• 전력전자학회논문지
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• 제20권3호
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• pp.280-289
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• 2015

A high-efficiency full-bridge DC-DC converter with a current-doubler rectifier and an asymmetric pulse-width modulation is proposed. Through the asymmetric pulse-width modulation, the proposed converter achieves zero-voltage switching of power switches without the circulating currents. The proposed converter reduces the output current ripple through the current-doubler rectifier. A control strategy is suggested for the proposed converter to charge battery banks. A constant current and constant voltage charging is performed. The proposed converter achieved a higher efficiency compared with the conventional full-bridge DC-DC converter with a phase-shift modulation. The performance of the proposed converter is evaluated by the experimental results for a 1.0 kW prototype circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.444-446
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• 2011

A bidirectional dual active converter with the power factor control capability is proposed as a battery charger. The source side half-bridge acts as a PWM converter that maintains the unity power factor. The battery side half-bridge converter acts as a dual active bridge (DAB) together shares the same DC link voltage with PWM converter. The imbalance voltage phenomenon is eliminated by employing asymmetric duty cycle technique. Simulation results are included to verify theoretical analysis.

• 전력전자학회논문지
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• 제22권5호
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• pp.431-439
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• 2017

An asymmetric half-bridge is one of the most promising topology in low-power application because of its small number of components and inherent zero-voltage switching capability. However, when it is designed taking into a hold-up time, it has large transformer offset current and small transformer turns-ratio, which severely decreases the total efficiency of s converter. In this paper, a new boost-integrated asymmetric half-bridge converter is proposed to solve these problems. The integrated boost converter compensates the hold-up time, thus facilitating optimal design in nominal state. As a result, the proposed converter can achieve high efficiency in nominal state. To verify the effectiveness of the proposed converter, an experiment is conducted using a 250-400 V input and 45 V/3.3 A output prototype.

• Journal of Power Electronics
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• 제15권6호
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• pp.1533-1546
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• 2015

This study presents a novel method for reducing the switching losses of an asymmetric half-bridge converter for a three-phase, 12/8 switched reluctance motor operated in low speed. In particular, this study aims to reduce the switching-off losses of chopping switches in the converter when operated in the current regulated mode (chopping mode). The proposed method uses the mixed parallel operation of IGBT (chopping switch) and MOSFET (auxiliary switch). MOSFET is precisely controlled to momentarily conduct prior to the turn-off interval of the IGBT. Consequently, the voltage across the switches is clamped to approximately zero, substantially decreasing the turn-off switching losses. The analytical expressions of power losses are extensively elaborated. Compared with the conventional asymmetric half-bridge converter, the modified converter can effectively minimize the switching losses. Therefore, the efficiency of the converter is eventually improved. Computer simulation and experimental results confirm the effectiveness of the proposed technique.

• Journal of Power Electronics
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• 제17권1호
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• pp.31-40
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• 2017

A novel voltage-fed single-stage power factor correction (PFC) full-bridge converter based on asymmetric phase-shifted control for battery chargers is proposed in this paper. The attractive feature of the proposed converter is that it can operate in a wide output voltage range without an output low-frequency ripple, which is indispensable in battery charger applications. Meanwhile, the converter can maintain a high power factor and a controllable dc bus voltage over a wide output voltage range. In this paper, the realization of PFC and the operation principle of asymmetric phase-shifted control are given. A small-signal analysis of the proposed single-stage power factor correction (PFC) full-bridge converter is performed. Experimental results obtained from a 1kW experimental prototype are given to validate the feasibility of the proposed converter. The PF is higher than 0.97 over the entire output voltage range with the proposed control strategy.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권1호
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• pp.77-84
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• 2007

In this paper, Takagi-Sugeno (TS) fuzzy integral control is investigated to regulate the output voltage of an asymmetric half-bridge (AHB) DC/DC converter; First, we model the dynamic characteristics of the AHB DC/DC converter with state-space averaging method and small perturbation at an operating point. After introducing an additional integral state of the output regulation error, we obtain the $5^{th}$-order TS fuzzy model of the AHB DC/DC converter. Second, the concept of the parallel distributed compensation is applied to design the fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, simulation results are presented to show the performance of the considered design method as the output voltage regulator and compared to the results for which the conventional loop gain method is used.

• Journal of Power Electronics
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• 제7권3호
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• pp.238-245
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• 2007

This paper considers the problem of regulating the output voltage of a current doubler rectified asymmetric half-bridge (CDRAHB) DC/DC converter via fuzzy integral control. First, we model the dynamic characteristics of the CDRAHB converter with the state-space averaging method, and after introducing an additional integral state of the output regulation error, we obtain the Takagi-Sugeno (TS) fuzzy model for the augmented system. Second, the concept of parallel distributed compensation is applied to the design of the TS fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, numerical simulations of the considered design method are compared to those of the conventional method, in which a compensated error amplifier is designed for the stability of the feedback control loop.

• 한국인터넷방송통신학회논문지
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• 제21권3호
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• pp.129-135
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• 2021

스위치드 릴럭턴스 전동기 (Switched Reluctance Motor, SRM)는 전류의 크기와 회전자와 고정자의 상대적 위치에 따라 인덕턴스가 매우 비선형적으로 변하는 특성이 있고, 토크는 이 인덕턴스의 기울기에 비례하여 발생하기 때문에 비선형 토크 특성을 가지며 토크 맥동이 크고 소음이 심한 단점도 있다. 이러한 문제점들을 고려하고 경제성과 회로의 간단화를 위하여 기존의 비대칭 컨버터 (Asymmetric Bridge Converter)에서 효율과 성능을 개선할 수 있는 구동용 토폴로지(Topology)에 대한 연구들이 많이 진행되었다. 따라서 본 논문에서는 SRM 구동용 토폴로지로 적용하여 사용되고 있는 각 컨버터들을 비교, 분석함으로써 성능을 확인하고자 한다. 비교, 분석에 적용된 구동용 컨버터는 가장 널리 사용되고 있는 비대칭 브리지 컨버터 (Asymmetric Bridge Converter)와 C-dump 컨버터 형태의 구조를 가진 Conventional C-dump, Modified C-dump, Energy efficient C-dump, 공진형 C-dump 컨버터, 그리고 일반 전동기의 범용으로 사용되고 있는 6-Switch 인버터이다.

• Journal of Power Electronics
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• 제18권2호
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• pp.343-355
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• 2018

A wide-voltage-conversion range bidirectional DC-DC converter is proposed in this paper. The topology is comprised of one typical LC energy storage component and a special common grounded asymmetric H-bridge with four active power switches/anti-parallel diodes. The narrow output PWM voltage is generated from the voltage difference between two normal (wider) output PWM voltages from the asymmetric H-bridge with duty cycles close to 0.5. The equivalent switching frequency of the output PWM voltage is double the actual switching frequency, and a wide step-down/step-up ratio range is achieved. A 300W prototype has been constructed to validate the feasibility and effectiveness of the proposed bidirectional converter between the variable low voltage side (24V~48V) and the constant high voltage side (200V). The slave active power switches allow ZVS turn-on and turn-off without requiring any extra hardware. The maximum conversion efficiency is 94.7% in the step-down mode and 93.5% in the step-up mode. Therefore, the proposed bidirectional topology with a common ground is suitable for energy storage systems such as renewable power generation systems and electric vehicles with a hybrid energy source.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.169-172
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• 2004

This paper presents the Asymmetric Half-Bridge converter using current-doubler rectifier. Resonant conditions of the asymmetrical soft switching Half-Bridge converter is analyzed. Current-doubler converter has small voltage and current ripple. The comparison of topology compared to the secondary rectification for center-tap type and current-doubler type are discussed. Experimental result are obtained on a 5V, 20A DC/DC Half-Bridge converter MOSFET based prototype for the 100W.