1. School of Automotive and Rail Transit, Nanjing Institute of Technology, Nanjing, China
2. Traction Power State Key Laboratory, Southwest Jiaotong University, Chengdu, China
3. School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, China
4. School of Mechanical Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China