Magnetic field and rotor impedance analysis of solid rotor induction motors using the multilayer analytical method

Abstract

This paper proposes a multilayer analytical model for calculating the magnetic field and equivalent circuit parameters of solid rotor induction motors (SRIM), and the B–H curve of rotor material is used to consider the influence of saturation effect of solid rotor. The equivalent circuit of SRIM based on surface impedance theory can fully consider the influence of rotor material. Then, the magnetic vector potential in the rotor is solved in the three-dimensional electromagnetic field, and the rotor is segmented along the axial direction to obtain the end coefficient considering the axial non-linear effect of the rotor. The air gap magnetic field distribution, rotor loss, rotor impedance and torque were analysed by finite element simulation, and the accuracy of the multilayer analytical model and end coefficient was verified. Compared with the finite element method, the analytical method proposed in this paper is time saving, resulting in that it is suitable for the optimised design. Finally, an experimental prototype is developed and tested, confirming the accuracy of both the finite element simulation and the analytical model.