1. Sumitomo Electric Industries, Ltd., Transmission Devices Laboratory 1 , 1-1-1, Koyakita, Itami-Shi, Hyogo 664-0016, Japan
2. Toyota Technological Institute, Research Center for Smart Energy Technologies 2 , 2-12-1, Hisakata, Tenpaku-ku, Nagoya-shi 468-8511, Aichi, Japan
3. Consultant 3 , 2-1-9, Suimeidai, Kawanishi-shi, Hyogo 666-0016, Japan