1. Department of Electrical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong
2. Department of Electrical Engineering, Shenzhen Research Institute, Centre for Advances in Reliability and Safety, and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Kowloon, Hong Kong
3. Department of Electrical Engineering and Computer Science, The University of Tennessee, Knoxville, TN, USA