Utilization of Finite Elements Programs and Matlab Simulink in the Study of A Special Electrical Motor

This paper presents the study of a single-phase synchronous motor with permanent magnets (PM) using some computer programs. This motor type is used especially in household applications, and it has a low power. It is known that PM synchronous motors have a great advantage consisting in the lack of rotor losses. For this motor the starting problem has been solved performing a variable air gap under polar shoes, what determine the occurrence of the starting torque due to the fact that the axis of the rotor field created by PM in the rest position differs from the axis of the stator. First the parameters of the motor have been determined by tests and finite elements (FE) simulations, without knowing the properties of the PM. At the beginning magnetostatic FE simulations have been performed and then in magnetodynamic regime. The obtained results in the two regimes are closed. Secondly, with the determined parameters, a Matlab Simulink model has been realized (this being the final goal), and the dynamic regime of the motor has been studied. The results regarding the motor speed in starting process, the current variation, are also presented and discussed. Keywords—parameters; synchronous motor; single-phase; permanent magnet; finite elements programs; Matlab/Simulink NOMENCLATURE V Nominal voltage I Total stator winding current IFe Current corresponding to the iron losses IL Magnetizing and load current L Inductance of the stator winding RCu Resistance of the stator winding RFe Resistance corresponding to the iron losses ve Voltage induced by the rotor PM g1 Large air gap g2 Small air gap Rest position of the rotor Instant rotor position (angle between the rotor and stator axes) N Number of turns of one stator coil ω Angular frequency Ω Rotor speed Vm Maximum value of the induced voltage Peak flux of the rotor PM J – Total moment of inertia of the rotor Trp – Peak reluctance torque; Tl – Load torque