Equivalent Circuit Considering the Harmonics of Core Loss in the Squirrel-Cage Induction Motor for Electrical Power Steering Application

Consideration of the saturation in the core is essential in designing motors for automotive application, because of the stringent size limitations in automotive electric motors, such as those equipped with electrical power steering. In the design of squirrel-cage induction motors, equivalent circuit analysis using lumped parameters is often used to investigate the motor performance. However, estimation of the motor characteristics has been limited because the standard equivalent circuit that considers space harmonics does not consider the core loss. To improve the reliability of the characteristic analysis, a new method that can solve these problems is required. Thus, study of a new equivalent circuit that considers the saturation in the core and the core loss harmonics is needed. Therefore, to obtain the reliable characteristics of induction motors, this paper presents a modified space harmonic equivalent circuit that considers the harmonics of core loss resistance. The modified equivalent circuit is verified by comparing the analysis results of the suggested method and the experimental results of the test model.