The basic principle and function of stepper motor drive circuit

The biggest feature that distinguishes a stepper motor from other control motors is that it is controlled by input pulse signals, that is, the total rotation angle of the motor is determined by the number of input pulses, and the speed of the motor is determined by the frequency of the pulse signal.

The drive circuit of the stepper motor works according to the control signal, which is generated by the microcontroller. Its basic principle and function are as follows:

(1) Control the commutation sequence

The process of switching phases after power on is called pulse distribution. For example, in the three-beat working mode of a three-phase stepper motor, the power-on sequence of each phase is ABC-D, and the power-on control pulse must strictly follow this sequence to control the on and off of phases A, B, C, and D respectively.

(2) Control the direction of the stepper motor

If the given working mode is positive sequence commutation, the stepper motor will rotate forward. If the commutation is reverse sequence, the motor will reverse.

(3) Control the speed of the stepper motor

If you send a control pulse to the stepper motor, it will turn one step, and if you send another pulse, it will turn another step. The shorter the interval between the two pulses, the faster the stepper motor will turn. By adjusting the pulse frequency sent by the microcontroller, the speed of the stepper motor can be adjusted.