1. Department of Electrical Engineering, Chungnam National University 1 , Daejeon 34134, South Korea
2. Alternative Fuels and Power System Research Center, Korea Research Institute of Ships and Ocean Engineering 2 , Daejeon 34103, South Korea
3. Department of Electric, Electronic, and Communication Engineering, Chungnam National University 3 , Daejeon 34134, South Korea
4. Department of Electrical Engineering, Changwon National University 4 , Changwon 51140, South Korea