Battery-Friendly DC-DC Converter with Ripple-Free Current Modulation Strategy

In this article, a battery-friendly dc-dc converter with a ripple-free current technique is proposed interfaced battery energy storage system (BESS). Two-phase interleaved circuits are adopted to cancel the current ripple on the BESS side. On the high voltage (HV) side, the circuit combined with a half-bridge circuit and full-bridge circuit is employed to achieve voltage-second balance control. With the associated control strategy, the power control variables can be decoupled. The voltage-second balance control on two ends of the leakage inductor is realized by the adjustment of the duty cycle. After that, the transferred power only changes monotonously along with the change of phase shift angle. The zero-voltage switching (ZVS) conditions are analyzed in detail to ensure that the ZVS of all switches can be achieved through parameter design. Moreover, a comparison is conducted to illustrate the merits of the proposed converter. The theoretical analysis has been fully validated experimentally by an experimental prototype of 40-60 V to 400 V/1 kW operating at 50 kHz. The accordance between the theoretical analysis and experimental verification further testifies to the effectiveness.