Basic study on the suitable structure of a permanent magnet synchronous motor with a powder magnetic core

A high-efficiency motor is required in order to address recent environmental issues. Permanent magnet synchronous motors (PMSMs) are widely used because of their high efficiency. However, even higher efficiency is required in order to reduce the power consumption of motors. The structures of PMSMs using a powder magnetic core are considered. Since the powder magnetic core has very little eddy current loss, the core loss is expected to be reduced. Therefore, multi-pole PMSMs with a powder magnetic core are examined based on the torque, the losses, and the efficiency characteristics. As a result, the efficiency of 16-pole models improved in the high-speed region and a 50% reduction in weight was achieved by using a powder magnetic core. In addition, a torque equal to that generated by 4-pole models was achieved by expanding the motor diameter of the lightweight model. However, the model using a powder magnetic core was not able to achieve an efficiency equal to that of 4-pole models.