Kenji Tojo

Development of self-starting permanentmagnet synchronous motors for compressor drives

A lot of saving energy policies are being globally instituted from the viewpoints of global warming and environmental preservation. Although a lot of effort has been put into improving industrial air conditioners, there are still efficiency problems with multisystem air conditioners in buildings where constant speed scroll compressors are used. We present the measurement results of a self-starting permanent magnet synchronous motor applied to a compressor drive. Compared with an isometric induction motor, efficiency improvements of 9% and 7% were confirmed for rated operation under 50 Hz and 60 Hz, respectively. The power factors also increased by 17% and 10% for the same rated operations, respectively. Moreover, the efficiency of the compressor equipped with the proposed motor was 9% and 7% higher than that with the conventional induction motor, under 50 Hz and 60 Hz operations, respectively. This result is consistent with the efficiency improvement of the proposed motor itself.