[1] Univ Shanghai Sci & Technol, Dept Elect Engn, Shanghai 200093, Peoples R China
[2] Shanghai Jiao Tong Univ, Key Lab Control Power Transmiss & Convers, Minist Educ, Shanghai 200240, Peoples R China
[3] IIT, Galvin Ctr Elect Innovat, Chicago, IL 60616 USA