1. National Taiwan University of Science and Technology,Dept. of Electrical Engineering,Taipei City,Taiwan,10607
2. National Chin-Yi University of Technology,Dept. of Electronic Engineering,Taichung City,Taiwan,41130
3. Institute of Electrical Power Engineering, Warsaw University of Technology,Warsaw,Poland
4. Polytechnic University of Bari,Dept. of Electrical and Information Engineering,Bari,Italy