1. School of Electrical Engineering and Automation, Wuhan University, Wuhan430072, China
2. School of electrical and electronic engineering, Wuhan Polytechnic University, Wuhan430023, China
3. Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan430068, China
4. State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing400044, China