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A nonisolated bidirectional dc–dc converter with high voltage gain, low voltage stress, low component count, and soft-switching features is presented in this paper. In this topology, coupled inductors and voltage multiplier cells are merged to achieve high step-up/down voltage gain. Also, due to using active clamp circuits, the voltage stress of power switches is relatively low. Thus, the low voltage switches with low on-resistance can be employed to reduce the conduction losses. Furthermore, zero-voltage switching is accomplished in both high step-up and high step-down modes for all power switches, and due to zero-current switching operation of all antiparallel diodes, the reverse recovery losses are reduced. In order to verify the theoretical analysis and the converter performance, a 200 W prototype circuit of the proposed converter is implemented in the laboratory. [ABSTRACT FROM AUTHOR]

This paper proposes a soft switching nonisolated dc/dc interleaved converter incorporating coupled inductors and switched capacitors for high step-up applications. The converter integrates the interleaved structure and winding-cross-coupled inductors technique to reduce current stress of semiconductor devices and diminish the input current ripple considerably. In addition, the interleaved converter has the automatic current sharing characteristic. The applied zero voltage transition cell provides soft switching in a wide range of load variations with a minimum number of elements. In this topology, all semiconductor devices are soft switched, having eliminated switching losses and alleviating the reverse recovery problem of the output diodes. In addition, the voltage stress across the switches is very low. The theoretical analysis and design procedure of the introduced topology are presented. Also, the proposed converter is compared to the latest similar soft switched high step-up converters. The accuracy of the theoretical analysis is validated by a 200-W prototype operating at 100 kHz. [ABSTRACT FROM PUBLISHER]

This paper presents high step-up dc-to-dc converter for low voltage sources such as solar photovoltaics, fuel cells, and battery banks. To achieve high voltage gain without large duty cycle operation, combination of coupled inductor and switched capacitor voltage doubler cells are used. By incorporating active clamp circuit, voltage spike due to the leakage inductance of the coupled inductor is alleviated and zero-voltage switching turn on of the main and auxiliary switch is obtained. Due to the use of MOSFETs of low voltage rating and soft turn on of the switches, conduction loss and switching losses are reduced. This improves the efficiency and power density of the converter. The proposed converter can achieve high voltage gain with reduced voltage stress on MOSFET switches and output diodes. Design and analysis of the proposed converter is carried out, and finally, a 500-W experimental prototype is built to verify theoretical analysis. [ABSTRACT FROM PUBLISHER]

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]

This paper presents a new soft-switching dc/dc converter for high-input-voltage applications. Two half-bridge converters connected in series with interleaved asymmetric pulsewidth modulation (PWM) are adopted to limit the voltage stress of each power switch at one-half of the input dc bus voltage. In each half-bridge converter, two asymmetrical dc/dc circuits with the same active switches are connected in parallel at the output side to share the load current and reduce the current stresses of the secondary windings and rectifier diodes. Since two half-bridge converters are operated with interleaved PWM, the output ripple currents partially cancel each other so that the resultant ripple current at the output side is reduced. Active switches in the proposed circuit can be turned on at zero-voltage switching during the transition interval due to the resonant behavior by the output capacitance of MOSFETs and the leakage inductance of transformers. Experiments based on a laboratory prototype with 960-W rated power are provided to demonstrate the performance of the proposed converter. [ABSTRACT FROM PUBLISHER]