Improved dq model and analytical parameters determination of a Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) under saturation using Frozen Permeability Method

The classic dq model does not take into account the machine's saturation and cross magnetization. This paper presents an improved dq model and a new technique to determine the electromagnetic parameters of a PMa-SynRM under saturation condition. These parameters are computed by means of an upgraded analytical magnetic model of the motor and the Frozen Permeability Method (FPM) is applied to separate the magnetic field sources effects, keeping the same magnetic state of the steel sheets as the one at the operation point. Permanent magnet flux in both dq-axis, apparent and incremental inductances are determined and they are implemented in a complete dq model. This model is validated by means of an accurate representation of PWM harmonics in relation to a numerical model implemented in Matlab/Simulink where the motor is represented by a flux map.