1. State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an, China
2. State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an, China
3. School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an, China
4. Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, USA