1. Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China
2. National Rail Transit Electrification and Automation Engineering Technique Research Centre, Southwest Jiaotong University, Chengdu 610031, China
3. State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
4. Department of Built Environment, Oslo Metropolitan University, 7491 Oslo, Norway