Motor drives and control

Summary form only given, as follows. The presentation will go over motor drive fundamentals including dc motor control and ac induction motor control. In general, the motor drive includes two control loops: (1) speed and (2) current. The speed loop normally deals with field and torque commands, and the current loop is to control the instantaneous armature current. Such a general motor drive control concept is applicable to both dc and ac motors. With understanding of dc motor speed control, the rationale for the need of ac motor vector control will be derived. Different vector control methods will be explained using the decoupled equivalent circuits. In terms of current control, both dc and ac motors need the so-called pulse-width-modulated (PWM) converters or inverters to regulate the current. Different PWM techniques will be explained in this presentation. Finally the PWM inverter related motor drive issues will be addressed.