[1] Chongqing Univ, Coll Aerosp Engn, Chongqing 400044, Peoples R China
[2] Chongqing Univ, State Key Lab Power Transmiss Equipment & Syst Sec, Chongqing 400044, Peoples R China
[3] Hebei Univ Technol, State Key Lab Reliabil & Intelligence Elect Equipm, Tianjin 300130, Peoples R China
[4] Hebei Univ Technol, Sch Mech Engn, Tianjin 300401, Peoples R China