The stepper motor driver can use AC power or DC power input. The principle inside the driver is to convert the input signal into a series of square wave pulses, which will be applied to the windings of the motor to power the stepper motor. The stepper motor itself can also be used as an AC motor, because even the DC power input is converted into a square wave to drive each motor winding. For stepper motors, the higher the applied voltage, the faster the current in the motor windings will rise. Therefore, a larger AC voltage input will produce more torque.
It is very important to optimize the performance of the stepper motor to match the appropriate driver. For example, a faster switching rate can be used to obtain a higher speed. But this depends on the inductance in the motor windings. Increasing the voltage of the driver can help overcome this limitation, but it can also cause higher current problems. The current must be limited to avoid burning the stepper motor windings.