LI Xin-ran1,CHEN Hong-lin1,LENG Hua2,CHEN Guo-min3
(1. College of Electrical and Information Engineering, Hunan Univ, Changsha,Hunan410082, China; 2. Electrical Research Institute of State Grid Hunan Electric Power Company, Changsha,Hunan410007, China; 3. School of Mechanical and Electrical Engineering,Hunan City Univ, Yiyang,Hunan413000, China)