Many users experience that 12V, as used in 3D printers for example, is too low for stepper motors. Is 24V or even 36V better? Is it generally true that a higher voltage is better for the best microstepping quality and dynamics?
This depends very much on the actual motor and its operating conditions, like the mechanical load, type of load, and target velocity. Basically, it's correct that higher voltage allows for higher motor velocity, or more torque at higher velocity. However, it doesn't make sense to increase 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
The motor resonance with StealthChop and SpreadCycle because the chopper can reach a full sine wave motor current as long as the following equation is fulfilled: Back EMF voltage=CBEMF * (Velocity[RPM] / 60) * (2 Pi).
A further rise 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 larger 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.