Dynamic Model of a Line-Start Permanent Magnet Synchronous Motor Equipped With Hybrid Rotor

This article presents a dynamic model allowing fast response predictions for a hybrid-rotor line-start permanent magnet synchronous motor (LSPMSM) operating at self-start processes with different load conditions. The model development starts with the modification of the motor state equations so as to consider the d- and q-axis coupling effects that could be neglected when the motor cores are assumed to be infinitely permeable but prevail in actual cases where the motor cores have a nonlinear magnetic property. Some critical motor parameters that periodically pulsate at a nonzero slip are then simplified into constant ones, and consequently, it can be ensured that the stator currents remain almost unchanged with negligible variance in output torque. Afterward, a model matching with the studied motor is developed by substituting the simplified motor parameters into the developed state equations. Finally, the accuracy of the developed model is validated by finite-element analysis and prototyping tests.