Computationally Efficient Design and Optimization Approach of PMa-SynRM in Frequent Operating Torque–Speed Range

Abstract

This paper proposes a design process of permanent magnet assisted synchronous reluctance motors (PMa-SynRM) intended for vehicular propulsion. This approach takes into account range optimization and a multiphysics evaluation without the use of finite element analysis during the electro-magnetic-thermal optimization stage. The design process is based on a predesign stage to calculate a first approximation of the motor dimensions. The geometry obtained in the predesign step is used to initialize a genetic algorithm during the optimization process, which evaluates different motor designs by means of coupled magnetic, thermal, and electrical models. The magnetic model is based on a nonlinear reluctance network, which calculates the inductances and magnet flux linkages. The temperature dependence of the phase resistance and the temperature distribution in the main parts of the machine are obtained from a lumped thermal network. Once obtained the electrical parameters of the machine, its behavior can be assessed considering current and voltage restrictions, by means of a dq model that evaluates the iron and copper losses. The optimization process is based on a multiobjective cost function within a torque–speed interval.