1. School of Electrical Engineering, Southwest Jiaotong University, Chengdu, China
2. Maglev Technology Research Center of CRRC QINGDAO SIFANG CO. LTD, Qingdao, China
3. Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle of Ministry of Education, Southwest Jiaotong University, Chengdu, China
4. CRRC Industrial Research Institute (Qingdao) Co. Ltd, Qingdao, China
5. School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, China