Partial series resonant coupled-inductor boost converter for high step-up DC-DC applications

A coupled-inductor boost (CIB) converter is a popular solution for non-isolated high step-up applications since a high voltage gain can be easily achieved by adjusting the turn ratio of the coupled-inductor (CI). On the other hand, at the cost of utilizing a CI, a CIB converter requires voltage snubbers. In order to relieve the drawbacks caused by a CI and to further improve the efficiency, the pulse-width modulation (PWM) partial series resonant (PSR) CIB converter is proposed. In the PSR CIB converter, the resonant operation is achieved with only a small modification to the conventional CIB converter without additional components. This resonant operation significantly reduces the turn-off loss of the switch and the reverse recovery of the high voltage diode. Moreover, it does not cause a large circulating current so that a conduction loss can still maintain similar to that of the conventional CIB converter. Experimental testing of a 24-V input, 110-W 220-V output prototype verifies the behavior and performance of the proposed circuit.