Irreversible Demagnetization Prediction Due to Overload and High-Temperature Conditions in PMSM Based on Nonlinear Analytical Model

In this article, an exact analytical model for predicting irreversible demagnetization in Permanent Magnet Synchronous Machines (PMSMs) under overload and high-temperature conditions is presented. The proposed model includes a nonlinear model combined with a process for determining demagnetization. First, the nonlinear model considers non-uniform magnetization by dividing each permanent magnet (PM) into numerous small segments with separated remanence flux densities (RFDs). Harmonic modeling (HM), combined with an iterative loop, is employed to obtain nonlinear solutions, accurately capturing saturation effects that lead to high demagnetizing fields. The RFDs are iteratively updated until convergence is achieved. The proposed model can accurately predict machine behavior, capturing both demagnetization and saturation effects. Validation using a PMSM shows excellent agreement with both Finite Element Analysis (FEA) and experimental results, significantly reducing computation time compared to FEA simulations. This approach provides a robust tool for engineers to design and evaluate PMSMs, ensuring machine reliability under adverse conditions.