Equivalent Magnetic Circuit Model of IPMSM

This paper proposes a magnetic equivalent circuit model for an interior permanent magnet synchronous motor (IPMSM) for the optimal design of the entire system. The computational speed of the proposed model is greater than that of the finite element method (FEM), and the model is suitable for large scale optimization problems. Unlike conventional magnetic circuit models, the proposed model can reflect the dq-axis saliency, which enables analysis under operating conditions using the reluctance torque, which is essential in IPMSMs. In the proposed model, rotor rotation is represented by an AC magnetomotive source, and the saliency characteristics are represented by a multiphase-q-axis transducer that simulates a q-axis magnetic path connected in parallel to the magnets. The effectiveness of the proposed method is verified by comparisons with the FEM, and the results reveal good agreement under several conditions. Furthermore, the computation of the N-T characteristics and efficiency maps is verified, and consequently, the proposed method is deemed capable of obtaining these maps with sufficient accuracy for the initial design, and the required computation time is four orders of magnitude lower. © 2023 The Institute of Electrical Engineers of Japan.