State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China;
State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China;
State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China;
State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China;