Comparison of Performances of PMLSM Fed by Two Power Supplies

Inverters provided non-sinusoidal voltage or current, and the tooth-slot and winding distribution of the motor could lead to a mass of space harmonic components, severely deteriorating the motor performance. In order to know the cause of electromagnetic thrust and mover velocity fluctuation of low-velocity PMLSM fed by SPWM-VS, the steady-state performances of low-velocity PMLSM are analyzed in this paper. the performances of permanent magnet linear synchronous motor by sinusoidal pulse width module voltage source inverter (SPWM-VI-PMLSM) and sinusoidal voltage source inverter (S-VS) were researched used the field-circuit coupled adaptive time-stepping finite element method. The characteristic of having thick air gap is considered in the field-circuit 2D model. The cosimulation using state equation and time-step finite element equation is used, the time step of the state equation is smaller than that of the time-step finite element equation. PWM-VI-PMLSM and S-VS-PMLSM have the same current periodicity and similar current amplitude. The current of SPWM-VI-PMLSM has various harmonic components distorted as a result of magnetic saturation and non-sinusoidal air gap field. The tangential electromagnetic thrust of SPWM-VI-PMLSM under steady state oscillate with a period decided by pole pitch, and it has various harmonic components dampening thrust fluctuation, Thus S-VS-PMLSM has better performance than SPWM-VIPMLSM. S-VS-PMLSM and SPWM-VI-PMLSM have the same periodicity of slip fluctuation, the slip value of SPWMVI-PMLSM is larger than that of S-VS-PMLSM. The simulation results accords with experimental data.