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Power Electronics, IEEE Transactions on

Issue 5 • Date May 2010

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Displaying Results 1 - 25 of 32
  • [Front cover]

    Page(s): C1
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  • IEEE Transactions on Power Electronics publication information

    Page(s): C2
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  • Table of contents

    Page(s): 1101 - 1102
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  • A High-Efficiency AC/DC Converter With Quasi-Active Power Factor Correction

    Page(s): 1103 - 1109
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB) |  | HTML iconHTML  

    This letter presents a novel ac/dc converter based on a quasi-active power factor correction (PFC) scheme. In the proposed circuit, the power factor is improved by using an auxiliary winding coupled to the transformer of a cascade dc/dc flyback converter. The auxiliary winding is placed between the input rectifier and the low-frequency filter capacitor to serve as a magnetic switch to drive an input inductor. Since the dc/dc converter is operated at high-switching frequency, the auxiliary windings produce a high frequency pulsating source such that the input current conduction angle is significantly lengthened and the input current harmonics is reduced. It eliminates the use of active switch and control circuit for PFC, which results in lower cost and higher efficiency. In order to achieve low harmonic content, the input inductor is designed to operate in discontinuous current mode. Operating principles, analysis, and experimental results of the proposed method are presented. View full abstract»

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  • Harmonic Modeling of Hysteresis Inverters in Frequency Domain

    Page(s): 1110 - 1114
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB) |  | HTML iconHTML  

    This letter derives a closed-form analytical approximation of the output harmonic spectrum of a single-phase two-level inverter under the action of hysteresis current control. The analytical approach consists of first describing the error current as a triangular signal of variable duty cycle and frequency, and subsequently, deriving the Fourier transform of the complex envelope of the modulated triangular signal. The spectrum of the error current is given in terms of Bessel functions of the first kind. MATLAB/Simulink results on a half-bridge inverter are presented in this letter to demonstrate the validity and accuracy of the proposed model. View full abstract»

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  • High Resolution FPGA DPWM Based on Variable Clock Phase Shifting

    Page(s): 1115 - 1119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB) |  | HTML iconHTML  

    This letter proposes a very high resolution digital pulsewidth modulator (DPWM) architecture that takes advantage of a field-programmable gate array (FPGA) advanced clock management capability - the fine phase shifting of the clock. This feature is available in almost every FPGA nowadays, thus allowing very small and programmable delays between the input and output clocks. An original use of this fine phase shifting pushes the limits of DPWM resolution. The experimental results show a time resolution of 19.5 ps in a Virtex-5 FPGA. View full abstract»

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  • Digital Sliding-Mode Controller For High-Frequency DC/DC SMPS

    Page(s): 1120 - 1123
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (515 KB) |  | HTML iconHTML  

    Digital control technique is becoming an attractive alternative for high-frequency switching mode power supply (SMPS). This paper introduces a fully synthesizable digital sliding-mode (SM) controller for high-frequency dc/dc SMPS. The proposed SM controller is associated with a digital pulsewidth modulation (DPWM) block to operate at constant and high switching frequency compared to already published approaches. The digital SM controller is experimentally validated by means of field-programmable gate array in a 4-MHz step-down converter with 10-bit analog-to-digital conversion (ADC) and 11-bit DPWM. Measured dynamic performances are superior to conventional digital controllers for dc/dc SMPS. View full abstract»

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  • Phenomenon Rotor Fault-Multiple Electrical Rotor Asymmetries in Induction Machines

    Page(s): 1124 - 1134
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (677 KB) |  | HTML iconHTML  

    In the literature, the effects caused by a single or several adjacently broken rotor bars, or a broken end ring are thoroughly investigated. The phenomenon of various nonadjacently broken rotor bars has not been studied so far in detail. Since nonadjacently broken rotor bars may give rise to fault signatures, which are not directly related with the fault extent, it is important to understand the nature of multiple electrical rotor asymmetries in induction machines. The purpose of this paper is thus to investigate several combinations of electrical rotor asymmetries, to systematically elaborate the phenomena related to the broken bars and end rings. In this paper, a sophisticated simulation model and measurement results are used to analyze the phenomenon rotor fault. View full abstract»

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  • On the Switched-Reluctance Motor Drive With Three-Phase Single-Switch Switch-Mode Rectifier Front-End

    Page(s): 1135 - 1148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1529 KB) |  | HTML iconHTML  

    This paper presents a switched reluctance motor (SRM) drive powered by a three-phase single-switch (3P1SW) switch-mode rectifier (SMR). The digital controls of both power stages are realized in a common DSP. In the front-end SMR, a robust current harmonic cancellation scheme and a robust voltage control scheme are developed. The undesired line current and output voltage ripples are regarded as disturbances and they are reduced via the proposed robust controls. In voltage control, a feedback controller is augmented with a simple robust error canceller. The robust cancellation weighting factor is automatically tuned according to load level to yield compromised voltage and power quality control performances. The chaotic phenomena can be automatically avoided and better SMR operating performance is obtained simultaneously. With boostable and regulated dc-link voltage, the current and speed dynamic responses of the followed SRM drive are enhanced, and the vibration and speed ripple are also lessened. As to the SRM drive, a random-band hysteresis current-controlled pulsewidth modulation (CCPWM) scheme (RB-HCCPWM) with harmonic spectrum shaping is developed and applied for its winding excitation control. The winding current harmonic spectrum is more dispersedly distributed to yield reduced stator vibration and speed ripple. Moreover, the commutation advanced shift is applied to yield further performance improvement of SRM drive. View full abstract»

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  • Zero-Voltage-Switching PWM Full-Bridge Converter Employing Auxiliary Transformer to Reset the Clamping Diode Current

    Page(s): 1149 - 1162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1563 KB) |  | HTML iconHTML  

    Introducing clamping diodes into the zero-voltage-switching (ZVS) pulsewidth-modulation (PWM) full-bridge (FB) converters can eliminate the voltage oscillation across the output rectifier diodes; however, the clamping diodes result in increase in conduction loss and suffer from serious reverse recovery at light load. In order to solve these problems, the clamping diode current should be reset rapidly. This paper proposes a scheme of resetting the clamping diode current over the full-load range by introducing an auxiliary transformer into the ZVS PWM FB converter. The operation principles of the proposed scheme under heavy-load and light-load conditions are analyzed in details. The design considerations of the introduced auxiliary transformer are also given. A performance comparison among the proposed scheme of resetting the clamping diode current and other ones are addressed. Experimental results verify the effectiveness of the analysis and prove that the proposed converter has improved reliability and reduced conduction loss compared with the classical one. View full abstract»

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  • High-Density EMI Filter Design for DC-Fed Motor Drives

    Page(s): 1163 - 1172
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1368 KB) |  | HTML iconHTML  

    This paper presents strategies to reduce both differential-mode (DM) and common-mode (CM) noise using a passive filter in a dc-fed motor drive. The paper concentrates on the type of grounding and the components to optimize filter size and performance. Grounding schemes, material comparison between ferrite and nanocrystalline cores, and a new integrated filter structure are presented. The integrated structure maximizes the core window area and increases the leakage inductance by integrating both CM and DM inductances onto one core. Small-signal and large-signal experiments validate the structure, showing it to have reduced filter size and good filtering performance when compared with standard filters at both low and high frequencies. View full abstract»

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  • Reduced-Order Flux Observers With Stator-Resistance Adaptation for Speed-Sensorless Induction Motor Drives

    Page(s): 1173 - 1183
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (471 KB) |  | HTML iconHTML  

    This paper deals with reduced-order flux observers with stator-resistance adaptation for speed-sensorless induction motor (IM) drives. A general analytical solution for the stabilizing observer gain is given. The gain has two free positive parameters (which depend on the operating point), whose selection significantly affects the damping, convergence rate, robustness, and other properties of the observer. The general stability conditions for the stator-resistance adaptation are derived. An observer design is proposed that yields a robust and well-damped system and requires a minimal amount of tuning work. The proposed observer design is experimentally tested using a 45-kW IM drive; stable operation at very low speeds under different loading conditions is demonstrated. View full abstract»

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  • Dead-Beat Control Algorithm for Single-Phase 50-kW AC Railway Grid Representation

    Page(s): 1184 - 1192
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB) |  | HTML iconHTML  

    The control of four-quadrant converters (4QC) of traction vehicles fed by an ac railway grid has to meet very restrictive limitations with regard to harmonics and stability. The challenge is increased by continuously changing the position-dependent grid impedance and voltage harmonics already contained in the grid voltage. Testing a 4QC control in a lab, therefore, requires a railway grid representation that both emulates variable grid impedance and grid-voltage harmonics. The paper presents an innovative solution to this problem that employs a 4Q inverter with a suitably designed new control scheme. As the rated power is not high, compared to the traction vehicle fed, the control has to be effective, taking each switching event of the inverter into account. For the design of the control, a suitable simulation is needed, which is also presented in this paper. A comparison of simulation and measurement results is given, proving excellent results. View full abstract»

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  • A Soft-Switching DC/DC Converter With High Voltage Gain

    Page(s): 1193 - 1200
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (655 KB) |  | HTML iconHTML  

    A soft-switching dc/dc converter with high voltage gain is proposed in this paper. It provides a continuous input current and high voltage gain. Moreover, soft-switching characteristic of the proposed converter reduces switching loss of active power switches and raises the conversion efficiency. The reverse-recovery problem of output rectifiers is also alleviated by controlling the current changing rates of diodes with the use of the leakage inductance of a coupled inductor. Experimental results obtained on 200 W prototype are discussed. View full abstract»

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  • Fault-Tolerant Structure and Modulation Strategies With Fault Detection Method for Matrix Converters

    Page(s): 1201 - 1210
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1066 KB) |  | HTML iconHTML  

    This paper proposes a fault-tolerant matrix converter with reconfigurable structure and modified switch control schemes, along with a fault diagnosis technique for open-circuited switch failures. The proposed fault recognition method can detect and locate a failed bidirectional switch with voltage error signals dedicated to each switch, based on a direct comparison of the input and the output voltages. Following the fault detection, the designed converter architecture isolates the faulty parts and bypasses the remaining load phase, resulting in a 3 ?? 2 matrix configuration with six bidirectional switches. Based on the reconfigured hardware topology, novel fault-tolerant modulation strategies are developed to produce three-phase balanced sinusoidal output voltages/currents with only six bidirectional switches, but at a reduced output voltage magnitude as compared with the normal matrix converter. Thus, the developed switching function matrices for the reconfigurable converter structure, containing an appropriate positive- and negative-sequence set of matrices with input voltage vector, can preserve continuous operation even after switch failures and improve reliability of the drives. View full abstract»

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  • Soft-Switched CCM Boost Converters With High Voltage Gain for High-Power Applications

    Page(s): 1211 - 1217
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (905 KB) |  | HTML iconHTML  

    This paper proposes a new soft-switched continuous-conduction-mode (CCM) boost converter suitable for high-power applications such as power factor correction, hybrid electric vehicles, and fuel cell power conversion systems. The proposed converter achieves zero-voltage-switched (ZVS) turn-on of active switches in CCM and zero-current-switched turn-off of diodes leading to negligible reverse-recovery loss. The components' voltage ratings and energy volumes of passive components of the proposed converter are greatly reduced compared to the conventional zero-voltage-transition converter. Voltage conversion ratio is almost doubled compared to the conventional boost converter. Extension of the proposed concept to realize multiphase dc-dc converters is discussed. Experimental results from a 1.5-kW prototype are provided to validate the proposed concept. View full abstract»

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  • New Modeling Approach and Equivalent Circuit Representation for Current-Mode Control

    Page(s): 1218 - 1230
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3065 KB) |  | HTML iconHTML  

    Constant on-time current-mode control has been widely used to improve light-load efficiency, because it can reduce the switching frequency to save switching-related loss. Therefore, an accurate model for constant on-time control is indispensable to system design. However, available models for constant on-time control are unable to provide accurate physical insight or predict system response very well. This paper introduces a new modeling approach for constant on-time control. The inductor, the switches, and the pulsewidth-modulated modulator are treated as a single entity and modeled based on the describing function method. The fundamental difference between constant on-time control and constant-frequency peak-current-mode control is analyzed through the proposed model. This proposed modeling method can be easily extended to other current-mode controls, including V2 controls. A simple equivalent circuit representation is proposed for the sake of easy understanding and simulation of current-mode controls. Simulation and experimental results are used to verify the proposed model. View full abstract»

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  • Evaluating Energy Storage Efficiency by Modeling the Voltage and Temperature Dependency in EDLC Electrical Characteristics

    Page(s): 1231 - 1239
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1233 KB) |  | HTML iconHTML  

    This study characterizes and models the temperature and charge voltage dependency in the electrical characteristics of a packed electric double layer capacitor (EDLC). The characterized results indicate that the frequency response of the terminal impedance in a packed EDLC varies with the charge voltage and temperature. The latter can be attributed mainly to the temperature change of the resistive component because the thermal sensitivity of the capacitive component is low, whereas the resistive component increases as the temperature drops. A multistage RC equivalent circuit model is developed, and three stages are determined to be adequate to reduce the model error for the studied EDLC. The charge voltage dependency in the capacitance of the extracted equivalent circuit is modeled by the physics-based Stern's model. The temperature dependency of the internal resistance is modeled by the quadratic function of temperature. The large signal response of the proposed model is verified with charge/discharge experiments at various temperatures. The proposed EDLC model suitably expresses the time response of the terminal voltage and current, can estimate the charged and discharged electrical power and energy of the EDLC, and explains the degradation of energy efficiency at low temperature. View full abstract»

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  • STATCOM-Based Indirect Torque Control of Induction Machines During Voltage Recovery After Grid Faults

    Page(s): 1240 - 1250
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB) |  | HTML iconHTML  

    This paper proposes a control method for limiting the torque of grid-connected cage induction machines during the recovery process after grid faults, by using a static synchronous compensator (STATCOM) connected at the machine terminals. When a STATCOM is used for transient stability improvement, common practice is to design the control system to keep reactive current at maximum level until the voltage has returned to its initial value. This will result in high torques during the recovery process after grid faults. The control method proposed in this paper is intended to limit such torque transients by temporarily defining a new voltage reference for the STATCOM control system. As torque is controlled through the voltage reference of the STATCOM, the method is labeled indirect torque control (ITC). The presented concept is a model-based approach derived from a quasi-static equivalent circuit of the induction machine, the STATCOM and a The??venin representation of the power system. For illustration and verification, time-domain simulations of a wind power generation system with a STATCOM at the terminals of an induction generator, are provided. As the objective of limiting the torque of the induction machine is achieved, the derivation of the concept proves to be reasonable. The approach is presented in its most general form, oriented to torque limitation of induction machines both in generating and motoring mode, and is not restricted to the presented example. View full abstract»

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  • Comprehensive Compact Models for the Circuit Simulation of Multichip Power Modules

    Page(s): 1251 - 1264
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1362 KB) |  | HTML iconHTML  

    This paper proposes the model development of a packaged semiconductor power module, for use in a circuit simulation environment. Focusing on railway traction applications, it considers a state-of-the-art 6.5 kV insulated gate bipolar transistor (IGBT) module, taking into account the antiparallel connection of IGBTs and free-wheeling diodes, and including all main electrothermal and electromagnetic effects associated with the multichip structure. The description of semiconductor physics is coupled with self-heating effects; electromagnetic phenomena associated with the packaging, layout, and interconnections are also taken into account. To optimize the compromise between accuracy and computational effort, the device models are based on a mixed physical and behavioral description, and are scalable to be representative of a desired number of parallel devices and to allow for the introduction of parasitic elements, as required. Electromagnetic effects are modeled by means of equivalent lumped elements, extracted by numerical simulation of an accurate 3-D structural assembly model. The description of transient thermal phenomena relies on a finite-difference approach that considers the use of both essentially 1-D lumped equivalent models and fully 3-D distributed description. The model is validated statically and dynamically, against both data-sheet information and measurements; a selection of simulation examples demonstrates its usefulness and versatility. Although developed for a specific application scenario, the proposed approach is of general validity. View full abstract»

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  • The Electrothermal Large-Signal Model of Power MOS Transistors for SPICE

    Page(s): 1265 - 1274
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1176 KB) |  | HTML iconHTML  

    In this paper, the isothermal model of power MOS transistors offered by the producer of these devices and the electrothermal model of these devices proposed by the authors are presented. The results of experimental verification of both the models are given as well. View full abstract»

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  • An AC Processing Pickup for IPT Systems

    Page(s): 1275 - 1284
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (430 KB) |  | HTML iconHTML  

    This paper presents a new type of inductive power transfer (IPT) pickup that directly regulates the power in ac form, hence producing a controllable high-frequency ac source suitable for lighting applications. The pickup has significant advantages in terms of increasing system efficiency, reducing pickup size, and lowering production cost compared to traditional pickups that also produce a controlled ac output using complex ac-dc-ac conversion circuits. The new ac processing pickup employs switches operating under zero-voltage-switching conditions to clamp parts of the resonant voltage across a parallel tuned LC resonant tank to achieve power regulation over a wide load range. The operation of the pickup is analyzed and the circuit waveforms have been verified by experimental results. A complete IPT system using the ac processing pickup was tested on a 500-W lighting system and an efficiency of 96% was obtained when delivering 500 W to multiple resistive light bulbs. View full abstract»

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  • Single-Phase to Three-Phase Drive System Using Two Parallel Single-Phase Rectifiers

    Page(s): 1285 - 1295
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1128 KB) |  | HTML iconHTML  

    This paper proposes a single-phase to three-phase drive system composed of two parallel single-phase rectifiers, a three-phase inverter, and an induction motor. The proposed topology permits to reduce the rectifier switch currents, the harmonic distortion at the input converter side, and presents improvements on the fault tolerance characteristics. Even with the increase in the number of switches, the total energy loss of the proposed system may be lower than that of a conventional one. The model of the system is derived, and it is shown that the reduction of circulating current is an important objective in the system design. A suitable control strategy, including the pulsewidth modulation technique (PWM), is developed. Experimental results are presented as well. View full abstract»

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  • A Fully Regulated Dual-Output DC–DC Converter With Special-Connected Two Transformers (SCTTs) Cell and Complementary Pulsewidth Modulation–PFM (CPWM-PFM)

    Page(s): 1296 - 1309
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1469 KB) |  | HTML iconHTML  

    A dual-output dc-dc converter based on the complementary pulsewidth modulation is proposed to overcome the cross-regulation problem between the outputs. Using a special-connected two transformers cell, one operational period is divided into two complementary parts. One output branch gets the pulsewidth and is regulated by the duty cycle; the other output branch gets the complementary pulsewidth and is regulated by the PFM. Only one full bridge and several passive components are needed, but both the two outputs have the fully regulated abilities even in the no-load situation. Moreover, a full zero-voltage-switching (ZVS) range is achieved in all the switches without auxiliary circuits. Therefore, the proposed topology has compact structure, high switching frequency, high-power density, and high efficiency. The operation principle, ZVS conditions, and design considerations are presented in the paper. The analysis is verified by a 300 V input, and 24 V/10 A and 48 V/5 A outputs prototype. View full abstract»

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  • An Adaptive Flux Observer With Online Estimation of DC-Link Voltage and Rotor Resistance For VSI-Based Induction Motors

    Page(s): 1310 - 1319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1630 KB) |  | HTML iconHTML  

    An adaptive observer is proposed for concurrent estimation of rotor fluxes, unknown dc-link voltage, and rotor resistance of induction motor with voltage source inverters. For the reported flux observers and parameter estimators, the implied assumption had been that the input voltages were measured by sensors, or presumed to be known, for example while plug-in converters were utilized. However, this assumption may not be valid due to bus voltage variations, such as for battery powered servo drives, or propulsion system in hybrid electric vehicles. A drift in input voltage measurement results in state and parameter estimation errors. The proposed observer is capable of concurrent flux and dc-link voltage observation with online tuning of rotor resistance, while the phase currents and rotor speed are measured. No terminal voltage measurement is needed for this adaptive observer. The stability of the proposed observer is proved based on a Lyapunov function. Besides, it is shown that injection of a diagnosis signal is necessary to force the estimated parameters converge to the right values regardless of their initial conditions. A complex programmable logic device is implemented for the experimental setup, which controls an intelligent power module including insulated gate bipolar transistors. Extensive simulation and experimental tests verify the asymptotic convergence of the proposed observer. View full abstract»

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Aims & Scope

IEEE Transactions on Power Electronics covers fundamental technologies used in the control and conversion of electric power.

Full Aims & Scope