A New Torque Ripple Analysis Method for Permanent Magnet Assisted Synchronous Reluctance Motor by using Load Angle Characteristic

摘要

In a synchronous reluctance motor (SynRM), large saliency ratio of rotor is required to achieve high torque and power factor. However it is very difficult to increase saliency ratio with small rotor. So, we place permanent magnets into the barriers for high torque. The motor can be called permanent magnet assisted (PMa) SynRM. The advantages of PMa-SynRM compared to EPM motor are low back emf and wide constant power region with a small d-axis current at the field weakening control area. On the contrary, PMa-SynRM has larger torque ripple due to its complex barrier structure. Some papers reducing torque ripple of PM motor have been presented[1][2].