A Novel Soft-Switching Bidirectional DC-DC Converter With High Voltage-Gain for Grid-Connected Energy Storage System

A novel soft-switching bidirectional DC-DC converter with high voltage-gain using dual equal PWM plus phase-shifted control is proposed for grid-connected energy storage system in this paper. The high voltage-gain can be achieved without high turns ratio of the transformer due to the employment of a current doubler and a voltage doubler. Two interleaved buck-boost bidirectional dc-dc converters (BDCs) are adopted to reduce the current ripple in the energy storage side. The inherent zero voltage switching (ZVS) is achieved by proper design of the magnetizing inductance. The associated control is adopted to achieve the decoupling of voltage-matching and power flow control. A 40-60 V/280 V 700-W prototype is constructed with 50-kHz switching frequency to verify the effectiveness of the proposed converter. The consistency between the analysis results and experimental results further proves its merits.