Shape Optimization of Rotor Slot in Induction Motor Using Circuit Parameter Calculation

Induction motor is considered as an alternative to replace permanent magnet motors, due to ease of manufacturing and lack of rare earth material. However, since induction motor is relatively large in size and has low power density, previous studies have performed to increase the performance by changing the pre-defined parameters of rotor slot. In this paper, level set-based shape optimization is applied to design the optimal shape of rotor slot for torque maximization. Material boundaries represented by level set function are moved by the sensitivity of the objective function. To identify the rated current at each optimization process, the equivalent circuit parameters of induction motor are calculated using the finite element method. Based on the calculated current, time-harmonic magnetic analysis is performed and the rated torque and power are evaluated. The proposed method is applied to the reference design problem and validated to obtain the improved design