PMSM Field Oriented Control using Svpwm for Control Moment Gyroscope (CMG)

Abstract

In space flight analysis it is very important to know the position and motion of the satellite. CMG(Control moment Gyroscope) are nowadays used in small satellites .The CMG depends on two motors for operation. One is a brushless DC motor(BLDC) which is used to spin the momentum wheel and the other one is a stepper motor used to gimbal the momentum wheel around an axis which is perpendicular to the spin axis. The objective of this thesis is to improve torque smoothness in CMG. For this BLDC motor is replaced with Permanent Magnet synchronous Motor(PMSM). The main disadvantage of BLDC motor is torque ripples which induce torque pulsations that deteriorate the performance of drives particularly at low speeds. In order to minimize harmonics the PWM technique used here is Space Vector Pulse Width Modulation(SVPWM). FOC(Field Oriented Control) is used to control the PMSM in order to achieve high performance control characteristics.FOC controlled PMSM drive provides better dynamic response and lesser torque ripples. The closed loop control of the PMSM drive using FOC and SVPWM is simulated in MATLAB SIMULINK.