A new soft-switched trans-inverse quasi-Z source DC-DC converter with low switch voltage stress.

This paper proposes a new ultra-high-voltage gain, soft-switching quasi-Z-source DC-DC converter for distributed generation system converters. This converter retains the benefits of the quasi-Z-source network and the switched-capacitor techniques, resulting in high voltage gain, high efficiency, low input current ripple, low switch voltage stress, and a common ground between the input and output sides. The presented circuit uniquely combines a Three-Winding Coupled-inductor (TWCI) with a voltage multiplier to achieve exceptional voltage conversion in a trans-inverse manner. This approach enables a higher voltage gain with a small total turns ratio in the TWCI. Notably, the single power switch attains zero-current switching (ZCS) at the turn-on instant across its entire operating range. Moreover, the efficiency of the introduced topology is further enhanced by recycling the leakage inductance energy of the TWCI through a clamp circuit across the power switch. In addition, all the converter diodes are operated without a reverse recovery issue. A comprehensive theoretical analysis, including operational principles and steady-state performance, is complemented by comparative evaluations with similar topologies. The feasibility of the proposed converter was confirmed through steady-state analyses and the implementation of a 200 W, 25 V-to-400 V sample prototype.