The influence of electromagnetic force upon the noise of an IPM motor used in a compressor

Recent power electronics and control technology have equipped air conditioners with additional functions such as air purification and energy saving, however, the noise and vibration originating with the compressor still remains to be improved. The interior permanent magnet (IPM) motor has become the compressor drive motor of choice became of the need for small high-powered compressors. Due to the structural peculiarity of IPM, it generates not only magnetic torque, but also reluctance torque which helps to achieve high power density while aggravating the noise problem. In this study the influences of natural frequencies and mode shapes of the structures were investigated to reduce the noise and vibration of an IPM motor. For better understanding of noise source, electromagnetic force has to be analyzed and this papers deals with noise problem caused only by electromagnetic force.