A Bidirectional On-Board Charging System for LEVs

The unidirectional power flow capability of the existing light electric vehicle (LEV) charging systems limits their contribution in today’s smart grid scenario and consequently imposes a major obstacle in their future growth. Further, such a charging system includes several other shortcomings such as compromised supply and battery side performance, high volume, and low efficiency. Therefore, a bidirectional onboard charger topology with high-performance characteristics both from supply and battery side perspectives is presented in this work for the LEVs. It is noteworthy that, the presented topology not only ensures effective charging from the grid but also owns a capability to meet grid demands as per the requirement of the distributors. In order to accomplish unity displacement and distortion factor at the supply while carrying out ripple free charging/discharging of the battery, a two stage structure comprising AC-DC and DC-DC stages, is effectively utilized. Unlike conventional approaches, the presented topology utilizes a non-isolated bidirectional switched inductor buck-boost (BSIBB) converter at the DC-DC stage. The high gain capability of the presented BSIBB converter enables the desired voltage gain between DC link and battery packs and, therefore, eliminates the requirement of transformers at the DC-DC stage. Finally, the acceptability of the charger for the LEVs charging is verified through design and performance analyses.