Bidirectional DC-DC Converter with a Wide-Range Voltage Conversion Ratio

A bidirectional DC-DC converter with a wide- range voltage conversion ratio is proposed in this paper. The characteristic of wide-range voltage conversion ratio can be utilized in the energy conversion of retired batteries, such as electric scooters, electric vehicles, electrical buses, electric trucks etc. with different voltage levels. The proposed converter is composed of cascading a two-phase interleaved half-bridge circuit and a voltage-doubler circuit. The two-phase interleaved half-bridge circuit and the voltage-doubler circuit are defined as terminals A and B, respectively to investigate the operational stages of the proposed converter and analyze the voltage conversion ratios under different voltage-level schemes. Due to the variable structure design and control of the proposed converter, a wide-range voltage converter ratio and bidirectional step-up/step-down function can be achieved. A prototype for the proposed bidirectional DC-DC converter with a rated voltage of 150V at terminal A, a rated voltage between 25V and 1050V at terminal B and a rated power of 1100W is designed and implemented in this paper. Experimental results demonstrate that the proposed bidirectional DC-DC converter can be operated in the different modes with respect to different voltage levels. Meanwhile, the maximum conversion efficiency of above 98% can be achieved.