What supply voltage is ideal for a stepper motor driver?


What supply voltage is ideal for a stepper motor driver? Many users experience that 12V, as used in 3D printers is too low. Is 24V better, or even 36V? Is it true, that generally a higher voltage is better for best microstepping quality and best dynamics?


This is very dependent on the actual motor and its operating conditions like mechanical load, kind of load, and target velocity. Basically, it is correct, that higher voltage allows higher motor velocity, or more torque at higher velocity. But it does not make sense to raise the voltage above this point.

* Microstepping quality at low velocity will be good from the point, where the full motor current can be achieved:
  Supply >= Rcoil*IRMS*1.41

* Chopper noise with spreadCycle is good with a multiple of at least 3-4 of this voltage:
  Supply >= 3*Rcoil*IRMS*1.41

* Motor resonance with stealthChop (and spreadCycle) is low for most motors, as long as the supply voltage is higher than the motor coil voltage including motor back EMF:
  Supply >= (Rcoil*IRMS*1.41) + Motor-Back-EMF voltage at desired velocity
  This is, because the chopper can reach full sine wave motor current, as long as the equation is fulfilled.

Back EMF voltage=CBEMF * (Velocity[RPM] / 60) * (2 Pi)

A further raise in motor voltage will normally not bring improvement when using stealthChop. A higher voltage will result in the PWM having to scale down to low values when the motor is at low velocity. This leads to bigger minimum steps in the current regulation loop, making the result more coarse and thus leading to reduced precision.

With spreadCycle, a further increment in voltage will not harm. It brings slightly lower chopper noise.

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