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Soft switching pulse-width modulation (PWM) dc–dc full-bridge converter with controlled rectifier on the secondary side of the high-frequency power transformer is presented in this paper. An active secondary switch, including new nondissipative passive energy recovery turn-off snubber on the secondary side and modified PWM control algorithm, provide conditions for zero-voltage and zero-current turn-on and zero-current turn-off of IGBT transistors on the primary side of the high-frequency dc–dc converter. The simple passive energy recovery snubber ensures also zero-voltage turn-off of the transistor on the secondary side of the power transformer. The principle of operation is explained and analyzed and consequently verified on a 2 kW, 50 kHz laboratory model of the converter. [ABSTRACT FROM PUBLISHER]

In this paper, a new zero-voltage switching and resonant core reset pulse width modulation forward converter with a simple auxiliary circuit is introduced. The proposed auxiliary circuit can be applied to both single-switch and two-switch forward converters. The main and the auxiliary mosfets of the proposed converters operate under soft switching condition independent of line and load variation. Also, due to the capability of operating at duty cycles higher than 0.5, the proposed converters can be used for wide input voltage applications. In comparison to the existing zero-voltage transition (ZVT) forward converters, this auxiliary circuit has low number of components and also does not require any additional magnetic element which has improved the power density. The proposed converter is compared with exiting ZVT forward converters in details. The converter steady-state operation is analyzed and various operating modes are explained. Also, in addition to a design example, a comprehensive design procedure is presented. The experimental results of a laboratory prototype of the converter with 85–180 V input voltage and 24 V output voltage at 150 W are provided which verify the theoretical analysis and confirm the converter operation. The overall efficiency of 93.5% is achieved for the proposed converter at full load. [ABSTRACT FROM PUBLISHER]

This paper proposes a pulse-width modulation three-level converter with reduced filter size using two transformers. The proposed converter has many advantages. All switches sustain only the half of the input voltage and since the secondary rectified voltage is a three-level waveform, the output filter inductor can be reduced. Also, because of the power sharing of transformer and reduced output inductor, high efficiency can be obtained. The operational principle, analysis, and design considerations of the proposed converter are presented in this paper. The validity of this study is confirmed by the experimental results from a prototype with 600 W, 500-600 V input, and 60 V output. [ABSTRACT FROM AUTHOR]

This paper proposes a zero-voltage switching (ZVS) pulsewidth modulation (PWM) dc/dc converter with current double rectifiers to achieve ZVS for all switches under a wide range of load conditions and input voltages. Two three-level PWM circuits sharing the same power switches are adopted in the proposed converter to reduce the voltage stress of each MOSFET at Vin/2 and achieve load current sharing. Thus, the current stress and power rating at the secondary-side components are reduced. The current double rectifiers are used at the secondary side to partially cancel the output ripple current. Thus, the sizes of the magnetic components and output filter capacitance are reduced. Due to the resonant behavior by the resonant inductance and resonant capacitance at the transition interval, all switches are turned on at ZVS. The experimental results based on a 1-kW prototype are provided to verify the operation principle of the proposed converter. [ABSTRACT FROM PUBLISHER]

A novel winding-coupled bidirectional dc/dc converter with zero-voltage-switching (ZVS) performance is proposed in this paper. In the low-voltage side, the parallel configuration is employed to share the large current and reduce the current ripple. In the high-voltage side, the series structure is adopted to sustain the high bus voltage and achieve large voltage ratio conversion. There are only two coupled inductors in the proposed interleaved bidirectional converter and their secondary windings are in series to serve as winding-coupled inductors. Furthermore, the two winding-coupled inductors can be integrated into a magnetic core to reduce the passive component numbers and improve the power density. Moreover, ZVS soft-switching operation is implemented for all the power switches to minimize the switching losses by introducing the active clamp scheme. In addition, the pulsewidth modulation plus phase-shift control strategy is employed to reduce the power MOSFET peak current and diminish the circulating losses. The duty cycle is applied to balance the voltages of both sides. The phase-shift angle is introduced to realize the power flow regulation. This decoupling control strategy is advantageous for bidirectional dc/dc conversion to realize high efficiency. Finally, a 1-kW prototype is built to verify the effectiveness of the proposed circuit. [ABSTRACT FROM AUTHOR]

Capacitor charging power supply (CCPS) is a developed technology that utilizes resonant converters topology for high power applications. This paper proposes new a capacitor charging power supply using leg-rotation control method within a phase-shifted PWM full-bridge dc/dc converter. The capacitor charging power supply was connected in series to increase output voltage. Also, the proposed system is designed with soft switching techniques in order to achieve high efficiency, and a leg-rotation control method was used to reduce the heat generated from the IGBTs. The operation of the converter and design methodology will be described. A simplified model of a high-voltage high-frequency transformer is given and the structure is designed to decrease high-voltage stress. The validity of the proposed system is then verified by experimental results. The performance test of the capacitor charging power supply was carried out with a 2 μF capacitive load with a 20 kV output voltage. [ABSTRACT FROM AUTHOR]