New Soft-Switched Three-Winding Built-In Transformer Step-Up DC/DC Converter with Low Voltage Stresses

This paper suggests a new single-switch fully soft-switched high step-up DC/DC converter with low input current ripple for interfacing renewable resources applications. This circuit utilizes a Three-Winding Built-In Transformer (TWBIT) in the form of a Y-source network along with a Cockcroft–Walton Voltage Multiplier (CW-VM) cell to create a high voltage gain. Also, in the proposed structure, due to the trans-inverse property, ultra-high voltage conversion ratios are achievable under a low number of turns ratio of the TWBIT. The vertical structure in the proposed topology results in the least voltage stress applied to the circuit components. The unique construction of the introduced circuit helps the Zero Current Switching (ZCS) performance in the single power switch at turn-on time and Low Reverse Recovery (LRR) operation for all diodes. Besides, to further efficiency improvement, a resonant cell is designed without needing additional elements. The theoretical operation principle along with steady-state analysis of the introduced topology are discussed in detail. Finally, a 200 W experimental sample prototype (25 V - 400 V- 50 kHz) was constructed in the laboratory to verify the analytical results of the converter.