Speed Control of DC/AC Motors

Speed control is essential in motor operation, referring to the regulation of motor rotational speed. There are several primary methods for motor speed regulation, including open-loop control, closed-loop control, vector control, direct torque control, and slip frequency control. Among these, open-loop and closed-loop control are the most commonly used approaches. Open-loop control adjusts motor speed by varying the input voltage without feedback, while closed-loop control utilizes real-time speed feedback to dynamically adjust voltage for precise regulation. Vector control represents a more advanced technique that enables simultaneous control of both motor speed and torque through coordinate transformation algorithms. Direct torque control focuses on managing motor torque while maintaining constant speed, employing hysteresis comparators and switching tables for rapid torque response. Slip frequency control achieves speed variation by modifying the power supply frequency, particularly effective in AC induction motor applications.

To facilitate deeper understanding of DC/AC motor speed control, accompanying source code examples are provided for reference and study, demonstrating practical implementation of PID controllers, space vector modulation, and flux observers in embedded systems.