Co-simulation model combining dynamic control and FEM for evaluation of PMSM drive cycle performance

A novel co-simulation model, combining motor FEM simulations in Ansys Maxwell with an inverter and control system in Twin Builder and MATLAB/Simulink, is presented. The objective is to more closely resemble real-life motor performance and assess high-frequency effects and motor losses of different supply and control systems. The effects from a three-phase two-level inverter with pulse-width modulation for three different switching frequencies on motor losses, efficiency, and torque ripple have been evaluated. The results have been compared against an ideal sinusoidal current supply, ideal voltage supply and a built-in toolkit provided by Ansys Electronics. The WLTP drive cycle has been used, quantified using Energy Center of Gravity. The results show that a current source is insufficient to evaluate motor efficiency and torque ripple, with differences most visible at low energy operating points. With switching, the overall drive cycle efficiency differs by almost half a percent compared to a current source. While the switching frequency is high enough compared to the fundamental frequency, the differences in efficiency for varying switching frequencies are almost negligible. For high speeds, an efficiency increase can be seen when the switching frequency is lowered. The increase in losses due to current ripple is negated by a decrease in the average current magnitude. • Novel model for more realistic drive cycle PMSM performance. • Co-simulation of finite element methods with dynamic motor control model. • PMSM drive cycle efficiency evaluated with switching dynamics implemented. • Large differences in efficiency between ideal current source and SPWM. • Lower switching frequency may increase motor efficiency at high speeds.