Working principles and differences between stepper motors and asynchronous motors

Working principles of stepper motors and asynchronous motors

Working Principle of Stepper Motor

A stepper motor is an open-loop control system that controls the motor's rotation through a drive circuit. The stepper motor's rotor consists of a set of permanent magnets or electromagnets, called the "pole pair" of the stepper motor. There are two control methods for stepper motors:

(1) Pulse control method

This control method uses pulse signals to control the movement of the motor. The controller sends a pulse signal of a specific frequency to the motor drive circuit to control the number of steps and direction of the motor's rotation. Each time a pulse signal is sent, the motor rotates a certain number of steps, thereby achieving precise control.

(2) Vector control method

This control method achieves more precise motion control through vector control. It can control the motor speed and direction, and can also add acceleration and deceleration during the motion process.

Working principle of asynchronous motor

Asynchronous motor is the most common induction motor, also known as AC motor. Its rotor consists of an aluminum or copper shaft and a conductor ring, called rotor conductor. When a three-phase AC power supply is energized, a rotating magnetic field is generated. The direction and frequency of the magnetic field rotation depend on the phase and frequency of the power supply. Under the action of the magnetic field, the rotor conductor will generate an induced electromotive force, which will generate torque and cause the rotor to start rotating. Since the torque of an asynchronous motor is proportional to the square of the rotor speed, when the motor load increases, the rotor speed will decrease, thereby increasing the output torque.

In general, the stepper motor is suitable for applications that require precise control because the number of steps and direction of the motor's rotation are precisely controlled by the controller. The asynchronous motor is a simple, reliable, and simple motor suitable for most general applications.

The difference between stepper motor and asynchronous motor

Stepper motors and asynchronous motors are two different types of motors. The differences between them are as follows:

1. Working principle: The working principle of the stepper motor is to rotate the motor in sequence according to the predetermined step angle by means of electric pulses; while the asynchronous motor uses the rotating magnetic field of the AC voltage to generate an induced electromotive force on the rotor, causing the rotor to rotate continuously.

2. Precision: The stepper motor has high rotation accuracy and can achieve very precise positioning and control; while the asynchronous motor has low accuracy and is generally used in situations that do not require high-precision control.

3. Control method: The control method of stepper motor is more flexible and intelligent than that of asynchronous motor, and can achieve high-precision rotation by controlling current and pulse; while the control method of asynchronous motor is mainly carried out through components such as transformers and capacitors, and the control range is relatively narrow.

4. Power: Since stepper motors need to continuously generate drive pulses, their power is relatively low; while asynchronous motors can output greater power and are suitable for occasions that need to withstand heavy loads.

Based on the above differences, stepper motors are suitable for applications that require high-precision positioning and control, such as printing, textiles, machine tools, etc.; while asynchronous motors are mainly used in applications with large flow and high power, such as refrigeration and air conditioning, compressors, electric vehicles, etc.