Magnetizing Inductance Estimation Method of Induction Motor for EV Traction Considering Magnetic Saturation Changes According to Current and Slip Frequency

Abstract

During the motor design stage, it is crucial to accurately predict the characteristics of the motor at various operating points. Performing finite-element analysis (FEA) for each point is time-consuming and impractical. Therefore, the motor parameters and losses are typically calculated for each load point and used to solve the voltage and torque equations, thereby reducing the time required for motor characteristic analysis. Thus, the accurate prediction of motor parameters is essential for optimizing the motor design. This study proposes a parameter estimation method for the design process of induction motors (IMs). Accordingly, the circuit parameters are estimated using a reduced amount of FEA data. A common approach for evaluating the circuit parameters of IMs is through locked-rotor and no-load tests. However, these methods have limitations, because they use a fixed frequency that may not be suitable for electric vehicle traction motors owing to their various driving points, high torque, and high power density. This article introduces an iterative method for estimating the magnetizing inductance in IMs, owing to its significant impact on torque. This method is based on the changes in saturation according to current and slip frequency.