Parallel Operation of Integrated Battery Chargers for All Wheel Drive Electric Vehicles

Abstract

In this paper, an integrated charging scheme for All Wheel Drive (AWD) Electric Vehicles (EVs) is proposed. The proposed scheme utilizes the existing driving hardware for charging the battery pack with minimum external components. As the driving hardware of AWD EVs include two motors and two inverters, an Integrated Battery Charger (IBC) with parallel configuration is proposed. In the existing topology of three phase IBC using split phase machine, the grid currents were not balanced. But in the proposed parallel IBC topology, the two split phase machines are proposed with different phase configurations, namely R-Y-B and Y-R-B, which will cancel the unbalance caused by each IBC, and make the grid currents balanced. The mathematical proof for the same is also included in this paper.The proposed parallel topology of IBCs has higher power rating and hence provides faster charging compared to conventional single IBCs. Circulating current mitigation for parallel IBCs is also presented in this paper. Exhaustive simulation and experimental results are included to validate the proposed scheme.