1. Key Laboratory of Special Motors and High Voltage Electrical Appliances of Ministry of Education Shenyang University of Technology 111 West Road Shenyang 110870 China
2. State Grid Ningxia Electric Power Co., Ltd. Electric Power Research Institute No. 716, Huanghe East Road, Jinfeng District Yinchuan 750002 China
3. TBEA Hengyang Transformer Co., Ltd. Hengyang City, Yanfeng District, Baishazhou Hengyang 420000 China
4. College of Electrical and Information Engineering Hunan University No. 2, Lushan South Road, Yuelu District Changsha 410082 China