ABSTRACT

 This research is aimed at modeling and simulating permanent magnet synchronous motor for improved performance using Matlab/Simulink for the analysis. The Matlab function program which is based on an explicit Runge-Kutta fourth order numerical method to solve a set of first order differential system of equations describing electrical and mechanical models was developed. Matlab m-files were developed and used to solve the Runge-Kutta fourth order method for both transient and steady state. 1 he motor differential equations are expressed in rotor reference frame with q- and d-axes stator currents, mechanical rotor speed, and rotor angular position as state variables. In this research, two motors (IPMSM and SPMSM) were modeled and simulated first without loading and varying the motor parameters before it is varied and loaded. I he motor used in this thesis is a 3-phase, 2 KW, 50 Hz, 4 poles, 220 V permanent magnet synchronous motor (IPMSM and SPMSM). The result of a typical transient and steady state responses of the motors were obtained which reveal that when core loss is introduced to the motor, it decreases the magnitude of the ripple of electromagnetic torque and output power but affects the speed ofthe motor as it takes more time to attain steady state. Increase in frequency leads to increase in motor synchronous speed (1500 rpm to 2250 rpm to 3000 rpm for 50 Hz, 75 Hz and 100 Hz respectively), and slightly increased electromagnetic torque and output power. The results also show that three phase currents have less distortion and torque curves have very little ripples. Hence SPMSM has the advantage ofless overshoot, lower torque pulsation and quick response but cannot be loaded beyond 22 Nm otherwise the motor goes out ofsynchronism, while on the other hand IPMSM shows more ripples, overshoot, slower response but is capable of carrying load of up to 90 Nm. The effect of higher stator resistance shows that it minimizes the magnitude of ripple of the output characteristics (torque, power and speed) but maintains the same steady state value, while the effect of increase in viscous friction coefficient decrease the magnitude ofripple and increase the value ofthe steady state. In the same vein, variation ofmoment ofinertia has little or no effect on the output characteristics of the motor. The effect of saliency caused by reluctance torque showed that the load angle during the rated operation increases, and so the pull-out torque is obtained at the power angle greater than 90°. The maximum fundamental and electromagnetic torque is achieved at saliency ratio of 0.5. The results obtained in this work as compared to other literatures show improved design of IPMSM and SPMSM with clear undeistanding of the parameters required of a particular motor for best operating performance.