Design Optimization of a PM Motor: A Practical Approach for Mass Production

This article discusses design and optimization of a permanent magnet (PM) motor for electric transmission oil pump (eTOP) applications. The PM motor is fed from the vehicle low voltage battery system (12 Vdc) and drives a mechanical pump assembly (MPA) in a generated-rotor (Gerotor) configuration. The eTOP is accommodated inside the transmission where it supplies required oil flows at specified pressures for lubrication and cooling purposes. The optimization is formulated as a multi-objective problem that is solved using a differential evolution (DE) algorithm. An existing PM motor is used as a benchmark machine against which an optimized solution for mass manufacturing considering real-world application constraints is proposed. A 3-phase winding approach that facilities a needle winding process is considered for the eTOP PM motor. Once the optimized solution is found the PM motor's performance is evaluated and presented. To validate the design a prototype PM motor with production materials and tooling is built and tested. The comparison of measured and predicted results shows good agreement.