Transient simulation of lamination material properties in electrical machines

All zero-speed-sensorless control schemes of electrical drives use a high-frequency excitation of the machine to determine local differences of the leakage inductances and to estimate the flux or the rotor position. One of these methods detects the local differences by evaluating the change of the stator current space phasor due to stator voltage test phasors. To get a deeper insight into the transient electric behavior of the machine, it is necessary to take into account also dynamic processes in the lamination material. To achieve this, a model has been developed to simulate the magnetization process in an induction motor fed by a voltage-source inverter. The proposed model calculates the current change due to voltage pulses taking into account the hysteresis as well as eddy currents. In order to limit the computation time, the model has to be kept simple. Measurements on an inverter-fed induction machine as well as on a stator lamination are presented. to verify the applicability of the model.