Microstepping
Microstepping is achieved by using pulse-width modulated (PWM) voltage to control current to the motor windings. The driver sends two voltage sine waves, 90 degrees out of phase, to the motor windings. While current increases in one winding, it decreases in the other winding. This gradual transfer of current results in smoother motion and more consistent torque production than full- or half-step control.
From https://www.linearmotiontips.com/microstepping-basics/
