Servo motors can be either AC or DC motors, and the two types differ in many aspects.
AC servo motor
Working principle: It is powered by AC power and controls the speed and position of the motor by adjusting the power frequency and voltage. Common types of AC servo motors include induction servo motors and permanent magnet synchronous servo motors.
Features: AC servo motors have the characteristics of stable operation, good controllability, fast response, high sensitivity, and strict nonlinearity indicators of mechanical characteristics and adjustment characteristics. In addition, AC servo motors can achieve smooth control in the entire speed range, almost no oscillation, high efficiency of more than 90%, less heat, high-speed control, high-precision position control (depending on encoder accuracy), and low inertia, low noise, no brush wear, and maintenance-free (suitable for dust-free and explosive environments).
Application areas: It is widely used in industrial automation, machine tools, printing, textiles, robots and other fields. Its high-speed response and high power density make it suitable for high-precision and high-performance applications.
DC servo motor
Working principle: It is powered by DC power and controls the speed and position of the motor by adjusting the power voltage and current. DC servo motors usually consist of a motor and an encoder.
Features: DC servo motors have precise speed control, very rigid torque-speed characteristics, simple control principles, easy use, and low price. However, DC servo motors have problems with brush commutation, which may lead to speed limitations, additional resistance, and the generation of wear particles (not suitable for dust-free and explosive environments). However, DC servo motors have good linear regulation characteristics and fast time response.
Application areas: Widely used in robotics, medical equipment, aerospace and other fields. DC servo motors have good speed and position control performance and are widely used in applications requiring precise control and response speed.
Summary
Whether to choose an AC servo motor or a DC servo motor depends mainly on specific application requirements and performance indicators. Generally speaking, AC servo motors perform better in terms of control accuracy, efficiency, noise, and maintenance-free, but the cost may be relatively high; while DC servo motors are still competitive in specific application scenarios due to their simplicity, cheapness, and ease of control.