A Wide Output Voltage Range Onboard Charger for E-2Ws and E-3Ws With Bidirectional Power Flow Capability

A wide output voltage range bidirectional onboard charger (BOC) with multipurpose functionalities, is realized in this work for E-2 wheelers (E-2Ws) and E-3 wheelers (E-3Ws) (collectively known as light duty electric vehicles, i.e., LDEVs). Presented BOC realizes desired real and reactive power flow between AC mains and LDEVs through grid to LDEVs (G-LDVEs or G2V) or LDEVs to grid (LDEVs-G or V2G) mode operation and, therefore, effectively converts LDEVs consumers into prosumers. Further, with wide output voltage range capability, i.e., from 36 V to 120 V, this charger establishes a universal BOC for diverse categories of LDEVs, and thus eliminates chaos at consumer’s end. For effectively realizing power transfer between low-voltage LDEV battery packs and high-voltage single-phase supply in wide voltage range conditions, presented BOC employs a bidirectional active switched capacitor buck-boost (BASCBB) DC-DC converter at battery end. BASCBB DC-DC stage exhibits a wide voltage transfer ratio, low switch voltage stress, minimum component count, low current ripple characteristics at input-output ends, and simple control, and thus, ensures effective charging/discharging of LDEVs battery over wide operating conditions. Besides, presented BOC employs a simple yet robust control for front-end active boost rectifier to ensure low harmonics distortion and desired power factor at AC side of charger at both healthy and unhealthy grid conditions. Finally, performance of BOC is tested through simulation and hardware, and relevant results are discussed and compared with existing solutions.