Efficient Approach Based on Equivalent Electric Circuit Model to Determine Rotor Bar Currents of Squirrel Cage Induction Machines

Nowadays, finite element method is the most accurate approach to study an electrical machine. However, its use in an optimization process remains often unsuitable because it can still require prohibitive calculation times. An analytical approach would then be more adapted but it should be as accurate as possible. In the case of an analytical model of a squirrel cage induction machine, currents induced in the rotor bars constitute quantities that are difficult to obtain. The equivalent electrical circuit to use should be well adapted and each of its elements has to be accurately estimated. In this article, an equivalent circuit based on bar lumped parameters is proposed and their identification is detailed. The proposed approach is validated through the comparisons of simulation results with the ones obtained by classical FEA in the case of two examples of squirrel cage induction machines with distributed and concentrated armature windings.