1. Department of Electrical Engineering, North China Electric Power University, Baoding, China
2. Department of Electrical Engineering, Zhejiang University, Hangzhou, China
3. Department of Electrical Engineering and Power Electronics, Vrije Universiteit Brussel, Brussel, Belgium
4. Department of Electrical and Computer Engineering, Memorial University of Newfoundland, St John's, NL, Canada
5. Department of Energy Technology, Aalborg University, Esbjerg, Denmark