1. School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China
2. School of Mechanical and Electronic Engineering, Qiqihar University, Qiqihar 161006, China
3. School of Mechanical and Power Engineering, Harbin University of Science and Technology, Harbin 150080, China
4. Harbin Electric and Power Equipment Co., Ltd., Harbin 150040, China