Stepper motor suppliers share three driving methods of stepper motor drivers

Stepper motors and stepper motor drivers constitute a stepper motor drive system. The performance of the stepper motor drive system not only depends on the performance of the stepper motor itself, but also depends on the quality of the stepper motor driver. The research on stepper motor drivers was carried out almost simultaneously with the research on stepper motors.

Stepper motor drivers have three basic stepper motor drive modes: full-step, half-step, and subdivision. The main difference lies in the control accuracy of the motor coil current (i.e. the excitation method). The editor below will introduce to you the characteristics of these three driving methods.

1. Full step drive

In full-step operation, the same stepper motor can be equipped with a full-step/half-step driver or a subdivision driver, but the operating effects are different. The stepper motor driver cyclically excites the two coils of the two-phase stepper motor according to the pulse/direction command (i.e., the coil charging set current). Each pulse of this driving method will cause the motor to move a basic step angle, that is, 1.80 degrees. (A standard two-phase motor has a total of 200 step angles per revolution).

2. Half-step drive

During single-phase excitation, the motor shaft stops at the full-step position. After the driver receives the next pulse, if it is excited to another phase and maintains the original excitation state, the motor shaft will move half a step angle and stop. In the middle of two adjacent full-step positions. Exciting a two-phase coil in one phase and then two phases in this manner will cause the stepper motor to rotate in half steps of 0.90 degrees per pulse. All full/half-step drives provided by the motor are available in both full-step and half-step drives, selected by the drive DIP switch dial. Compared with the full-step mode, the half-step mode has the advantages of twice the accuracy and small vibration during low-speed operation. Therefore, the half-step mode is generally used when full/half-step driving is actually used.

3. Split drive

The subdivided driving method has two advantages: minimal low-speed vibration and high positioning accuracy. For stepper applications that sometimes require low-speed operation (that is, the motor shaft sometimes operates below 60rpm) or that require positioning accuracy less than 0.90 degrees, subdivision stepper motor drivers are widely used. The basic principle is to accurately control the current of the two coils of the motor according to sine and cosine steps respectively, thereby dividing the distance of one step angle into several sub-steps. For example, the sixteen-step driving method can make a stepper motor with 200 standard steps per revolution reach an operating accuracy of 200*16=3200 steps per revolution (i.e. 0.1125°).

Generally speaking: in full-step operation, the angular displacement of the motor shaft is one step angle for each input pulse. In half-step operation, the angular displacement of the motor shaft is half the step angle of each input pulse. trumpet. It is best not to use the stepper motor in the full-step state, as the vibration will be greater in the full-step state.

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