Input Current Ripple Suppression of Single-Stage Bidirectional DC-AC Converter in Battery Energy Storage System

In this paper, a single-stage high-frequency isolated battery charging and discharging converter is proposed. The circuit topology and control strategy of this DC-AC converter are deeply studied, and the secondary ripple current of the system is decoupled by Buck active power decoupling circuit to suppress the secondary ripple current of the DC side. The control strategy uses a bidirectional rectifier circuit to convert the sinusoidal pulse width and pulse position modulation wave of the high-frequency transformer into a sinusoidal pulse width modulation (SPWM) wave that outputs a positive half-cycle or a negative half-cycle. The secondary ripple power is transferred by calculating the on-duty ratio of the switch tube in the decoupling circuit. The theoretical analysis and simulation results show that the system can realize bidirectional power flow, single-stage power conversion, high-frequency isolation of input and output, and has the characteristics of simple circuit, high conversion efficiency, small size, low cost and wide application prospect.