional converter control, the control system usually takes the voltage measured at the point where the converter is connected and calculates the reference voltage for the converter; with a modulati...
F. J. De la Hidalga-W; Malik, O.
2013-01-01
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 obtain...
Performance analysis of samarium cobalt P.M. synchronous motor fed from PWM inverters
International Nuclear Information System (INIS)
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
The Application of FPGA in PWM Controlled Resonant Converter for an Ozone Generator
Mochammad Facta; Tole Sutikno; Zainal Salam
2013-01-01
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...
High performance direct instantaneous power control of PWM rectifiers
International Nuclear Information System (INIS)
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.
Single Phase Voltage Source Inverter Photovoltaic Application
Bauer, J.
2010-01-01
Photovoltaic applications have been developing and spreading rapidly in recent times. This paper describes the control strategy of the Voltage Source Inverter that is the important tail end of many photovoltaic applications.In order to supply the grid with a sinusoidal line current without harmonic distortion, the inverter is connected to the supply network via a L-C-L filter. The output current is controlled by the hysteresis controller. To improve the behaviors of the L-C-L filter, active d...
Single Phase Voltage Source Inverter Photovoltaic Application
Directory of Open Access Journals (Sweden)
J. Bauer
2010-01-01
Full Text Available Photovoltaic applications have been developing and spreading rapidly in recent times. This paper describes the control strategy of the Voltage Source Inverter that is the important tail end of many photovoltaic applications.In order to supply the grid with a sinusoidal line current without harmonic distortion, the inverter is connected to the supply network via a L-C-L filter. The output current is controlled by the hysteresis controller. To improve the behaviors of the L-C-L filter, active damping of the filter is being used. This paper discusses controller design and simulation results.
Directory of Open Access Journals (Sweden)
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.
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...
Comparison of a three phase single stage PV system in PSCAD and PowerFactory
Jose, Della
2012-01-01
The main objective of the project is to develop a Photovoltaic (PV) system using three phase Pulse Width Modulation (PWM) converter as the interfacing component in Power factory. Already existing model in Power factory tool uses static generator as the interfacing converter. Moreover the control technique implemented within the PV model is very basic. Aworking model is already available in PSCAD simulation tool using PWM converter but it is a very detailed one in terms of modeling which resul...
Control to Three-phase Inverter by Sliding Mode
Directory of Open Access Journals (Sweden)
Mouhamadou Thiam
2014-03-01
Full Text Available In this study, it is treated the modeling and the ordering of a three-phase inverter. The studied system is a load supplied with a three-phase inverter by means of a transformer. The ordering of the inverter is with PWM (pulse-width modulation/pulse-width Modulation and its regulation is made by the sliding method. This method is presented in this document with its various laws. The simulation of the unit is made and the results presented.
Directory of Open Access Journals (Sweden)
P. Avirajamanjula
2015-03-01
Full Text Available A direct Selective current harmonic elimination pulse width modulation technique is proposed for induction motor drive fed from voltage source inverter. The developed adaptive filtering algorithm for the selective current harmonic elimination in a three phase Voltage Source Inverter is a direct method to improve the line current quality of the Voltage Source Inverter base drive at any load condition. The self-adaptive algorithm employed has the capability of managing the time varying nature of load (current. The proposed Normalized Least Mean Squares algorithm based scheme eliminates the selected dominant harmonics in load current using only the knowledge of the frequencies to be eliminated. The algorithm is simulated using Matlab/Simulink tool for a three-phase Voltage Source Inverter to eliminate the fifth and seventh harmonics. The system performance is analyzed based on the simulation results considering total harmonic distortion, magnitude of eliminated harmonics and harmonic spectrum. The corroboration is done in the designed Voltage Source Inverter feeding induction motor using digital signal processor-TMS320L2812.The developed algorithm is transferred to digital signal processor using VisSimTM software.
Application of Discontinuous PWM Modulation in Active Power Filters
DEFF Research Database (Denmark)
Blaabjerg, Frede; Asiminoaei, Lucian; Rodriguez, Pedro
2008-01-01
Classical discontinuous pulsewidth modulations (DPWMs) may not be efficiently applied in active power filters (APFs), 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...... three-phase voltage source inverter, rated at 7 kVA 400 V, controlled as an APF....
Energy Technology Data Exchange (ETDEWEB)
Kazmierkowski, M.P.; Dzieniakowski, M.A.; Sobczuk, D.L. [Politechnika Warszawska, Warsaw (Poland)
1995-07-01
A conception and results of simulation tests of a neural network current controller for three-phase transistor PWM inverters are presented. This converter realizes discrete modulation and can be used for both hard and soft (resonant) commutated inverters. For teaching a multilayer neural network use is made of a PWM voltage pattern generated by an optimal controller which minimizes the RMS value of current error in each sampling cycle. As shown in this article the neural network controller can guarantee a practically optimal control quality with no need for any complex optimization procedures. Therefore this controller can be used for operation with inverters of very high switching frequency. (author). 12 refs., 6 figs., 1 tab.
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.
Dynamics of voltage source converter in a grid connected solar photovoltaic system
DEFF Research Database (Denmark)
Haribabu, Divyanagalakshmi; Vangari, Adithya; Sakamuri, Jayachandra N.
2015-01-01
This paper emphasises the modelling and control of a voltage source converter (VSC) for three phase grid connected PV system. The transfer functions for inner current control and outer DC link voltage control for VSC are derived. The controllers for VSC are designed based on PI and K factor control methods and the performance of VSC using both the methods are presented with the simulations performed using PSCAD/EMTDC. The design of LC filter to meet the specified THD requirement for grid connect...
DEFF Research Database (Denmark)
Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand; Pedersen, John Kim
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 index. The flat motor current spectrum generates an acoustical noise close to the white noise, which may improve the acoustical performance of the drive. The new carrier wave is easy to implement digita...
Optimal condition of memristance enhancement circuit using external voltage source
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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, B. Shanthi, S.P. Natarajan
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; Mawby, P.A.
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 Comparative Study of Sinusoidal PWM and Space Vector PWM of a Vector Controlled BLDC Motor
Directory of Open Access Journals (Sweden)
LYDIA ANU JOSE, K.B.KARTHIKEYAN
2013-06-01
Full Text Available This paper focuses on the vector control of a BLDC motor with two different concepts of Pulse Width Modulation- the Sinusoidal PWM and the Space Vector Modulation strategy. The paper deals with the basics of a BLDC motor, its dynamic modeling and its speed control using two different strategies of Pulse Width Modulation. The vector control is one of the methods used in variable frequency drives or variable speed drives to control the torque (and thus the speed of three-phase AC electric motors by controlling the current. The results prove that the Space Vector Modulation technique helps to improve the performance and thus the efficiency of the system.
A Comparative Study of Sinusoidal PWM and Space Vector PWM of a Vector Controlled BLDC Motor
LYDIA ANU JOSE, K.B.KARTHIKEYAN
2013-01-01
This paper focuses on the vector control of a BLDC motor with two different concepts of Pulse Width Modulation- the Sinusoidal PWM and the Space Vector Modulation strategy. The paper deals with the basics of a BLDC motor, its dynamic modeling and its speed control using two different strategies of Pulse Width Modulation. The vector control is one of the methods used in variable frequency drives or variable speed drives to control the torque (and thus the speed) of three-phase AC electric moto...
Vector control of an induction motor fed by a PWM inverter with output LC filter
Energy Technology Data Exchange (ETDEWEB)
Salomaeki, Janne; Luomi, Jorma
2004-07-01
This paper introduces a control method for an induction motor that is supplied by a PWM voltage source inverter through an LC filter. A full-order observer is used to estimate the system states, and no additional voltage or current measurements are needed for the vector control of the motor. Simulation and experimental results are presented confirming the functionality of the proposed control method. (author)
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.
A high-precision voltage source for EIT
Saulnier, Gary J.; Ning LIU; Ross, Alexander S
2006-01-01
Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes...
Design of New Single-phase Multilevel Voltage Source Inverter
Rasoul Shalchi Alishah; Daryoosh Nazarpour; Seyyed Hossein Hosseini; Mehran Sabahi
2014-01-01
Multilevel inverters with more number of levels can produce high quality voltage waveforms. In this paper, a new single-phase structure for multilevel voltage source inverter is proposed which can generate a large number of levels with reduced number of IGBTs, gate driver circuits and diodes. Three algorithms for determination of dc voltage sources’ magnitudes are presented which provide odd and even levels at the output voltage waveform. A comparison is presented between proposed multilevel ...
Indirect Vector Control of Three Phase Induction Motor using PSIM
Directory of Open Access Journals (Sweden)
Nagulapati Kiran
2014-03-01
Full Text Available 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, current controller gets saturated due to higher CEMF and hense becomes difficult to track due to which there will be a phase lag with respect to command current. All such problems are solved using Synchronous Current Control.
Scientific Electronic Library Online (English)
Alberto, Berzov; Julio, Viola; José, Restrepo.
2012-09-01
Full Text Available Este trabajo presenta dos técnicas de control de corriente para convertidores trifásicos de voltaje trabajando como rectificadores controlados, operando con factor de potencia unitario. El primer algoritmo está basado en la escogencia del mejor vector natural, entre los 7 vectores espaciales natural [...] es del convertidor de dos niveles de voltaje trifásico, mediante una función de costo. El segundo está basado en el cómputo y síntesis del vector espacial óptimo de convertidores trifásicos tal que se obtiene el vector que proporciona un mínimo absoluto de la función de costo. El primer algoritmo es un método sencillo que controla muy bien el factor de potencia y presenta una considerable compensación del contenido armónico. El segundo algoritmo provee una nueva fórmula cerrada para calcular el vector de voltaje óptimo aplicado al convertidor. Para este segundo método se necesita generar la señal de control con un modulador de ancho de pulso para así controlar directamente la corriente de línea permitiendo seguir la referencia de corriente. Las simulaciones y resultados experimentales muestran las ventajas del algoritmo propuesto. Abstract in english This work presents two current loop techniques, for three phase voltage source converters (VSC) used as controlled rectifiers (CR) operating at unity power factor. The first one is based on choosing the best natural vector, among the natural space vectors produced by two level voltage source inverte [...] rs, with the use of a cost function. The second one is based on computing and synthesizing a space vector such that an absolute minimum in the cost function is obtained. The first algorithm is a simple method that presents power factor correction and good total harmonic distortion compensation. The second algorithm provides a novel and closed form formula to calculate the optimum voltage vector applied by the converter. In this method, pulse width modulation (PWM) is required to modulate the voltage vector that controls directly the line current, to follow the current reference. The simulations and experimental results show the advantages of the proposed control algorithm.
Directory of Open Access Journals (Sweden)
Sérgio Augusto Oliveira da Silva
2005-06-01
Full Text Available This paper presents a three-phase line-interactive uninterruptible power supply (UPS system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF-based controller is used for harmonic and reactive power compensation generated from any configuration of non-linear loads. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulsewidth modulation (PWM converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD. The parallel active filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. The performance of the UPS system is evaluated in three-phase, four-wire systems. Experimental results are presented to confirm the theoretical studies.Este artigo apresenta um sistema de energia ininterrupta (SEI line-interactive trifásico com capacidade de condicionamento ativo de potência série e paralelo. Um controlador baseado no sistema de eixo de referência síncrona (SRF é usado na compensação de potência reativa e harmônica geradas por quaisquer configurações de cargas não lineares. Sob condições normais da rede elétrica o SEI trabalha na compensação das correntes de entrada e das tensões de saída. Dois conversores controlados em tensão e modulados por largura de pulso (PWM, chamados de filtros ativos série e paralelo, são usados para realizar o condicionamento ativo de potência série e paralelo. O filtro ativo série trabalha como uma fonte de corrente senoidal em fase com a tensão de entrada, drenando da rede correntes senoidais, balanceadas com baixas taxas de distorção harmônica (TDH. O filtro ativo paralelo trabalha como uma fonte de tensão senoidal em fase com a tensão de entrada, fornecendo para a carga tensões reguladas, senoidais e com baixas taxas de distorção harmônica. O desempenho do SEI é avaliado para sistemas trifásicos com quatro fios. Resultados experimentais são apresentados para confirmar os estudos teóricos.
Scientific Electronic Library Online (English)
Sérgio Augusto Oliveira da, Silva; Pedro F., Donoso-Garcia; Porfírio C., Cortizo; Paulo F., Seixas.
2005-06-01
Full Text Available Este artigo apresenta um sistema de energia ininterrupta (SEI) line-interactive trifásico com capacidade de condicionamento ativo de potência série e paralelo. Um controlador baseado no sistema de eixo de referência síncrona (SRF) é usado na compensação de potência reativa e harmônica geradas por qu [...] aisquer configurações de cargas não lineares. Sob condições normais da rede elétrica o SEI trabalha na compensação das correntes de entrada e das tensões de saída. Dois conversores controlados em tensão e modulados por largura de pulso (PWM), chamados de filtros ativos série e paralelo, são usados para realizar o condicionamento ativo de potência série e paralelo. O filtro ativo série trabalha como uma fonte de corrente senoidal em fase com a tensão de entrada, drenando da rede correntes senoidais, balanceadas com baixas taxas de distorção harmônica (TDH). O filtro ativo paralelo trabalha como uma fonte de tensão senoidal em fase com a tensão de entrada, fornecendo para a carga tensões reguladas, senoidais e com baixas taxas de distorção harmônica. O desempenho do SEI é avaliado para sistemas trifásicos com quatro fios. Resultados experimentais são apresentados para confirmar os estudos teóricos. Abstract in english This paper presents a three-phase line-interactive uninterruptible power supply (UPS) system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF)-based controller is used for harmonic and reactive power compensation generated from any configuration of n [...] on-linear loads. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulsewidth modulation (PWM) converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD). The parallel active filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. The performance of the UPS system is evaluated in three-phase, four-wire systems. Experimental results are presented to confirm the theoretical studies.
Three-Phase Grid-Connected of Photovoltaic Generator Using Nonlinear Control
DEFF Research Database (Denmark)
Yahya, A.; El Fadil, H.; Guerrero, Josep M.; Giri, F.; Erguig, H.
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...
Scientific Electronic Library Online (English)
Diana Jimena, López Mesa; Guillermo Alberto, Camacho Muñoz; Jaime Oscar, Díaz Chávez; Carlos Alberto, Gaviria López; Gilberto, Bolaños Pantoja.
2009-04-01
Full Text Available Este artículo presenta el diseño y validación de un nuevo algoritmo de modulación por ancho de pulso (PWM) híbrido que supera el desempeño armónico de varios algoritmos de modulación empleados en procesos de conversión de potencia en accionamientos eléctricos AC. A partir del análisis armónico de lo [...] s algoritmos PWM más comunes en la literatura, se establece una metodología para diseñar un esquema de modulación híbrido que ofrece un desempeño armónico superior; este desempeño es verificado teórica y experimentalmente utilizando el factor de distorsión armónica total F DIST y el índice de distorsión armónica de corriente V WTHD. Abstract in english This paper presents a novel hybrid modulation algorithm which improves the harmonic performance of eight of the most common pulse width modulation (PWM) algorithms for voltage source inverters (VSI) in the electric drive field. From harmonic analysis of these eight algorithms, a methodology was esta [...] blished for designing a hybrid modulation scheme offering superior harmonic performance. The algorithm so designed was validated theoretically by calculating the total harmonic distortion factor F DIST and experimentally by measuring the weighted total harmonic distortion factor V WTHD.
Implementation of a Hybrid High Power Factor Three-Phase Unidirectional Rectifier
Directory of Open Access Journals (Sweden)
Ankusha Biradar,
2013-03-01
Full Text Available This paper presents a new hybrid three phase rectifier composed by the parallel association of a single switch three phase boost rectifier with a pwm three phase unidirectional rectifier. According to this proposal each rectifier processes about half of the output rated power. The diode rectifier operates at a low frequency and has a higher output power rating Therefore ,the pwm unidirectional rectifier is designed to operate with a small power rating and a high switching frequency. In the proposed scheme, dsPIC30F2010 controller is used to produce signals. A resistive load(Two incandescent lamps with different watts are used as load for testing the developed hardware. Textronics TDS2024B storage oscilloscope is used to store the gate pulses and waveforms. The perfectly sinusoidal input currents with improved power factor can be obtained by this hybrid rectifier.
Soft Commutated Three-Phase Dc-Dc Converter
Directory of Open Access Journals (Sweden)
Silpa.P.T
2014-08-01
Full Text Available 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-pull dc-dc converter with active clamping was developed. This converter topology allows the reuse of the energy from the leakage inductances and reduces the electromagnetic interferences (EMI. The topology was designed and simulated using MATLAB/SIMULINK. The input supply voltage used for the converter is 120V DC.
Power Loss Calculation and Thermal Modelling for a Three Phase Inverter Drive System
Directory of Open Access Journals (Sweden)
Z. Zhou
2005-12-01
Full Text Available Power losses calculation and thermal modelling for a three-phase inverter power system is presented in this paper. Aiming a long real time thermal simulation, an accurate average power losses calculation based on PWM reconstruction technique is proposed. For carrying out the thermal simulation, a compact thermal model for a three-phase inverter power module is built. The thermal interference of adjacent heat sources is analysed using 3D thermal simulation. The proposed model can provide accurate power losses with a large simulation time-step and suitable for a long real time thermal simulation for a three phase inverter drive system for hybrid vehicle applications.
A high-precision voltage source for EIT.
Saulnier, Gary J; Ross, Alexander S; Liu, Ning
2006-05-01
Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes the capability of measuring both the applied voltage and applied current. A calibration circuit and calibration algorithm are described which enables all voltage sources in an EIT system to be calibrated to a common standard. The calibration minimizes the impact of stray shunt impedance, passive component variability and active component non-ideality. Simulation data obtained using PSpice are used to demonstrate the effectiveness of the circuits and calibration algorithm. PMID:16636413
Component-Minimized Buck-Boost Voltage Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.; Blaabjerg, Frede; Teodorescu, Remus; Vilathgamuwa, D.M.
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...
Energy Technology Data Exchange (ETDEWEB)
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.)
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.
Voltage Source Inverter/Converter for the Improvement of Power Quality Using Fuzzy Logic Controller
Directory of Open Access Journals (Sweden)
T Jagan Mohan Rao
2014-05-01
Full Text Available In recent years, the applications of power electronics have grown tremendously. These power electronic systems offer highly nonlinear characteristics. To overcome those non linearities active power filters are preferred. This paper presents and compares the performance of two controllers namely Fuzzy Logic and Proportional Integral (PI applied to a voltage source inverter / converter which operates as an active power filter. The active power filter is operated to compensate harmonics generated by the non-linear load . This work is done to make an accurate comparison of the performance of fuzzy logic controller and classical control technique such as PI controller in compensating harmonics in the ac mains current. Fuzzy control rule design is based on the general dynamic behavior of the process. A novel control method is implemented for suppressing the harmonics. The compensation process is instantaneous, which is achieved without employing any complicated control logic. The control scheme is based on sensing line currents only; an approach different from convention ones, which are based on sensing harmonics of the nonlinear load. In the control scheme a hysteresis controller based on current control is employed to generate switching signals to the PWM converter.
Analysis and Minimization of Output Current Ripple of Multiphase Carrier-Based PWM Inverters
Directory of Open Access Journals (Sweden)
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
Tutkun, N.; Moses, A. J.
2003-06-01
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.
Measurements of power loss distribution in a typical stator core under PWM voltage excitation
International Nuclear Information System (INIS)
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
Directory of Open Access Journals (Sweden)
S. Senguttuvan
2014-08-01
Full Text Available The aim of study of this paper is design and implementation of a simple and efficient soft switched Pulse Width Modulation (PWM for three-phase induction motor drives. Soft-switching techniques have gained popularity in recent times because they offer many advantages over hard-switched Pulse Width Modulated inverters such as higher efficiency, higher power density and better performances. The quasi-resonant DC-link is being designed, the simulation and experimental results prove that it achieves soft switching of all the main switches and resonant circuit switches at the same time it posses all the capabilities of conventional sinusoidal modulated PWM inverter. Finally, the efficiency of the Soft Switched Sinusoidal PWM (SSSPWM inverter calculated from experimental results is compared with the conventional Hard Switched Sinusoidal PWM (HSSPWM inverter, under identical load conditions. It is of great significance to improve the efficiency by reducing switching losses, high power density, high reliability and low electro management interference.
The Application of FPGA in PWM Controlled Resonant Converter for an Ozone Generator
Directory of Open Access Journals (Sweden)
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.
Directory of Open Access Journals (Sweden)
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.
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Maheshwari, Ram Krishan
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) scheme to reduce the maximum value of the flux linkage and the core losses in the circulating current filter. In the proposed PWM scheme, the dwell time of an active vector is divided within a half-carrier cycle to ensure simultaneous occurrence of the same zero vectors in both VSCs. A function to decide the ratio of the dwell time of the divided active vector is also presented. The effect of the proposed PWM scheme on the maximum value of the flux linkage and the core losses is analyzed and compared with that of the space vector modulation and 60$^circ$ clamped DPWM schemes. The analytical expressions for the maximum value of the flux linkage are derived for each of these PWM schemes. In addition, the effect of the proposed PWM scheme on the line current ripple and the switching losses is also analyzed and compared. To verify the analysis, experimental results are presented, which prove the effectiveness of the proposed PWM scheme.
Dynamics of voltage source converter in a grid connected solar photovoltaic system
DEFF Research Database (Denmark)
Haribabu, Divyanagalakshmi; Vangari, Adithya
2015-01-01
This paper emphasises the modelling and control of a voltage source converter (VSC) for three phase grid connected PV system. The transfer functions for inner current control and outer DC link voltage control for VSC are derived. The controllers for VSC are designed based on PI and K factor control methods and the performance of VSC using both the methods are presented with the simulations performed using PSCAD/EMTDC. The design of LC filter to meet the specified THD requirement for grid connected VSC is presented and the corresponding harmonic analysis is performed for different solar radiation conditions. The effectiveness of the proposed controller is illustrated by evaluating the response of PV system for power system voltage sag and swell conditions as well as grid faults.
An imroved design for ZVT DC-DC PWM converters with snubber assisted auxiliary switch
Scientific Electronic Library Online (English)
J., Russi; M. L., Martins; H. A., Gründling; H., Pinheiro; J. R., Pinheiro; H. L., Hey.
2005-03-01
Full Text Available Este artigo propõe uma metodologia de projeto aprimorada para determinação dos componentes auxiliares para o conversor ZVT CC-CC PWM snubber assisted auxiliary switch. O procedimento de projeto proposto é baseado na redução das perdas de condução no circuito auxiliar. Isto é somente possível devido [...] à localização do capacitor snubber de bloqueio, o qual é compartilhado por ambas as chaves ativas. Através do procedimento de projeto proposto o rendimento do conversor pode ser aumentado. Uma análise comparativa do rendimento é apresentada e os resultados experimentais, obtidos de protótipos de laboratório de 1 kW, 100 kHz, mostram uma melhoria relevante em relação ao rendimento apresentado pelo projeto original. Além disso, os resultados experimentais também confirmam que o projeto proposto para o conversor ZVT snubber assisted auxiliary switch torna-o competitivo em relação ao conversor ZVT PWM com fonte auxiliar de tensão constante (true PWM ZVS pole). Abstract in english This paper proposes an improved design to calculate the snubber auxiliary elements of ZVT DC-DC PWM converters with snubber assisted auxiliary switch. The proposed improved design guidelines are based on the reduction of the conduction losses through the auxiliary circuit. It is accomplished by the [...] unique location of the turn-off snubber capacitor, which is shared by both active switches. By means of this improved design guidelines the converter efficiency can be increased. An efficiency comparative analysis is carried out and the experimental results, obtained from 1 kW, 100 kHz laboratory prototypes, show a relevant improvement in converter efficiency compared to the original converter design. In addition, experimental results also confirm that with the improved design the ZVT PWM converters with snubber assisted auxiliary switch can be competitive with ZVT PWM converters with constant auxiliary voltage source (True PWM ZVS pole).
Energy Technology Data Exchange (ETDEWEB)
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.
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 x 10(-7) over 6.5 h and a noise level equal or smaller than 30 nV/square root(Hz) is achieved. PMID:20590260
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.
Czech Academy of Sciences Publication Activity Database
Bartoš, Stanislav; Jehli?ka, Vladimír; Škramlík, Ji?í; Valouch, Viktor
Cambridge, MA : Electromagnetics Academy, 2007, s. 93-97. ISBN 978-1-934142-02-8. [Progress In Electromagnetics Research Symposium 2007. Prague (CZ), 27.08.2007-30.08.2007] R&D Projects: GA ?R GA102/06/0112 Institutional research plan: CEZ:AV0Z20570509 Keywords : electromagnetic interference (EMI) * induction motor drive * IGCT voltage source inverter Subject RIV: JA - Electronics ; Optoelectronics, Electric al Engineering
Power Quality Improvement using Dual Voltage Source Converter Based DVR
A.Suresh; Govindaraj, V
2014-01-01
In any power system, The modelling and simulation of three and seven-level Dual Voltage Source Converter based dynamic voltage restorer (DVR) aimed at correcting the supply voltage sag/swell and interruption in low voltage distribution networks. The proposed design models of DVSC based DVR are expected to be most powerful solutions to minimize supply voltage disturbances of the sensitive loads. A DVR is a VSC based power electronics device connected in series between the supply and the critic...
Voltage harmonic variation in three-phase induction motors with different coil pitches
International Nuclear Information System (INIS)
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%
A classification methodology for zero-voltage transition PWM converters
Directory of Open Access Journals (Sweden)
M. L. Martins
2005-03-01
Full Text Available This paper presents a classification methodology of the ZVT soft-transition technique, which is based on different ways of implementation of the auxiliary circuit voltage source. The merits and limitations of each class are presented and their key features and characteristics are discussed and experimentally analyzed on the 1kW/100kHz laboratory prototypes. By means of the proposed classification criteria, any ZVT topology can be classified, even the unpublished ones. Additionally, an overview of the main ZVT PWM converters proposed in the last decades is also presented.Este artigo propõe uma metodologia de classificação para a técnica de comutação suave conhecida como ZVT. Esta classificação é baseada nos diferentes modos de implementação da fonte auxiliar de tensão. Os méritos e limitações de cada classe são apresentados. As particularidades e características de cada classe são discutidas e analisadas experimental-mente em protótipos de laboratório de 1kW/100kHz. Por meio do critério de classificação proposto, qualquer topologia ZVT pode ser classificada, mesmo aquelas inéditas na literatura. Além disso, é apresentada uma visão geral dos principais con-versores ZVT PWM propostos nas últimas décadas.
Indirect Vector Control of Three Phase Induction Motor using PSIM
Directory of Open Access Journals (Sweden)
Nagulapati Kiran
2014-03-01
Full Text Available 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, current controller gets saturated due to higher CEMF and hense becomes difficult to track due to which there will be a phase lag with respect to command current. All such problems are solved using Synchronous Current Control.Â
Component-Minimized Buck-Boost Voltage Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.; Blaabjerg, Frede; Teodorescu, Remus; Vilathgamuwa, D.M.
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...... additional voltage relationship between dc input and ac output which is beyond the expectation when continuous inductor current is assumed. These theoretical findings, together with the inverter practicality, have been confirmed in Matlab/PLECS simulations and experimentally using laboratory implemented...
Directory of Open Access Journals (Sweden)
Valantina Stephen
2012-01-01
Full Text Available This study proposes different configurations of PWM techniques for harmonic reduction and improvement of fundamental peak voltage. For providing adjustable frequency power to industrial applications, three-phase inverter is preferred. The general aim of this study is to reduce the third order harmonics and improve the Harmonic Spread Factor by different PWM techniques using matlab modelsim cosimulation. The gating signals to the inverter are produced by means of SPWM, RFPWM, Third Harmonic Injection (THI and Hybrid Random Frequency THIPWM. FPGA because of its suitability in time critical systems it is used to produce gating signals to the switches in a three-phase bridge inverter. This study will provide the insight of trends and technologies of Third Order Harmonic Elimination and improvement of HSF using different PWM techniques. In addition, a performance comparison of proposed methods with modified PWM methods is also provided. The result of the proposed work shows that there is improvement in fundamental voltage, THD, HSF when a combination of RF-THI PWM techniques is used.
Low-cost PWM speed controller for an electric mini-baja type vehicle
Samuel Euzédice de Lucena; Márcio Abud Marcelino; Francisco José Grandinetti
2007-01-01
This paperwork presents a Pulse Width Modulation (PWM) speed controller for an electric mini-baja-type car. A battery-fed 1-kW three-phase induction motor provides the electric vehicle traction. The open-loop speed control is implemented with an equal voltage/frequency ratio, in order to maintain a constant amount of torque on all velocities. The PWM is implemented by a low-cost 8-bit microcontroller provided with optimized ROM charts for distinct speed value implementations, synchronized tra...
Parallel operation of voltage-source converters: issues and applications
Energy Technology Data Exchange (ETDEWEB)
Almeida, F.C.B.; Silva, D.S. [Federal University of Juiz de Fora (UFJF), MG (Brazil)], Emails: felipe.brum@engenharia.ufjf.br, salomaoime@yahoo.com.br; Ribeiro, P.F. [Calvin College, Grand Rapids, MI (United States); Federal University of Juiz de Fora (UFJF), MG (Brazil)], E-mail: pfribeiro@ieee.org
2009-07-01
Technological advancements in power electronics have prompted the development of advanced AC/DC conversion systems with high efficiency and flexible performance. Among these devices, the Voltage-Source Converter (VSC) has become an essential building block. This paper considers the parallel operation of VSCs under different system conditions and how they can assist the operation of highly complex power networks. A multi-terminal VSC-based High Voltage Direct Current (M-VSC-HVDC) system is chosen to be modeled, simulated and then analyzed as an example of VSCs operating in parallel. (author)
Four-switch three-phase space-vector PWM AC-DC converter.
Czech Academy of Sciences Publication Activity Database
Klíma, J.; Škramlík, Ji?í; Valouch, Viktor
2008-01-01
Ro?. 95, ?. 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
A new cascaded multilevel inverter with series and parallel connection ability of DC voltage sources
BABAEI, Ebrahim; GOWGANI, Saeed SHEERMOHAMMADZADEH; SABAHI, Mehran
2015-01-01
In this paper, a new multilevel inverter is proposed based on the connection of DC voltage sources in series and parallel. The proposed topology is composed of series basic units that consist of series and parallel connections of DC voltage sources. The values of the DC voltage sources differ from one unit to another. A new algorithm to determine the magnitude of the DC voltage sources of the proposed structure is presented. All of the related equations for the proposed multilevel inverter ar...
New Space Vector Selection Scheme for VSI Supplied Dual Three-Phase Induction Machine
Directory of Open Access Journals (Sweden)
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.
Three-phase multilevel inverter configuration for open-winding high power application
DEFF Research Database (Denmark)
Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick William; Olorunfemi Ojo, Joseph
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...... 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...
Review of multilevel voltage source inverter topologies and control schemes
International Nuclear Information System (INIS)
In this study, the most common multilevel inverter topologies and control schemes have been reviewed. Multilevel inverter topologies (MLIs) are increasingly being used in medium and high power applications due to their many advantages such as low power dissipation on power switches, low harmonic contents and low electromagnetic interference (EMI) outputs. The selected switching technique to control the inverter will also have an effective role on harmonic elimination while generating the ideal output voltage. Intensive studies have been performed on carrier-based, sinusoidal, space vector and sigma delta PWM methods in open loop control of inverters. The selection of topology and control techniques may vary according to power demands of inverter. This paper and review results constitute a useful basis for matching of inverter topology and the best control scheme according to various application areas.
Review of multilevel voltage source inverter topologies and control schemes
Energy Technology Data Exchange (ETDEWEB)
Colak, Ilhami [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey); Kabalci, Ersan, E-mail: kabalci@nevsehir.edu.t [Department of Technical Programs, Vocational Collage of Haci Bektas, Nevsehir University, Hacibektas, Nevsehir 50800 (Turkey); Bayindir, Ramazan [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey)
2011-02-15
In this study, the most common multilevel inverter topologies and control schemes have been reviewed. Multilevel inverter topologies (MLIs) are increasingly being used in medium and high power applications due to their many advantages such as low power dissipation on power switches, low harmonic contents and low electromagnetic interference (EMI) outputs. The selected switching technique to control the inverter will also have an effective role on harmonic elimination while generating the ideal output voltage. Intensive studies have been performed on carrier-based, sinusoidal, space vector and sigma delta PWM methods in open loop control of inverters. The selection of topology and control techniques may vary according to power demands of inverter. This paper and review results constitute a useful basis for matching of inverter topology and the best control scheme according to various application areas.
High-Speed Fuses in IGBT based Voltage Source Converters
DEFF Research Database (Denmark)
Iov, Florin; Blaabjerg, Frede; Rasmussen, Henrik
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....
Power Quality Improvement using Dual Voltage Source Converter Based DVR
Directory of Open Access Journals (Sweden)
A.Suresh
2014-01-01
Full Text Available In any power system, The modelling and simulation of three and seven-level Dual Voltage Source Converter based dynamic voltage restorer (DVR aimed at correcting the supply voltage sag/swell and interruption in low voltage distribution networks. The proposed design models of DVSC based DVR are expected to be most powerful solutions to minimize supply voltage disturbances of the sensitive loads. A DVR is a VSC based power electronics device connected in series between the supply and the critical loads, which are to be protected from the supply side voltage quality problems, other than outages, by injecting the required compensating voltage through DVR into the distribution line. The proposed models of DVR together with the controllers are simulated by using MAT LAB Simulink and the results are presented to assess the performance of each device.
Diode-Assisted Buck-Boost Voltage-Source Inverters
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus; Blaabjerg, Frede
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......, a number of diode-assisted inverter variants can be designed with each having its own operational principle and voltage gain expression. For controlling them, a generic modulation scheme that can be used for controlling all diode-assisted variants with minimized harmonic distortion and component...
Multilevel cascade voltage source inverter with seperate DC sources
Peng, Fang Zheng (Knoxville, TN); Lai, Jih-Sheng (Blacksburg, VA)
2002-01-01
A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.
Multilevel cascade voltage source inverter with separate DC sources
Peng, F.Z.; Lai, J.S.
1997-06-24
A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.
Directory of Open Access Journals (Sweden)
Robinson F. de Camargo
2004-09-01
Full Text Available Este artigo propõe dois novos algoritmos de limitação para inversores de tensão trifásicos a quatro braços. Estes baseiam-se na limitação do vetor de comando dentro da região de operação linear do inversor. O primeiro algoritmo utiliza um elipsóide inscrito no dodecaedro definido pelas extremidades dos possíveis vetores de comutação do inversor, e o segundo é baseado nos planos limites desse poliedro. Uma descrição detalhada, abordando os principais pontos requeridos para a implementação digital, da modulação space vector e dos algoritmos de limitação são apresentados. Ainda, as tensões de saída e as correntes nos indutores são dinamicamente reguladas, por meio de servo controladores MIMO em eixos síncronos dq0. Estes controladores são projetados usando a técnica do regulador linear quadrático discreto de regime permanente, o qual assegura estabilidade para o sistema em toda a faixa de operação. Além disso, para prover transições suaves entre os diferentes modos de operação do inversor, são propostos algoritmos MIMO não lineares para limitar a sobrecarga da ação integral, quando o vetor de comando for limitado, e atualizar dinamicamente as variáveis dos servo controladores. Finalmente, são apresentados resultados experimentais obtidos de um protótipo de 15 kVA, totalmente controlado por um DSP TMS320F241, para validar os algoritmos propostos e demostrar o desempenho do sistema como um todo.This paper proposes two novel limiting algorithms for three-phase four-leg voltage source inverters to constrain the command vector inside the dodecahedron defined by the boundaries of the inverter linear operating range. The first algorithm uses an inscribed ellipsoid on the dodecahedron, and the second one is based on the polyhedron boundary planes. A detailed description, with the key points required for a digital implementation of space vector and limiting algorithms, is given. In addition, the output voltages and the inductors currents are dynamically regulated by means of MIMO servo controller in dq0 coordinates. These controllers are designed using optimal discrete linear quadratic regulator technique, which ensures stability for the system at all operating conditions. In order to provide smooth transitions among the different modes of operation, nonlinear MIMO anti-windup algorithms are proposed to dynamically update the controllers servo variables. Finally, experimental results on a 15 kVA PWM inverter fully controlled by a DSP controller, TMS320F241, has been used to validate the feasibility of the proposed algorithm and to demonstrate the performance of the overall system.
Scientific Electronic Library Online (English)
Robinson F. de, Camargo; Fernando, Botterón; Humberto, Pinheiro; José R., Pinheiro; Hilton, Gründling; Hélio, Hey.
2004-09-01
Full Text Available Este artigo propõe dois novos algoritmos de limitação para inversores de tensão trifásicos a quatro braços. Estes baseiam-se na limitação do vetor de comando dentro da região de operação linear do inversor. O primeiro algoritmo utiliza um elipsóide inscrito no dodecaedro definido pelas extremidades [...] dos possíveis vetores de comutação do inversor, e o segundo é baseado nos planos limites desse poliedro. Uma descrição detalhada, abordando os principais pontos requeridos para a implementação digital, da modulação space vector e dos algoritmos de limitação são apresentados. Ainda, as tensões de saída e as correntes nos indutores são dinamicamente reguladas, por meio de servo controladores MIMO em eixos síncronos dq0. Estes controladores são projetados usando a técnica do regulador linear quadrático discreto de regime permanente, o qual assegura estabilidade para o sistema em toda a faixa de operação. Além disso, para prover transições suaves entre os diferentes modos de operação do inversor, são propostos algoritmos MIMO não lineares para limitar a sobrecarga da ação integral, quando o vetor de comando for limitado, e atualizar dinamicamente as variáveis dos servo controladores. Finalmente, são apresentados resultados experimentais obtidos de um protótipo de 15 kVA, totalmente controlado por um DSP TMS320F241, para validar os algoritmos propostos e demostrar o desempenho do sistema como um todo. Abstract in english This paper proposes two novel limiting algorithms for three-phase four-leg voltage source inverters to constrain the command vector inside the dodecahedron defined by the boundaries of the inverter linear operating range. The first algorithm uses an inscribed ellipsoid on the dodecahedron, and the s [...] econd one is based on the polyhedron boundary planes. A detailed description, with the key points required for a digital implementation of space vector and limiting algorithms, is given. In addition, the output voltages and the inductors currents are dynamically regulated by means of MIMO servo controller in dq0 coordinates. These controllers are designed using optimal discrete linear quadratic regulator technique, which ensures stability for the system at all operating conditions. In order to provide smooth transitions among the different modes of operation, nonlinear MIMO anti-windup algorithms are proposed to dynamically update the controllers servo variables. Finally, experimental results on a 15 kVA PWM inverter fully controlled by a DSP controller, TMS320F241, has been used to validate the feasibility of the proposed algorithm and to demonstrate the performance of the overall system.
Three phase AC motor controller
Vuckovich, Michael (Elizabeth, PA); Wright, Maynard K. (Bethel Park, PA); Burkett, John P. (South Huntington Township, Westmoreland County, PA)
1984-03-20
A motor controller for a three phase AC motor (10) which is adapted to operate bidirectionally from signals received either from a computer (30) or a manual control (32). The controller is comprised of digital logic circuit means which implement a forward and reverse command signal channel (27, 29) for the application of power through the forward and reverse power switching relays (16, 18, 20, 22). The digital logic elements are cross coupled to prevent activation of both channels simultaneously and each includes a plugging circuit (65, 67) for stopping the motor upon the removal of control signal applied to one of the two channels (27, 29) for a direction of rotation desired. Each plugging circuit (65, 67) includes a one-shot pulse signal generator (88, 102) which outputs a single pulse signal of predetermined pulsewidth which is adapted to inhibit further operation of the application of power in the channel which is being activated and to apply a reversal command signal to the other channel which provides a reversed phase application of power to the motor for a period defined by the pulse-width output of the one-shot signal generator to plug the motor (10) which will then be inoperative until another rotational command signal is applied to either of the two channels.
Mitigation of Lower Order Harmonics with Filtered Svpwm In Multiphase Voltage Source Inverters
Directory of Open Access Journals (Sweden)
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.
Scientific Electronic Library Online (English)
O., Malik; F. J., De la Hidalga-W..
2013-02-01
Full Text Available Cualquier sistema de instrumentación consiste de tres elementos: el sensor o dispositivo de entrada, el procesador de señales, y el receptor o dispositivo de salida. Diversos sistemas de control automático o con retroalimentación requieren una señal eléctrica de salida en forma de pulsos con modulac [...] ión en su ancho (PWM). Generalmente la señal analógica de salida se transforma usando un convertidor de señal PWM. En este trabajo se muestra que una señal de salida PWM, con una razón ancho-de-pulso/período (duty cycle) controlado por la intensidad de la iluminación, puede obtenerse directamente utilizando un circuito que contiene un capacitor metal (compuerta semitransparente) -óxido-semiconductor (MOS-C) conectado en serie con una fuente de DC y un generador de funciones que proporciona un voltaje periódico en forma de dientes de sierra. Internamente, la conversión de señal a PWM se logra explotando los procesos físicos fuera de equilibrio que se presentan dentro del sustrato de silicio del MOS-C. La señal cuadrada PWM, cuya amplitud está limitada a 10-20 V, se obtiene mediante la amplificación de la señal de transductor usando un amplificador estándar de transimpedancia de 60 dB. La señal de salida amplificada presenta una forma de onda PWM positiva y negativa que pueden separarse usando diodos. La razón ancho-de-pulso/período de la parte positiva es proporcional a la intensidad de la iluminación, mientras que la parte negativa es inversamente proporcional a dicha intensidad. La frecuencia de operación de este instrumento se encuentra en el rango de 1 Hz hasta algunos kilohertz. La razón ancho-de-pulso/período de la señal de salida PWM varía entre 2 y 98% cuando la potencia de la iluminación es del orden de microwatts. Este nuevo transductor o sensor podría ser útil para aplicaciones en control automático, en robótica, control de iluminación, sistemas de retroalimentación, y para la detección óptica de posición sin contacto para mediciones de centrado y anulación. Finalmente, se presenta una descripción detallada de los principios físicos y de operación de este nuevo transductor. Abstract in english This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can be obtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and a metal (semitransparent gate) oxide semiconductor capacitor (MOS-C). [...] The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductor substrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification of the sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive and negative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional to the light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating range of this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from 2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors could be useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contact optical position sensing for nulling and centering measurements.
PERFORMANCE ANALYSIS OF SENSORLESS BLDC MOTOR DRIVE SYSTEM USING ASYMMETRIC PWM CONTROL TECHNIQUE
R. Meenakshi; S.Sella Kumar; Dr.M.Sasikumar
2012-01-01
This paper describes the simulation model for four-switch three-phase (FSTP) brushless dc (BLDC) motor drives using novel voltage PWM technique. In this paper a back EMF based sensor less scheme is clearly explained with the help of MATLABSIMULINK models. The low cost BLDC driver is achieved by the reduction of switch device count, cost down of control, and saving of hall sensors for commercial applications. Field programmable gate array was chosen as the hardware platform beca...
Diode-assisted buck-boost voltage source inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.
2007-01-01
This paper proposes buck-boost voltage source inverters with a unique X-shape diode-capacitor network inserted between inverter circuitry and dc source for producing a large voltage boost gain. Comparing with other voltage buck-boost techniques, the presented topologies with only a little more passive components can significantly enhance voltage boost capability for dc-ac inversion. With different front-end circuitries, the diode-assisted buck-boost inverters can show different operational principle and voltage boost ratio. Carefully analyzing the operational principle for the inherent energy charging and discharging processes of passive components reveals that the dc-link voltage can alternate between two levels, which therefore demonstrate the phenomena that the specified modulation schemes should note. A modulation scheme that can achieve optimized harmonic switching is first designed with symmetrical state placement in each switching sequence to avoid unnecessary voltage stress across both passive and active components. To reduce the total commutation count, the designed modulation scheme is then modified without increasing voltage stress. All theoretical findings were verified experimentally using a number of scale-down laboratory prototypes.
Directory of Open Access Journals (Sweden)
Robinson F. de Camargo
2005-12-01
Full Text Available Este trabalho desenvolve um procedimento de projeto sistemático para o controle das correntes de entrada e da tensão de saída de retificadores PWM trifásicos. Primeiramente é apresentado o modelo discreto em eixos síncronos dq do retificador PWM trifásico com filtro de entrada L, o qual leva em conta o tempo de processamento necessário para a implementação em tempo real. A operação do retificador com resposta de tempo mínimo é obtida utilizando o método de desacoplamento por retroação de estados no domínio discreto, sem a necessidade de um controlador de corrente adicional no eixo d. Além disso, são desenvolvidos servos controladores de corrente e tensão a fim de garantir fator de deslocamento unitário e regulação de tensão no barramento CC respectivamente. Finalmente, resultados experimentais são apresentados, a fim de validar o procedimento proposto e verificar o desempenho do retificador PWM trifásico.This paper develops a systematic design procedure based on discrete decoupling by state feedback applied to three-phase PWM rectifiers. A discrete model for synchronous frame is developed for three-phase PWM rectifier with an L filter. This model takes into account the computational delays presents in the discrete implementation. Deadbeat response is obtaining without the requirement of a current controller in the axis d. Moreover, discrete servo controllers to ensure unit displacement power factor and regulated DC link voltage are developed. Finally, experimental results are presented to demonstrate the feasibility of the proposed procedure, algorithms and the performance of the overall system.
An imroved design for ZVT DC-DC PWM converters with snubber assisted auxiliary switch
Directory of Open Access Journals (Sweden)
J. Russi
2005-03-01
Full Text Available This paper proposes an improved design to calculate the snubber auxiliary elements of ZVT DC-DC PWM converters with snubber assisted auxiliary switch. The proposed improved design guidelines are based on the reduction of the conduction losses through the auxiliary circuit. It is accomplished by the unique location of the turn-off snubber capacitor, which is shared by both active switches. By means of this improved design guidelines the converter efficiency can be increased. An efficiency comparative analysis is carried out and the experimental results, obtained from 1 kW, 100 kHz laboratory prototypes, show a relevant improvement in converter efficiency compared to the original converter design. In addition, experimental results also confirm that with the improved design the ZVT PWM converters with snubber assisted auxiliary switch can be competitive with ZVT PWM converters with constant auxiliary voltage source (True PWM ZVS pole.Este artigo propÃµe uma metodologia de projeto aprimorada para determinaÃ§Ã£o dos componentes auxiliares para o conversor ZVT CC-CC PWM snubber assisted auxiliary switch. O procedimento de projeto proposto Ã© baseado na reduÃ§Ã£o das perdas de conduÃ§Ã£o no circuito auxiliar. Isto Ã© somente possÃvel devido Ã localizaÃ§Ã£o do capacitor snubber de bloqueio, o qual Ã© compartilhado por ambas as chaves ativas. AtravÃ©s do procedimento de projeto proposto o rendimento do conversor pode ser aumentado. Uma anÃ¡lise comparativa do rendimento Ã© apresentada e os resultados experimentais, obtidos de protÃ³tipos de laboratÃ³rio de 1 kW, 100 kHz, mostram uma melhoria relevante em relaÃ§Ã£o ao rendimento apresentado pelo projeto original. AlÃ©m disso, os resultados experimentais tambÃ©m confirmam que o projeto proposto para o conversor ZVT snubber assisted auxiliary switch torna-o competitivo em relaÃ§Ã£o ao conversor ZVT PWM com fonte auxiliar de tensÃ£o constante (true PWM ZVS pole.
Performance of voltage source multilevel inverter - fed induction motor drive using Simulink
Neelashetty Kashappa; Ramesh Reddy K.
2011-01-01
This paper deals with performance of voltage source multilevel inverter-fed induction motor drive. A Voltage source inverter (VSI) is compared with multilevel inverter. A conventional Voltage Source Inverter-fed induction motor drive is modeled and simulated using Matlab/ Simulink and the results are presented. Multilevel inverter employing Selective Harmonic Elimination (SHE) method is also simulated and the corresponding results are presented. The FFT spectrum for the outputs is analyzed to...
Performance of voltage source multilevel inverter - fed induction motor drive using Simulink
Directory of Open Access Journals (Sweden)
Neelashetty Kashappa
2011-06-01
Full Text Available This paper deals with performance of voltage source multilevel inverter-fed induction motor drive. A Voltage source inverter (VSI is compared with multilevel inverter. A conventional Voltage Source Inverter-fed induction motor drive is modeled and simulated using Matlab/ Simulink and the results are presented. Multilevel inverter employing Selective Harmonic Elimination (SHE method is also simulated and the corresponding results are presented. The FFT spectrum for the outputs is analyzed to study the reduction in harmonics.
Inverted sine carrier for fundamental fortification in PWM inverters and FPGA based implementations
Directory of Open Access Journals (Sweden)
Jeevananthan S.
2007-01-01
Full Text Available This paper deals with a novel natural sampled pulse width modulation (PWM switching strategy for voltage source inverter through carrier modification. The proposed inverted sine carrier PWM (ISCPWM method, which uses the conventional sinusoidal reference signal and an inverted sine carrier, has a better spectral quality and a higher fundamental component compared to the conventional sinusoidal PWM (SPWM without any pulse dropping. The ISCPWM strategy enhances the fundamental output voltage particularly at lower modulation index ranges while keeping the total harmonic distortion (THD lower without involving changes in device switching losses. The presented mathematical preliminaries for both SPWM and ISCPWM give a conceptual understanding and a comparison of the strategies. The detailed comparison of the harmonic content and fundamental component of the ISCPWM output for different values of modulation index with the results obtained for the SPWM is also presented. Finally, the proposed modulator has been implemented in field programmable gate array (FPGA- Xilinx Spartan 3 and tested with the proto-type inverter.
An Integrated Inductor for Parallel Interleaved VSCs and PWM Schemes for Flux Minimization
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand
2015-01-01
The interleaving of the carrier signals of the parallel Voltage Source Converters (VSCs) can reduce the harmonic content in the resultant switched output voltages. As a result, the size of the line filter inductor can be reduced. However, in addition to the line filter, an inductive filter is often required to suppress the circulating current. The size of the system can be reduced by integrating these two inductors in a single magnetic component. A integrated inductor, which combines the functionality of both the line filter inductor and the circulating current filter inductor is presented. The PulseWidth Modulation (PWM) schemes to reduce the flux in some parts of the integrated inductor are also analyzed. The flux reduction achieved by using these schemes is demonstrated by comparing these schemes with the conventional space vector modulation and the $60\\degree$ clamped discontinuous PWM scheme. The impact of these PWM schemes on the harmonic performance is also discussed. Simulation and experimental results are presented to validate the analysis.
Three-phase power supply, output 60v and 100a, with unit power factor and low RFI level
Directory of Open Access Journals (Sweden)
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.
A low cost rapid prototype platform for a three phase PFC rectifier application
DEFF Research Database (Denmark)
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...... then performed using automatic code generation for embedded targets, which provided a close link between simulation and implementation of the PFC controller. The paper shows how this rapid prototype platform developed and how it was used for the design and implementation of the controller for a high...... efficient SiC based PFC application....
Scalar Controlled Boost PWM Rectifier for Micro Wind Energy Systems
Directory of Open Access Journals (Sweden)
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 (Bloomfield Hills, MI)
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).
Directory of Open Access Journals (Sweden)
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.Â 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.
A Three-Phase Dual-Input Matrix Converter for Grid Integration of Two AC Type Energy Resources
DEFF Research Database (Denmark)
Liu, Xiong; Wang, Peng; Chiang Loh, Poh; Blaabjerg, Frede
2013-01-01
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-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 a...
SAFDAR FASAL T K, UNNIKRISHNAN L
2013-01-01
This paper presents a performance study of the proportionalintegral controller andthe fuzzy logic controller in scalar speed control of three phase squirrel cage induction motor drive. Here the speed control is possible by varying supply frequencyusing a voltage source inverter while keeping voltage to frequency ratio as a constant. Speed error is given as inputto the proportional integral controller, and speed error and change in speed error are given as input to the fuzzy logic controller.T...
P.Narasimhulu; N.Sreekanth*
2014-01-01
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 vo...
A device for trouble shooting rectifiers in a three phase bridge converter
Energy Technology Data Exchange (ETDEWEB)
Levitin, I.I.; Elkin, A.G.; Rozhdestvenskiy, S.V.
1982-01-01
The device contains indication elements and an alternating current source. To increase reliability the device is equipped with resistors based on the number of phases, while the alternating voltage source is made in the form of a step down three phase transistor, whose secondary winding is switched in through the cited resistors to the input of the converter, while the indication elements are designed for switching in in parallel to each of the rectifiers of the converter. To increase efficiency the device is equipped with three filtering capacitors connected into a triangle, whose outleads are designed for switching to the input of the converter.
Three-Phase Grid-Connected of Photovoltaic Generator Using Nonlinear Control
DEFF Research Database (Denmark)
Yahya, A.; El Fadil, H.
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 of PV panels, ii) guaranteeing a power factor unit in the side of the grid, iii) ensuring the global asymptotic stability of the closed loop system. Based on the nonlinear model of the whole system, the controller is carried out using a Lyapunov approach. It is formally shown, using a theoretical stability analysis and simulation results that the proposed controller meets all the objectives.
Czech Academy of Sciences Publication Activity Database
Chomát, Miroslav; Schreier, Lud?k
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 ?R 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
DEFF Research Database (Denmark)
Kouchaki, Alireza; Nymand, Morten
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. This paper investigates how changing three-wire PFC to four-wire counterpart influences the inductor design in terms of size, losses, and overall efficiency of the converter. Therefore, the inductor current and voltage waveforms are analyzed and generalized in both cases for one switching cycle to build a foundation for comparison. Accordingly, the analyses are able to interpret the differences between both configurations and explain the core losses and the copper losses of inductors, especially those caused by the high frequency ac current ripple. Finally, two inductors are designed for a 5 kW PFC experimental setup. The experimental results which are performed for three-wire and four-wire PFC show a good match with the analyses.
Low-cost PWM speed controller for an electric mini-baja type vehicle
Scientific Electronic Library Online (English)
Samuel Euzédice de, Lucena; Márcio Abud, Marcelino; Francisco José, Grandinetti.
2007-03-01
Full Text Available This paperwork presents a Pulse Width Modulation (PWM) speed controller for an electric mini-baja-type car. A battery-fed 1-kW three-phase induction motor provides the electric vehicle traction. The open-loop speed control is implemented with an equal voltage/frequency ratio, in order to maintain a [...] constant amount of torque on all velocities. The PWM is implemented by a low-cost 8-bit microcontroller provided with optimized ROM charts for distinct speed value implementations, synchronized transition between different charts and reduced odd harmonics generation. This technique was implemented using a single passenger mini-baja vehicle, and the essays have shown that its application resulted on reduced current consumption, besides eliminating mechanical parts.
Scientific Electronic Library Online (English)
Leandro, Michels; Robinson F. de, Camargo; Fernando, Botterón; Humberto, Pinheiro.
2005-06-01
Full Text Available Este artigo apresenta uma metodologia sistematizada de projeto de filtros de saída de segunda ordem para inversores que sintetizam tensões senoidais através de modulação por largura de pulso (PWM) digital. O propósito desta metodologia é o de determinar os parâmetros do filtro que assegure a especif [...] icação da máxima taxa de distorção harmônica total (THD) admissível nas tensões de saída do inversor PWM, para cargas lineares e não-lineares. A metodologia proposta é discutida em detalhes, incluindo a descrição das etapas necessárias para a derivação do procedimento de projeto para diferentes topologias de inversores de tensão e o procedimento para obtenção das curvas necessárias para o projeto. Finalizando, são apresentados alguns exemplos de projeto para topologias de inversores monofásicos e trifásicos com saída a três fios e a quatro fios. Resultados experimentais são apresentados para demonstrar a validade da metodologia de projeto proposta. Abstract in english This paper presents a systematized methodology of second-order output filter for inverters that synthesize sinusoidal voltage waveforms through digital pulse-width modulation (PWM). The objective of this methodology is to determine the largest corner frequency of the filter that ensure the specifica [...] tion of the maximum total harmonic distortion (THD) admissible in the output voltages of the PWM inverter, for linear and non-linear loads. The proposed methodology is discussed in detail, including the description of the required steps for the derivation of the design procedure for different topologies of voltage inverters and the procedure to obtain the design curve. Finally, it is presented some design examples for single-phase, three-phase three-wire and three-phase four-wire filters topologies. Experimental results have been provided to demonstrate the validity of the proposed design methodology.
Directory of Open Access Journals (Sweden)
Leandro Michels
2005-06-01
Full Text Available Este artigo apresenta uma metodologia sistematizada de projeto de filtros de saída de segunda ordem para inversores que sintetizam tensões senoidais através de modulação por largura de pulso (PWM digital. O propósito desta metodologia é o de determinar os parâmetros do filtro que assegure a especificação da máxima taxa de distorção harmônica total (THD admissível nas tensões de saída do inversor PWM, para cargas lineares e não-lineares. A metodologia proposta é discutida em detalhes, incluindo a descrição das etapas necessárias para a derivação do procedimento de projeto para diferentes topologias de inversores de tensão e o procedimento para obtenção das curvas necessárias para o projeto. Finalizando, são apresentados alguns exemplos de projeto para topologias de inversores monofásicos e trifásicos com saída a três fios e a quatro fios. Resultados experimentais são apresentados para demonstrar a validade da metodologia de projeto proposta.This paper presents a systematized methodology of second-order output filter for inverters that synthesize sinusoidal voltage waveforms through digital pulse-width modulation (PWM. The objective of this methodology is to determine the largest corner frequency of the filter that ensure the specification of the maximum total harmonic distortion (THD admissible in the output voltages of the PWM inverter, for linear and non-linear loads. The proposed methodology is discussed in detail, including the description of the required steps for the derivation of the design procedure for different topologies of voltage inverters and the procedure to obtain the design curve. Finally, it is presented some design examples for single-phase, three-phase three-wire and three-phase four-wire filters topologies. Experimental results have been provided to demonstrate the validity of the proposed design methodology.
Active control of flying capacitor currents in multilevel voltage-source inverters.
Czech Academy of Sciences Publication Activity Database
Kokeš, Petr; Semerád, Radko
2013-01-01
Ro?. 58, ?. 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
International Nuclear Information System (INIS)
This paper presents a new zero voltage transition (ZVT), power factor corrected three phase ac-ac converter with single phase high frequency (HF) link. It is a two stage converter; the first stage is a boost integrated bridge converter (combination of a 3 ph boost converter and a bridge converter) operated at fixed frequency and that operates in two modes at ZVT for all switches and establishes a 1 ph square wave HF link. The second stage is a bi-directional pulse width modulation (PWM) 3 ph bridge that converts the 1 ph HF link to a 3 ph voltage using a novel switching strategy. The converter modes of operation and key equations are outlined. Simulation of the overall system is conducted using Simulink. The switching strategy and its corresponding control circuit are clearly described. Experimental verification of the simulation is conducted for a prototype of 100 V, 500 W at 10 kHz link frequency
DIGITAL CONTROL OF MULTI LEVEL CASCADE INVERTER WITH VARIABLE DC VOLTAGE SOURCES
S.NARASIMHA; Dr M Sushama
2015-01-01
Cascade inverters have been widely an applied for the covering of high voltage and high power systems. The input power sources for an inverters needs separate DC voltage sources, if the fluctuations occur at the input voltage, The traditional method are difficult to implement conducting angels of switches to minimize the harmonic distortion of output voltage on a single chip, A switching control algorithm is proposed and validated for multilevel inverter with fluctuating DC voltage sources. I...
Cascaded Multilevel Inverter with PWM Control Method
Directory of Open Access Journals (Sweden)
M.Kiran Kumar #1 , M.Saikiran *2 , Ch.Venkateswarlu
2013-05-01
Full Text Available A hybrid cascaded multilevel inverter with PWM method is presented in this paper. It consists of a standard 3-leg inverter (one leg for each phase and Hbridge in series with each inverter leg. It can use only a single DC power source to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. Multilevel carrier- based PWM method is used to produce a five-level phase voltage. The inverter can be used in hybrid electric vehicles (HEV and electric vehicles (EV. A simulation model based on PSIM and MATLAB/SIMULINK is developed. An experimental 5 kW prototype inverter is built and tested. The results experimentally validate the proposed PWM hybrid cascaded multilevel inverter.
Conversor Boost PWM Entrelaçado com Comutação Suave
Directory of Open Access Journals (Sweden)
Lúcio dos Reis Barbosa
2002-01-01
Full Text Available Este artigo apresenta uma topologia aprimorada de um conversor Boost PWM com comutação suave. O circuito proposto, tendo duas chaves ativas entrelaçadas, opera com chaveamento suave, sob odulação PWM (pulse-width-modulation. Além disso, este conversor fornece alta rendimento sob as condições de operação, para uma larga variação de carga, e operando à altas freqüências. Para ilustrar o princípio de operação deste novo conversor apresenta-se um estudo pormenorizado, incluindo simulações e resultados. A validade deste novo conversor é confirmada por meio dos resultados obtidos.
Cascaded Multilevel Inverter with PWM Control Method
M.Kiran Kumar #1 , M.Saikiran *2 , Ch.Venkateswarlu
2013-01-01
A hybrid cascaded multilevel inverter with PWM method is presented in this paper. It consists of a standard 3-leg inverter (one leg for each phase) and Hbridge in series with each inverter leg. It can use only a single DC power source to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. Multilevel carrier- based PWM method is used to produce a five-level phase voltage. The inverter can be used in hybrid electric vehicles (HEV) and electric vehicles (EV)....
Harmonics mitigation of dead time effects in PWM converters using a repetitive controller
DEFF Research Database (Denmark)
Yang, Yongheng; Zhou, Keliang
2015-01-01
In order to prevent the power switching devices (e.g., the Insulated-Gate-Bipolar-Transistor, IGBT) from shoot-through in voltage source converter during a switching period, a dead time is added either in the hardware drivers of the IGBTs or implemented in the software Pulse-Width Modulation (PWM) scheme. Both methods will lead to a degradation of the injected current power quality. Thus, the harmonics induced by the dead time have to be compensated in order to achieve a satisfactory current as required by the standards. In this paper, a repetitive controller has been introduced to eliminate the dead-time effect in grid-connected PWM converters. The repetitive controller has been plugged into a proportional resonant based fundamental controller. Compared with the traditional dead-time compensation solutions, the repetitive controller can effectively compensate the dead-time harmonics as well as other low-order distortions, and also it is a simple method without hardware modifications. Experimental results are demonstrating the advantages of the proposed dead-time effect mitigation method compared to the resonant based harmonic compensator.
Harmonics mitigation of dead time effects in PWM converters using a repetitive controller
DEFF Research Database (Denmark)
Yang, Yongheng; Zhou, Keliang; Wang, Huai; Blaabjerg, Frede
In order to prevent the power switching devices (e.g., the Insulated-Gate-Bipolar-Transistor, IGBT) from shoot-through in voltage source converter during a switching period, a dead time is added either in the hardware drivers of the IGBTs or implemented in the software Pulse-Width Modulation (PWM...... as other low-order distortions, and also it is a simple method without hardware modifications. Experimental results are demonstrating the advantages of the proposed dead-time effect mitigation method compared to the resonant based harmonic compensator.......) scheme. Both methods will lead to a degradation of the injected current power quality. Thus, the harmonics induced by the dead time have to be compensated in order to achieve a satisfactory current as required by the standards. In this paper, a repetitive controller has been introduced to eliminate the...... dead-time effect in grid-connected PWM converters. The repetitive controller has been plugged into a proportional resonant based fundamental controller. Compared with the traditional dead-time compensation solutions, the repetitive controller can effectively compensate the dead-time harmonics as well...
Three-phase electric arc plasma torches
International Nuclear Information System (INIS)
Peculiarities of the electric arc plasma torches ac powering are considered in this article. Schematic and design of the three-phase 'Zvezda'-type plasma torch are described along with its characteristics. Method of the plasma torch calculation, based on similarity theory, is outlined. Analysis of ac arc magnetic rotation in the plasma torch is presented. Schematic and design of the three-phase EDP-type plasma torch are described along with its characteristics. The results of experimental investigation of electrode operating modes are presented. (author)
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.
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.
PWM pneumatic clutch/shift systems
Ricón Ruiz, José Manuel
2009-01-01
In this thesis a gear position system for the UMSAE race car is designed in order to know exactly which gear selected in the gearbox of the car. Knowing the gear selected for the gearbox, the time spent by the PWM pneumatic clutch/shift system for shifting from one gear to another one will be greatly reduced (about 200 ms per gear shifting).
Novel PWM Modifying Method for Detecting DC-bus Current to Facilitate Noise Adaptation
Arakawa, Yoichiro; Aoyagi, Shigehisa; Nagata, Koichiro; Arao, Yusuke
A well-known problem encountered while using method for the detection of DC-bus current in order to reconstruct three-phase-currents is the short DC pulse duration. In order to increase the pulse duration, several PWM modifying methods have been proposed. “Half Pulse Shift method (HPS)“ is one of the promising methods that are both robust to detection error caused by current ripple and offer the advantage of low acoustic noise. In general, common-mode noise current affects DC-bus current and causes detection error, therefore, pulse duration increased by using the PWM modifying method is longer than the decay time of the common-mode noise. This decay time is dependent on the electrical environment, especially on the power -supply cable from the inverter to the motor. Although the pulse duration required to avoid common-mode noise can be estimated, this pulse duration is limited by the controllable range of output voltages. In this paper, a new PWM modifying method in order to ease the limit of the pulse duration is proposed. The results of numerical analysis confirmed that by using the proposed method the operation area over which current can detected is broadened. From the experimental results, it is confirmed that the proposed method guarantees stable operation and robustness for noisy environments.
Assessment of the impact that individual voltage source has on a generator’s stability
DEFF Research Database (Denmark)
Dmitrova, Evgeniya; Jóhannsson, Hjörtur
2012-01-01
This paper presents an approach for splitting equivalent Thevenin voltage into components induced by each voltage source in the reduced grid. Thevenin equivalent representation of the system is sometimes used for stability assessment of a given generator, where the Thevenin voltage is one of the key variables affecting the stability conditions. Thevenin voltage is formed by components induced by each voltage source in the grid, while depending on topology and system parameters, the impact of these components on the equivalent Thevenin voltage Eth might vary considerably. This paper demonstrates how the impact of individual voltage source to the Eth might be defined utilizing system admittance matrix. Knowledge about alternation of Eth while applying changes to either admittance matrix or generators’ excitation and torque gives promising perspective for determination of effective countermeasures aimed on instability prevention. Suggested approach for Eth decomposition is applied to the IEEE 30 bus test system.
Control of direct three-phase to single-phase converters under balanced and unbalanced operations
Energy Technology Data Exchange (ETDEWEB)
Babaei, Ebrahim, E-mail: babaeiebrahim@yahoo.co [Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of)
2011-01-15
In this paper, a new control method based on pulse width modulation (PWM) technique is presented for direct three-phase to single-phase converters. This control method can be easily developed to direct three-phase to n-phase converters based on the exact principle of operation. The results of the proposed control method have been presented for two conventional topologies of direct three-phase to single-phase converters with four and six power switches. The suggested control method does not depend on the balanced or unbalanced input voltages. In balanced operation, the maximum output/input voltage transfer ratios are 0.5 and 1.5 for converters with four and six power switches, respectively. Also, the proposed method has no restrictions in frequency transformation. Another advantage of the proposed control method in comparison with the conventional control methods is dv/dt reduction in switches and loads. The operation and performance of the proposed control method has been verified by the simulation and experimental results.
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...
A low cost rapid prototype platform for a three phase PFC rectifier application
DEFF Research Database (Denmark)
Haase, Frerk; Kouchaki, Alireza
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 algorithm. The digital controller is based on a for motor and power control widely used DSP/MCU platform from Texas Instruments. The design and simulation of the PFC controller is performed using the data flow driven graphical programming language MATLAB/SIMULINK. The actual programming of the processor is then performed using automatic code generation for embedded targets, which provided a close link between simulation and implementation of the PFC controller. The paper shows how this rapid prototype platform developed and how it was used for the design and implementation of the controller for a high efficient SiC based PFC application.
A low cost rapid prototype platform for a three phase PFC rectifier application
DEFF Research Database (Denmark)
Haase, Frerk; Kouchaki, Alireza; Nymand, Morten
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...... algorithm. The digital controller is based on a for motor and power control widely used DSP/MCU platform from Texas Instruments. The design and simulation of the PFC controller is performed using the data flow driven graphical programming language MATLAB/SIMULINK. The actual programming of the processor is...... then performed using automatic code generation for embedded targets, which provided a close link between simulation and implementation of the PFC controller. The paper shows how this rapid prototype platform developed and how it was used for the design and implementation of the controller for a high...
A vector modulated three-phase four-quadrant rectifier - Application to a dc motor drive
Energy Technology Data Exchange (ETDEWEB)
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)
High-frequency, three-phase current controller implementation in an FPGA
Energy Technology Data Exchange (ETDEWEB)
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)
High performance predictive current control of a three phase VSI: An experimental assessment
Indian Academy of Sciences (India)
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.
The overview of damping methods for three-phase grid-tied inverter with LLCL-filter
DEFF Research Database (Denmark)
Huang, Min; Blaabjerg, Frede
2014-01-01
Compared with LCL filter, an LLCL-filter is characterized with smaller size and lower cost for grid-connected inverters. But this high order filter may also have resonant problem which will affect the system stability. Many methods can be used to alleviate the resonant problem including active damping, passive damping or even without damping if it is designed conservative. In this paper, an overview of damping methods for three-phase voltage-source grid-tied with LLCL-filter is given. This paper also analyzes damping principle of each method including passive damping and active damping and shows the advantages as well as disadvantages of these methods.
A Single Phase to Three Phase PFC Half-Bridge Converter Using BLDC Drive with SPWM Technique.
Srinu Duvvada; Manmadha Kumar B
2014-01-01
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 ach...
The overview of damping methods for three-phase grid-tied inverter with LLCL-filter
DEFF Research Database (Denmark)
Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang
2014-01-01
Compared with LCL filter, an LLCL-filter is characterized with smaller size and lower cost for grid-connected inverters. But this high order filter may also have resonant problem which will affect the system stability. Many methods can be used to alleviate the resonant problem including active damping, passive damping or even without damping if it is designed conservative. In this paper, an overview of damping methods for three-phase voltage-source grid-tied with LLCL-filter is given. This paper...
Rheology of Three-Phase Magmas
Pistone, M.; Caricchi, L.; Ulmer, P.; Reusser, E.; Marone, F.; Burlini, L.
2012-04-01
Luigi Burlini was a conscious supervisor, a brilliant teacher and a dear friend. He instilled in me optimism and passion for research. His scientific eclecticism to combine several disciplines and methodologies to challenge and solve science issues has enhanced my approach of analysis and observation. His "simple" curiosity to test new scientific pathways and truly know the validity of own proposals represents my primary inspiration to continue the academic career. He was the far-seeing and carpe diem man at the same time; from this I learnt to live intensively day by day without forgetting what will be next. The work I will present is dedicated to him. We present experimental results from a study mainly aiming to constrain the dependence of rheology of three-phase magmas (ranging from dilute suspensions to crystal mushes) on the viscosity of the suspending silicate melt, on the relative contents of crystals and bubbles and on the interactions occurring between the three phases during deformation. Hydrous haplogranitic magmas containing variable amounts of quartz crystals (between 24 and 65 vol%), and fixed bubble volume (9-12 vol% CO2-rich bubbles) were deformed in simple shear with a Paterson-type rock deformation apparatus at high temperature (823-1023 K) and high pressure (200 MPa), in strain-rate stepping (5•10-5 s-1 - 4•10-3 s-1) from low to high deformation rate. The rheological results suggest that three-phase suspensions are characterized by strain rate-dependent rheology (non-Newtonian behavior). Two kinds of non-Newtonian behaviors were observed: shear thinning (decrease of viscosity with increasing strain rate) and shear thickening (increase of viscosity with increasing strain rate). Microstructural observations suggest that: shear thinning dominantly occurs in crystal-rich magmas (55-65 vol% crystals) because of crystal size reduction and shear localization; shear thickening prevails in dilute suspensions (24-44 vol% crystals) due to outgassing promoted by bubble coalescence.
Self oscillating PWM modulators, a topological comparison
Poulsen, Søren; Andersen, Michael Andreas E.
2006-01-01
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. Achi...
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.
HIGH ??? CURRENT PWM BIPOLAR STEPPER MOTOR CONTROL AND DRIVE
Alexandru MORAR
2011-01-01
The paper presents some investigations and research results concerning the general purpose PWM (pulse-width modulation) with applications to stepper motor control and drive. In order to improve the dynamic performances of the motor, a PWM inverter has been realised using dedicateded ICs. The bridges are capable of sustaining 46V and include internal pulse-widht modulation(PWM) control of the output curent to 2A. The laboratory prototype of the implemented digital control system, and experimen...
International Nuclear Information System (INIS)
The relationships for the calculation of the circuit of the constant voltage source with regard to the transformer inductive scattering and valve non-linear characteristic have been obtained. When designing the constant voltage source of the considered type the circuit parameters must be chosen so that the natural frequency of the circuit was similar to the frequency of the feeding network
Three Phase to Three Phase Direct Matrix Converter using SPWM Technique
Directory of Open Access Journals (Sweden)
Sharon D. Ronald,
2013-05-01
Full Text Available The principle of three phase SPWM AC-AC matrix converter using 9 bidirectional switching devices is explained. IGBT-power diode combination is used is main power switching device. Constant voltage and frequency sinusoidal supply voltage can be converted to variable voltage and frequency voltage using this converter. The working is described based on the working three phase to single phase matrix converter. MATLAB/ Simulink software is used for the simulation. The operation is analyzed for various modulation indexes and input voltages. The results are compared and the optimum condition for favorable operation is obtained.
Directory of Open Access Journals (Sweden)
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.
The Investigation of Sinusoidal Single Phase Voltage Source Inverter Output Filter
Directory of Open Access Journals (Sweden)
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
Rodríguez Monter, Ana
2013-01-01
El trabajo desarrollado en esta Tesis se centra en optimizar el comportamiento de Voltage-Source Converters (VSCs) cuando son utilizados como interfaz con la red eléctrica, tanto para absorber como para entregar energía de la red con la mejor calidad posible y cumpliendo con los estándares. Para tal fin, esta Tesis se centra en el control de sistemas lineales conectados en cascada aplicados al control de VSCs conectados en paralelo con la red eléctrica a través de un filtro L, especialmente e...
Dynamic Modeling of UPFC by Two Shunt Voltage- Source Converters and a Series Capacitor
Farzad Mohammadzadeh Shahir; Ebrahim Babaei
2013-01-01
The unified power flow controller (UPFC) is one of the FACTS devices vastly applied in power systems. This paper presents the modeling of a new structure of UPFC consists of two shunt voltage-source converters and a series capacitor. Through the presented modeling, the transient and steady states responses of UPFC are well investigated. The results of the investigation are presented for the transient and steady states by simulating proposed system in MATLAB changing each system parameter.
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 resu...
Amiri RABIE; Fellah Mohammed KARIM; Hadjeri SAMIR; Zidi Sid AHMED; Khatir MOHAMED
2009-01-01
Voltage Source Converter (VSC) based HVDC transmission technology hasbeen selected as the basis for several recent projects due to its controllability,compact modular design, ease of system interface, and low environmentalimpact. This paper investigates the dynamic performance of a 200MW,±100kV VSC-HVDC transmission system under some faulted conditionsusing MATLAB/Simulink. Simulation results confirm the satisfactoryperformance of the proposed system under active and reactive powervariations ...
Passivity-based design of robust passive damping for LCL-filtered voltage source converters
DEFF Research Database (Denmark)
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...
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
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 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 ...
Voltage Balancing of 4-level Capacitor-Clamped Voltage Source Inverter.
Czech Academy of Sciences Publication Activity Database
Kokeš, Petr; Semerád, Radko
Prague : Institute of Thermomechanics AS CR, v. v. i., 2008, s. 32-40. 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 MPO FT-TA4/077 Institutional research plan: CEZ:AV0Z20570509 Keywords : capacitor-clamped voltage source inverter * multilevel inverter * capacitor balancing Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
MODELING AND SIMULATION OF A NOVEL SERIES/PARALLEL VOLTAGE SOURCES MULTILEVEL INVERTER
N.SANTHOSH SINGH.B,; DR.B.BRAHMAIAH
2011-01-01
In this paper, a new topology of cascaded multilevel inverter with a high number of steps associated with a low number of switches is presented. A multilevel voltage is obtained by cascading two H-bridges and an inverter. Voltage sources are connected in series/parallel by the switching devices. The size, complexity and power consumption in the gate driving circuits is also reduced. Reduction of rating of the switches is another advantage. The total harmonic distortion (THD) is reduced with m...
Variable speed wind turbine generator system with current controlled voltage source inverter
Energy Technology Data Exchange (ETDEWEB)
Muyeen, S.M., E-mail: muyeen0809@yahoo.co [Dept. of Electrical Engineering, Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Al-Durra, Ahmed [Dept. of Electrical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Tamura, J. [Dept. of EEE, Kitami Institute of Technology, 165 Koen-cho, Kitami 090-8507 (Japan)
2011-07-15
highlights: {yields} Current controlled voltage source inverter scheme for wind power application. {yields} Low voltage ride through of wind farm. {yields} Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.
Variable speed wind turbine generator system with current controlled voltage source inverter
International Nuclear Information System (INIS)
highlights: â†’ Current controlled voltage source inverter scheme for wind power application. â†’ Low voltage ride through of wind farm. â†’ 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.
Intelligent Positioning Fuzzy Servomechanism Under PWM Nonlinear Loads
D. Rangel; Rivera, A. L.; P.D. Alaníz; Castañeda, R. (Ruiz); V. M. Castaño
2010-01-01
An experimental intelligent angular positioning fuzzy servomechanism excited by a nonlinear load based on a mechanicaltransient Pulse Width Modulation (PWM) is developed. This fuzzy positioning system is capable of reaching the angular positionwith high precision even when the response is affected by the application of different PWM nonlinear loads.
Single-Phase Optimal Odd PWM Problem.
Czech Academy of Sciences Publication Activity Database
Kujan, Petr; Hrom?ík, 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 ?R(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
Mohamadou, Youssoufa; In Oh, Tong; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee
2012-10-01
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?M? 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 comparison to the current source-based BIS system where the SNR drops below 40 dB for frequencies greater than 1 MHz.
International Nuclear Information System (INIS)
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?M? 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 comparison to the current source-based BIS system where the SNR drops below 40 dB for frequencies greater than 1 MHz. (paper)
Apparatus and method for heat-run test on high-power PWM converters with low energy expenditure
Indian Academy of Sciences (India)
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.
Selective Harmonic Virtual Impedance for Voltage Source Inverters with LCL filter in Microgrids
DEFF Research Database (Denmark)
Savaghebi, Mehdi; Vasquez, Juan Carlos; Jalilian, Alireza Jalilian; Guerrero, Josep M.; Lee, Tzung-Lin
This paper presents a new control approach for voltage source inverters ended with LCL filters for microgrid applications. The control approach consists of voltage and current inner control loops in order to fix the filter capacitor voltage and a virtual impedance loop. The virtual impedance is...... impedance for negative sequence of fundamental component as well as positive and negative sequences of main harmonic components. Furthermore, resistive virtual impedances are added at these components in order to provide a proper load sharing and make the overall system more damped. Simulation results are...
Stability analysis and design of the improved droop controller on a voltage source inverter
DEFF Research Database (Denmark)
Calabria, Mauro; Schumacher, Walter
2015-01-01
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.
Influence of current limitation on voltage stability with voltage sourced converter HVDC
DEFF Research Database (Denmark)
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...
Effect of Supply-Voltage Unbalanced on Voltage-Source Inverter.
Czech Academy of Sciences Publication Activity Database
Chomát, Miroslav; Schreier, Lud?k; Bendl, Ji?í
Dublin : The Institution of Engineering and Technology, Power Conversion and Applications, Profesional Network, 2006, s. 312-315. ISBN 0-86341-618-7. ISSN 0537-9989. [IET International Conference on Power Electronics, Machines and Drives (PEMD 2006) /3./. Dublin (IE), 04.04.2006-06.04.2006] R&D Projects: GA ?R(CZ) GA102/06/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : unbalanced voltage supply * voltage-source inverter * pulse width modulation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
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
PERFORMANCE ANALYSIS OF SENSORLESS BLDC MOTOR DRIVE SYSTEM USING ASYMMETRIC PWM CONTROL TECHNIQUE
Directory of Open Access Journals (Sweden)
R.Meenakshi
2012-05-01
Full Text Available This paper describes the simulation model for four-switch three-phase (FSTP brushless dc (BLDC motor drives using novel voltage PWM technique. In this paper a back EMF based sensor less scheme is clearly explained with the help of MATLABSIMULINK models. The low cost BLDC driver is achieved by the reduction of switch device count, cost down of control, and saving of hall sensors for commercial applications. Field programmable gate array was chosen as the hardware platform because of its benefits like high operating frequency and parallel processing capabilities. Asymmetric pulse width modulation scheme is developed to drive FSTP BLDC motors with the desired dynamic and static speed–torque characteristics. The simulation analysis of the back EMF based sensor less BLDC driver will be discussed and the performance using novel schemes will be evaluated.
Faiz, A.; Guyomar, D.; Petit, L.; Buttay, C.
2005-09-01
This paper deals with the so called SSD (stands for Synchronized Switch Damping) technique that is a semi-passive approach developed to address the problem of structural vibration damping and noise reduction. Compared to standard passive piezoelectric damping, this technique offers the advantage of self-adaptation with environmental variations (e.g. temperature). On the contrary to the active damping systems, its implementation does not require any sophisticated signal processing or any bulk power. In the semi passive approach, the piezoelectric element is continuously switched from open circuit to short circuit synchronously to the strain. Due to this switching mechanism, a phase difference appears between the strain induced by an incident acoustic wave and the resulting voltage, thus creating energy dissipation. With the non-linear process, damping performances directly depend on the electromechanical coupling coefficient of the system. For the weakly coefficient coupling systems, the voltage amplitude of the piezoelectric elements can be artificially increased by switching on voltage sources. Using this new method SSDV (stands for Synchronized Switch Damping on Voltage source), 16.1?dB attenuation on the transmitted wave pressure in the tube is obtained whereas only 8?dB were achieved with the classical SSDI (stands for Synchronized Switch Damping on Inductor). Furthermore, as this method is adaptive, attenuation is observed over a 600?Hz-wide frequency band.
Evolutionary Computing Based Area Integration PWM Technique for Multilevel Inverters
Directory of Open Access Journals (Sweden)
S. Jeevananthan
2007-06-01
Full Text Available 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 (fundamental output and the total area of the output pulses are made equal. An attempt is made to incorporate two soft computing techniques namely evolutionary programming (EP and genetic algorithm (GA in the generation and placement of switching pulses. The results of a prototype seven-level cascaded inverter experimented with the novel PWM strategies are presented.
A Novel SVPWM Technology Used in PWM Rectifiers of WPGS
Zhang Junli; Li Yuren; Fu Longfei; Zhang Wenjuan
2013-01-01
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 gene...
International Nuclear Information System (INIS)
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
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.
Scientific Electronic Library Online (English)
Ricardo Q., Machado; Amílcar F. Q., Gonçalves; Simone, Buso; José A., Pomilio.
2009-09-01
Full Text Available Este artigo propõe uma solução para a conexão direta de geradores de indução trifásicos em uma rede monofásica com regulação de vazão o que faz com que, a velocidade do gerador de indução se mantenha acima de sua velocidade síncrona. Para que a conexão entre gerador e rede monofásica seja satisfatór [...] ia e para que os critérios de qualidade de energia sejam preservados, o controle do fluxo de energia, entre a rede monofásica e o conversor PWM trifásico, é realizado empregando a idéia de sistema interligado ajustando a defasagem e amplitude da tensão sintetizada pelo conversor em relação a tensão da rede monofásica de forma que o fator de potência na rede monofásica seja unitário. Em relação ao conversor de potência, espera-se que o mesmo produza tensões senoidais, com freqüência e amplitude fixas para que o gerador de indução opere balanceado. O artigo descreve a estratégia de controle do inversor, o critério de projeto dos controladores e apresenta alguns resultados experimentais. Abstract in english This paper proposes a solution for the direct connection of a three-phase induction generator to a single-phase feeder. This high power quality system is intended to be used in micro-hydro power plants applications with control of the water flow. It is employed to maintain the speed of the induction [...] generator greater than its synchronous value. The difference between the generated power and the power consumed by the local load flows through the single-phase feeder. The power flow control is provided by a three-phase PWM inverter that additionally guarantees the local power quality. A system with good power quality must have sinusoidal and constant amplitude voltages, fixed frequency operation, balanced induction generator voltages and currents, harmonics and reactive power compensation. The paper describes the inverter control strategy, presents design criteria of the controllers, and shows experimental results.
Simulation of Five Phase Voltage Source Inverter with Different Excitation for Star Connected Load
Directory of Open Access Journals (Sweden)
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.
Passivity-based design of robust passive damping for LCL-filtered voltage source converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede
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 current control is included, which allows a relaxed design of the passive damper with the reduced power loss and improved stability robustness against grid parameters variations. Design procedures of two commonly used passive dampers with LCL-filtered VSCs are illustrated. Experimental results validate the effectiveness of the approach.
Virtual-Impedance-Based Control for Voltage-Source and Current-Source Converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Li, YunWei
2015-01-01
The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models. Different virtual impedances and their implementation issues are then discussed. A number of practical examples are demonstrated to illustrate the feasibility of virtual impedances. Emerging applications and future trends of virtual impedances in power electronic systems conclude this paper.
A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources
Shen, Hui; 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, thus creating energy dissipation. By supplying the energy collected from the piezoelectric materials to the switching circuit, a new low-power device using the SSDV technique is proposed. Compared with the original self-powered SSDI (synchronized switch damping on inductor), such a device can significantly improve its performance of vibration control. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results.
Influence of current limitation on voltage stability with voltage sourced converter HVDC
DEFF Research Database (Denmark)
Zeni, Lorenzo; Jóhannsson, Hjörtur
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.
Directory of Open Access Journals (Sweden)
Tian Yizhi
2013-01-01
Full Text Available Nowadays, there are several renewable power sources connected into power grid with full power Voltage Source Inverter (VSI, such as photovoltaic power system and variable speed wind turbines. The operation state variables of full power VSI should be adjusted seamlessly in order to reduce the fluctuation of output power. The current linearization control strategy leads a certain extent impact component during the dynamic motion process. This study present the Brochistos Chronos Control Strategy (BCCS based on Hamilton theory, with the flexibility of full power VSI system, the smoothness and promptness is reflected in integrated process by the way of regulates state variables precisely. The effectiveness of this control strategy is be verified by the simulation results and the overall process fulfill the requirements of the duration as short as possible.
FPGA techniques based new hybrid modulation strategies for voltage source inverters.
Sudha, L U; Baskaran, J; Elankurisil, S A
2015-01-01
This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results. PMID:25821852
High-performance feedback-type active damping of LCL-filtered voltage source converters
DEFF Research Database (Denmark)
Wang, Xiongfei; Blaabjerg, Frede
2015-01-01
Active damping of LCL-filter resonance based on single-state feedback control is widely used with voltage source converters. Its robustness against grid impedance variation has always been a major concern with its controller design. To deal with this issue, this paper begins by developing a generalized impedance-based model of grid current control with feedback-type active damping. Then, a controller design method based on the z-domain root contours and frequency-domain passivity theorem is proposed. It not only allows a co-design of the grid current controller and damping controller, but ensures also a robust stabilization against the grid parameters variations. For illustration, the approach is applied to design three single-state feedback-damping schemes, and their damping robustness are compared under both inductive and resonant grid impedances. Experimental results validate the effectiveness of the method.
Modulation and Circulating Current Suppression for Parallel Interleaved Voltage Source Converters
DEFF Research Database (Denmark)
Gohil, Ghanshyamsinh Vijaysinh
2016-01-01
optimization process takes into account the yearly load profile and it is used to minimize the energy loss, rather than minimizing the losses at a specific operating point. In a dual converter fed open-end transformer topology, each of the VSCs has to process the rated current. In many high power applications......The two-level Voltage Source Converters (VSCs) are often connected in parallel to increase the current handling capability. In such systems, the multi-level voltage waveforms can be obtained by interleaving the carrier signals of the parallel connected two-level VSCs. The multi-level voltage...... waveform facilitates reduction in both the switching frequency and the size of the harmonic filter components. This leads to the improvement in both the system efficiency and power density. However, when VSCs are connected in parallel and share the same dc-link, the circulating current flows through the...
MODELING AND SIMULATION OF A NOVEL SERIES/PARALLEL VOLTAGE SOURCES MULTILEVEL INVERTER
Directory of Open Access Journals (Sweden)
N.SANTHOSH SINGH.B,
2011-06-01
Full Text Available In this paper, a new topology of cascaded multilevel inverter with a high number of steps associated with a low number of switches is presented. A multilevel voltage is obtained by cascading two H-bridges and an inverter. Voltage sources are connected in series/parallel by the switching devices. The size, complexity and power consumption in the gate driving circuits is also reduced. Reduction of rating of the switches is another advantage. The total harmonic distortion (THD is reduced with more number of steps in output voltage without using pulse width modulation techniques. The proposed setup configures theoretical approach along with simulations carried on MATLAB/SIMULINK environment. Simulation results are shown and compared with theoretical results.
Estimation of the Plant Time Constant of Current-Controlled Voltage Source Converters
DEFF Research Database (Denmark)
Vidal, Ana; Yepes, Alejandro G.
2014-01-01
Precise knowledge of the plant time constant is essential to perform a thorough analysis of the current control loop in voltage source converters (VSCs). As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included in the model, through an equivalent series resistance. In a recent work, an algorithm to identify this parameter was developed, considering the inductance value as known and practically constant. Nevertheless, the plant inductance can also present important uncertainties with respect to the inductance of the VSC interface filter measured at rated conditions. This paper extends that method so that both parameters of the plant time constant (resistance and inductance) are estimated. Such enhancement is achieved through the evaluation of the closed-loop transient responses of both axes of the synchronous reference frame when a proportional integral current controller is implemented. Experimental results validate the approach.
Directory of Open Access Journals (Sweden)
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.
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.
Three phase power conversion system for utility interconnected PV applications
Porter, David G.
1999-03-01
Omnion Power Engineering Corporation has developed a new three phase inverter that improves the cost, reliability, and performance of three phase utility interconnected photovoltaic inverters. The inverter uses a new, high manufacturing volume IGBT bridge that has better thermal performance than previous designs. A custom easily manufactured enclosure was designed. Controls were simplified to increase reliability while maintaining important user features.
Directory of Open Access Journals (Sweden)
SAFDAR FASAL T K, UNNIKRISHNAN L
2013-07-01
Full Text Available This paper presents a performance study of the proportionalintegral controller andthe fuzzy logic controller in scalar speed control of three phase squirrel cage induction motor drive. Here the speed control is possible by varying supply frequencyusing a voltage source inverter while keeping voltage to frequency ratio as a constant. Speed error is given as inputto the proportional integral controller, and speed error and change in speed error are given as input to the fuzzy logic controller.The controller output controls the reference of sinusoidal pulse width modulation. Hence, the fundamental frequency and fundamental voltage of inverter output can be varied to control the motor speed.The performance of proportional integral controller and fuzzy logic controller underload torqueand reference speed variationisevaluated by simulation results in Simulink.
EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier
Directory of Open Access Journals (Sweden)
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.
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.
Realise of PWM-generating based on FPGA
International Nuclear Information System (INIS)
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)
Neural network based PWM AC chopper fed induction motor drive
Directory of Open Access Journals (Sweden)
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. .
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
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
Three-Phase Harmonic Analysis Method for Unbalanced Distribution Systems
Jen-Hao Teng; Shu-Hung Liao; Rong-Ceng Leou
2014-01-01
Due to the unbalanced features of distribution systems, a three-phase harmonic analysis method is essential to accurately analyze the harmonic impact on distribution systems. Moreover, harmonic analysis is the basic tool for harmonic filter design and harmonic resonance mitigation; therefore, the computational performance should also be efficient. An accurate and efficient three-phase harmonic analysis method for unbalanced distribution systems is proposed in this paper. The variations of bus...
Dynamical Model Averaging and PWM Based Control for Pneumatic Actuators
Hodgson, Sean; Tavakoli, Mahdi; Pham, Minh Tu; Leleve, Arnaud
2014-01-01
A pneumatic actuator with solenoid valves is a discontinuous-input system because each valve can be either in on or off state. For such an actuator, this paper proposes a sliding-mode control scheme based on an averaged continuous-input equivalent model for the open-loop system. The averaged model is obtained from the nonlinear dynamics of the open-loop discontinuous-input system undergoing pulse-width-modulation (PWM) at the input (i.e., valve open/close action). The PWM duty cycle will be r...
Selective Harmonic Elimination PWM Technique Implementation for a Multilevel Converter
Directory of Open Access Journals (Sweden)
Dilip Kumar N
2015-06-01
Full Text Available This paper presents the selective harmonic elimination technique implementation for hybrid seven-level cascaded multilevel converter. The converter configuration is the cascaded connection of a three-level Active neutral-pointclamped (ANPC converter and an H-bridge per phase, thus forming a hybrid seven-level multilevel converter. The converter is operated by maintaining the switching frequency of a converter to a minimum value using selective harmonic elimination pulse width modulation (SHE-PWM. Analysis of the topology operated under SHE-PWM is presented on the basis of simulation results obtained from MATLAB/SIMULINK
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 ...
ZAD strategy with lateral PWM applied to a Boost converter
Directory of Open Access Journals (Sweden)
AndrÃ©s Amador
2012-01-01
by lateral PWM (Pulse Width Modulator and ZAD (Zero Average Dynamics strategy. Different nonlinear phenomena like bifurcations and chaos are reported when the parameters associated to the system are varied. Finally, chaos present in the converter is controlled using FPIC (Fixed Point Induced Control and TDAS (Time-Delay Autosynchronization techniques.
Spectra of Grid Current Generated by High Power PWM Rectifiers.
Czech Academy of Sciences Publication Activity Database
Šimek, Petr; Škramlík, Ji?í; 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
Simple PWM modulator topology with excellent dynamic behavior
DEFF Research Database (Denmark)
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....
Control Strategy of PWM Rectifiers Connected to Unbalanced Grids.
Czech Academy of Sciences Publication Activity Database
Bejvl, Martin; Švec, J.; Tlustý, J.; Valouch, V.
-, ?. 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
A new Zero-Current-Transition PWM switching cell
Energy Technology Data Exchange (ETDEWEB)
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.
A new Zero-Voltage-Transition PWM switching cell
Energy Technology Data Exchange (ETDEWEB)
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.
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.
Boosted PWM open loop control of hydraulic proportional valves
International Nuclear Information System (INIS)
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
Boosted PWM open loop control of hydraulic proportional valves
Energy Technology Data Exchange (ETDEWEB)
Amirante, R.; Catalano, L.A. [Dipartimento di Ingegneria Meccanica e Gestionale, Politecnico di Bari, Via Re David 200, 70125 Bari (Italy); Innone, A. [Universita degli Studi di Foggia, via Napoli, 25 Foggia (Italy)
2008-08-15
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. (author)
Losses in armoured three-phase submarine cables
DEFF Research Database (Denmark)
Ebdrup, Thomas; Silva, Filipe Miguel Faria da; Bak, Claus Leth; Jensen, Christian Flytkjær
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 anal...
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control ...
PWM Regulation of Grid-Tied PV System on the Base of Photovoltaic-Fed Diode-Clamped Inverters
Directory of Open Access Journals (Sweden)
Oleschuk V.I.
2015-12-01
Full Text Available Investigation of grid-tied photovoltaic system on the base of two diode-clamped inverters, controlled by specific algorithms of pulse-width modulation (PWM, has been done. This system includes two strings of photovoltaic panels feeding two diode-clamped inverters. The outputs of inverters are connected with the corresponding windings on the primary side of three-phase transformer, connected with a grid. In order to reduce phase voltage distortion and to increase efficiency of operation of the system, special scheme of control and modulation of inverters has been used, providing minimization of common-mode voltages and voltage waveforms symmetries under different operating conditions. Detailed simulation of processes in this photovoltaic-fed power conversion system has been executed. The results of simulations verify good performance of photovoltaic system regulated in accordance with specific strategy of control and modulation.
An NPC/H-bridge modular photovoltaic grid connected inverter with new-phase shifted PWM technique
Energy Technology Data Exchange (ETDEWEB)
Wanjekeche, T.; Nicolae, D.V.; Jimoh, A.A. [Tshwane Univ. of Technology, Pretoria (South Africa). Dept. of Electrical Engineering
2010-08-13
The commonly used topologies for converting direct current power generated by solar panels to high quality alternating current power at the interface to the grid are the high- frequency and line frequency voltage source grid interface system. These topologies utilize transformers which come with negative features such as increase in cost, size and weight of the whole inverter. In addition, the efficiency and reliability of the system is reduced. A novel option for inverters is the multilevel concept as it is based on low frequency switching and provides voltage or current of low sharing between the power semiconductors. The key topologies which have been suggested for multilevel converters are diode clamped or neutral point clamped (NPC); capacitor clamped of flying capacitors (FC); and cascaded H-bridge inverters with separate direct current sources. The cascaded H-bridge converter demonstrates superior qualities among the multilevel converter topologies as a result of its modularity and flexibility. This paper investigated the operating principle of a cascaded NPC/H-bridge inverter for photovoltaic-grid application. The superior characteristics of the model were analyzed using the state space techniques and double Fourier principle. A new and improved phase sifted PWM technique was proposed and its performance was compared. The main system configuration, mathematical modeling, and simulation model were presented. The state space equation showed that the model has 8 different operating modes which can be utilized to realize 5 level voltages per cell. 13 refs., 1 tab., 6 figs.
A high-quality multi-level voltage source inverter suitable for high power/high voltage applications
International Nuclear Information System (INIS)
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 Î£3k 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
DEFF Research Database (Denmark)
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 to exchange stored energy with the AC system by varying the overall DC voltage level of the MTDC network...... within a safe and pre-defined range. A theoretical treatment of the INEC algorithm and its implementation and integration within a conventional VSC control system are presented, and the impact on the total DC capacitance required within the MTDC network to ensure that DC voltages vary within an...
Vormedal, Pål Kristian Myhrer
2010-01-01
This master thesis has investigated the possible application of voltage source converters (VSC) for the interconnection of offshore installations, i.e. wind farms and petroleum platforms, in a multiterminal DC (MTDC) grid. The master thesis is written at the Norwegian University of Science and Technology, Department of Electric Power Engineering and is a continuation of the project written during the autumn of 2009. The work has been carried out in cooperation with Statnett SF, the Norwegian ...
DEFF Research Database (Denmark)
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 digital computation and modulation delays is thus compensated by the virtual capacitor. The frequency region that allows using resonant controllers is then identified with the virtual damper. It reveals tha...
Jostock, Markus; Sachau, Jürgen
2012-01-01
This paper presents a structured development of a compound state space model of an inverter driven power grid. It allows to perform stability investigations on power grids, depending on the inverter parameters influencing their dynamich behavior and on the grid structure. The general approach is to separate the active components, i.e. the inverters, from the passive components, i.e. the grid, and model them separately. A state space model of a single voltage source inverter is developed and t...
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.
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
Overhead three-phase transmission lines - Non-diagonalizable situations
Energy Technology Data Exchange (ETDEWEB)
Faria, J.A.B. (Centro de Electrotecnia da U.T.L. - Instituto Superior Tecnico, 1096 Lisboa (PT))
1988-10-01
Physically realizable transmission lines exist to which the standard modal theory does not apply since the ZY diagonalization cannot always be undertaken successfully. In this paper the non-diagonalizing conditions for typical overhead three-phase lines are established. Algorithms are described and implemented to synthesize concrete non-diagonalizable configurations, numerical examples being presented and discussed.
Three-Phase Flow and Capillarity in Porous Media
Energy Technology Data Exchange (ETDEWEB)
Helset, H.M.
1996-06-01
Multiphase flow occurs in most production operations on the reservoir rock of an oil field. Three-phase flow occurs in many oil recovery processes, such as gas or water alternating gas injection into water flooded reservoirs, thermal oil recovery and surfactant flooding. In this doctoral thesis, three-phase flow in porous media is modeled using the method of characteristics and simple wave theory. The general mathematical methods are used to model different flow processes: secondary migration of hydrocarbons, gravity segregated three-phase flow, and displacement experiments for relative permeabilities. The main conclusions from applying the methods to the migration process through a water-saturated carrier bed to a partially permeable seal are: (1) the three-phase solutions are generally dominated by the very low gas viscosity and gas density, (2) countercurrent flow and interference between the gas and oil mobilities can lead to trapping in situations where the permeability contrast between the seal and the carrier bed is insufficient to trap oil alone, (3) zones in which pressures exceed those from hydrostatic gradients (overpressured zones) exist even when the permeability contrast between the seal and the carrier bed is modest. The discussion of gravity segregated flow identifies stable displacement fronts, which usually occur only for a single value of the gas-water injection ratio. The new method developed for interpreting displacement experiments, with capillary pressure included, is based on the travelling wave solution of the flow equations. 185 refs., 69 figs., 5 tabs.
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.
MODULACIÓN PWM EN FPGA BASADO EN MÁQUINAS DE ESTADO FINITO
Directory of Open Access Journals (Sweden)
DORA MARÍA BALLESTEROS
2008-01-01
Full Text Available La modulación por ancho de pulsos PWM, consiste en la generación de pulsos que varían en su ciclo útil de acuerdo con el valor de la señal de entrada. En este artículo se presenta una técnica basada en máquinas de estado finito FSM para modular PWM en dispositivos lógicos programables FPGAs. A la entrada se tiene una señal digital de tres bits y una señal de reloj, y a la salida se obtiene una señal con ciclo útil proporcional al valor de la señal de entrada con una frecuencia igual a 1/9 la frecuencia de la señal de reloj. La programación de la FSM se realiza en una herramienta CAE de Xilinx, la cual permite generar automáticamente el código VHDL, y finalmente se simula su funcionamiento.
Mechouma Rabiaa; Azoui Boubekeur
2014-01-01
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...
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...
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.
HIGH EFFICIENCY BRIDGELESS PWM CUK CONVERTER WITH SOFT SWITCHING TECHNIQUE
ANJAN KUMAR SAHOO, SARIKA KALRA, NITIN SINGH
2013-01-01
High efficiency bridgeless single-phase ac-dc PWM cuk converter with soft-switching (ZVS) technique is proposed. This paper emphasizes more on the converter efficiency. The conduction losses and input current harmonics of the proposed converter is very less due to the absence of the input diode bridge and also during each switching cycle, only two semiconductor switches are present in the current path unlike other conventional Cuk converters. Soft switching (ZVS)technique is applied by using ...
Spread Spectrum Modulation by Using Asymmetric-Carrier Random PWM
DEFF Research Database (Denmark)
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 very effective and is independent from the modulation index. The flat motor current spectrum generates an acoustical noise close to the white noise, which improves the acoustical performance of the dri...
Solving the optimal PWM problem for odd symmetry waveforms.
Czech Academy of Sciences Publication Activity Database
Kujan, Petr; Hrom?ík, 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
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.
CARRIER OVERLAPPING PWM METHODS FOR ASYMMETRICAL MULTILEVEL INVERTER
Dr. R. Seyezhai
2011-01-01
Multilevel inverter has gained attention in recent years due to its high power capability associated with lower output harmonics. Several multilevel topologies have been reported in the literature and thispaper focuses on asymmetric cascaded multilevel inverter employing Carrier Overlapping PWM (COPWM) technique. This technique provides reduced harmonics in the output voltage and significantly improves the root mean square value of the output voltage compared to the conventional Sinusoidal Pu...
Voltage Balancing in Diode Clamped Multilevel Inverter Using Sinusoidal PWM
Shalini, S
2013-01-01
Multilevel inverters offer several advantages compared to the conventional 3-phase bridge inverter in terms of lower dv/dt stresses, lower electromagnetic compatibility, smaller rating and better output features. This project presents a 9-level diode Clamped inverter using Sinusoidal pulse width Modulation techniques as the control strategies. The algorithm has been developed within the carrier-based PWM framework to facilitate its implementation in diode clamped converters with three or more...
A "nearly parametric" solution to Selective Harmonic Elimination PWM
Shang, Bao-Xin; Zhang, Shu-Gong; Lei, Na; Chen, Jing-Yi
2015-01-01
Selective Harmonic Elimination Pulse Width Modulation (SHEPWM) is an important technique to solve PWM problems, which control the output voltage of an inverter via selecting appropriate switching angles. Based on the Rational Univariate Representation (RUR) theory for solving polynomial systems, the paper presents an algorithm to compute a "nearly parametric" solution to a SHEPWM problem. When the number of switching angles N is fixed, a "nearly parametric" solution can be considered as funct...
Single Phase Bidirectional PWM Converter for Microgrid System
C.Kalavalli; K.ParkaviKathirvelu; Balasubramanian, R
2013-01-01
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 ...
Neural network based PWM AC chopper fed induction motor drive
Venkatesan Jamuna; Sathi Reddy Rama
2009-01-01
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 driv...
Analysis of Dither in PWM Control on Electro-hydraulic Proportional Valve
Directory of Open Access Journals (Sweden)
Guoping LIU
2013-11-01
Full Text Available Plus with modulation (PWM is widely used in proporational control systems for it is efficient, flexible and anti-interference. Due to the friction and hysteresis of electromagnet, hysteresis exists when hydraulic valve in steady-state, and hysteresis influences the dynamic characteristics of the valve seriously,the hysteresis can be improved by superimposing dithers with certain frequency and amplitude to the valve coil. Aiming at the character of anti-unloading power driver circuit ,this paper analyzed the parasitic dither which exists in ±24V PWM control?besides?the experiment shows that in a high frequency PWM, dither with independent frequency and amplitude can be generated by changing the frequency of the PWM, in this way, the dithers and average current of coil can be adjusted separately by changing PWM frequency and PWM duty cycle.
Losses in armoured three-phase submarine cables
DEFF Research Database (Denmark)
Ebdrup, Thomas; Silva, Filipe Miguel Faria da
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 installation of cables with excessive phase conductor cross section. This paper also presents an example of the potential economic benefits of having a better knowledge of the losses introduced by the armour.
Three-phase Photovoltaic Systems: Structures, Topologies, and Control
DEFF Research Database (Denmark)
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...
Backstepping controller of five-level three-phase inverter
Directory of Open Access Journals (Sweden)
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.
Three-phase radionuclide scintigraphy of the hand
International Nuclear Information System (INIS)
Three-phase radionuclide scintigraphy of the hand was performed on 116 patients. Normal and abnormal patterns for radionuclide angiography, immediate post-injection blood-pool images, and delayed scans (3-4 hr.) were established. Of 80 patients with normal circulation, 61 (76%) had equal radial and ulnar artery flow bilaterally, while in 19 (24%) either the radial or ulnar artery was dominant. Abnormal studies were grouped into three categories: suspected vascular lesions (Group I), pain of uncertain etiology (Group II), and patients evaluated before and after reconstructive surgery (Group III). The diagnosis was correct in 89% of the patients in Group I (34/38), 89% of those in Group II (57/64), and all of those in Group III (14/14). Three-phase scintigraphy of the hand yields significant information about perfusion and bone metabolism
Three-phase Photovoltaic Systems: Structures, Topologies, and Control
DEFF Research Database (Denmark)
Kerekes, Tamas; Sera, Dezso
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, maximum power point tracking, as well as grid integration requirements and support functions are reviewed.
Correlation for bed voidage in three-phase fluidized bed
Energy Technology Data Exchange (ETDEWEB)
Hirata, A.; Bulos, F.; Noguchi, M. [Waseda University, Tokyo (Japan)
1995-08-20
Previously published data of three-phase fluidization were correlated to develop a new empirical correlation for predicting bed voltage in gas-liquid-solid fluidized beds. The proposed correlation model, when used in conjunction with any suitable two-phase model for bed voltage, can serve as a correlation for bed voltage in both two- and three-phase fluidized beds. It describes the bed expansion and contraction phenomena observed during fluidization and is valid even as the superficial gas velocity approaches zero. A new criterion for quantifying the bed expansion and contraction phenomena based on this empirical model is derived and is also discussed in this paper. 19 refs., 3 figs., 4 tabs.
A three phase model of a batch fluidized bed
Aly, S. E.; Fathalah, K. A.
A three phase mathematical model of simultaneous heat and mass transfer of a batch operation for a fluidized bed is presented. The three phases are a solid free bubble, emulsion and solid phases. The model employs an elaborate five equations porosity model. Various correlations for the minimum fluidization parameters are surveyed and compared with the adequate one is being adopted in the model. The governing equations together with the boundary and initial conditions are presented for a cyclic operation of the bed. These are numerically solved for a test case where the bed is charged with silica gel particles to dehumidify a process air stream. Thus the bed works in an air dehumidification mode/bed regeneration mode cyclic operation with matching conditions.Results for the bed operation are presented as the temperature and humidity ratio variations for the test case. The results indicate the ability of the developed model to provide the required data for the concerned batch operated fluidized bed.
Program for three-phase power transformer design
Olivian Chiver; Eleonora Pop; Ionut Barsan
2011-01-01
This paper presents a program developed for designing three-phase power transformers used in power systems. The program was developed in Visual Basic because this programming language allows us to realize a friendly and suggestive interface with minimum effort. The second reason, which is the most important, is to use Visual Basic, because this language is recognized by the used finite elements analysis (FEA) software, MagNet produced by Infolytica. This software package is designed for calcu...
Evaluation of Three-Phase Transformerless Photovoltaic Inverter Topologies
Kerekes, Tamas; Liserre, Marco; TEODORESCU, Remus; Klumpner, C.; M. Sumner
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 leakage current paths. The model is validated by both simulation and experimental results. These will be used to compare the selected topologies, and to explain the influence of system unbalance and the...
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...
Three phase load flow; Fluxo de carga trifasico
Energy Technology Data Exchange (ETDEWEB)
Zago, Maria Goretti
1992-12-01
The phase model which is used in the analysis and planning of electric power system is based on the hypothesis that both the transmission system and load are equilibrated. Such a system, which presents the advantage of being simple,presents satisfactory results in several cases, however, for certain applications this system is inadequate. this work presents an alternative method based on three-phase load flow which an be applied to electric power distribution networks 19 refs., 25 figs., 24 tabs.
Direct Torque Control of Three-Phase Flux Reversal Machine
D S PHANI GOPAL CHEERLA, L.MALLESWARI, DR. G R K MURTHY
2013-01-01
In this paper the mathematical model of three phase Flux Reversal Machine (FRM), electrical gear ratio of the machine and the Direct torque control of FRM is discussed. The mathematical equations are similar to that of permanent magnet synchronous machine (PMSM). The machine model is also simulated using MATLAB for the case of machine working as a motor. Output speed, flux locus and inverter output voltages are acquired at the steady state conditions.
Direct Torque Control of Three-Phase Flux Reversal Machine
Directory of Open Access Journals (Sweden)
D S PHANI GOPAL CHEERLA, L.MALLESWARI, DR. G R K MURTHY
2013-05-01
Full Text Available In this paper the mathematical model of three phase Flux Reversal Machine (FRM, electrical gear ratio of the machine and the Direct torque control of FRM is discussed. The mathematical equations are similar to that of permanent magnet synchronous machine (PMSM. The machine model is also simulated using MATLAB for the case of machine working as a motor. Output speed, flux locus and inverter output voltages are acquired at the steady state conditions.
Differential Protection for Arbitrary Three-Phase Power Transformers
Gaji?, 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...
Dynamics of IGBT based PWM Converter A Case Study
Directory of Open Access Journals (Sweden)
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.
Precise derating of three phase induction motors with unbalanced voltages
International Nuclear Information System (INIS)
Performance analysis of three phase induction motors under supply voltage unbalance conditions is normally conducted using the well-known symmetrical components analysis. In this analysis, the voltage unbalance level at the terminals of the machine is assessed by means of the NEMA or IEC definitions. Both definitions lead to a relatively large error in predicting the performance of a machine. A method has recently been proposed in which, in addition to the voltage unbalance factor (VUF), the phase angle has been taken into account in the analysis. This means that the voltage unbalance factor is regarded as a complex value. This paper shows that although the use of the complex VUF reduces the computational error considerably, it is still high. This is proven by evaluating the derating factor of a three phase induction motor. A method is introduced to determine the derating factor precisely using the complex unbalance factor for an induction motor operating under any unbalanced supply condition. A practical case for derating of a typical three phase squirrel cage induction motor supplied by an unbalanced voltage is studied in the paper
Ultrasound assisted three phase partitioning of a fibrinolytic enzyme.
Avhad, Devchand N; Niphadkar, Sonali S; Rathod, Virendra K
2014-03-01
The present investigation is aimed at ultrasound assisted three phase partitioning (UATPP) of a fibrinolytic enzyme from Bacillus sphaericus MTCC 3672. Three phase partitioning integrates the concentration and partial purification step of downstream processing of a biomolecule. Three phase system is formed with simultaneous addition of ammonium sulfate to crude broth and followed by t-butanol. UATPP of a fibrinolytic enzyme was studied by varying different process parameters such as ammonium sulfate saturation concentration, pH, broth to t-butanol ratio, temperature, ultrasound frequency, ultrasonication power, and duty cycle. The optimized parameters yielding maximum purity of 16.15-fold of fibrinolytic enzyme with 65% recovery comprised of 80% ammonium sulfate saturation, pH 9, temperature 30 °C, broth to t-butanol ratio 0.5 (v/v), at 25 kHz frequency and 150 W ultrasonication power with 40% duty cycle for 5 min irradiation time. SDS PAGE analysis of partitioned enzyme shows partial purification with a molecular weight in the range of 55-70 kDa. Enhanced mass transfer of UATPP resulted in higher fold purity of fibrinolytic enzyme with reduced time of operation from 1 h to 5 min as compared to conventional TPP. Outcome of our findings highlighted the use of UATPP as an efficient biosepartion technique. PMID:24184008
Single-carrier phase-disposition PWM implementation for multilevel flying capacitor converters
Ghias, Amer M.Y.M; Pou Félix, Josep; Capellá Frau, Gabriel José; Agelidis, Vassilios; Aguilera, Ricardo P; Meynard, Thierry A.
2015-01-01
This letter proposes a new implementation of phase-disposition pulse-width modulation (PD-PWM) for multilevel flying capacitor (FC) converters using a single triangular carrier. The proposed implementation is much simpler than conventional PD-PWM techniques based on multiple trapezoidal-shaped carriers, generates the same results as far as natural capacitor voltage balance is concerned and offers better quality line-to-line voltages when compared to phase-shifted PWM. The proposed algorithm i...
Prediction of power losses in silicon iron sheets under PWM voltage supply
International Nuclear Information System (INIS)
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.))
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...
Analysis and Design of a Higher Current ZVS-PWM Converter for Industrial Applications
Directory of Open Access Journals (Sweden)
Navid Golbon
2013-03-01
Full Text Available A new auxiliary circuit that can be implemented in DC-DC and AC-DC ZVS-PWM converters is proposed in the paper. The circuit is for ZVS-PWM converters used in applications where high-frequency operation is needed and the load current is higher than that of typical ZVS-PWM converters. In the paper, the operation of a new ZVS-PWM converter is described, its steady-state operation is analyzed, and a procedure for its design is derived and then demonstrated. The feasibility of the new converter is confirmed by experimental results obtained from a prototype.
Analysis and Design of a Higher Current ZVS-PWM Converter for Industrial Applications
Navid Golbon; Gerry Moschopoulos
2013-01-01
A new auxiliary circuit that can be implemented in DC-DC and AC-DC ZVS-PWM converters is proposed in the paper. The circuit is for ZVS-PWM converters used in applications where high-frequency operation is needed and the load current is higher than that of typical ZVS-PWM converters. In the paper, the operation of a new ZVS-PWM converter is described, its steady-state operation is analyzed, and a procedure for its design is derived and then demonstrated. The feasibility of the new converter is...
Effects of 60Co ?-rays on PWM and LPS induced lymphocytes
International Nuclear Information System (INIS)
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 ?-rays. When PWM-induced cells and LPS-induced cells were incubated together, with one kind of cells exposed to 60Co ?-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 ?-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
Three-Phase High-Power and Zero-Current-Switching OBC for Plug-In Electric Vehicles
Directory of Open Access Journals (Sweden)
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.
Scientific Electronic Library Online (English)
Milton E. de, Oliveira Filho; Alfeu J., Sguarezi Filho; Ernesto, Ruppert.
2012-06-01
Full Text Available Este trabalho apresenta aspectos relacionados a implementação experimental de um conversor trifásico em matriz. As chaves bidirecionais empregadas na construção do protótipo foram construídas com a utilização de componentes discretos como IGBT's e diodos rápidos. Aspectos relacionados a proteção con [...] tra sobre tensão e curto circuito, processo de comutação das chaves bidirecionais e filtro de entrada são apresentados neste trabalho juntamente com resultados experimentais da operação do conversor. Abstract in english This paper presents some implementation details of a three-phase to three-phase matrix converter prototype. The bidirectional semiconductor switches were built using discrete IGBTs and fast diodes. Design aspects such as protection against overvoltage and short-circuit, commutation process of bi-dir [...] ectional switches, and input filter are addressed in this paper.
DEFF Research Database (Denmark)
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 virtua...
Ali, Imran
2013-01-01
In this master thesis it has been investigated to utilize the matrix as a shunt active power filter and an adjustable speed drive and then compare the matrix converter with the Back-to-Back voltage source converter in terms of active filtering capability and reactive power compensation.In first steps to utilize the matrix converter as a motor drive and a shunt active power filter the control systems for the Permanent magnet synchronous machine, shunt active power filter and 3-phase LC-filter ...
DEFF Research Database (Denmark)
Teodorescu, Remus; Blaabjerg, Frede
2004-01-01
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 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 an...
A modified two-level three-phase quasi-soft-switching inverter
DEFF Research Database (Denmark)
Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede; Chung, Henry Shu Hung
2014-01-01
A traditional Voltage Source Inverter (VSI) has higher efficiency than a Current Voltage Source (CSI) due to the less conduction power loss. However, the reverse recovery of the free-wheeling diode limits the efficiency improvement for the silicon devices based hard-switching VSI. The traditional quasi-soft-switching inverter can alternate between VSI and CSI by using a proper control scheme and thereby reduce the power losses caused by the reverse recovery of the free-wheeling diode. Neverthele...
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.
Nonlinear acoustic wave generation in a three-phase seabed
Kukarkin, A B; Zhileikin, Ya M
2015-01-01
Generation of an acoustic wave by two pump sound waves is studied in a three-phase marine sediment that consists of a solid frame and the pore water with air bubbles in it. To avoid shock-wave formation the interaction is considered in the frequency range where there is a significant amount of sound velocity dispersion. Nonlinear equations are obtained to describe the interaction of acoustic waves in the presence of air bubbles. An expression for the amplitude of the generated wave is obtained and numerical analysis of its dependence on distance and on the resonance frequency of bubbles is performed.
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...
Transient three-phases three-component flow. Pt. 1
International Nuclear Information System (INIS)
Starting from the conservation principles a nonconservative form of a system of 18 quasilinear partial differential equations describing the three-phase three-component flow is obtained. The flow is described using the three-velocity field approach. Each of the flow-fields consists of one inert and one noninert component. Full thermodynamical and mechanical nonequilibrium between the fields is modelled. The simplest possible concentration and entropy equations are obtained, without any simplifying assumptions. Also the definition of the Mach number, the critical mass flow rate, and the criticality condition for this physical system is obtained. (orig.)
Three-Phase Unbalanced Load Flow Tool for Distribution Networks
DEFF Research Database (Denmark)
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 most of the systems are single phase. New ancillary service such as static reactive power support by PV inverters can be also merged together with the load flow solution tool and thus, the impact of th...
Evaluation of Three-Phase Transformerless Photovoltaic Inverter Topologies
DEFF Research Database (Denmark)
Kerekes, Tamas; Liserre, Marco; Teodorescu, Remus; Klumpner, C.; Sumner, M.
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 leakage current paths. The model is validated by both simulation and experimental results. These will be used to compare the selected topologies, and to explain the influence of system unbalance and the ne...
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 most of the systems are single phase. New ancillary service such as static reactive power support by PV inverters can be also merged together with the load flow solution tool and thus, the impact of...
A DSP controlled one-to-three phase matrix converter
Energy Technology Data Exchange (ETDEWEB)
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.
DEFF Research Database (Denmark)
Zhu, Jiebei; Guerrero, Josep M.
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 to exchange stored energy with the AC system by varying the overall DC voltage level of the MTDC network within a safe and pre-defined range. A theoretical treatment of the INEC algorithm and its implementation and integration within a conventional VSC control system are presented, and the impact on the total DC capacitance required within the MTDC network to ensure that DC voltages vary within an acceptable range are discussed. The proposed INEC scheme is validated using a Matlab/Simulink model under various changes in demand and in response to AC network faults. The model incorporates a multi-machine AC power system connected to a MTDC transmission system with multiple converter-interfaced nodes. The effectiveness of the INEC in damping post-fault oscillations and in enhancing AC system frequency stability is also investigated. The system is shown to perform well and is attractive for providing a stable MTDC system that is capable of providing valuable support to the connected AC systems.
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.
Energy Technology Data Exchange (ETDEWEB)
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)
A Single Phase to Three Phase PFC Half-Bridge Converter Using BLDC Drive with SPWM Technique.
Directory of Open Access Journals (Sweden)
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.
A fuzzy controlled three-phase centrifuge for waste separation
International Nuclear Information System (INIS)
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
Cellular automata approach to three-phase traffic theory
Kerner, B S; Wolf, D E; Kerner, Boris S.; Klenov, Sergey L.; Wolf, Dietrich E.
2002-01-01
The cellular automata (CA) approach to traffic modeling is extended to allow for spatially homogeneous steady state solutions that cover a two dimensional region in the flow-density plane. Hence these models fulfill a basic postulate of 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 the one of the leading vehicle. In the CA models presented, the modelling of the free and safe speeds, the slow-and-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 three-phase traffic theory [B. S. Kerner and S. L. Klenov. 2002. J. Phys. A: Math. Gen....
Three-phase CFD analytical modeling of blood flow.
Jung, Jonghwun; Hassanein, Ahmed
2008-01-01
The behavior of blood cells in disturbed flow regions of arteries has significant relevance for understanding atherogenesis. However, their distribution with red blood cells (RBCs) and leukocytes is not so well studied and understood. Our three-phase computational fluid dynamics approach including plasma, RBCs, and leukocytes was used to numerically simulate the local hemodynamics in such a flow regime. This model has tracked the wall shear stress (WSS), phase distributions, and flow patterns for each phase in a concentrated suspension shear flow of blood. Unlike other computational approaches, this approach does not require dispersion coefficients as an input. The non-Newtonian viscosity model was applied to a wide physiological range of hematocrits, including low shear rates. The migration and segregation of blood cells in disturbed flow regions were computed, and the results compared favorably with available experimental data. The predicted higher leukocyte concentration was correlated with relatively low WSS near the stenosis having a high WSS. This behavior was attributed to flow-dependent interactions of the leukocytes with RBCs in pulsatile flow. This three-phase hemodynamic analysis may have application to vulnerable plaque formation in arteries with in vivo complex flow conditions. PMID:17244522
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...
Experimental prototype for PWM – Based Sliding Mode Boost Converter
Directory of Open Access Journals (Sweden)
R. A. Abdulhalem
2011-06-01
Full Text Available The paper dells with a modified experimental prototype for pulse-width modulation (PWM sliding mode control (SMC applied to a DC-to-DC-boost converter operated in continuous conduction mode (CCM. Experimental results show that the proposed control schme provides good voltage regulation and is suitable for common DC-to-DC conversion purposes. The prototype and its implementation are given in detail. The static and dynamic performances of the The static and dynamic performances of the experimental system are recorded. Experimental results show that the proposed control scheme provides good voltage regulation and is suitable for common DC-to-DC conversion purposes.
THD Analysis of Cascaded Mli for Various PWM Techniques
Directory of Open Access Journals (Sweden)
K.L.Dheeraj
2014-05-01
Full Text Available Cascaded inverters are ideal for connecting renewable energy sources with an AC grid, because of the need for separate dc sources, which is the case in applications such as photo voltaics or fuel cells. The inverter could be controlled to either regulate the power factor of the current drawn from the source or the bus voltage of the electrical system where the inverter was connected. The modulation techniques are crucial in operating any inverter at desired conditions. In this paper different pwm techniques are implemented for three level and five level cascaded mli and THD variation is analysed with variation of modulation index.
Simulink Implementation of PWM Strategies for Diode Clamped MLI
Directory of Open Access Journals (Sweden)
V.Harish
2014-04-01
Full Text Available Multilevel inverters has got more concern over conventional two level inverters because of their features like yielding output with low harmonics, output tending to sinusoidal, the voltage stress across each switching device is low. The diode clamped inverter is widely multilevel inverter configuration due to ease of operation when compared to other topologies. The variation in output voltage magnitude and frequency is achieved using various modulation strategies. In this paper various PWM strategies are implemented for three level and five level diode clamped MLI and results are compared.
High flexibility and low cost digital implementation for modern PWM strategies
DEFF Research Database (Denmark)
Mathe, Laszlo; Sera, Dezso
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.
A NOVEL THREE PHASE UNITY POWER FACTOR CONVERTER
Directory of Open Access Journals (Sweden)
Bekir Sami SAZAK
1998-03-01
Full Text Available The proposed unity power factor converter system which is able to operate from a 150V three-phase supply whilst delivering the required 200V DC voltage has been built and tested. This circuit functions as a high power factor low harmonic rectifier based on the concept that the peak capacitor voltages are proportional to the line input currents. Hence the low frequency components of the capacitor voltages are also approximately proportional to the line input currents. The system can be designed to achieve nearly sinusoidal supply input currents, when operated with discontinuous resonant capacitor voltages Output power control is achieved by variations of the IGBTs switching frequency. The converter is therefore able to compensate for any changes in the load resistance. The proposed topology offers advantages, including: a relatively simple power, control and protection circuits, high power capability, and high converter efficiencies.
Mucormycosis and bone scintillography of three phases. Case description
International Nuclear Information System (INIS)
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
Directory of Open Access Journals (Sweden)
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.
Transient three-phase three-component flow. Pt. 3
International Nuclear Information System (INIS)
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.)
Three-phase radionuclide bone imaging in sports medicine
International Nuclear Information System (INIS)
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
Myositis ossificans and the three-phase bone scan
International Nuclear Information System (INIS)
Myositis ossificans circumscripta (or paraosteoarthropathy) in paraplegics has been a well known entity since its classic description in 1918 by Dejerine and Ceillier. The disease is characterized by ectopic bone formation, primarily occurring in the particular soft tissues of the hips and knees. Hypotheses concerning its origin have been proposed, but its etiology is still unknown. Myositis ossificans can occur after traumatic injury, but develops in paraplegics without apparent injury in the involved regions. Radionuclide techniques have been used in the evaluation of myositis ossificans, particularly with serial studies to stage the activity of the disease. The author reports a case of myositis ossificans in a paraplegic that emphasizes the benefit of the three-phase bone scan in the early diagnosis of this disorder
A system for placing a three phase grid in symmetry
Energy Technology Data Exchange (ETDEWEB)
Kurbiel, A.; Kurk, J.; Loziak, W.
1983-03-15
Three versions of a system for symmetrizing the load of a three phase grid which powers single phase induction furnaces or other similar types of consumers. The basic conditions for symmetry are: a direct sequence of voltage phases, an equality of the square root of 3/2 time the value of the coefficient of the load power ZO, an equality to the full resistance to load of ZO of the inductive resistance of the choke coil Ls. In this case the cited variant will be used. If with equal conditions the coefficient of power is less than or greater than the cited, the symmetry is provided by the circuits cited, respectively. Precise symmetry may be achieved through regulating the values of the inductive choke coils Ls and the capacity of the battery of capacitors Cs.
Cellular automata approach to three-phase traffic theory
International Nuclear Information System (INIS)
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
Directory of Open Access Journals (Sweden)
Vargese Jegathesan
2008-01-01
Full Text Available This paper presents an efficient and reliable Genetic Algorithm-based solution for Specific Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. The determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. In this proposed method, harmonics up to 17th are eliminated using Genetic Algorithm without using Dual transformer. Simulations using Matlab 7.0 and PSIM 6.1 are carried out so as to validate the solution.
DEFF Research Database (Denmark)
Teodorescu, Remus; Blaabjerg, Frede
2004-01-01
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 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) inverter is also described.
Improved Passive-Damped LCL Filter to Enhance Stability in Grid-Connected Voltage-Source Converters
DEFF Research Database (Denmark)
Beres, Remus Narcis; Wang, Xiongfei
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 switching harmonics due to pulse width modulation are to be cancelled. Since the tuned circuit of the C-type filter suppresses the switching harmonics more effectively, the total inductance of the filter can be reduced. Additionally, the rating of the damping resistor is lower, compared with conventional passive-damped LCL filter. To verify the benefits of the proposed filter, a comparison with the conventional filter is made in terms of losses and ratings when both the filters are designed under the same condition.
Energy Technology Data Exchange (ETDEWEB)
Svensson, Jan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering
1996-12-01
In this paper the hybrid wind farm connected to a weak grid is investigated. By combining different electrical wind power plant systems a cost-efficient solution is obtained. The point of common connection voltage level can be controlled by injecting reactive power from a phase-compensating capacitor battery and a voltage source inverter (VSI). If the short-circuit impedance ratio is lower than 1, the demanded reactive power injection to keep the voltage at nominal level is unrealistic. For short-circuit impedance ratios of 2 or higher the demanded reactive power level is acceptable. When using both induction generators and thyristor inverters the reactive power injector VSI size should be about 0.2 pu. If the hybrid farm consists of THYs, IGs and VSIs and the active power is equally shared between the systems, the VSI had to be scaled up by 5% to handle both active and reactive power. 7 refs, 10 figs, 2 tabs
CLOSED LOOP SPEED CONTROL OF DC MOTOR USING PWM
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Mangesh J Nemade
2015-08-01
Full Text Available 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 easily. PWM technique to the digital circuit drives the components correspondingly speed wi ll change. The project basically consists of micro controller ATmega16 and motor driver, comparator, key pad, 16X2 dot matrix LCD display and rotation feedback sensor (optical encoder. The program is written in micro controller to take the input values from the user, then rotates the motor by placing 50% duty cycle pulse on the motor. The motor is rotated at X RPM speed, can be detected by using feedback sensor and micro controller. If the speed is above the specified speed then the micro controller cont inuously reduces the duty cycle till the speed comes to a predetermined level. If the detected speed is less than the pre determined speed then the micro controller continuously increases the duty cycle till the determined level. The micro controller keeps on tracking the determined speed by varying duty cycle in a closed loop control system
An Improved Switching Period Optimization Space Vector PWM Strategy
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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.
Directory of Open Access Journals (Sweden)
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.
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...
Pengaruh Penambahan PWM (Pulse Width Modulation Pada Generator HHO Tipe Dry Cell
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Fungky Dyan Pertiwi
2013-09-01
Full Text Available Generator HHO memanfaatkan proses elektrolisis air agar mendapatkan gas H2. Namun, pada praktiknya pemakaian arus dari aki yang besar dan temperatur tinggi membuat bejana generator menjadi cepat rusak, sehingga dibutuhkan tambahan rangkaian elektronika PWM pada pengujian generator HHO guna mengatasi permasalahan tersebut. Penelitian menggunakan elektroda plat berjumlah 9 berdimensi 120mm 120mm, tebal 1mm dan dibatasi oleh o-ring dengan diameter 126mm, tebal 3mm. Pengujian dilakukan secara eksperimen dengan 2 kelompok yaitu kelompok control yang mana pengujian tanpa menggunakan PWM serta kelompok uji dimana pengujian menggunakan PWM dengan variasi duty cycle 30%, 50% dan 70%. Pengujian dilakukan hingga temperatur elektrolit 93oC. Hasil uji didapatkan bahwa arus, laju produksi dan efisiensi terbesar didapatkan pada pengujian tanpa PWM yang mencapai 60,6A, 6,033 10-6kg/s dan 25,69%. Namun, pada pengambilan data kedua efisiensi turun menjadi 19,74%. Penambahan PWM pada pengujian berpengaruh pada arus dan temperatur yang stabil meskipun laju produksi dan efisiensi lebih kecil daripada pengujian tanpa PWM. Pengujian dengan PWM pada duty cycle 70% menghasilkan laju produksi dan efisiensi terbesar yang mencapai 1,843 10-6 kg/s dan 15,19%.
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.
ISOBUTANOL FROM SYNGAS IN A THREE PHASE SYSTEM
Energy Technology Data Exchange (ETDEWEB)
Peter Tijrn
2002-12-29
With growing interest in oxygenates as octane booster for automotive fuels, various synthesis routes for these chemicals are being investigated. Among others, alternative routes to isobutene, the C4-components in MTBE-synthesis are under investigation. A promising path to isobutene is the heterogeneously catalyzed CO-hydrogenation to isobutanol with following dehydration (Fig. 1). As shown by thermodynamical studies, the heterogeneously catalyzed CO-hydrogenation to isobutanol is not expected to experience any thermodynamic constraints. However, heterogeneous hydrogenation of CO is a very exothermic process, a problem which can only be partly solved when being conducted in a plug flow reactor. When carried out in reaction vessels with moving catalyst bed (e.g. three phase stirred tank), heat transfer problems can be resolved, along with additional benefits connected with this reactor type. Several heterogeneous catalytic systems have been under investigation for their capability of isobutanol synthesis from syngas. Most promising catalysts for an active and selective isobutanol synthesis from CO are modified high temperature methanol catalysts.
Deterministic microscopic three-phase traffic flow models
International Nuclear Information System (INIS)
Two different deterministic microscopic traffic flow models, which are in the context of the Kerner's there-phase traffic theory, are introduced. In an acceleration time delay model (ATD model), different time delays in driver acceleration associated with driver behaviour 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), vehicle speed adaptation occurs in synchronized flow depending on driving conditions. It is found that the ATD and SA models show spatiotemporal congested traffic patterns that are adequate with empirical results. In the ATD and SA models, the onset of congestion in free flow at a freeway bottleneck is associated with a first-order phase transition from free flow to synchronized flow; moving jams emerge spontaneously in synchronized flow only. Differences between the ATD and SA models are studied. A comparison of the ATD and SA models with stochastic models in the context of three-phase traffic theory is made. A critical discussion of earlier traffic flow theories and models based on the fundamental diagram approach is presented
Analysis of Dc/Dc converters with PWM and sliding mode controls
International Nuclear Information System (INIS)
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
Interleaved selective harmonic elimination PWM for single-phase rectifiers in traction applications
Konstantinou, Georgios; Agelidis, Vassilios; Pou FÃ©lix, Josep
2013-01-01
Interleaved four-quadrant, single-phase rectifiers are widely used in traction applications as part of an AC-DC-AC conversion system. This paper presents selective harmonic elimination pulse-width modulation (SHE-PWM) patterns for single-phase interleaved PWM rectifiers based on both H-bridges and full-bridge NPCs (H-NPCs). SHE-PWM waveforms are defined so that the low-order harmonics of the combined voltage and input currents on the primary of the supply transformer are eliminated. The formu...
Trabelsi, Mohamed; Boussak, Mohamed; Gossa, Moncef
2012-03-01
This paper deals with a fault detection technique for insulated-gate bipolar transistors (IGBTs) open-circuit faults in voltage source inverter (VSI)-fed induction motor drives. The novelty of this idea consists in analyzing the pulse-width modulation (PWM) switching signals and the line-to-line voltage levels during the switching times, under both healthy and faulty operating conditions. The proposed method requires line-to-line voltage measurement, which provides information about switching states and is not affected by the load. The fault diagnosis scheme is achieved using simple hardware and can be included in the existing inverter system without any difficulty. In addition, it allows not only accurate single and multiple faults diagnosis but also minimization of the fault detection time to a maximum of one switching period (T(c)). Simulated and experimental results on a 3-kW squirrel-cage induction motor drive are displayed to validate the feasibility and the effectiveness of the proposed strategy. PMID:22153956
HIGH EFFICIENCY BRIDGELESS PWM CUK CONVERTER WITH SOFT SWITCHING TECHNIQUE
Directory of Open Access Journals (Sweden)
ANJAN KUMAR SAHOO, SARIKA KALRA, NITIN SINGH
2013-06-01
Full Text Available High efficiency bridgeless single-phase ac-dc PWM cuk converter with soft-switching (ZVS technique is proposed. This paper emphasizes more on the converter efficiency. The conduction losses and input current harmonics of the proposed converter is very less due to the absence of the input diode bridge and also during each switching cycle, only two semiconductor switches are present in the current path unlike other conventional Cuk converters. Soft switching (ZVStechnique is applied by using an auxiliary circuit to improve the efficiency of the proposed converter. Output voltage regulating control technique is provided to regulate the output which also ultimately improves the efficiency. Power factor is almost unity due to less input current harmonics. The circuit configuration, principle of operation, design procedure and simulation results are presented.
CARRIER OVERLAPPING PWM METHODS FOR ASYMMETRICAL MULTILEVEL INVERTER
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DR.R.SEYEZHAI
2011-08-01
Full Text Available Multilevel inverter has gained attention in recent years due to its high power capability associated with lower output harmonics. Several multilevel topologies have been reported in the literature and thispaper focuses on asymmetric cascaded multilevel inverter employing Carrier Overlapping PWM (COPWM technique. This technique provides reduced harmonics in the output voltage and significantly improves the root mean square value of the output voltage compared to the conventional Sinusoidal Pulse Width Modulation (SPWM. A detailed study of the proposed modulation technique is carried out throughMATLAB/SIMULINK for Total Harmonic Distortion (THD. An experimental seven-level inverter test rig has been built to implement the proposed algorithm. Gating signals are generated using PIC microcontroller. The performance of the inverter has been analyzed and compared with the result obtained from theory and simulation.
Voltage Balancing in Diode Clamped Multilevel Inverter Using Sinusoidal PWM
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S.Shalini
2013-12-01
Full Text Available Multilevel inverters offer several advantages compared to the conventional 3-phase bridge inverter in terms of lower dv/dt stresses, lower electromagnetic compatibility, smaller rating and better output features. This project presents a 9-level diode Clamped inverter using Sinusoidal pulse width Modulation techniques as the control strategies. The algorithm has been developed within the carrier-based PWM framework to facilitate its implementation in diode clamped converters with three or more levels. A simulation model of 9-level DCMI has been designed and developed. The results obtained from the simulation model have been compared with the 3-level and 5-level diode clamped inverter. By increasing the level of inverter, effective balancing in line voltage and reduced THD is obtained.
Single Phase Bidirectional PWM Converter for Microgrid System
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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.
ADVANCED COMPUTATIONAL MODEL FOR THREE-PHASE SLURRY REACTORS
International Nuclear Information System (INIS)
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
International Nuclear Information System (INIS)
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
Energy Technology Data Exchange (ETDEWEB)
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.
Prechanon Kumkratug
2011-01-01
Abstract: Problem statement: Static Synchronous Compensator (STATCOM) and Static Synchronous Series Compensator (SSSC) have been individually applied to improve stability of power system. Approach: This study presents the coordination of a STATCOM and SSSC for improving power system stability. The swing curves of the three phase faulted power system with various cases are tested and compared. Results: The swing curve of system without FACTS devices has undamped oscill...
A new PWM based control method for forced commutated cycloconverters
International Nuclear Information System (INIS)
Highlights: â–º A new control method is proposed for three-phase to single-phase cycloconverters from balanced and unbalanced input voltages. â–º The proposed method has no limitation on frequency conversion and is independent of the load. â–º In proposed method, the low order harmonics are not generated in the input and output quantities. â–º The proposed method can be easily extended to three-phase to n-phase cycloconverters. â–º 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.
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.
Study on High Current PWM Unipolar Four Phases Driver for Stepper Motor Control
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Alexandru Morar
2013-06-01
Full Text Available This paper presents the study on high – current PWM, unipolar stepper motor controller/driver, are remarkable for simplicity, high – reliability, multifunctional facilities for four phases hybrid stepper motor.
Yu, Kwang Min; Kim, Wan Seop; Lee, Sang Hwa; Han, Kwon Soo; Kang, Jeon Hong
2014-07-01
We present a method for measuring high resistances using one voltage source and one voltmeter. With this method, there exist two techniques. One is to measure a high resistance with a much lower resistance and the other is to cancel the leakage effect effectively using two nominally equal resistances without an auxiliary guarding apparatus. To demonstrate the method's validity, a 1 G? resistance was measured using the two techniques replacing a dummy 1 G? resistance as a leakage resistance; the measurement results agree well with the theoretical results within the measurement uncertainty of 3 × 10-6 (k = 2) level. We used the method to determine 10 M?, 1 G? and 1 T? resistances with an active-guard type and a T-type. The best expanded uncertainties at k = 2 from the results were estimated as 0.3 × 10-6, 0.8 × 10-6 and 20 × 10-6, respectively. We also show that while the expanded uncertainty of 70 × 10-6 is obtained using an 81/2 digit digital multimeter, it is improved to 20 × 10-6 using an electrometer with high-input resistance, low bias current and high resolution when the second technique is used to measure high resistances.
Energy Technology Data Exchange (ETDEWEB)
Lee, Ho-Young; Kang, In Man, E-mail: imkang@ee.knu.ac.kr [School of Electronics Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Shon, Chae-Hwa [Korea Electrotechnology Research Institute, Changwon 642-120 (Korea, Republic of); Lee, Se-Hee, E-mail: shlees@knu.ac.kr [Department of Electrical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of)
2015-05-07
A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.
Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee
2015-05-01
A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B-H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.
International Nuclear Information System (INIS)
A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source
Directory of Open Access Journals (Sweden)
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.
Electrical Discharge Machining Flyback Converter using UC3842 Current Mode PWM Controller
Directory of Open Access Journals (Sweden)
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.
Led spectral and power characteristics under hybrid PWM/AM dimming strategy
DEFF Research Database (Denmark)
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 and phosphor-converted white diodes under hybrid PWM/AM modulation. Feed forward control schemes that provide stable peak wavelength position during dimming and the ability to compensate the thermally i...
Energy Technology Data Exchange (ETDEWEB)
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 and reactive power flow, formulated as generalized equations for current reference calculation. A simple, but general, implementation is therefore achieved, where the control objective and the power flow characteristics can be selected according to the requirements of any particular application. Thus, the same control structure can be used to achieve for instance balanced sinusoidal currents or elimination of double frequency active power oscillations during unbalanced conditions. In case of voltage sags, current references corresponding to a specified active or reactive power flow might exceed the current capability of the converter. The limits for active and reactive power transfer during unbalanced conditions have therefore been analyzed, and generalized strategies for current reference calculation when operating under current limitations have been derived. The specified objectives for active and reactive power flow characteristics can therefore be maintained during unbalanced grid conditions, while the average active and reactive power flow is limited to keep the current references within safe values. All concepts and techniques proposed in this Thesis have been verified by simulations and laboratory experiments. The SOGI-based method for Virtual Flux estimation and the strategies for active and reactive power control with current limitation can also be easily adapted for a wide range of applications and can be combined with various types of inner loop control structures. Therefore, the proposed approach can potentially be used as a general basis for Virtual Flux-based voltage-sensor-less operation of VSCs under unbalanced grid voltage conditions.(Author)
Convection chimneys in three-phase magmas (Invited)
Rust, A.; Fowler, A. C.; McGuinness, M. J.; Mitchell, S.
2010-12-01
Lavas are three-phase mixtures of viscous liquid (silicate melt), vapour bubbles and solid crystals. The contrasting density and deformability of the phases can lead to complex flows and segregation features. Here we focus on the origin of vertical cylinders of vesicular (bubbly) magma that form in many basalt lava flows that have been inflated by the injection of molten lava below a solid crust. The very top and bottom of the lava flows cool quickly enough for bubbles to be quenched in place but in the hot interior, bubbles rise easily and collect below the crust. The rise of bubbles leaves a non-vesicular core; however, as the base cools and crystallizes, water concentrates in the residual melt, and new bubbles form in the mush, making the interstitial fluid (melt and bubbles) buoyant. Obstructed by crystals, the bubbles do not rise freely; rather, their growth causes segregation by pushing residual melt and bubbles out between the crystals. The bubbly residuum somehow rises through the lava in regularly-spaced vertical cylinders and then seems to spread laterally into vesicular sheets. The generally-accepted origin of the vesicular cylinders in lava flows is that bubbly residual fluid collects on the top of mush at the base of the lava and regularly-spaced bumps that become cylindrical conduits spontaneously grow from ambient noise once the buoyant layer thickness exceeds a critical value. However, our analogue experiments, combined with existing theory, suggest that such Rayleigh-Taylor instabilities are not the origin of the vesicular lava cylinders. An alternative explanation is ”mushy convection” where flow within a stationary crystallizing mush is driven by gradients in liquid density that are generated because some components are preferentially incorporated into the crystals leaving a buoyant residual liquid. Such mushy convection is known to focus flow in vertical “chimneys” devoid of crystals in mushy (crystal-rich) layers of sea ice and metal alloys. We present a theoretical and numerical analysis of mushy convection in lava as it cools from above and below. A mush layer grows upwards from the base of the flow and is overlain by crystal-poor lava. Rayleigh numbers for this crystal-poor magma indicate that it will convect vigorously, but since it is cooled from above and below, dense plumes of fluid will descend towards the lower unit, where they will pond, and deliver a conductive heat flux to the underlying mush. The model for convection within the mush itself assumes a simplified phase diagram for the magma, that the pore liquid and gas move homogeneously through the pore space of the mush, and also that the pressure in the liquid and gas phases are equal. One difference between classic mushy convection in metal alloys and mushy convection in lava, is that in the latter, the residual melt contains bubbles. The much lower bulk density of the bubbly fluid will help drive convection, although bubbles can reduce the effective permeability of the mush if bubbles are trapped in constrictions due to capillary stress.
Three-Phase Four-Switch PFC and Its Analytical Model.
Czech Academy of Sciences Publication Activity Database
Klíma, J.; Škramlík, Ji?í; 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 ?R IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch converter * space- vector PWM * closed-form solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Instantaneous Power Compensation in Three-Phase Systems by Using p-q-r Theory
DEFF Research Database (Denmark)
Kim, Hyosung; Blaabjerg, Frede; Bak-Jensen, Birgitte; Choi, Jaeho
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...
Asymmetrical Six-Phase Space Vector Pwm Scheme
Directory of Open Access Journals (Sweden)
Tadas Lipinskis
2014-05-01
Full Text Available Multiphase electric motors have smaller torque pulsations and are more reliable that their three-phase alternatives. However, standard electricity grids around the world are three-phase, so power inverter is needed to drive multiphase motors. Inverter is used not only to power the motor, but also to control the amplitude and frequency of the produced voltage, thus controlling motor speed and torque. Multiphase systems with odd number of phases have been widely investigated; therefore, this paper focuses on a six-phase inverter with a single neutral symmetrical load. A novel asymmetrical space vector modulation scheme is proposed and evaluated using simulations in Matlab/Simulink. Simulation results are compared to other modulation schemes. The proposed method is suitable for generating near-sinusoidal output voltages; however, it might not be suited for driving motors with sinusoidally distributed stator windings.
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...
Research on a New Control Strategy of Three Phase Inverter for Unbalanced Loads
Chunxi LIU; 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...
Measurement of Reactive Power in Three-Phase Electric Power Systems by Use of Walsh Functions
Adalet Abiyev
2010-01-01
This paper presents a new method for measuring of three-phase reactive power (RP) in three-phase systems. Extraction of three-phase reactive power RP from entire instantaneous power signal is achieved by multiplication the phase instantaneous powers with the Walsh function(WF). This method simplifies the multiplication procedure required for the evaluation the tree-phase reactive power components due to the use of the peculiar properties of the WF. In contrast to the existing met...
Generalisation of Helmholtz-Thevenin theorem to three-phase electrical circuits
Mihai, Gheorghe
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 ...
Generalisation of Helmholtz-Thevenin theorem to three-phase electrical circuits
Mihai, Gheorghe
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.
Performance Analysis of Fuzzy Flatness Based Speed Control of Three Phase Induction Motor
C.SASIKUMAR, DR. C.MUNIRAJ
2013-01-01
Induction motor plays a vital role in engineering and industry. Induction motor offer a convenient means for controlling the operation of different equipment used in industry. Induction motor input supply will give from the voltage source inverter for its speed control purpose. If we connect induction motor directly to the AC supply its speed control will not applicable, so that we go inverter fed induction motor speed control. Gate pulse has been given by using FPGA processor. Fuzzy flatness...
Salehifar, Mehdi; Moreno Eguilaz, Juan Manuel
2016-01-01
Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of...
Directory of Open Access Journals (Sweden)
Md. Aziz Ul Huq
2013-05-01
Full Text Available 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 interfacing hardware. N-channel MOSFET is used as power device but may be replaced with IGBT. A special one way delay circuit is introduced to ensure non short circuit situation. The input frequency to the inverter can be varied by varying the input voltage to the Voltage Controlled Oscillator (VCO. The proper input voltage to the inverter is set by Automatic Voltage Regulator (AVR instructed by the computer. Though the frequency of the inverter can be varied between a wide range, the inter phase separation remains always 1200 yielding a true pattern of a three-phase power supply. Introduction of microcomputer and associate of software programs in three-phase induction motor control system as proposed is accurate and reliable in terms of accurate and complex speed control of the motor.
A modified two-level three-phase quasi-soft-switching inverter
DEFF Research Database (Denmark)
Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede; Chung, Henry Shu Hung
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...
Leakage Current Elimination of Four-Leg Inverter for Transformerless Three-Phase PV Systems
DEFF Research Database (Denmark)
Guo, Xiaoqiang; He, Ran; Jian, Jiamin; Lu, Zhigang; Sun, Xiaofeng; Guerrero, Josep M.
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 mechanism...
AC Motor Drive Fed by Renewable Energy Sources with PWM
Directory of Open Access Journals (Sweden)
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.
Synchronization of the distributed PWM carrier waves for modular multilevel converters
DEFF Research Database (Denmark)
Burlacu, Paul Dan; Mathe, Laszlo
2014-01-01
The half-bridge modular multilevel converter has proven itself to be a suitable solution for HVDC application. In order to achieve high modularity and fault tolerance, distributed control strategy is one possible solution and is discussed in this paper. When distributed control strategy is used, there is a central controller and a local controller in each sub-module (SM). A problem appears when implementing the modulation using this type of control strategy; this is the lack of synchronization between the internal clocks of the different submodules controllers of the MMC. This will cause a 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.
Isolated PDM and PWM DC-AC SICAMs[Pulse Density Modulated; Pulse Width Modulated
Energy Technology Data Exchange (ETDEWEB)
Ljusev, P.
2004-03-15
In this report a class of isolated PDM and PWM DC-AC SICAMs is described, which introduce the audio reference only in the output stage. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitor. Isolation from the AC mains is achieved using a high frequency (HF) transformer, receiving the HF voltage pulses from the input 'inverter' stage and transferring them to the output 'rectifier+inverter' stage, which can use either PDM or PWM. The latter stage is then interfaced to the load using an output low-pass filter. Each of the dedicated stages is discussed in detail. Measurements on the master/slave PWM DC-AC SICAM prototype are presented to help benchmarking the performance of this class of SICAMs and identify the advantages and drawbacks. (au)
High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit
Directory of Open Access Journals (Sweden)
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.
EVALUATION OF VARIOUS UNIPOLAR MULTICARRIER PWM STRATEGIES FOR FIVE LEVEL FLYING CAPACITOR INVERTER
Directory of Open Access Journals (Sweden)
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.
A deadbeat control method for a PWM converter applied to a superconducting magnet
International Nuclear Information System (INIS)
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
Indian Academy of Sciences (India)
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 DCâ€“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 DCâ€“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.
Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller
Directory of Open Access Journals (Sweden)
Sreenivasappa Veeranna Bhupasandra
2010-01-01
Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.
Performance Comparison of Phase Shifted PWM and Sorting Method for Modular Multilevel Converters
DEFF Research Database (Denmark)
Haddioui, Marcos Rejas; Máthé, Lászlo
2015-01-01
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 and NLC plus sorting methods.
Effect of dead-time in interleaved PWM for two parallel-connected inverters
DEFF Research Database (Denmark)
Maheshwari, Ramkrishan; Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Munk-Nielsen, Stig
2015-01-01
Parallel-connected inverters are used for high power application. Due to the parallel-connection, there exists a circulating current which does not contribute to the ac side current. The analysis presented in the paper shows that the circulating current is affected by the dead-time. The effect of the dead time on the circulating current for the space vector pulse width modulation (PWM) and a discontinuous PWM is analyzed. The dead-time causes a dc value of the circulating current for the discont...
Novel, Four-Switch, Z-Source Three-Phase Inverter
Antal, Robert; Muntean, Nicolae; Boldea, Ion; Frede BLAABJERG
2011-01-01
This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the ...
Novel, Four-Switch, Z-Source Three-Phase Inverter
DEFF Research Database (Denmark)
Antal, Robert; Muntean, Nicolae; Boldea, Ion; Blaabjerg, Frede
2010-01-01
This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the pro...
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...... of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods...
DPC controlled three-phase active filter for power quality improvement
Energy Technology Data Exchange (ETDEWEB)
Chaoui, Abdelmadjid; Krim, Fateh [Laboratoire d' Electronique de Puissance et Commande Industrielle (LEPCI), Universite de Setif (Algeria); Gaubert, Jean-Paul; Rambault, Laurent [Laboratoire d' Automatique et d' Informatique Industrielle (LAII-ESIP), Universite de Poitiers (France)
2008-10-15
This paper presents a new control method entitled direct power control (DPC) for shunt active power filtering (5th, 7th, 11th,..) (SAPF), which is applied to eliminate line current harmonics and compensate reactive power. Its main goal is to rebuild active and reactive powers to be compared to references values using hysteresis control. The outputs of hysteresis controllers associated with a switching table, control the instantaneous active and reactive power by selecting the optimum switching state of the voltage source inverter (VSI). A theoretical analysis with a complete simulation of the system and experimental results are presented to prove the excellent performance of the proposed control technique. (author)
Control of a Three Phase Induction Motor using Single Phase Supply
Directory of Open Access Journals (Sweden)
G. R. Sreehitha, A. Krishna Teja, Kondenti. P. Prasad Rao
2012-06-01
Full Text Available 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 Induction Motor is done by Frequency variable method. Single-Phase to Three-Phase for motors offered by using high in performance, low on maintenance and is used to reduce of breakdown of electrical equipment, our range is also suitable for saving energy and require low maintenance.
Linear power networks. Three-phase systems; Reseaux electriques lineaires. Systemes triphases
Energy Technology Data Exchange (ETDEWEB)
Escane, J.M.; Bastard, P. [Ecole Superieure d' Electricite, 91 - Gif-sur-Yvette (France)
2005-01-01
DC and AC are the two main possible regimes for the transportation and distribution of electric power. Historically, the use of transformers to change the voltage has led to keep the AC regime for the development of big networks. For technical and economical reasons, the three-phase systems is of particular importance both for the generation and for the use of electricity. The aim of this article is to describe the operation of these three-phase systems: 1 - general principles and different connections: first approach, star connection, delta connection, star/delta transformation, three-phase powers; 2 - equivalent single-phase scheme: basic principle, connected circuits, synchronous machine, transformer, overhead and buried lines, asynchronous machines; 3 - unbalanced three-phase sinusoidal regimes: description and origin of unbalancing, decomposition in symmetrical components, direct, inverse and homopolar single-phase schemes. (J.S.)
Efficiency analysis on a two-level three-phase quasi-soft-switching inverter
DEFF Research Database (Denmark)
Geng, Pan; Wu, Weimin
2013-01-01
When designing an inverter, an engineer often needs to select and predict the efficiency beforehand. For the standard inverters, plenty of researches are analyzing the power losses and also many software tools are being used for efficiency calculation. In this paper, the efficiency calculation for 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.
Novel, Four-Switch, Z-Source Three-Phase Inverter
DEFF Research Database (Denmark)
Antal, Robert; Muntean, Nicolae
2010-01-01
This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F3011 digital signal processor.
Vector Control of Three-Phase Induction Motor with Two Stator Phases Open-Circuit
Directory of Open Access Journals (Sweden)
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.
The comparison of radiosensitivity of human lymphocytes stimulated with PHA Con A and PWM
International Nuclear Information System (INIS)
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 0âˆ¼8 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 0âˆ¼30 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
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.
The PWM auto-control circuit of neutron tube atmospheric pressure
International Nuclear Information System (INIS)
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 efficiency of three-level Active NPC converter for different PWM strategies
DEFF Research Database (Denmark)
Floricau, D.; Gateau, G.; Leredde, A.; Teodorescu, Remus
The efficiency of power conversion is an important factor to design static converters. The paper is focused on the calculus of total losses of 3L-NPC and 3L-Active-NPC converters for different PWM strategies. The calculus was made in the most critical operating points when certain switches have t...
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
Active and reactive power control of a current-source PWM-rectifier using space vectors
Energy Technology Data Exchange (ETDEWEB)
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.
Directory of Open Access Journals (Sweden)
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.
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...
A Comparision of Three Phase 27 Level Inverter Scheme under No Load and Multiple Load Conditions
C. Kannan; C.K. Kishore
2014-01-01
Multilevel inverters have been used in the industrial as well as the drive applications. Here three phase system of the 27 level inverter scheme with and without loads have been presented by combining the three single phase inverters of various and asymmetrical voltage ranges. Here capacitors, batteries may be used for multiple dc sources in order to achieve high voltage output. It is shown that by implementing the single phase model in the three phase system the harmonic content is lowered e...
J. B. V. Subrahmanyam; C. Radhakrishna; K. Pandukumar
2010-01-01
The aim of the study is to develop a simple and direct approach for unbalanced radial distribution system three-phase load flow solution .The special topological characteristics of unbalanced radial distribution networks have been fully utilized to make the direct three phase load flow solution possible. Two developed matrices-the node-injection to line section-current matrix and the line section-current to node-voltage matrix - and a simple matrix multiplication are used to obtain the three ...
Study on three-phase vapour-liquid-solid equilibrium of binary deuterium-helium system
International Nuclear Information System (INIS)
The line of three-phase vapour-liquid-solid equilibrium of binary eD2-He4 system has been measured from the triple point of deuterium up to the pressure of approximately 60 atm. The He4 solubility in deuterium on three-phase line has been estimated. The difference in effect of Ne and 4He impurities on the solidification temperature of hydrogen isotopes is considered
Quaternion-Valued Single-Phase Model for Three-Phase Power Systems
Gou, Xiaoming; Liu, Zhiwen; LIU Wei; Xu, Yougen; Wang, Jiabin
2016-01-01
In this work, a quaternion-valued model is proposed in lieu of the Clarke's \\alpha, \\beta transformation to convert three-phase quantities to a hypercomplex single-phase signal. The concatenated signal can be used for harmonic distortion detection in three-phase power systems. In particular, the proposed model maps all the harmonic frequencies into frequencies in the quaternion domain, while the Clarke's transformation-based methods will fail to detect the zero sequence voltages. Based on the...
Single phase inverter for a three phase power generation and distribution system
Lindena, S. J.
1976-01-01
A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.
The analysis of magnesium oxide hydration in three-phase reaction system
International Nuclear Information System (INIS)
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
Double Two Switch Forward Soft Switching PWM DC-DC Converter
Hamada, Satoshi; Moisseev, Serguei; Koudriavtsev, Oleg; Nakaoka, Mutsuo
A novel prototype of a double two-switch forward transformer linked zero-voltage and zero-current mode soft-switching (ZVZCS) pulse width modulation (PWM) DC-DC power converter using IGBTs for high power applications is presented. Based on a conventional two-switch forward transformer linked PWM DC-DC converter topology, this converter circuit configuration doesn't include any complex auxiliary resonant circuit. Combining two identical two-switch forward type DC-DC power conversion circuits with a tapped-inductor type DC smoothing filter into a power DC-DC conversion system makes it possible to achieve soft-switching conditions for the active power switches with aid of lossless snubber capacitors and transformer parasitic inductors. Lowered peak voltage across the power switching devices and their related peak current stresses, no transformer saturation effect, reducing of idle and circulating currents through circuit components are practically attained for this converter. This soft-switching PWM DC-DC power converter has some unique advantages such as better power conversion efficiency, lowered output DC ripple current, high power density, constant frequency PWM control scheme, cost effective and wide soft-switching operation range under load variations and PWM regulation settings for high power utilizations. The basic operating principle of the new soft switching power converter treated here is illustrated with approximate periodic steady-state circuit analysis for each mode equivalent circuit. The practical effectiveness of the proposed soft-switching DC-DC power converter is confirmed by the simulation results and is experimentally evaluated on basis of 500W-100kHz breadboard setup using the fast switching IGBTs.
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2013-01-01
A new pulse width modulation (PWM) strategy which is an alternative approach of discontinuous PWM (DPWM) for a three-level neutral point clamped (NPC) inverter is developed and presented in this paper. The proposed PWM scheme not only takes advantage of the special properties available in NPC...... inverters, but also reduces the switching loss of the inverter along with an inherent neutral point (NP) voltage control. Based on a circuit-level decoupling concept, the NPC inverter can be decoupled into two three-level Buck converters in every defined operating section, and thereby the controller design...
Directory of Open Access Journals (Sweden)
Marcelo Gradella Villalva
2011-06-01
Full Text Available This paper describes the modeling and control of a three-phase grid-connected converter fed by a photovoltaic array. The converter is composed of an isolated DC-DC converter and a three-phase DC-AC voltage source inverter The converters are modeled in order to obtain small-signal transfer functions that are used in the design of three closed-loop controllers: for the output voltage of the PV array, the DC link voltage and the output currents. Simulated and experimental results are presented.Este artigo descreve a modelagem e o controle de um conversor trifásico conectado à rede alimentado por um conjunto fotovoltaico. O conversor é composto de um estágio CC-CC isolado um estágio CC-CA. São obtidas funções de transferência com as quais são projetados três sistemas de controle em malha fechada: um para a tensão de entrada do arranjo de painéis solares, um para a tensão do do barramento de tensão contínua e outro para as correntes trifásicas de saída.
Scientific Electronic Library Online (English)
Marcelo Gradella, Villalva; Marcos Fernando, Espindola; Thais Gama de, Siqueira; Ernesto, Ruppert.
2011-06-01
Full Text Available Este artigo descreve a modelagem e o controle de um conversor trifásico conectado à rede alimentado por um conjunto fotovoltaico. O conversor é composto de um estágio CC-CC isolado um estágio CC-CA. São obtidas funções de transferência com as quais são projetados três sistemas de controle em malha f [...] echada: um para a tensão de entrada do arranjo de painéis solares, um para a tensão do do barramento de tensão contínua e outro para as correntes trifásicas de saída. Abstract in english This paper describes the modeling and control of a three-phase grid-connected converter fed by a photovoltaic array. The converter is composed of an isolated DC-DC converter and a three-phase DC-AC voltage source inverter The converters are modeled in order to obtain small-signal transfer functions [...] that are used in the design of three closed-loop controllers: for the output voltage of the PV array, the DC link voltage and the output currents. Simulated and experimental results are presented.
The comparing results of carcinoma between three-phase and delayed whole body bone scan
International Nuclear Information System (INIS)
Purpose: Three phase bone scan is an imaging technology in nuclear medicine, which composed of blood flow phase, blood pool phase and delayed phase and the last one is often performed in routine works in department of nuclear medicine. The purpose of this study is to evaluate the merit of three-phase bone scan.Methods: In this study, we chose 54 patients who were having an regional pain which caused by benign or malignant carcinoma that diagnosed by CT, X-ray, ECT, MRI or other examinations. The imaging were acquired simultaneously from both anterior and posterior views, after a bolus injection of 1110 MBq technetium-99m-labelled methylene diphosphonate (MDP), blood phase contains 20 frame sand 3 seconds per frame, blood pool phase contains 5 frames and 1 minute per frame, delayed phase was performed 2.5 hour later. According to the results of three-phase bone scan, the patients were divided into 2 groups: normal and abnormal groups. The abnormal group includes early phase positive,delay positive and all three phase positive sets. The comparing among the 3 sets were analyzed by chi-square test and other statistic means.Results: There were 54 patients who had suffered lung cancer, breast cancer and other cancer,involved in this study, 34 males and 20 females, ranged age 17 to 88 years, were normal in 15 cases,positive in 22 cases, the results in delayed phase were positive in 9 cases, blood flow and blood pool phase showed blood flow changes in 4 cases and soft tissue tumors were seen in 4 cases. Three phase bone scan was more sensitive than delayed whole body bone scan in detecting the abnormal sites (p0.05) The sensitivity of detecting tumors in blood flow and blood pool phase,delayed phase were respectively lower than in three phase bone scan (p<0.001).Conclusion: It is more sensitivity of detecting tumor lesions in three phase bone scan than in delayed phase whole body bone scan and the changes of blood flow and soft tissue can be seen in three phase bone scan. So it is more suitable way to improve the sensitivity of detecting abnormal sites in three-phase bone scan. (authors)
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.
International Nuclear Information System (INIS)
Objective: To investigate the difference between the early phases and delay phase of three-phase bone scintigraphy on hemiplegic patients with earlier complex regional pain syndrome (CRPS). Methods: Twenty-nine stroke patients with hemiplegia complicating CRPS received three-phase bone scintigraphy after intravenous injection of 99Tcm-methylene diphosphonate (MDP). The region of interest (ROI) technique was used to obtain the radioactive counts of involved joints and contralateral sites on wrists, metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints. The total counts of these four sites in each patient were then obtained and the total uptake ratios of involved joints/contralateral joints for each phase were calculated to compare the difference among the three phases. Wilcoxon test and ANOVA were used in data analyses. Results: The involved joints of hemiplegic side displayed higher tracer uptake. There were significant differences of the radioactive counts between involved joints and uninvolved ones in the perfusion, pool and delay phase (Wilcoxon test, Z: -4.73 to -2.10, P<0.05). There was no significant difference of total uptake ratios of involved joints/contralateral joints among the three phases (ANOVA, F = 0. 807, P < 0.05). Conclusions: Due to higher bone seeking agent accumulation on three-phase bone scintigraphy, both early phases and delay phase imaging showed similar value in stroke patients with hemiplegia complicating earlier CRPS. (authors)
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
Chaotic Recurrence Analysis of Oil-Gas-Water Three-phase Flow in Vertical Upward Pipe
Directory of Open Access Journals (Sweden)
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.
Stiffness predictions of carbon nanotube reinforced two and three-phase polymer composites
Neer, Eric
Carbon nanotubes are a relatively new area of research which has gained significant attention in published literature. One reason for this interest is their use in multi-phase composites, specifically where they can enhance traditional polymer matrices. Many authors have attempted to adapt conventional micromechanical analyses reserved for microfibers to the nano scale. A review of these works is presented. In depth analysis is provided on one of these two phase (nanotube and matrix) models, the Anumandla-Gibson model, originally published in 2006. A discussion of its strengths and sensitivities is given, with numerical data to support the conclusions. It is extended to three-phase composites through the use of classical laminated plate theory. A literature survey is conducted to gather published two and three-phase experimental results for comparison. Two phase experimental results agree well with the present model, whereas three phase data was limited, but initial comparisons were promising.
A Novel Unit Power Factor Rectifier Based on Three-phase Digital PLL
Directory of Open Access Journals (Sweden)
Xuegui Zhu
2013-07-01
Full Text Available A novel three-phase phase-locked loop solution is proposed based on D-Q transformation aiming at the AC-DC rectifier with high efficiency and high power factor. The phase-locked loop is implemented digitally using the Xilinx blockset integrated with Matlab/Simulink. The three-phase digital phase-locked loop (TDPLL is elaborately designed with the parameters defined in detail. The AC-DC converter (rectifier model with the TDPLL is built and simulated in the high-speed VHS-ADC simulation platform from Canada. The simulation and test results show the TDPLL is locked right after the different three-phase voltage disturbances and very suitable for control of the rectifier with high parallelism through space vector pulse width modulation (SVPWM.
Adaptive nonlinear control of single-phase to three-phase UPS system
Directory of Open Access Journals (Sweden)
Kissaoui M.
2014-01-01
Full Text Available This work deals with the problems of uninterruptible power supplies (UPS based on the single-phase to three-phase converters built in two stages: an input bridge rectifier and an output three phase inverter. The two blocks are joined by a continuous intermediate bus. The objective of control is threefold: i power factor correction “PFC”, ii generating a symmetrical three-phase system at the output even if the load is unknown, iii regulating the DC bus voltage. The synthesis of controllers has been reached by two nonlinear techniques that are the sliding mode and adaptive backstepping control. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.
Proposed Method for Shoot-Through in Three Phase ZSI and Comparison of Different Control Techniques
Directory of Open Access Journals (Sweden)
Byamakesh Nayak
2014-07-01
Full Text Available This paper presented the new methodology for different control techniques applied to three phase Z-source inverter for minimisation of switching losses. The procedure for proposed control techniques and its effects on the performance of operation of three phase Z-source inverter are analyzed. The graphs for voltage gain and voltage stress are drawn for different control methods. The flow-chart for the symmetrical and unsymmetrical control techniques for creating pulse signals for switches of three phase inverter are shown. All the methods are studied and compared with each other. The Total harmonic distortion (THD of output voltage of both the control methods has been analyzed using FFT analysis. The experiments done and the results shown for capacitor voltage, load current and load line voltage for simple boost and constant boost control techniques are presented using MATLAB/ Simulink.
Design of materials with extreme thermal expansion using a three-phase topology optimization method
DEFF Research Database (Denmark)
Sigmund, Ole; Torquato, S.
1997-01-01
-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...... by designing materials having maximum directional thermal expansion (thermal actuators), zero isotropic thermal expansion, and negative isotropic thermal expansion. It is shown that materials with effective negative thermal expansion coefficients can be obtained by mixing two phases with positive......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...
Secondary Voltage Unbalance Compensation for Three-Phase Four-Wire Islanded Microgrids
DEFF Research Database (Denmark)
Tang, Fen; Zhou, Xiao; Meng, Lexuan; Guerrero, Josep M.; Vasquez, Juan Carlos
2014-01-01
This paper proposes a secondary voltage unbalance control approach that compensate voltage unbalances in three-phase four-wire islanded microgrid systems. It is implemented in the secondary control level of the microgrid hierarchical control structure. By sending information through low-bandwidth......This paper proposes a secondary voltage unbalance control approach that compensate voltage unbalances in three-phase four-wire islanded microgrid systems. It is implemented in the secondary control level of the microgrid hierarchical control structure. By sending information through low...
THRIVE : a data reduction program for three-phase PDV/PDI and VISAR measurements.
Energy Technology Data Exchange (ETDEWEB)
Jones, Scott Christopher; Dolan, Daniel H.
2008-06-01
THRIVE (THRee Interferometer VElocimetry) is an analysis package for reducing three-phase interferometry measurements. Three-phase displacement interferometry measurements are the primary application of this program, although velocity interferometry is also supported. THRIVE uses a push-pull approach to transform measured signals to a pair of quadrature signals, from which fringe shift, target position, and target velocity are inferred. The program can analyze the signals in an ideal sense or compensate for non-ideal measurement conditions using ellipse characterization. The program can be run in any current version of MATLAB (release 2007a or later) or as a Windows XP executable.
TORQUE ANALYSIS OF THREE-PHASE INDUCTION MOTOR UNDER VOLTAGE UNBALANCE USING 2D FEM
Directory of Open Access Journals (Sweden)
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.
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...
Three-Phase Modulated Pole Machine Topologies Utilizing Mutual Flux Paths
DEFF Research Database (Denmark)
Washington, Jamie G.; Atkinson, Glynn J.
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 stacked axially. The results show that the new “combined-phase MPM” exhibits a greater torque density, while offering a reduction in the number of components. The results obtained from two prototypes are also presented to verify the concept; the results show that the “combined-phase” machine could provide both performance and constructional benefits over prior MPM topologies.
Performance Evaluation of an Extended Gain Three-Phase Grid Connected Boost-inverter
DR. A.ELSEROUGI; DR. A.S.ABDEL-KHALIK; DR. A.MASSOUD; DR. S.AHMED
2013-01-01
Three-phase boost-inverter consists of three DC-to-DC boost converters with a common point and operates with boosting capability to feed three-phase star connected Load. The main advantage of that inverter is the use of only six IGBTs andsmall passive elements to obtain an AC output larger than the DC input. This inverter can amplify power sources such as fuelcells, small turbines, and photovoltaic arrays (i.e. it is suitable for distributed power applications). In this paper, two main contri...
Area Based Approach for Three Phase Power Quality Assessment in Clarke Plane
Directory of Open Access Journals (Sweden)
S. CHATTOPADHYAY
2008-03-01
Full Text Available This paper presents an area-based approach for electric power quality analysis. Some specific reference signals have been defined and areas formed by the real power system data with the reference signal have been calculated wherefrom contributions of fundamental waveform and harmonic components have been assessed separately. Active power, reactive power and total harmonic distortion factors have been measured. Clarke transformation technique has been used for analysis in three-phase system, which has reduced the computational effort to a great extent. Distortion factors of individual phase of a three-phase system have also been assessed.
Juvenile Dermatomyositis Diagnosed by {sup 99m}Tc-HDP Three-phase Bone Scintigraphy
Energy Technology Data Exchange (ETDEWEB)
Kim, Ja Hye; Song, Ho Chun; Yoo, Su Ung; Ha, Jung Min; Chong, A Ri; Oh, Jong Ryool; Min, Jung Joon; Bom, Hee Seung; Jeong, Eun Hui; Lee, Min Chul [Chonnam National University Hospital, Gwangju (Korea, Republic of)
2009-12-15
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 {sup 99m}Tc-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 {sup 99m}Tc-HDP three-phase bone scan was useful in diagnosis and assessing therapy response.
Juvenile Dermatomyositis Diagnosed by 99mTc-HDP Three-phase Bone Scintigraphy
International Nuclear Information System (INIS)
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
Kerner, B S; Brakemeier, A
2007-01-01
A testbed for wireless vehicle communication based on a microscopic model in the framework of three-phase traffic theory is presented. In this testbed, vehicle motion in traffic flow and analyses of a vehicle communication channel access based on IEEE 802.11e mechanisms, radio propagation modeling, message reception characteristics as well as all other effects associated with ad-hoc networks are integrated into a three-phase traffic flow model. Based on simulations of this testbed, some statistical features of ad-hoc vehicle networks as well as the effect of C2C communication on increase in the efficiency and safety of traffic are studied.
CFD Modeling of Three-Phase Bubble Column: 2. Effect of Design Parameters
Wasewar, K. L.; Anil, M.; Agarwal, V. K.
2008-01-01
The effect of design parameters on the flow pattern in a three-phase bubble column by means of Computational Fluid Dynamics (CFD) has been studied. The simulations were performed for air-water-glass beads in a bubble column of H = 0.6m, D = 0.1m and ds = 0.05m to study the flow pattern. Eulerian-Eulerian three-phase simulations with k-Îµ turbulence for liquid phase were carried out using the commercial flow simulation software CFX-5.6, with a focus on characterizing the dynamics properties of ...
Power quality improvement using DPC controlled three-phase shunt active filter
Energy Technology Data Exchange (ETDEWEB)
Chaoui, Abdelmadjid [Laboratoire d' Automatique et d' Informatique Industrielle (LAII-ESIP), Universite de Poitiers (France); Gaubert, Jean-Paul; Krim, Fateh [Laboratoire d' Electronique de Puissance et Commande Industrielle (LEPCI), Universite de Setif (Algeria)
2010-06-15
This paper presents a new control method entitled direct power control (DPC) for shunt active power filter (APF), which is applied to eliminate line current harmonics and compensate reactive power. Its main goal is to rebuild active and reactive source powers to be compared to references values using hysteresis control. The active power reference is issue of DC-side of inverter and reactive power reference is set to zero for unity power factor. The outputs of hysteresis controllers associated with a switching table, control the instantaneous active and reactive power by selecting the optimum switching state of the voltage source inverter (VSI). A theoretical analysis with a complete simulation of the system and experimental results are presented to prove the excellent performance of the proposed technique. (author)
Directory of Open Access Journals (Sweden)
Olivier Barre
2015-06-01
Full Text Available Mutual inductance is a phenomenon caused by the circulation of the magnetic flux in the core of an electrical machine. It is the result of the effect of the current flowing in one phase on the other phases. In conventional three-phase machines, such an effect has no influence on the electrical behaviour of the device. Although these machines are powered by power inverters, no problem should occur. The result is not the same for multi-star machines. If these machines are using a conventional winding structure, namely distributed windings, and are powered by voltage source converters, current ripples appear in the power supply lines. These current ripples are related to magnetic couplings between the stars. Designers should check these current ripples in order to stay within the limits imposed by the specifications. These electric current disturbances also provide torque ripples. With concentrated windings, a new degree of freedom appears; the configuration—number of slots/number of poles—can have a positive impact. The circulation of the magnetic flux is the initial phenomenon that produces the mutual inductance. The main goal of this discussion is to describe a design method that is able to produce not only a machine with low mutual inductance between phases, but also a multi-star machine where the stars and the phases are magnetically decoupled or less coupled. This discussion only takes into account the machines that use permanent magnets mounted on the rotor surface. This article is part of a study aimed at designing a high efficiency generator using fractional-slot concentrated-windings (FSCW.
Performance of the Push-Pull LLC Resonant and PWM ZVS Full Bridge Topologies
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S. Rama Reddy
2011-01-01
Full Text Available The soft switched PWM ZVS full bridge DC to DC converter and push-pull type LLC series resonant converter are compared for use in low output voltage power supply applications. It is shown that push-pull type LLC series resonant converter takes on the desirable characteristics of the conventional push-pull converter and LLC series resonant converter. Push-pull type has less conduction loss than that of full bridge converter. Analyses and simulation shows that for low power applications required turn ratio of the transformer is less so efficiency is more and switching stress is less for push-pull LLC series resonant converter than PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using both DC to DC converters using 20KHZ switching frequency and all parameters are compared.
A family of improved ZVT PWM converters using an auxiliary resonant source
Scientific Electronic Library Online (English)
M. L., Martins; H., Pinheiro; J. R., Pinheiro; H. A., Gründling; H. L., Hey.
2003-12-01
Full Text Available Este trabalho apresenta uma nova família de conversores CC-CC PWM ZVT os quais utilizam um circuito ressonante como fonte auxiliar para controlar a corrente através da chave auxiliar sem agregar esforços adicionais de corrente nos dispositivos principais. A célula de comutação aperfeiçoada possibili [...] ta a comutação da chave principal sob tensão nula e a comutação da chave auxiliar sob corrente nula desde carga nula até carga nominal. Abstract in english This paper presents a novel family of Zero Voltage Transition (ZVT) DC-DC PWM Converters that uses a resonant circuit as auxiliary commutation source to control the current through the auxiliary switch without additional current stresses on main devices. The improved ZVT commutation cell enables the [...] main switch to be turned on and off at Zero Voltage Switching (ZVS) and the auxiliary switch to be turned on and off at Zero Current Switching (ZCS) from zero to full-load.
SIMULATION AND ANALYSIS OF PWM-CONTROLLED QUASI-RESONANT CONVERTER FOR DRIVES
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Helen Priscilla A.S.
2012-05-01
Full Text Available This paper presents the development of a new resonant capacitor assisted pulse width modulationcontrolled quasi resonant converter with an auxiliary circuit which does the load regulation by controlling the ripple of the resonant voltage. This resonant converter is simulated through MATLAB/SIMULINK. This newly developed quasi resonant DC-DC converter can regulate its DC output under a principle of constant frequency soft switching commutation by a controllable PWM duty cycle control scheme. The ripple of the resonant voltage across the primary resonant capacitor is controlled with a bidirectional auxiliary circuit, while the main switches are operated at a fixed duty ratio and fixed switching frequency. The operating performances of the newly proposed PWM-controlled quasi resonant converter are represented based on simulation results from an applications point of view.
Kathalingam, Sebasthi Rani; Karantharaj, Porkumaran
2012-07-01
This work presents the simulation of a shunt active filter using seven-level cascaded inverter. The ultimate objective is to bring out the influence of multiple carrier level shifted PWM techniques on the performance of a shunt active filter. Classical disposition PWM techniques such as PD, POD and APOD have been used to generate the gating signals for the inverter active switches. A comparison is presented to substantiate the effect of these techniques in filtering. The comparison is made from the perspective of reduction in THD of source currents after filtering. For compensation current extraction synchronous detection method has been used. The harmonic reduction is achieved in source currents as well as source voltages.
Piyarat, Wekin; Kinnares, Vijit
This paper presents a performance evaluation and a simple speed control method of an asymmetrical parameter type two-phase induction motor drive using a three-leg VSI (Voltage Source Inverter). The two-phase induction motor is adapted from an existing single-phase induction motor resulting in impedance unbalance between main and auxiliary windings. The unbalanced two-phase inverter outputs with orthogonal displacement based on a SPWM (Sinusoidal Pulse Width Modulation) method are controlled with appropriate amplitudes for improving the motor performance. Dynamic simulation of the proposed drive system is given. A simple speed controller based on a slip regulation method is designed. The overall system is implemented on a DSP (Digital Signal Processor) board. The validity of the proposed system is verified by simulation and experimental results.
High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit
C. P. Sai Kiran; M. Vishnu Vardhan
2014-01-01
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 in...
Design of Intelligent Solar Grid Oriented PWM Inverter for Livelihood Generation in Rural Areas
Akella Ramakrishna,; Kambampati Manasa,; Chandrupatla Anusha,; Anusha Balabhadrapatruni,
2013-01-01
Excessive demand of power is always difficult to meet and as a result national economy is being hampered severely due to this deregulation of electricity. Unfortunately most IPS i.e., Instant Power Supply system has poor charge controlling mechanism which makes it a massive power consumer. The cost of solar panel and the consumers’ awareness to preserve AC power has stimulated the demands of high effective Grid connected power sources. Here the designed interfacing PWM inverter is operated by...
Closed loop control of ZVS half bridge DC-DC converter with DCS PWM Control
Directory of Open Access Journals (Sweden)
JANAPATI SIVAVARA PRASAD
2012-10-01
Full Text Available
The main drawback of the conventional symmetric control is that both primary switches in the converter operate at hard switching condition. Moreover, during the off-time period of two switches, the oscillation between the transformer leakage inductance and junction capacitance of the switches results in energy dissipation and electromagnetic interference (EMI emissions due to reverse recovery of MOSFETs body diodes. The asymmetric (complementary control was proposed to achieve ZVS operation for HB switches. However, asymmetric stresses distribution on the corresponding components may occur due to the asymmetric duty cycle distribution for the two primary switches. A new control scheme, to be known as duty-cycle shifted PWM (DCS PWM control, is proposed and applied to the conventional HB dc–dc converters to achieve ZVS for both the switches without adding extra components and without adding asymmetric penalties of the complementary control. The concept of this new control scheme is shifting one of the two symmetric PWM driving signals close to the other, such that ZVS may be achieved for the lagging switch due to the shortened resonant interval. Moreover, based on the DCS PWM control, a new half-bridge topology is proposed to achieve ZVS for both the main switches and auxiliary switch by adding an auxiliary switch and diode in the proposed half bridge. ZVS for the switch is achieved by utilizing the energy trapped in the leakage inductance. There are two control schemes. One is open loop and the other is closed loop. In open loop scheme, the given dc-dc converter is operating under disturbance. This disturbance effect is eliminated in closed loop scheme.
Space Vector PWM Control Synthesis for a H-Bridge Drive in Electric Vehicles
Abdelfatah, Kolli; BÃ©thoux, Olivier; De Bernardinis, Alexandre; LabourÃ©, Eric; Coquery, GÃ©rard
2013-01-01
This paper deals with a synthesis of Space Vector PWM control methods applied for a H-bridge inverter feeding a 3-phase Permanent Magnet Synchronous Machine in Electric Vehicle application. First, a short survey of existing power converter architectures, especially those adapted to degraded operating modes, is presented. Standard SVPWM control methods are compared with three innovative ones using EV-drive specifications in the normal operating mode. Then, a rigorous analysis of the margins le...
A NOVEL CASCADED H- BRIDGE MULTILEVEL INVERTER BASED ON OPTIMAL PWM TECHNIQUE
MAHESWARI, A.; GNANAMBAL.I
2013-01-01
In this paper, a novel cascaded H- bridge multilevel inverter has been proposed using less number of switches. A standard cascaded multilevel inverter requires 4h number of switches for (2h + 1) levels whereas h is the number of dc sources. This proposed scheme allows less number of switches for the same level. A novel cascaded H- bridge multilevel inverter fed induction motor shows better performance due to fundamental frequency switching scheme using optimal PWM Technique (OPWM). High qual...
SIMULATION AND ANALYSIS OF PWM-CONTROLLED QUASI-RESONANT CONVERTER FOR DRIVES
Helen Priscilla A.S.; Ms. Ashly Mary Tom
2012-01-01
This paper presents the development of a new resonant capacitor assisted pulse width modulationcontrolled quasi resonant converter with an auxiliary circuit which does the load regulation by controlling the ripple of the resonant voltage. This resonant converter is simulated through MATLAB/SIMULINK. This newly developed quasi resonant DC-DC converter can regulate its DC output under a principle of constant frequency soft switching commutation by a controllable PWM duty cycle control scheme. T...
Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter
S. Arumugam S. Ramareddy M. Sridhar
2011-01-01
This paper presents a novel soft-switching pulse width modulation (PWM) utility frequency AC to high frequency (HF) AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which ...
A NOVEL CASCADED H- BRIDGE MULTILEVEL INVERTER BASED ON OPTIMAL PWM TECHNIQUE
A. Maheswari; I. Gnanambal
2013-01-01
In this paper, a novel cascaded H- bridge multilevel inverter has been proposed using less number of switches. A standard cascaded multilevel inverter requires 4h number of switches for (2h + 1) levels whereas h is the number of dc sources. This proposed scheme allows less number of switches for the same level. A novel cascaded H- bridge multilevel inverter fed induction motor shows better performance due to fundamental frequency switching scheme usingÂ optimal PWM Technique (OPWM). High qual...
Juarez B. Silva; Vilson Gruber; Roderval Marcelino
2012-01-01
Remote experiments may be an important tool to implement new technologies in the teaching/learning process, since it enables experimenting with real plants, essential to consolidate the concepts acquired in the theoretical classes, especially in technical and scientific disciplines.This article presents the “modulator PWM” remote experiment, its operational architecture and construction. It seeks to demonstrate its integration with theory and the use of the 3G cellular net...
Energy Technology Data Exchange (ETDEWEB)
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.
Energy Technology Data Exchange (ETDEWEB)
Ito, Y. (Sony Corp., Tokyo (Japan)); Furuhashi, T.; Okuma, S.; Uchikawa, Y. (Nagoya Univ., Nagoya (Japan))
1991-06-20
The output current follow-up performance of a PWM inverter is degraded by changes of load impedances, which is further degraded by the delay required for the calculation of the digital controller. Neural network is employed for the digital current control of the PWM inverter, and it is shown that the degradation of the current follow-up performance, caused by the changes of load impedances and operation delay of the control system, can be compensated. The time required for learning in this control method is approximatly 10 cycles, and the said compensation is found to be feasible. As regards the step change of the current command values after learning, the error is converged after one cycle if there is no change in the contained higher harmonic wave component. The optimum value and the upper limit of the learning rate are clarified. As to the deviations of the load impednaces, stable region of the current controller is obtained by simulations, and the range of variation is shown to have no problem for practical use. 6 refs., 14 figs., 1 tab.
Modeling & Simulation of PWM Controlled Cycloconverter FED Split Phase Induction Motor
Directory of Open Access Journals (Sweden)
VINAMRA KUMAR GOVIL
2013-03-01
Full Text Available Single Phase induction motors are widely accepted motor due to their energy efficient characteristics. To drive varying mechanical loads for long duty the machine needs to be controlled to increase its efficiency and minimize transient. To control the output parameters of the motor i.e., Speed and Electromagnetic torque the fixed frequency of the system is varied for which a Cycloconverter is employed along with PWM technique to increase the system efficiency. The Cycloconverter is built on with IGBT due to its improved dynamic performance and efficiency and reduction in the level of audible noise. Low driving power and a simple drive circuit due to the input MOS gate structure. It can be easily controlled as compared to current controlled devices (Thyristor, BJT in high voltage and high current applications. With the help of PWM the output voltage control can be obtained without addition of any external components and PWM minimizes the lower order harmonics, while the higher order harmonics can be eliminated using a filter
Development of a current-type PWM converter with high power factor. 1
International Nuclear Information System (INIS)
A power supply system for superconducting poloidal field coils of a next generation tokamak-type fusion device can be operated on the relatively low voltage for the duration of discharge except the plasma initiation. In the case of the conventional phase-controlled thyristor converters are adopted in such a system, the input power factor would be low in average, and a reactive power fluctuation caused by the change of DC output voltage may produce serious effects on the commercial transmission line. From the above viewpoint, a current-type PWM (Pulse Width Modulation) converter, which can work with the power factor of unity for the input power, is regarded as one of the promising candidates of the converters for the power supplies of next generation fusion devices. Hence, a 100kW-class current-type PWM converter has been developed by using IGBT (Insulated Gate Bipolar Transistor) as switching devices. In this development, the basic performance has been preliminary investigated whether this converter is applicable to the power supply for the next generation fusion device. In addition, two different PWM control methods were examined whether these methods can realize a unit power factor and suppress the transient oscillation of converter input current at the same time in case that the reference of DC output current is changed rapidly. (author)
Directory of Open Access Journals (Sweden)
Juarez B. Silva
2012-01-01
Full Text Available Remote experiments may be an important tool to implement new technologies in the teaching/learning process, since it enables experimenting with real plants, essential to consolidate the concepts acquired in the theoretical classes, especially in technical and scientific disciplines.This article presents the “modulator PWM” remote experiment, its operational architecture and construction. It seeks to demonstrate its integration with theory and the use of the 3G cellular network as a communications channel for remote experimenting. The PWM modulators are often used in disciplines of higher education courses in electrical engineering, telecommunications and electronics. This article shows that it is possible to perform the practical activity completely remotely, via 3G cellular networks or through the internet to access the experiment and perform the experiments needed to fully understand the theories of the PWM modulator.This article is a further initiative for remote experiments in the world of different engineering specialties, involving the cellular networks that are rapidly expanding at this time.
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.