1. State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
2. Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, Nanchang, Jiangxi 330013, China
3. CRRC Qingdao Sifang Co., Ltd., Qingdao, Shandong 266111, China