[1] Beijing Inst Technol, Beijing Coinnovat Ctr Elect Vehicles, Natl Engn Lab Elect Vehicles, Beijing, Peoples R China
[2] Beijing Inst Technol, Chongqing Innovat Ctr, Beijing, Peoples R China
[3] Univ Witwatersrand, Sch Elect & Informat Engn, Johannesburg, South Africa