1. College of Electrical and Information Engineering, Hunan University, Changsha, China
2. Electrical Research Institute, China Railway Signal and Communication (Changsha) Railway Traffic Control Technology Company Ltd, Changsha, China
3. College of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha, China
4. R&D of Zhuzhou National Engineering Research Center of Converters, Zhuzhou CRRC Times Electric Company Ltd, Zhuzhou, China