Modified magnetic equivalent circuit model for magnetic field analysis of one cage‐rotor induction motor used in electric submersible pumps

Abstract

Abstract Here, a modified magnetic equivalent circuit model which can accurately consider the air‐gap region is presented. The main defect of magnetic equivalent circuit model is in the modelling of air‐gap region. To solve this problem, a new approach based on conformal mappings is presented to accurately calculate the air‐gap permeances between the elements of stator and rotor while considering the real paths of flux tubes in air gap. The distributions of equivalent virtual currents on the both sides of air gap are obtained through modified magnetic equivalent circuit model, which represent the effects of slots, magneto motive force drops in iron parts, and magneto motive force sources. The conformal mapping method is then used to calculate the components of air‐gap magnetic field for every operating point under starting conditions and different loads. One typical cage‐rotor induction motor, which is used in electric submersible pumps, is considered to investigate the accuracy of modified magnetic equivalent circuit model. Some of the analytical results obtained through modified magnetic equivalent circuit model are verified by comparing with the corresponding results obtained from finite element method and experiment set up.

Keywords

• AC machines
• AC motors