A ZVS bidirectional three-level DC-DC converter with direct current slew rate control of leakage inductance

A bidirectional isolated three-level DC-DC converter is proposed. Direct current slew rate (DCSR) control of leakage inductance is proposed to minimize conduction loss and current stress facing turns-ratios mismatch and parasitic parameters. Limitations of conventional PWM plus phase shift (PPS) control, comparison between PPS control and the proposed DCSR control are given. Besides, the voltage balance issue and the implementation of the proposed DCSR control are also given. With the proposed DCSR control, lower conduction loss, lower peak current can be obtained when the turns-ratio mismatch and parasitic parameters are considered. A 1kw prototype is built to verify the proposed topology employing the proposed DCSR control.