Full Soft-Switching Ultra-High Gain DC/DC Converter Using Three-Winding Coupled-Inductor

This paper presents a new type of non-isolated single-switch step-up DC/DC converter with continuous input current, low voltage stress, and soft-switching performance, and modular scalability. To achieve an ultra-high voltage gain without a large duty cycle, a Three-Winding Coupled-Inductor (TWCI) along with a unit of Voltage Multiplier Cell (VMC) and Voltage Multiplier Rectifier (VMR) are employed. The energy stored in the leakage inductor is recycled by a regenerative clamp capacitor, limiting the maximum voltage stress across the single power switch. Besides, Zero Current Switching (ZCS) at the turn-on time of the power switch is achieved, and by applying a Quasi-Resonance (QR) operation, the switch turn-off current is also reduced significantly. With the help of the leakage inductor of the TWCI, all diodes can operate under the ZCS condition, which eliminates the reverse recovery losses in the proposed converter. Therefore, the introduced circuit can provide an ultra-high voltage gain under high efficiency. Steady-state analysis, comprehensive comparisons with other related converters, and design considerations are discussed. Finally, a 160 W sample prototype with 200 V output voltage is implemented to justify the theoretical analysis's correctness.