Furukawa Electric Review No.49The Development of Next-Generation Technologies in the Domain of Winding Wires of Main Electric Motors

Keiichi Tomizawa, Mamoru Shimada, Keisuke Ikeda, Daisuke Muto, Hideo Fukuda

Recently, the number of hybrid electric vehicles (HEV) and of electric vehicles (EV) are growing rapidly. Motors integrated in these vehicles are required to be smaller in size and larger in the output power to improve the driving performance and the fuel efficiency. The winding wire applied to these motors is required to have an insulation coating with a higher insulation performance and conductors with lower loss. We have proved that the Partial Discharge Inception Voltage (PDIV) was greatly improved by introducing micro cellulars into the insulation coating and have succeeded in the development of an unprecedented insulation material with a very low permittivity. Further, we have found out that the segmented conductors could reduce the eddy current loss drastically and have examined the relation between the driving frequency and the effect in loss reduction to show there was a noticeable effect in the range of 1 kHz frequency and higher.