1. School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, China
2. State Key Laboratory of Operation and Control of Renewable Energy and Storage System, China Electric Power Research Institute, Beijing, China
3. Electric Power Research Institute, State Grid Ningxia Electric Power Comapny Ltd., Yinchuan, China
4. Department of Energy Technology, Aalborg University, Aalborg, Denmark