High-frequency model and parameter identification of electrical machines using numerical simulations

This paper presents a high-frequency (HF) model and the parameter identification of electrical machines in hybrid or electric vehicles. For improved results, the winding design in the finite element analysis (FEA) considers individual wires and parallel wire strands. A linear approximation of the BH characteristic of the iron sheets is carried out for the determination of the frequency dependent self inductance and resistance of one single coil. The equivalent circuit model is realized with parallel RL-branches for simulation in the time and frequency domain. Furthermore, an electrostatic solver is used to calculate the parasitic capacitances. An analytical approximation is presented for consideration of the winding overhang in the capacitance determination. The proposed HF model and its parameters are validated by measurements. There is good agreement of simulation and measurements, which proves not only the values of the parasitic capacitances, but the full HF model can be parametrized by FEA (with the exception of in-feed conductors and connector inductance).