Unsymmetrical Dual-Input Isolated High Gain Bidirectional DC–DC Converter With Inherent Current Sharing for Light EV Applications

In hybrid electric vehicles (EVs), multi-input dc–dc converters with different sources of energy storage are preferred to enhance the EV market penetration. The proposed new topology is a modified SEPIC converter with an integrated boost cell, capable to handle the battery and ultracapacitor (UC) with different terminal voltages. It is also having single source transition capability. This multi-input dc–dc converter provides high voltage gain, input–output isolation, and bidirectional power flow feature. The essential of regeneration in the EV is demonstrated to achieve better energy utilization. The current sharing between the energy storage systems (ESSs) (battery and UC) is inherently provided by the topological structure of the proposed converter. Hence, it eliminates the inner current control loop requirement. Accordingly, cost and control complexity are minimized with improved storage utility. Therefore, the proposed converter’s functional capabilities are suitable for battery/UC-based light EV applications. The operating performance is evaluated on a 250-W hardware prototype to validate the functional capability of the proposed converter.