Hysteresis effects of laminated steel materials on detent torque in permanent magnet motors

Hysteresis effects of laminated steel materials on the detent torque in permanent magnet (PM) motors are described physically. There are many methods to simulate hysteresis effects. However most studies only focus on loss calculation but not on other important issues. Based on field orientation interpolation method, four-quadrant hysteresis effects are taken into consideration in the proposed cogging torque computation. Simulation results using finite element analysis (FEA) show that laminated materials with high hysteresis effects give higher detent torque when compared to those with narrow hysteresis loops. Two brushed type PMDC motors, with a 4-pole, 22-slot configuration and with different laminated steel materials, are built, and their test data are used to validate the analysis.