Showing papers on "PWM rectifier published in 1998"
Book•
01 Jan 1998
TL;DR: In this paper, the authors present an analytical solution to calculate the current waveform of an AC-to-AC converter and demonstrate the effect of current waveforms on the performance of the converter.
Abstract: Preface. 1 Principles and Methods of Electric PowerConversion. 1.1 What Is Power Electronics? 1.2 Generic Power Converter. 1.3 Waveform Components and Figures of Merit. 1.4 Phase Control. 1.5 Pulse Width Modulation. 1.6 Calculation of Current Waveforms. 1.6.1 Analytical Solution. 1.6.2 Numerical Solution. 1.6.3 Practical Examples: Single-Phase Diode Rectifiers. 1.7 Summary. Example. Problems. Computer Assignments. Literature. 2 Semiconductor Power Switches. 2.1 General Properties of Semiconductor Power Switches. 2.2 Power Diodes. 2.3 Semicontrolled Switches. 2.3.1 SCRs. 2.3.2 Triacs. 2.4 Fully Controlled Switches. 2.4.1 GTOs. 2.4.2 IGCTs. 2.4.3 Power BJTs. 2.4.4 Power MOSFETs. 2.4.5 IGBTs. 2.5 Comparison of Semiconductor Power Switches. 2.6 Power Modules. 2.7 Summary. Literature. 3 Supplementary Components and Systems. 3.1 What Are Supplementary Components and Systems? 3.2 Drivers. 3.2.1 Drivers for SCRs, Triacs, and BCTs. 3.2.2 Drivers for GTOs and IGCTs. 3.2.3 Drivers for BJTs. 3.2.4 Drivers for Power MOSFETs and IGBTs. 3.3 Overcurrent Protection Schemes. 3.4 Snubbers. 3.4.1 Snubbers for Power Diodes, SCRs, and Triacs. 3.4.2 Snubbers for GTOs and IGCTs. 3.4.3 Snubbers for Transistors. 3.4.4 Energy Recovery from Snubbers. 3.5 Filters. 3.6 Cooling. 3.7 Control. 3.8 Summary. Literature. 4 AC-to-DC Converters. 4.1 Diode Rectifiers. 4.1.1 Three-Pulse Diode Rectifier. 4.1.2 Six-Pulse Diode Rectifier. 4.2 Phase-Controlled Rectifiers. 4.2.1 Phase-Controlled Six-Pulse Rectifier. 4.2.2 Dual Converters. 4.3 PWM Rectifiers. 4.3.1 Impact of Input Filter. 4.3.2 Principles of Pulse Width Modulation. 4.3.3 Current-Type PWM Rectifier. 4.3.4 Voltage-Type PWM Rectifier. 4.4 Device Selection for Rectifiers. 4.5 Common Applications of Rectifiers. 4.6 Summary. Examples. Problems. Computer Assignments. Literature. 5 AC-to-AC Converters. 5.1 AC Voltage Controllers. 5.1.1 Phase-Controlled Single-Phase AC Voltage Controller. 5.1.2 Phase-Controlled Three-Phase AC Voltage Controllers. 5.1.3 PWM AC Voltage Controllers. 5.2 Cycloconverters. 5.3 Matrix Converters. 5.4 Device Selection for AC-to-AC Converters. 5.5 Common Applications of AC-to-AC Converters. 5.6 Summary. Examples. Problems. Computer Assignments. Literature. 6 DC-to-DC Converters. 6.1 Static DC Switches. 6.2 Step-Down Choppers. 6.2.1 First-Quadrant Chopper. 6.2.2 Second-Quadrant Chopper. 6.2.3 First-and-Second-Quadrant Chopper. 6.2.4 First-and-Fourth-Quadrant Chopper. 6.2.5 Four-Quadrant Chopper. 6.3 Step-Up Chopper. 6.4 Current Control in Choppers. 6.5 Device Selection for Choppers. 6.6 Common Applications of Choppers. 6.7 Summary. Example. Problems. Computer Assignments. Literature. 7 DC-to-AC Converters. 7.1 Voltage-Source Inverters. 7.1.1 Single-Phase Voltage-Source Inverter. 7.1.2 Three-Phase Voltage-Source Inverter. 7.1.3 Voltage Control Techniques for Voltage-SourceInverters. 7.1.4 Current Control Techniques for Voltage-SourceInverters. 7.2 Current-Source Inverters. 7.2.1 Three-Phase Square-Wave Current-Source Inverter. 7.2.2 Three-Phase PWM Current-Source Inverter. 7.3 Multilevel Inverters. 7.4 Soft-Switching Inverters. 7.5 Device Selection for Inverters. 7.6 Common Applications of Inverters. 7.7 Summary. Examples. Problems. Computer Assignments. Literature. 8 Switching Power Supplies. 8.1 Basic Types of Switching Power Supplies. 8.2 Nonisolated Switched-Mode DC-to-DC Converters. 8.2.1 Buck Converter. 8.2.2 Boost Converter. 8.2.3 Buck Boost Converter. 8.2.4 uk Converter. 8.2.5 SEPIC and Zeta Converters. 8.2.6 Comparison of Nonisolated Switched-Mode DC-to-DCConverters. 8.3 Isolated Switched-Mode DC-to-DC Converters. 8.3.1 Single-Switch Isolated DC-to-DC Converters. 8.3.2 Multiple-Switch Isolated DC-to-DC Converters. 8.3.3 Comparison of Isolated Switched-Mode DC-to-DCConverters. 8.4 Resonant DC-to-DC Converters. 8.4.1 Quasi-Resonant Converters. 8.4.2 Load-Resonant Converters. 8.4.3 Comparison of Resonant DC-to-DC Converters. 8.5 Summary. Examples. Problems. Computer Assignments. Literature. 9 Power Electronics and Clean Energy. 9.1 Why Is Power Electronics Indispensable in Clean EnergySystems? 9.2 Solar and Wind Renewable Energy Systems. 9.2.1 Solar Energy Systems. 9.2.2 Wind Energy Systems. 9.3 Fuel Cell Energy Systems. 9.4 Electric and Hybrid Cars. 9.5 Power Electronics and Energy Conservation. 9.6 Summary. Literature. Appendix A PSpice Simulations. Appendix B Fourier Series. Appendix C Three-Phase Systems. Index.
168 citations
15 Feb 1998
TL;DR: In this article, the structure of the power circuit of a new single-stage three-phase boost-type PWM rectifier system (VIENNA Rectifier II) is developed.
Abstract: Based on an analysis of basic realization possibilities, the structure of the power circuit of a new single-stage three-phase boost-type PWM rectifier system (VIENNA Rectifier II) is developed. This system has continuous sinusoidal time behavior of the input currents and high-frequency isolation of the output voltage which is controlled in a highly dynamic manner. As compared to a conventional two-stage realization, this system has substantially lower complexity and allows to realize several isolated output circuits with minimum effort. The basic function of the new PWM rectifier system is described based on the conducting states occurring within a pulse period. Furthermore, a straightforward space vector oriented method for the system control is proposed which guarantees a symmetric magnetization of the transformer. Also, it makes possible a sinusoidal control of the mains phase currents in phase with the associated phase voltages. By digital simulation the theoretical considerations, the stresses on the power semiconductors of the new converter system are determined. Finally, problems of a practical realization of the system are discussed, as well as the direct start-up and the short circuit protection of the converter. Also, the advantages and disadvantages of the new converter system are compiled in the form of an overview.
62 citations
15 Feb 1998
TL;DR: Three three-phase, single-switch, high-power-factor rectifier implementations were evaluated on a comparative basis with respect to their efficiencies, compliance with the IEC555-2 specifications, volumes, weights, and costs.
Abstract: Three three-phase, single-switch, high-power-factor rectifier implementations were evaluated on a comparative basis. Specifically, the discontinuous-conduction-mode boost rectifier with a 5/sup th/-harmonic-trap filter, the discontinuous-conduction-mode boost rectifier with a harmonic-injection circuit, and the multi-resonant, zero-current-switching buck rectifier were compared with respect to their efficiencies, compliance with the IEC555-2 specifications, volumes, weights, and costs. The comparisons were done for the three-phase, line-to-line input voltage of 380 V/sub rms//spl plusmn/20% and for 0-6 kW output-power range.
46 citations
17 May 1998
TL;DR: A basic steady-state analysis and analytical considerations on power loss are described, and these analysis are confirmed by experiments.
Abstract: The power efficiency of a three-arm-type UPS has been examined. In this UPS configuration, the center arm, called the "common arm", operates in both PWM rectifier mode and PWM inverter mode. In this paper, a basic steady-state analysis and analytical considerations on power loss are described, and these analysis are confirmed by experiments.
24 citations
Proceedings Article•
01 Oct 1998TL;DR: In this paper, a PWM modulation strategy for reconstructing three phase currents from the DC link current is given, where the states of the rectifier switch are modified so that all phase currents can be reconstructed in a switching period although one of active vectors is applied only for a short time.
Abstract: This paper proposes a control method for three-phase PWM rectifier using only single current sensor in DC link A PWM modulation strategy for reconstructing three phase currents from the DC link current is given. The states of the rectifier switch are modified so that all phase currents can be reconstructed in a switching period although one of active vectors is applied only for a short time Therefore, a novel current control using an adjustment scheme of the modulation signal for a three-phase PWM rectifier will be discussed, and verified with the experimental results.
23 citations
TL;DR: In this paper, a control algorithm for an induction motor fed by a fully controlled rectifier and inverter is developed to reduce the common mode neutral-to-ground voltage of the induction motor.
Abstract: High frequency common mode voltage produced by power converters are a major cause of conducted EMI, creating motor ground currents, bearing currents and other harmful by-products. In this paper a control algorithm for an induction motor fed by a fully controlled rectifier and inverter is developed to reduce the common mode neutral-to-ground voltage of the induction motor. A bearing current model is used to evaluate the effects on the bearing currents of the double bridge modulation scheme when the new algorithm and conventional algorithms are used. Simulation results are shown to demonstrate the benefits of the new PWM approach.
19 citations
15 Feb 1998
TL;DR: In this paper, an input/output filter topology with interconnection to DC-link midpoint is proposed to reduce both common mode and differential mode dv/dt at the motor terminals, permitting the use of long motor leads, and the filter components can be installed within the rectifier/inverter enclosure.
Abstract: In this paper, it is shown via analysis and experiments that common mode dv/dt transitions at motor terminals is twice as severe in a regenerative (PWM rectifier/PWM inverter) type ASD compared to a nonregenerative (diode rectifier/PWM inverter) type ASD system. It should be noted that higher common mode dv/dt at the motor terminals results in: (i) higher induced shaft voltage at each dv/dt transition, which can result in bearing currents and cause pitting/fluting of the bearings, and (ii) higher leakage currents to ground which can interfere with the plant zero sequence protection system. The paper proposes a method to reduce these effects. An input/output filter topology with interconnection to DC-link midpoint is proposed. This method reduces both common mode and differential mode dv/dt at the motor terminals, permits the use of long motor leads, and the filter components can be installed within the rectifier/inverter enclosure. Finally experimental results are presented on a 20 kW PWM ASD test stand.
18 citations
31 Aug 1998
TL;DR: In this paper, a single-phase PWM current source rectifier with a neutral leg is presented and thoroughly analyzed in a novel topology is implemented by adding an extra leg to a step-down single phase PWM rectifier.
Abstract: A single-phase PWM current source rectifier with a neutral leg is presented and thoroughly analyzed in this paper. This novel topology is implemented by adding an extra leg to a step-down single-phase PWM rectifier. A single-phase PWM space vector modulation method to reduce the DC output voltage harmonics is proposed. The PWM pattern generation needs a digital system or a DSP based implementation. As compared with a conventional single-phase PWM rectifier, over a 20% improvement of the total harmonic distortion in the output voltage can be obtained. The proposed converter could be applied as a power conditioner module for an electrochemical pilot plant such as an electrowinning copper process and for fast battery chargers in the range of medium power applications.
17 citations
17 May 1998
TL;DR: In this article, the authors presented a new ZCS turn-on and ZVS turn-off unity power factor PWM rectifier, which features soft switching with no auxiliary switches and reduced conduction losses.
Abstract: This paper presents a new ZCS turn-on and ZVS turn-off unity power factor PWM rectifier, which features soft switching with no auxiliary switches and reduced conduction losses. The ZVS and ZCS switching are achieved by using a simple commutation circuit with no auxiliary switches, and reduced conduction losses are achieved by employing a single converter, instead of a typical front-end diode rectifier followed by a boost rectifier. Furthermore, thanks to good features such as simple PWM control at constant frequency, low switch stress and low VAr rating of commutation circuits, it is suitable for high power applications. The principle of operation is explained and analyzed, and the design considerations and experimental results of the new converter are included.
14 citations
01 Sep 1998
TL;DR: A control loop of these three-level PWM rectifier-multilevel inverter permanent magnet synchronous machine cascade is presented in order to control the input DC voltage of the inverters and the current in the network.
Abstract: This paper studies the control of the multilevel PWM rectifier-multilevel inverter permanent magnet synchronous machine (PMSM) cascade. We present the field oriented speed control of the PMSM, and develop the control model of the three-level inverters by using the generating functions. We propose a new calculated strategy of the inverter which uses its control model. We show the problem of the middle point of the inverter input DC voltage source. A solution to this problem is to control this input DC voltage and then the potential of its middle point by a feedback control of the three-level PWM rectifier. Thus, we present a control loop of these three-level PWM rectifiers in order to control the input DC voltage of the inverters and the current in the network. This drive system finds applications in high power and high speed drive fields such as the electric traction.
12 citations
21 Sep 1998
TL;DR: In this article, the authors present a control strategy to apply in the control of current type PWM rectifiers using the voltages across the AC inductors as feedback variables, which allows a transfer function linearization between the modulation index, that is the output of the PI controller, and the DC current.
Abstract: This paper presents a control strategy to apply in the control of current type PWM rectifiers. These converters use LC filters on the AC side, and as a consequence, undesired oscillations take place. These oscillations are not dependent on the PWM technique used but depend on the LC filter size. A simple, cost effective and efficient damping system is presented and discussed in this paper. This damping system uses the voltages across the AC inductors as feedback variables. The DC current is controlled with an outer linear PI controller with anti-reset windup and a nonlinear function that determines the AC current references by the product of the PI output and the actual DC current. This allows a transfer function linearization between the modulation index, that is the output of the PI controller, and the DC current. The system is analysed with a simplified model and analytical expressions are presented to synthesise the feedback loops. The PWM space vector modulation technique adapted to current inverters is used to verify the performance of the proposed feedback loops. The results presented show excellent behaviour in steady state and in transient regime.
31 Aug 1998
TL;DR: In this paper, an electric model for electrolysis cells used in copper electrowinning processes is developed, which is applied to the analysis of cells, using series configurations of bipolar floating electrodes.
Abstract: An electric model for electrolysis cells used in copper electrowinning processes is developed. It is applied to the analysis of cells, using series configurations of bipolar floating electrodes. This technology has been used in several fields of electrochemistry, but has not yet been applied by the copper industry. Its main advantage is that, for the same copper production, the cell requires a much lower DC current, as compared to conventional electrolysis cells, which use a parallel configuration of unipolar electrodes. This feature allows it to be supplied from a modular and compact PWM rectifier instead of a bulk and high current thyristor rectifier. Finite difference algorithms in two dimensions are derived to obtain the graphical distribution of the potential and the electric field inside the cell, and around the bipolar electrodes. The proposed modeling algorithms are implemented in the MATLAB software package. Different geometrical distributions of the floating electrodes in the cell are analyzed.
Patent•
09 Oct 1998
TL;DR: In this paper, the authors proposed a rectifier circuit for general purpose inverter in which generation of harmonics is suppressed while improving the power factor through simple circuitry and the size can be reduced while facilitating connection.
Abstract: PROBLEM TO BE SOLVED: To provide a rectifier circuit for general purpose inverter in which generation of harmonics is suppressed while improving the power factor through simple circuitry and the size can be reduced while facilitating connection. SOLUTION: The rectifier circuit for general purpose inverter principally comprises a PWM rectifier circuit and a control circuit 9' turns an IGBT constituting the bridge circuit 8' in the PWM rectifier circuit on/off to bring the differential voltage between an output voltage Vdc and a target voltage Vdc* to zero based on a pseudo sine wave generated from the output voltage va of a rectifier, a signal based on the differential voltage and an input current detected by an AC current detector 17. The zero differential voltage is applied to dead time compensation circuits 22, 23. Consequently, on/off timing of the IGBT can be controlled while suppressing error to a command value. The pseudo sine wave generating circuit comprises an operational amplifier for detecting the input current immediately after turn on power and delivers the phase of a detected sine wave as the phase of a power supply voltage Vs.
12 Oct 1998
TL;DR: In this article, the authors proposed a finite difference algorithm to obtain the distribution of the potential and the electric field inside the cell, which is a useful tool for analysis and design of electrowinning cells, reducing the timeconsuming laboratory implementations.
Abstract: This paper is a contribution to the electric modeling of electrochemical cells. Specifically, cells for a new copper electrowinning process, which uses bipolar electrodes, are studied. Electrowinning is used together with solvent extraction and has gained great importance, due to its significant cost and environmental advantages, as compared to other copper reduction methods. Current electrowinning cells use unipolar electrodes connected electrically in parallel. Instead, bipolar electrodes, are connected in series. They are also called floating, because they are not wire-connected, but just immersed in the electrolyte. The main advantage of this technology is that, for the same copper production, a cell requires a much lower DC current, as compared with the unipolar case. This allows the cell to be supplied from a modular and compact PWM rectifier instead of a bulk high current thyristor rectifier, having a significant economic impact. In order to study the quality of the copper, finite difference algorithms in two dimensions are derived to obtain the distribution of the potential and the electric field inside the cell. Different geometrical configurations of cell and floating electrodes are analyzed. The proposed method is a useful tool for analysis and design of electrowinning cells, reducing the time-consuming laboratory implementations.
01 Jan 1998
18 May 1998
TL;DR: This paper presents an easy to implement method for the control of active AC/DC power converters based on the combination of adaptive hysteresis and predictive current fixed frequency current (PCFF) control.
Abstract: Several methods for the DC voltage control of voltage (boost) type AC/DC power converters are known. They differ in the performance and the complexity of used hardware/software. One of the basic requirements also included in control method is nearly sinusoidal input (AC) current with unity power factor. The aim of this paper is to present an easy to implement method for the control of active AC/DC power converters. It is based on the combination of adaptive hysteresis and predictive current fixed frequency current (PCFF) control. For the fast and accurate response of output voltage load, feedforward control is included. It controls the output voltage, ensuring the unity power factor and minimal harmonic distortion of both current and voltage at the input of the power converter.
TL;DR: In this article, the authors have proposed a novel topology of the PWM rectifier and reported its operation principles, and the operation limit influenced by the circuit parameters, especially capacitance of the input capacitor, is discussed.
Abstract: The generation of harmonics and their subsequent propagation into power line is a topic of increasing concern to power supply authorities. To prevent the obstacles on the power system, Unity-Power-Factor PWM converter is going to apply to AC-DC power conversion circuit. However, PWM converter, especially at single phase circuit, has some serious defects, that is low frequency ripple current which flows into the battery connected to the DC output or low frequency ripple voltage which appears on the DC output capacitor. Especially, in case of the batteries are connected with the DC output, the low frequency ripple current flows into the battery and cause power loss on the battery. The power loss cause high temperature of the battery and shortens the life of it. To accomplish the reduction of the low frequency ripple current, the authors have been proposed a novel topology of the PWM rectifier and reported its operation principles. In this paper, the operation limit influenced by the circuit parameters, especially capacitance of the input capacitor, is discussed. It is shown that the operation limit can be estimated based on the calculation of the ripple energy that is stored in the input capacitors. By adopting the ripple energy expression on both the input capacitor and the DC output, the limitation for the DC ripple reduction can be clearly expressed. The calculated results agree well with that of the experimental results. The proposed calculation technique is useful for the practical design of the proposed PWM converter.
TL;DR: In this article, a novel topology for the PWM rectifier is presented, which consists of a pair of switching devices to the conventional PWM converter circuit, and the theoretical characteristics are obtained by using the state-space averaging method.
Abstract: The generation of harmonics and their subsequent propagation into power lines is a topic of increasing concern to power-supply authorities. To prevent obstacles in the power system, a unity-power-factor PWM converter will be applied at ac-dc power conversion plants. However, the PWM converter, especially at single-phase circuit, has some serious defects, including low-frequency ripple current that flows into the dc line and gives rise to a low-frequency ripple voltage that appears on the dc output. In usual cases, it is necessary to connect a very large capacitor or a passive L-C resonant circuit to the dc line for reduction of low-frequency ripple voltage. However, when batteries are connected to the dc output, most of the dc ripple current flows into the battery even if the above circuits are used, because the impedance of the battery is very low compared to that of the circuits. The low-frequency ripple current causes power loss on the battery and the temperature rises. It is well known that the life of a battery is deeply influenced by the temperature. The ripple current, therefore, should be reduced as low as possible.
To accomplish reduction of the low-frequency ripple current, a novel topology for the PWM rectifier is presented in this paper. The main circuit is constituted by adding only a pair of switching devices to the conventional PWM converter circuit. With a simple control technique, the ripple energy on the dc line is converted into stored energy on the input ac capacitors through additional switches. The theoretical characteristics are obtained by using the state-space averaging method. The effect of ripple reduction is confirmed by experiments using a breadboard setup. © 1998 Scripta Technica, Electr Eng Jpn, 123(1): 51–62, 1998
01 Dec 1998
TL;DR: In this paper, a cascade dynamic decoupling compensator of boost PWM rectifier in the synchronous reference frame is presented, which not only decouples the crossing influence of d, q current in real time but also modifies the current nature response characteristic.
Abstract: Transitional current overshoot, DC offset and slow current response are the inherent drawbacks of conventional indirect or phase amplitude current control of three phase voltage source PWM rectifier Analyses show that it is essentially a steady decoupling method, all the drawbacks are caused by current control based on steady state viewpoint A new cascade dynamic decoupling compensator of boost PWM rectifier in the synchronous reference frame is firstly presented The compensator not only decouples the crossing influence of d, q current in real time but also modifies the current nature response characteristic The current response speed can be designed arbitrarily by assigning appropriate poles of the compensator All above mentioned defects are eliminated after the compensator was employed In addition, the proposed scheme doesn't need current sensors at all Simulation shows that it is a high performance and competitive control scheme
21 Sep 1998
TL;DR: In this article, a three-phase current-source soft-switching PWM rectifier with new auxiliary resonant commutated circuits is proposed which can operate under zero current softswitching principle.
Abstract: In this paper, a novel prototype of a three-phase current-source soft-switching PWM rectifier with new auxiliary resonant commutated circuits is proposed which can operate under zero current soft-switching principle. This rectifier is composed of six bridge-type main power switches with a reverse blocking diode and their related six auxiliary resonant commutation circuits including a switched type resonant capacitor in parallel with each main power circuit switch and two resonant inductors. The current flowing into the main power bridge circuit is transferred into an auxiliary resonant circuit and main power circuit switch is turned-off and on based on a principle of zero current soft-switching commutation. This new topology reduces switching losses without requiring complex energy recovery circuits. The proposed rectifier, operating at zero current switching transition, can be efficiently operated with a conventional hard switching PWM rectifier. In this paper, the steady-state operation mode of the current-fed ZCS-PWM rectifier is described for high-power applications, and analyzed for a design consideration. The effectiveness of this new active PWM rectifier is proved on the basis of some illustrative results obtained from computer simulation analysis.
21 Sep 1998
TL;DR: In this article, a three-phase power factor PWM rectifier with galvanic isolation, a single voltage control loop and a single switch is presented, where three bidirectional flybacks working in the discontinuous current mode allow the attainment of a unity power factor.
Abstract: This summary introduces a new scheme of a three-phase power factor PWM rectifier with galvanic isolation, a single voltage control loop and a single switch. The association of three bidirectional flybacks working in the discontinuous current mode allows the attainment of a unity power factor. A step-down or step-up voltage operation and an appropriated transformer ratio makes it possible to obtain a large range of output voltage.
01 Dec 1998
TL;DR: In this paper, an AC/DC/AC converter with a power factor correction to improve the power quality in the AC mains and a pseudorandom noise generator to reduce the emitted acoustic noise for induction motor drive is presented.
Abstract: This paper presents an AC/DC/AC converter with a power factor correction to improve the power quality in the AC mains and a pseudorandom noise generator to reduce the emitted acoustic noise for induction motor drive The space vector modulation with hysteresis current regulator is adopted to simplify the control algorithm The control scheme is proposed to force the line current in phase with the source voltage The current reference for the pulse width modulated (PWM) rectifier is derived from the DC bus voltage regulator and the estimated output power In order to reduce the annoying tonal noise and resonant vibration from the drive, random switching frequency technique for a three-phase induction motor control is described By randomly varying the instantaneous PWM switching frequency from one cycle to the next, the frequency distribution of harmonics is spread in a wide frequency range Experimental results show the nearly unity power factor at the PWM rectifier and the absence of acoustic noise concentrated at specific tones which is usually present with conventional sinusoidal modulation
Proceedings Article•
01 Oct 1998
TL;DR: In this article, a voltage-source inverter without DC link components is proposed to reduce waveform distortion of the AC source current, the current-controlled PWM-rectifier with di/dt feedback is introduced.
Abstract: The voltage-source inverters are normally equipped with an electrolytic capacitor in their DC link, however, the electrolytic capacitor has several disadvantages such as increasing size, limiting converter life and reliability. Therefore, several approaches for removing the DC link capacitor have been studied by the authors. This paper proposes a new voltage-source inverter without DC link components. To reduce waveform distortion of the AC source current, the current-controlled PWM-rectifier with di/dt feedback is introduced. The di/dt feedback gain and LC parameters are investigated by calculation for a 0.75kW induction motor driven by this inverter. The calculated AC source currents maintain nearly sinusoidal waveforms with a unity power factor.
01 Dec 1998
TL;DR: In this article, a simple PWM scheme for half controlled MCT based AC/DC converter has been suggested to contain simultaneously the minimum amount of input current and output voltage harmonics while at the same tune it is simple to implement as compared to similar other schemes.
Abstract: The lower on state voltage drop along with high dv/dt, di/dt are some of the attractive features which makes MCT the most suitable device for motor drive application A simple PWM scheme for half controlled MCT based AC/DC converter has been suggested This pulse pattern has been optimised to contain simultaneously the minimum amount of input current and output voltage harmonics while at the same tune it is simple to implement as compared to similar other schemes An analytical simulation has been carried out for this converter with DC motor load The simulation results shows that the converter input performances like power factor and harmonic factor are relatively good The output performance parameters like the ripple factor and peak factor are comparatively improved as compared to the published work A MCT based converter with three phase input and the proposed control strategy has been assembled and tested in the laboratory to check the validity of its implementation The overall converter performance has been found to be satisfactory Some of the essential waveforms obtained from the experimental set up are shown in this paper
12 Oct 1998
TL;DR: Three different types of control applications have been implemented on a PWM rectifier using the real time code generator, and the paper compares the three different control systems implemented.
Abstract: A real time code generator which can generate 'C' code from a Simulink block diagram suitable for power electronic control applications has been developed. The 'C' code developed is down loaded to a digital signal processor control board. The software has been developed using Delphi. Three different types of control applications have been implemented on a PWM rectifier using the real time code generator. The paper compares the three different control systems implemented.