AC Copper Loss Evaluation Method for High-Speed PM Motors with Rectangular Coils

Abstract

One way to reduce the size and increase the power density of a motor is to increase its rotational speed. However, to drive motors at high speeds, the operating frequency must be increased, which increases in harmonic losses, primarily iron loss and AC copper loss. Therefore, harmonic losses must be quantitatively evaluated with high accuracy at the design stage. In this study, the validity of the method for evaluating the AC copper loss during high-speed operation is examined by comparing the difference between analytical values and evaluation formulas based on the relationship between the harmonic components of the voltage and current and slot shape.