[1] Hunan Univ, Coll Elect & Informat Engn, Changsha 410082, Hunan, Peoples R China
[2] Beijing Kedong Elect Power Control Syst Co Ltd, Beijing 100192, Peoples R China
[3] State Grid Hunan Elect Power Corp Ltd, Yiyang Power Supply Co, Yiyang 413002, Peoples R China
[4] Southeast Univ, Sch Elect Engn, Nanjing 210096, Jiangsu, Peoples R China