Working Principle Of DC Servo Motors

DC servo motors achieve precise control by adjusting the armature voltage or current.

 

Basic Electromagnetic Principle: Its working principle is based on the law of electromagnetic induction and Fleming's left-hand rule. When current flows through the armature (rotor) winding, it experiences electromagnetic force in the magnetic field generated by the stator (produced by either permanent magnets or excitation windings), thereby producing electromagnetic torque that drives the rotor to rotate.

 

Speed Control Method: For common permanent magnet DC servo motors, the magnetic flux is constant, and the speed is mainly controlled by adjusting the average voltage applied across the armature. Modern drivers generally use Pulse Width Modulation (PWM) technology, which linearly changes the average voltage by altering the duty cycle of power switches, achieving smooth speed control.

 

Closed-Loop Control Implementation: DC servo motors generate power through the above electromagnetic principles and rely on closed-loop control composed of sensor feedback and driver computation to achieve fast and accurate response to input signals. Its control characteristics include a small electromechanical time constant and high linearity, allowing the output (speed, position) to closely follow input changes.