A soft-switched, trans-inverse step-up DC-DC converter with minimal components based on built-in transformer
摘要
A new single-switch, high-gain DC-DC converter with low component count and low input current ripple is proposed for renewable energy systems. The proposed topology integrates a Three-Winding Built-In Transformer (TWBIT) with zero DC magnetizing current and a voltage multiplier to achieve a high voltage conversion ratio without requiring a large duty cycle. Its real trans-inverse configuration enables higher gains by driving the TWBIT’s effective secondary turns ratio toward zero. This approach surpasses the limits of traditional coupled-inductor designs and provides superior design flexibility through adjustable turns ratios. The design also incorporates a regenerative clamp capacitor to limit the switch’s voltage stress. This structure provides three primary advantages: (1) low voltage stress and ZCS operation for the power switch; (2) utilization of the TWBIT’s leakage inductances for soft-switching and diode reverse-recovery mitigation; and (3) the formation of a resonant cell from these leakage inductances to reduce switching dissipation. These features collectively enhance the overall conversion efficiency of the circuit. The operational principles and steady-state performance are analyzed theoretically. Owing to the real trans-inverse characteristic, the proposed converter achieves higher voltage gain and lower switch voltage stress than its counterparts, while maintaining acceptable maximum diode voltage stress with a smaller number of components. This is supported by comparative evaluations against existing topologies. The theoretical findings are validated experimentally with a 200 W, 25 V-to-400 V prototype. The results confirm the converter’s superior performance characteristics.