PWM Plus Secondary-Side Phase-Shift Controlled Soft-Switching Full-Bridge Three-Port Converter for Renewable Power Systems

In this paper, a pulsewidth modulation (PWM) plus secondary-side phase-shift (SSPS) controlled full-bridge three-port converter (FB-TPC) is proposed for a renewable power system, which is derived by integrating two interleaved buck/boost circuits (IBBC) and a SSPS full-bridge converter (FBC), to interface the energy source, energy storage element, and output load simultaneously. The two switching legs are shared by the IBBC and FBC, which improves the active devices sharing ratio and power density. With PWM plus SSPS control scheme, decoupled power control can be realized and the converter can achieve wide input voltage range power conversion. In addition, zero-voltage switching (ZVS) of both the primary and secondary switches are achieved in a wide range. Furthermore, the circulating current can be greatly eliminated, which helps to reduce conduction losses. Moreover, the voltage stresses on the secondary rectifier are effectively suppressed since the power switches and diodes are clamped to output voltage. The operation principles, output characteristics, ZVS performances, and control strategy are analyzed in detail. Experimental results of a 600-W prototype are provided to verify the effectiveness and the advantages of the proposed converter.