Torque Ripple Minimization, Suppress Harmonics, and Noise of Brushless Pm Synchronous Motors Derived by Field Oriented Control

Conventional field oriented control for brushless PM synchronous motor depends upon mathematical model so the parameters variations, noise, electromagnetic interface, non-sinusoidal flux and harmonics in the motor or in power converter will cause performance deteriorating of the drive system. They are causing speed oscillations, ripples in torque, ripples in current and an increase the total harmonics distortion (THD). This paper is addressed these problems and suggested novel two PI controller for solving these problems. One for the torque and the other for the flux. The first PI controller is feeding from the torque error between the reference and estimated torques to get new q-axis current component representing modifier current arises from uncertain things such as earliest problems. This current will add to reference q-axis current to get robust new q-axis current to satisfy the drive requirement and solve the torque problem. With robust current, the total harmonic distortion is a decrease but doesn’t reach the best value so the other PI controller is used to adjust the THD. In this PI controller, the d-axis flux is compared to rotor permanent magnet flux to solve this problem arises from non-sinusoidal of the magnetic flux. The output of the PI controller is introduced to the reference d-axis current. The new d-axis current will reach the best value of THD. The simulation of the proposed controller is compared to the simulation of conventional controller to show the advantages of the proposed controller. To display the effectiveness of the second PI controller (flux controller), the result of the new controller is displayed with new PI torque controller only and with new two proposed controller. MATLAB SIMULINK is used to simulate the drive system.