Time efficient FEM modeling of a PMSM by iteration between field calculations and state

This paper investigates a time efficient method for estimating the iron losses in a permanent magnet motor using FEM modeling. The methodology comprises of using iteration between FEM electromagnetic simulations and Analytical state space modeling. Results show that by using fast field calculations as input to the state space model accurate mean torque calculations can be made, even during high saturation, eg deviating only 0.7% at three times the rated torque. This high accuracy is reached due to an improved torque calculation method compared to models used in previous work. The methodology is based on that the current response obtained from the analytical calculations have been fed back to the FEM calculations for determination of the magnet and iron losses in the motor, reducing the simulation time significantly compared to a voltage fed FEM model. The temperature dependence of the magnet strength and stator resistance have also been taken into account when comparing the simulation result with measurements.