Showing papers in "IEEE Transactions on Power Electronics in 1997"
TL;DR: In this paper, direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drives has been investigated, and it is proved that the increase of electromagnetic torque in a permanent magnet motor is proportional to the angle between the stator and rotor flux linkages, and therefore the fast torque response can be obtained by adjusting the rotating speed of the stators flux linkage as fast as possible.
Abstract: This paper describes an investigation of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drives. It is mathematically proven that the increase of electromagnetic torque in a permanent magnet motor is proportional to the increase of the angle between the stator and rotor flux linkages, and, therefore, the fast torque response can be obtained by adjusting the rotating speed of the stator flux linkage as fast as possible. It is also shown that the zero voltage vectors should not be used, and stator flux linkage should be kept moving with respect to the rotor flux linkage all the time. The implementation of DTC in the permanent magnet motor is discussed, and it is found that for DTC using available digital signal processors (DSPs), it is advantageous to have a motor with a high ratio of the rated stator flux linkage to stator voltage. The simulation results verify the proposed control and also show that the torque response under DTC is much faster than the one under current control.
932 citations
Abstract: A new mathematical model of the power circuit of a three-phase voltage source converter (VSC) was developed in the stationary and synchronous reference frames. The mathematical model was then used to analyze and synthesize the voltage and current control loops for the VSC. Analytical expressions were derived for calculating the gains and time constants of the current and voltage regulators. The mathematical model was used to control a 140-kW regenerative VSC. The synchronous reference-frame model was used to define feedforward signals in the current regulators to eliminate the cross coupling between the d and q phases. It allowed the reduction of the current control loops to first-order plants and improved their tracking capability. The bandwidths of the current and voltage-control loops were found to be approximately 20 and 60 times (respectively) smaller than the sampling frequency. All control algorithms were implemented in a digital signal processor. All results of the analysis were experimentally verified.
849 citations
TL;DR: In this paper, a three-phase four-wire shunt active power filter using a conventional three-leg converter without the need of power supply at DC bus has been described.
Abstract: This paper describes a three-phase four-wire shunt active power filter using a conventional three-leg converter, without the need of power supply at DC bus Two approaches have been developed to control the active filter Both control strategies consider harmonics and zero sequence components in the voltage and current simultaneously The first one provides constant power and the second one sinusoidal current to the source, even under unbalanced voltage conditions Simulation results from a complete model of shunt active filter are presented to validate and compare the control strategies
543 citations
TL;DR: In this paper, a new method for predicting the stray capacitance of inductors is presented, which is based on an analytical approach and the physical structure of the inductors, where the inductor winding is partitioned into basic cells.
Abstract: A new method for predicting the stray capacitance of inductors is presented. The method is based on an analytical approach and the physical structure of inductors. The inductor winding is partitioned into basic cells-many of which are identical. An expression for the equivalent capacitance of the basic cell is derived. Using this expression, the stray capacitance is found for both single- and multiple-layer coils, including the presence of the core. The method was tested with experimental measurements. The accuracy of the results is good. The derived expressions are useful for designing inductors and can be used for simulation purposes.
393 citations
TL;DR: In this paper, a general-purpose fuzzy controller for DC-DC converters is investigated and, based on a qualitative description of the system to be controlled, fuzzy controllers are capable of good performances, even for those systems where linear control techniques fail.
Abstract: In this paper, a general-purpose fuzzy controller for DC-DC converters is investigated. Based on a qualitative description of the system to be controlled, fuzzy controllers are capable of good performances, even for those systems where linear control techniques fail, e.g., when a mathematical description is not available or is in the presence of wide parameter variations. The presented approach is general and can be applied to any DC-DC converter topologies. Controller implementation is relatively simple and can guarantee a small-signal response as fast and stable as other standard regulators and an improved large-signal response. Simulation results of buck-boost and Sepic converters show control potentialities.
301 citations
TL;DR: In this article, a two-layer controller consisting of a tracking controller and a repetitive controller is proposed to improve both the transient and steady-state responses of a closed-loop regulated pulsewidth-modulated (PWM) inverter for high-quality sinusoidal AC voltage regulation.
Abstract: This paper proposes a new control scheme based on a two-layer control structure to improve both the transient and steady-state responses of a closed-loop regulated pulse-width-modulated (PWM) inverter for high-quality sinusoidal AC voltage regulation. The proposed two-layer controller consists of a tracking controller and a repetitive controller. Pole assignment with state feedback has been employed in designing the tracking controller for transient response improvement, and a repetitive control scheme was developed in synthesizing the repetitive controller for steady-state response improvement. A design procedure is given for synthesizing the repetitive controller for PWM inverters to minimize periodic errors induced by rectifier-type nonlinear loads. The proposed control scheme has been realized using a single-chip digital signal processor (DSP) TMS320C14 from Texas Instruments. A 2-kVA PWM inverter has been constructed to verify the proposed control scheme. Total harmonic distortion (THD) below 1.4% for a 60-Hz output voltage under a bridge-rectifier RC load with a current crest factor of 3 has been obtained. Simulation and experimental results show that the DSP-based fully digital-controlled PWM inverter can achieve both good dynamic response and low harmonics distortion.
279 citations
TL;DR: In this article, the authors examined AC motor shaft voltages and the resulting bearing currents when operated under pulse width modulation (PWM) voltage source inverters under the theory of electric discharge machining (EDM), including component calculations of the system elements.
Abstract: This paper examines AC motor shaft voltages and the resulting bearing currents when operated under pulse width modulation (PWM) voltage source inverters. The paper reviews the mechanical and electrical characteristics of the bearings and motor in relation to shaft voltages and bearing currents. A brief review of previous work is addressed, including the system model and experimental results. The theory of electric discharge machining (EDM) is presented, including component calculations of the system elements. The effect of system elements on shaft voltages and bearing currents are evaluated experimentally and the results compared to theory. A design calculation is proposed that provides the relative potential for EDM. Finally, the paper presents quantitative results on one solution to the shaft voltage and bearing current problem.
268 citations
TL;DR: In this article, an SVPWM control integrated circuit (IC) has been developed using state-of-the-art field-programmable gate array (FPGA) technology.
Abstract: This paper presents a new circuit realization of the space-vector pulse-width modulation (SVPWM) strategy. An SVPWM control integrated circuit (IC) has been developed using state of-the-art field-programmable gate array (FPGA) technology. The proposed SVPWM control scheme can be realized using only a single FPGA (XC4010) from Xilinx, Inc. The output fundamental frequency can be adjusted from 0.094 to 1500 Hz. The pulse-width modulation (PWM) switching frequency can be set from 381 Hz to 48.84 kHz. The delay time for the PWM gating signals is adjustable. This SVPWM IC can also be included in the digital current control loop for stator current regulation. The designed SVPWM IC can be incorporated with a digital signal processor (DSP) to provide a simple and effective solution for high-performance AC drives. Simulation and experimental results are given to verify the implemented SVPWM control IC.
254 citations
TL;DR: In this article, a Walsh function harmonic elimination method is proposed for a PWM inverter using the Walsh domain waveform analytic technique, where the harmonic amplitudes of the inverter output voltage can be expressed as functions of switching angles.
Abstract: A pulse-width-modulated (PWM) inverter using the Walsh function harmonic elimination method is proposed in this paper. By using the Walsh domain waveform analytic technique, the harmonic amplitudes of the inverter output voltage can be expressed as functions of switching angles. Thus, the switching angles are optimized by solving linear algebraic equations instead of solving nonlinear transcendental equations. The local piecewise linear relations between the switching angles and the fundamental amplitude can be obtained under an appropriate initial condition. By searching all feasible initial conditions, the global solutions are obtained. The relations between switching angles and fundamental amplitude can be approximated by straight-line curve fitting. Thus, on-line control of fundamental amplitude and frequency is possible for the microcomputer-based implementation. The developed algorithm can be applied to both bipolar and unipolar switching schemes. The theoretical predictions are confirmed by computer simulations and DSP-based hardware implementation.
210 citations
TL;DR: In this paper, the authors proposed to design a controller using H/sup /spl infin// control theory, via the solution of two algebraic Riccati equations, to stabilize the system and guarantee an almost constant output voltage.
Abstract: The controller in a pulse-width-modulation (PWM) power converter has to stabilize the system and guarantee an almost constant output voltage in spite of the perturbations in the input voltage and output load over as large a bandwidth as possible. Boost and flyback power converters have a right-half-plane zero (RHPZ) in their transfer function from the duty cycle to the output voltage, which makes it difficult to achieve the aforementioned goals. Here, the authors propose to design a controller using H/sup /spl infin// control theory, via the solution of two algebraic Riccati equations. The almost optimal H/sup /spl infin// controller is of the same order as the converter and has a relatively low DC gain. The closed-loop characteristics of a typical low-power boost power converter with four different control schemes were compared by computer simulation. The H/sup /spl infin// control was found to be superior in a wide frequency range, while being outperformed by the others at extremely low frequencies. Good agreement was found between simulation results and experimental measurements.
205 citations
TL;DR: In this paper, a space vector modulation for four-switch inverter (SVMFSI) is proposed for a low-cost PWM voltage-source inverter employing only four switches, four diodes, and a split-capacitor bank in the DC link.
Abstract: This paper presents a new space-vector modulation strategy suitable for a low-cost pulse-width-modulation (PWM) voltage-source (VS) inverter employing only four switches, four diodes, and a split-capacitor bank in the DC link. The work is motivated by the need for an efficient and flexible modulation method, which is optimized with respect to minimum machine-torque ripple. The modulation strategy is named space-vector modulation for four-switch inverter (SVMFSI), and it is realized by planning the switching patterns between four active voltage vectors on the basis of a desired flux trajectory for the stator-flux vector in the AC machine. The strategy is implemented in a single 8-bit microcontroller as a double-sided modulation strategy. Simulations of the machine-torque ripple are performed at a switching frequency of 4 kHz and indicate a torque ripple of 14% at nominal load. Finally, selected results are verified experimentally on a 1.5-kVA prototype B4 inverter. The test results indicate high-quality output-voltage spectra with no low-order voltage harmonics and a harmonic-loss factor (HLF) of 1.12% at unity modulation index.
TL;DR: In this paper, a small signal analysis of DC-D converters with sliding mode control is presented, which allows selection of control coefficients, analysis of parameter variation effects, characterization of the closed loop behavior in terms of audiosusceptibility, output and input impedances, and reference to output transfer function.
Abstract: This paper deals with small-signal analysis of DC-D converters with sliding mode control. A suitable small signal model is developed which allows selection of control coefficients, analysis of parameter variation effects, characterization of the closed loop behavior in terms of audiosusceptibility, output and input impedances, and reference to output transfer function. Unlike previous analyses, the model includes effects of the filters used to evaluate state variable errors. Simulated and experimental results demonstrate model potentialities.
TL;DR: In this paper, a comparison study was conducted to characterize the loss mechanisms, component stresses, and overall efficiencies of a group of voltage-mode soft-switching pulse width modulation (PWM) methods, including two methods developed by the authors.
Abstract: A comparison study was conducted to characterize the loss mechanisms, component stresses, and overall efficiencies of a group of voltage-mode soft-switching pulse width modulation (PWM) methods, including two methods developed by the authors. All soft-switching methods in the selected group allow zero voltage turn-on and turn-off of the main switch and utilize a single auxiliary switch with some resonant components. Advantages and disadvantages are identified for each method. Experimental verification for each soft-switching method is provided. It was found that only those methods that softly switch the auxiliary switch, minimize redirection current, and recover the auxiliary circuit energy improve efficiency over most of the load range.
TL;DR: In this paper, a simple and fast prediction of the hysteresis band is added to a linearized version of the phase-locked loop control, thus ensuring constant switching frequency and tight control of the position of modulation pulses.
Abstract: A new, substantial improvement of the hysteresis current control method for voltage source inverters is presented. A simple and fast prediction of the hysteresis band is added to a linearized version of the phase-locked loop control, thus ensuring constant switching frequency and tight control of the position of modulation pulses. This allows high accuracy in tracking highly distorted current waveforms and minimizes the ripple in multiphase systems. The implementation of this technique is very simple and robust, employing only a small number of conventional inexpensive analog and logic components. It does not require trimmings or tunings, giving the control the capability to adjust itself to the different operating conditions. The proposed method is compared with the most diffused modulation techniques, demonstrating its superior performance in responding to the most demanding conditions met in active filters. The behavior of the method has been fully verified by simulation and by experimental tests.
TL;DR: This paper shows that it is possible to use available commercial software to model and simulate a vector-controlled induction machine system, and a technique for generating pulse-width modulation (PWM) phase commands to extend machine operation to higher speeds before field weakening occurs is simulated.
Abstract: This paper shows that it is possible to use available commercial software to model and simulate a vector-controlled induction machine system. The components of a typical vector control system are introduced and methods given for incorporating these in the MATLAB/SIMULINK software package. The identification of rotor resistance is important in vector control, if high-performance torque control is needed, and modeling of the extended Kalman filter (EKF) algorithm for parameter identification is discussed. It is certainly advisable, when feasible, to precede implementation of new algorithms, whether for control or identification purposes, with an extensive simulation phase. Additionally, a technique for generating pulse-width modulation (PWM) phase commands to extend machine operation to higher speeds before field weakening occurs is simulated in a vector-controlled induction machine, driven by a PWM inverter. This demonstrates the versatility of the vector-controlled induction machine system model.
TL;DR: In this article, an electric arc model that can approximately represent both the static and dynamic characteristics of an arc load controlled by a power electronic circuit is presented, based on the combination and modifications of the classical Cassie and Mayr equations.
Abstract: This paper presents an electric arc model that can approximately represent both the static and dynamic characteristics of an arc load controlled by a power electronic circuit. The proposed model was developed from the combination and modifications of the classical Cassie and Mayr equations. The model equations have been expressed in a form suitable for incorporation into circuit simulators employing the nodal analysis method of equation solving. The model has been test-implemented in the Saber circuit simulator. Simulated and experimental results appear to be in good agreement.
TL;DR: In this paper, a new approach to the position sensor elimination of permanent magnet synchronous motor (PMSM) drives is presented, where the actual rotor position as well as the machine speed can be estimated accurately even in the transient state using the "electrical steady-state" operation concepts.
Abstract: A new approach to the position sensor elimination of permanent magnet synchronous motor (PMSM) drives is presented in this paper. With the help of the modern drive technique, the actual rotor position as well as the machine speed can be estimated accurately even in the transient state using the "electrical steady-state" operation concepts. Due to the angle-modification scheme with error-tracking function, the sensorless drive system has robustness to parameter variations. As well as giving a detailed explanation of the new algorithm, the paper presents a wide range of experimental results, demonstrating the feasibility of the proposed method under full operating conditions in the /spl plusmn/50/spl sim//spl plusmn/2000 [RPM] speed range and 0/spl sim/1 per unit (p.u.) load conditions.
TL;DR: In this article, the authors present the reasons that make series operation of insulated gate bipolar transistors (IGBTs) attractive and challenging and review the methods that may be used, which uses the IGBT's gate-controlled active regime in place of large voltage-sharing snubbers.
Abstract: This paper presents the reasons that make series operation of insulated gate bipolar transistors (IGBTs) attractive and challenging and reviews the methods that may be used. Then, a new approach, which uses the IGBT's gate-controlled active regime in place of large voltage-sharing snubbers, is proposed. Analytical and simulation techniques are used to study the performance and conditions for stability given. It is concluded that when making each IGBT voltage follow a reference input, with closed-loop voltage control, the IGBTs are able to share the transient turn-off voltage without turn-off snubbers. This technique may lead to more compact and efficient high-voltage-power modules.
TL;DR: In this article, two new controllers are proposed: a mixedmode controller of sinusoidal band added to a fixed band, and an equidistant-band current controller, performances of the proposed controllers are compared with the conventional fixed-band and sinusoid-band controllers.
Abstract: Hysteresis current controllers having fixed bands are used in inverters of high-performance AC drives. The switching frequency of such controllers varies over the fundamental period of the modulating signal. The maximum switching frequency (MSF) of these controllers is high. To limit the MSF within the limit of inverter switches, fixed carrier lockouts are usually incorporated. The incorporation of carrier lockouts causes current distortion, and load currents do not confine within the predetermined band. In this paper, two new controllers are proposed. One is a mixed-mode controller of sinusoidal band added to a fixed band, and the other is an equidistant-band current controller, performances of the proposed controllers are compared with the performances of the conventional fixed-band and sinusoidal-band controllers.
TL;DR: A symbolic analysis package that uses this averaging method to automatically generate an analytical averaged model for a switching power converter is described and can be used for modeling DC/DC power converters employing different switching techniques.
Abstract: Symbolic analysis methods for the averaged modeling of switching power converters are presented in this paper. A general averaging method suitable for computer-aided modeling is discussed first. Then, a symbolic analysis package that uses this averaging method to automatically generate an analytical averaged model for a switching power converter is described. The package is implemented using the computer algebra system Mathematica and can be used for modeling DC/DC power converters employing different switching techniques, including hard-switching pulse-width modulation (PWM), quasi-resonant soft switching, and soft transition. Several examples are provided to demonstrate the applications of the package. Further applications of symbolic analysis methods in power electronics are also discussed.
TL;DR: In this paper, a model reference adaptive control (MRAC) system for the speed control of indirect field-oriented (IFO) induction motor drives based on using fuzzy laws for the adaptive process and a neuro-fuzzy procedure to optimize the fuzzy rules is presented.
Abstract: This paper deals with the design and experimental realization of a model reference adaptive control (MRAC) system for the speed control of indirect field-oriented (IFO) induction motor drives based on using fuzzy laws for the adaptive process and a neuro-fuzzy procedure to optimize the fuzzy rules. Variation of the rotor time constant is also accounted for by performing a fuzzy fusion of three simple compensation strategies. A performance comparison between the new controller and a conventional MRAC control scheme is carried out by extensive simulations confirming the superiority of the proposed fuzzy adaptive regulator. A prototype based on an induction motor drive has been assembled and used to practically verify the features of the proposed control strategy.
TL;DR: In this article, the lumped-charge modeling technique is used to build a simple, physics-based power diode model for circuit simulators, which consists of simplified, but fundamental semiconductor device equations.
Abstract: The lumped-charge modeling technique is used to build a simple, physics-based power diode model for circuit simulators. The model consists of simplified, but fundamental semiconductor device equations. The important characteristics of power diodes under static and dynamic conditions are obtained in this compact and efficient model.
TL;DR: In this article, a new driver technique that allows optimization of the switching speed, reduction of the energy losses during the switching time, and limitation of the electromagnetic interference (EMI) was proposed.
Abstract: MOSFETs and insulated gate bipolar transistor (IGBT) devices are increasingly used in electronic circuits due to both their easy driving and ability to handle high currents and voltages at high-switching frequencies. This paper deals with a new driver technique that allows optimization of the switching speed, reduction of the energy losses during the switching time, and limitation of the electromagnetic interference (EMI). First, an analysis of voltage- and current-switching waveforms of gate-insulated devices is performed. Then, a method of controlling voltage and current slopes independently is shown using the "one-cycle" method or a suitable adaptive-driving technique based on a phase-locked loop (PLL) approach. These techniques were adopted in order to allow correct generation of the gate signals regardless of the operating conditions. Finally, practical results of the proposed driving circuit obtained using a single IGBT switch chopper are presented.
TL;DR: In this paper, a systematic approach for the behavior-mode simulation of power electronic circuits is presented to solve the problem of switch-state detection in behaviormode simulation, a simple-to-implement reinitialization technique is introduced.
Abstract: In this paper, a systematic approach for the behavior-mode simulation of power electronic circuits is presented. To solve the problem of switch-state detection in behavior-mode simulation, a simple-to-implement reinitialization technique is introduced. Furthermore, the issue of time-step selection is discussed. It is illustrated through examples that behavior-mode simulation complements the detailed-mode simulation and enhances the efficiency of the computer-aided analysis and design of power electronic circuits.
TL;DR: In this article, a new SPICE subcircuit model for power p-i-n diodes is proposed based on a moment-matching approximation of the ambipolar diffusion equation, which takes into account emitter recombination in the highly doped end regions, conductivity modulation in the base and the moving-boundaries effect during reverse-recovery.
Abstract: A new SPICE subcircuit model for power p-i-n diodes is proposed in this paper. The model is based on a moment-matching approximation of the ambipolar diffusion equation. It is shown that both the quasistatic model and the lumped charge model can be obtained as ion-order moment-matching approximations while new and more accurate models can be obtained from higher-order solutions. The proposed model takes into account emitter recombination in the highly doped end regions, conductivity modulation in the base and the moving-boundaries effect during reverse-recovery, showing good convergence properties and fast simulation times. Comparisons between the results of the SPICE model and both numerical device simulations and experimental results are presented.
TL;DR: In this paper, the authors introduced a new family of zero-voltage switching (ZVS) pulsewidth modulation (PWM) active-clamping DC-to-DC boost power converters.
Abstract: The purpose of this paper is to introduce a new family of zero-voltage switching (ZVS) pulse-width modulation (PWM) active-clamping DC-to-DC boost power converters. This technique presents ZVS commutation without additional voltage stress and a significant increase in the circulating reactive energy throughout the power converters. So, the efficiency and the power density become advantages when compared to the hard-switching boost power converter. Thus, these power converters may become very attractive in power factor correction applications. In this paper, the complete family of boost power converters is shown, and one particular circuit, taken as an example, is analyzed, simulated and experimented. Experimental results are presented, taken from a laboratory prototype rated at 1600 W, input voltage of 300 V, output voltage of 400 V, and operating at 100 kHz. The measured efficiency at full load was 98%, and the power converter kept an efficiency up to 95% from 17% to 100% of full load, without additional voltage and current stresses.
TL;DR: In this paper, the selection of the motor parameters and the inverter power ratings for a permanent magnet synchronous motor drive in order to meet a given flux-weakening torque versus speed characteristic is dealt with.
Abstract: This paper deals with the selection of the motor parameters and the inverter power ratings for a permanent magnet (PM) synchronous motor drive in order to meet a given flux-weakening torque versus speed characteristic. Appropriate combinations of stator PM flux linkage, d- and q-axis inductances, and inverter current rating at a given voltage are derived, in normalized values, as functions of the specified flux-weakening speed range and torque limits. By means of these sets of data, the drive designer can easily individuate and compare all the suitable synchronous motors (defined by the d- and q-axis inductances and flux linkage) and the related inverter volt-ampere ratings, for the desired flux-weakening performance. Therefore, this paper can be considered a synthesis work rather than an analysis one and can profitably be used for an optimal design of a synchronous motor drive.
TL;DR: In this article, the authors proposed a boost topology which has continuous or ripple-free input current when it operates with discontinuous inductor-current and compared it with traditional converter topologies such as the Sepic and Cuk power converters.
Abstract: Coupled inductor techniques supply a method to reduce the power converter size and weight and achieve ripple-free current. The boost power converter is a very popular topology in industry. However, the input-current ripple hinders efforts to meet electromagnetic interference (EMI) requirements. In particular, the input current becomes discontinuous and pulsating when the conventional boost power converter operates in the discontinuous inductor-current mode. This paper describes a boost power converter which has the same discontinuous properties as the conventional boost power converter. However, the proposed boost topology has continuous or ripple-free input current when it operates with discontinuous inductor-current. The proposed topology is compared with traditional converter topologies, such as the Sepic and Cuk power converters. Simulation results are presented. The prototype is built to demonstrate the theoretical prediction. The proposed boost topology is simple, with straightforward control ~the same as pulse-width modulation (PWM)\.
TL;DR: In this paper, a fuzzy adaptive model following mechanism for position control of a traveling-wave-type ultrasonic motor (USM) is described, and a simple linear position control loop is designed and augmented by the model-following error-driven fuzzy adaptive mechanism to reduce the influence of parameter variations.
Abstract: A fuzzy adaptive model following mechanism for the position control of a traveling-wave-type ultrasonic motor (USM) is described in this study. Since the dynamic characteristics of the USM are difficult to obtain and the motor parameters are time varying, fuzzy adaptive control is applied to design the position controller of the USM for high-performance applications. The driving circuit for the USM, which is composed of a high-frequency boost DC-DC chopper, a two-phase series-loaded resonant inverter and an inner speed loop, is built first. Next, the control algorithm for fuzzy adaptive control is discussed. Then, a simple linear position control loop is designed and augmented by the model-following error-driven fuzzy adaptive mechanism to reduce the influence of parameter variations. The effectiveness of the proposed controller is demonstrated by some experimental results.
TL;DR: In this paper, two energy-efficient converter topologies, derived from the conventional C-dump converter, are proposed for switched reluctance motor (SRM) drives, and the converters have simple control requirements, and allow the motor phase current to freewheel during chopping mode.
Abstract: Two energy-efficient converter topologies, derived from the conventional C-dump converter, are proposed for switched reluctance motor (SRM) drives. The proposed topologies overcome the limitations of the conventional C-dump converter, and could reduce the overall cost of the SRM drive. The voltage ratings of the dump capacitor and some of the switching devices in the proposed converters are reduced to the supply voltage (V/sub dc/) level compared to twice the supply voltage (2V/sub dc/) in the conventional C-dump converter. Also, the size of the dump inductor is considerably reduced. The converters have simple control requirements, and allow the motor phase current to freewheel during chopping mode. Simulation and experimental results of the converters are presented and discussed.