Step-down converter with wide voltage conversion ratio

A non-isolated dc-dc converter with a wide step-down voltage gain is presented, which combines one coupled inductor and two energy-transferring capacitors. The corresponding voltage conversion ratio is much lower than that of the traditional synchronously rectified buck converter, and the proposed converter can achieve an extremely low output voltage by adjusting the turns ratio and duty cycle. Furthermore, the proposed converter can achieve zero-voltage-switching turn-on, and the leakage inductance energy of the coupled inductor can be recycled to the capacitors, thereby causing the voltage spikes on some of the switches and all diodes to be quite low. In this study, theoretical deductions and experimental results are given to verify the feasibility and effectiveness of the proposed converter.