Efficiency Optimization of PMSM Drives Using Field-Circuit Coupled FEM for EV/HEV Applications

This paper proposes an efficiency optimization method for the permanent magnet synchronous motor (PMSM) based powertrain by using field-circuit coupled finite-element method (FEM) for electric vehicle or hybrid electric vehicle applications. In this paper, an alterable flux-weakening (FW) angle is employed in the armature current control strategy for the FW operation. The optimal FW angle for each certain operating condition can be obtained through the pre-selection, which improves the system efficiency compared to conventional FW methods. Then, the lookup table (LUT) for optimal armature current control commands is obtained. Through using this optimal LUT in the drive system, the system efficiency can be significantly improved for the entire operation range. The time-stepping FEM is used to simulate the PMSM system, which integrates the electromagnetic field analysis of the motor prototype and the control algorithm of the drive system. A 2-D transient FEM model is built for a 15 kW PMSM in ANSYS Maxwell, and a vector control circuit model is set up in ANSYS Simplorer. Experiments are carried out on the 15 kW PMSM prototype to verify the accuracy of the simulation results and the effectiveness of the proposed design method.