Mamo, Mengesha (PhD)Eskezia, Derege2018-06-282023-11-282018-06-282023-11-282016-05http://etd.aau.edu.et/handle/12345678/4628Permanent magnet synchronous motor (PMSM) is the most used drive in machine tool servos and other modern high performance applications. In this thesis, a quasi-continuous higher order sliding mode controller is designed for PMSM in order to regulate the desired reference speed with robustness and minimized chattering. Proportional, Integral and derivative (PID) controllers are also designed for direct and quadrature components of the current in order to control the flux and torque. For the investigation of the problem, the controller is tested through a reference speeds as well as with load variations through simulation using MATLAB/SIMULINK. In the simulation, the SVPWM algorithm was written in M-file and embedded on simulation block. To make system control simple, field oriented control (FOC) is used for the operation of the motor to control the torque and flux of the motor directly as DC motor. Simulation results demonstrate that the speed response of the proposed drive is unaffected by load torque and parameters variation. Furthermore, the developed controller has good performance when the reference speed is changed, i.e., the developed controller speed regulation is unaffected by the nature of the reference speed. From the simulation result, the speed error in steady state response is zero, the speed response has a maximum over shoot of 1.08% and the chattering effect on the system is reduced. Keywords: PMSM, HOSM controller, FOC, quasi-continuous HOSM controller, chattering effectenPMSM; HOSM controller; FOC;quasi-continuous HOSM controller; chattering effectThesis