A fast simulation model for permanent magnet synchronous motor (PMSM) based system

This paper presents a method for reducing the simulation execution time associated with modelling a Permanent Magnet Synchronous Motor and Voltage Source Inverter (PMSM-VSI) based drive system. The proposed method is based on an analytical estimation of the `average' ac voltage across each phase of the PMSM during each PWM switching period and then using these averages as piecewise-linear voltage sources for each motor phase. The model reproduces the functionality of the VSI and outputs 3 phase ac phase currents from a DC voltage source based on the existing PMSM motor and digital controller models such that machine and controller performance/limitations can still be evaluated and optimised. The VSI based model and average voltage model have been implemented in the PORTUNUS simulation package. Simulation results for a small <1kW PMSM shows excellent agreement of the average voltage model with the switching model over the complete operating range, including the non-sinusoidal phase current field-weakening region, but with the execution time of the average voltage model being typically five times faster.