A step-up resonant converter for grid-connected renewable energy sources

Due to soft-switching for switching devices, resonant converters are suitable for high-power applications. This paper proposes a resonant converter which is suitable for grid-connected renewable energy sources. The converter can achieve high voltage-gain using LC parallel resonant tank. It has the features such as zero-voltage-switching (ZVS) turn-on, nearly ZVS turn-off, and zero-current-switching (ZCS) turn-off of rectifier diode. In addition, compared with the conventional resonant converter, the switching frequency variation of the proposed resonant converter is smaller over the entire load range. The operation principle of the converter and the selection of the resonant parameters are presented in the paper. A 1kW prototype is built in the lab to verify the effectiveness of the converter. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved.