1. Electric Power Research Institute of State Grid Henan Electric Power Company, Zhengzhou 450000, China
2. College of New Energy, Harbin Institute of Technology at Weihai, Weihai 264209, China
3. College of Lilac, Harbin Institute of Technology at Weihai, Weihai 264209, China
4. School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China