A novel hybrid model of electromagnetic performance for induction machine

Abstract

This study represents a new hybrid analytical method for predicting magnetic flux distribution and electromagnetic performance criteria of induction machines. This hybrid analytical method proposes to combine magnetic equivalent circuit (MEC) and subdomain. The combined method's fundamental contribution is that an easy calculation of magnetic flux density is presented by considering steel permeability. On the other hand, the induction machine takes a lot of computation time in both steady-state and transient regimes while analyzing the finite element method. Therefore, another contribution is that the proposed method provides a great time saving since it performs the analysis directly in the stable regime. Firstly, the subdomain method, which uses the Fourier series to calculate magnetic flux distribution in the air-gap, is applied to improve the simplicity of the induction machine's modeling in this study. Therefore, magnetic flux distribution at an infinite permeability state is easily obtained. The magnetic saturation effect is then calculated through reluctances on the magnetic core simultaneously in each machine's movement. Furthermore, the proposed combined MEC and subdomain are applied to improve electromagnetic performance prediction, taking into winding leakage and steel core saturation. Defined reluctances in the hybrid analytical model can be selected resiliently according to magnetic saturation. Moreover, the electromagnetic criteria such as back-EMF and output torque at both no-load and on-load state are calculated by the proposed combined MEC and subdomain. Finally, the proposed analytical model is verified by the finite element method. Comparing results shows that the hybrid analytical model agrees well with the finite element method.