1. National Rail Transit Electrification and Automation Engineering Technology Research Center, Southwest Jiaotong University, Chengdu, China
2. School of Electrical Engineering, Southwest Jiaotong University, Chengdu, China
3. School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
4. Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI, USA
5. School of Electrical Engineering, Chongqing University, Chongqing, China