Performance evaluation of a 1kW non-isolated high step-up/step-down bidirectional converter for distributed battery storage system

A bidirectional DC/DC converter with high step-up/step-down is presented for battery storage power systems. This converter consists of a Buck-Boost converter, a half bridge module and an embedded coupled inductor. The voltage stresses of the power switches are reduced significantly. PWM plus phase-shift (PPS) control strategy is employed to regulate the intermediate capacitor voltage and the output voltage, due to which the conduction losses of the converter are reduced and ZVS for all power switches are achieved. The converter can switch between the battery charging and discharging modes smoothly. The operation principle, performance analysis and design consideration are analyzed in detail. Finally, a 1kW prototype is built and tested to verify the analysis.