1. Department of Electrical Engineering, School of Automation, Guangdong University of Technology, Guangzhou, China
2. Brunel Interdisciplinary Power Systems Research Centre, Department of Electronic & Electrical Engineering, Brunel University London, London, U.K.
3. Guangdong Key Laboratory of Clean Energy Technology, South China University of Technology, Guangzhou, China
4. Department of Energy Technology, Aalborg University, Aalborg, Denmark