Dual-Input High Gain DC-DC Converter with Two Energy Storage Systems for Light EV Applications

This article proposes a new topology for a multi-input DC-DC converter that can handle unsymmetrical terminal voltages, providing high voltage gain, inherent current sharing, input-output isolation, and bidirectional power flow capability. The modified iSEPIC structure facilitates minimum-phase nature (eliminates the RHP Zero effect) with zero DC magnetizing current in the isolated transformer. Accordingly converter offers a 45% higher gain per component count (at D=0.5) than other reported converters. The current sensor less feature of the proposed converter, which is not common in reported multi-input converters, eliminates the need for inner current loop control during acceleration by supplying 70% of the required peak power (at D=0.6) from the ultracapacitor. The functional capabilities of the proposed converter make it suitable for battery/ultracapacitor-based EV applications. A 200W hardware prototype has been developed to validate the claimed functionalities of the proposed converter.