The drive circuit must meet requirements such as current waveform optimization, power consumption control, and microstepping functionality. Common technologies include chopper drive, frequency modulation and voltage regulation drive, and microstepping drive. Unipolar drives simplify circuit design through center-tapped coils, while bipolar drives require a high-cost upper-end module but eliminate the need for clamping circuits. Stepper motors are mainly used for feed motion control in CNC machine tools, featuring high open-loop control accuracy, but are susceptible to vibration noise and step loss. Control signals include step pulses (PUL), direction pulses (DIR), and free signals. Drive modes cover full-step, half-step, and single/double-step combinations.
When selecting a stepper motor drive system, the following performance parameters should be given special attention:
Step Angle: This is the angle the motor rotates for each received pulse signal. Common values include 0.9° and 1.8°. The smaller the step angle, the higher the positioning accuracy.
Holding torque: The maximum torque the motor can output when energized, directly affecting load capacity.
Number of phases: Usually two-phase or three-phase. More phases result in smoother motor operation, but also higher cost.
Current: The current output by the driver directly affects the motor's torque and heat generation; it must be selected appropriately based on load requirements.
Microstepping: The driver further subdivides each step angle, improving the smoothness and accuracy of motor operation. Common microstepping values include 16, 32, and 64.