One Analytical Method Based on Winding Function Theory and Magnetic Equivalent Circuit Model for Electromagnetic Analysis of Induction Motors under Healthy Condition and Broken-Rotor Bar Fault

In this paper, one hybrid analytical model (HAM) based on winding function theory (WFT) was presented for cage-rotor induction motors (CRIMs), which helps from the magnetic equivalent circuit (MEC) for considering the effect of slots and magnetic saturation in stator and rotor cores. A non-linear MEC model is used to calculate the magneto motive force (MMF) drops in iron parts of stator and rotor for every operating point under the healthy condition and broken-rotor bar (BRB) fault. The distribution of MMF drop in stator and rotor is separately expressed in terms of the distribution of equivalent virtual currents and the virtual winding function. The inductances are then calculated using WFT while considering the effect of slots and magnetic saturation. To model the starting of no-load CRIM, the system of electrical and mechanical differential equations is solved using the finite difference method (FDM) under the healthy condition and BRB fault. Hague's solution and one simple conformal mapping (CM) are used to calculate and analysis of air-gap magnetic field. To verify the proposed model, some analytical results are compared with the corresponding results obtained through finite element method (FEM).