A PM Dimensions Design Method for Hybrid Less Rare-Earth Permanent Magnet Motors Based on Analytical Approach

To address compatibility issues between ferrite and rare-Earth (RE) materials in hybrid less RE (HLRE) motors, caused by differences in magnetic properties and cost, this article proposes a simplified and systematic optimization method for permanent magnet (PM) dimensions in HLRE PM-assisted synchronous reluctance motors (PmaSRM). First, the analytical model of the motor is simplified to reduce analysis complexity. Then, PM dimension variation rules for two types of PMs are designed to ensure the motor’s output performance within a limited cost. Simultaneously, demagnetization criteria are proposed. By adjusting the thickness of the two types of PMs to meet these criteria, the demagnetization robustness can be enhanced. The final optimized motor achieves significant cost and computational savings while maintaining output torque and demagnetization resistance. Finite element analysis (FEA) and experimental results confirm that the prototype motor meets design expectations.