Minimizing leakage inductor current RMS control strategy of bidirectional three-level DC-DC converter

Aiming at the large stress of switching devices and low transmission efficiency of converter when the gene-ralized bidirectional isolated DC-DC converter with two-level H-bridge topology operates under the phase-shift control mode, a scheme with the minimizing inductor current RMS control based on the three-level half-bridge topology is proposed. The proposed scheme replaces the two-level H-bridge topology with three-level half-bridge topology, and adds the corresponding control for the leakage inductor current RMS of transformer to reduce the loss of converter and the stress of switching devices and improve the transmission efficiency of the converter. The control curve is plotted and deduced detailedly based on the expression of inductor current RMS and the condition of ZVS(Zero Voltage Switching), which is used to design the key controller based on FPGA. The experimental platform is established by using SiC MOSFET. The experimental results show that the converter can be improved in aspects of the voltage stress, switching loss and transmission efficiency, verifying the correctness and feasibility of the proposed scheme. © 2018, Electric Power Automation Equipment Press. All right reserved.