Highly efficient brushless motor design for an air-conditioner of the next generation 42 V vehicle

In the past few years, worldwide awareness of environmental problems has grown dramatically. The idling stop and 42 V battery system has attracted large attention for next generation vehicle. In order to adapt to idling stop, air-conditioning compressors are required to be changed to electric-motor driven from gasoline engine driven. This paper discusses the optimum design of a high speed and high efficiency brushless motor for a compressor of the 42 V operated vehicle. The compressor motors require high efficiency at high speeds. Therefore, turning attention to an IPMSM which guarantees structural strength, improved techniques such as an optimal method of designing a magnet layout that minimizes iron loss, and concentrated winding technology using rectangular wire that minimizes copper loss have been developed. As a result, a method of designing IPMSM that offers high efficiency of 94% at 15,000 min/sup -1/ and is suitable for the 42 V vehicle has been established.