Realization of highly efficient and small IPM motors for the compressors of air-conditioners

In the world, 50 million air-conditioners are set up every year. It is important to save the power consumed by air-conditioners. Therefore, the price of IPM motors has to be reduced. The price of IPM motors decreases if the cost of the material of the IPM motors decreases through decreasing the size of the IPM motors. In this paper, the smallest IPM motor whose stator outer diameter is 90 mm for compressors of 2.2kW and 2.5kW air-conditioners was developed. The experimental results showed that the efficiency of the motor was higher than 90% at a load of 120g-m(3,500rpm) to achieve the Japanese standard of COP for 2.2kW air conditioners of 5.28. The motors have been mass-produced.