Stepping Motor reverse phase excitation brake principle
The reverse rotation braking is shown in the following figure. The positioning point of the stepping motor is at phase B, that is, the last stop position is in phase B. Since the rotor is still excited by phase A, phase A must be OFF, phase B is excited, and the rotor is operated from phase A stable point to phase B stable point. As this operates, the rotor will surpass the equilibrium point of phase B and oscillate back and forth at the equilibrium point until it stabilizes.
On the other hand, when the rotor is operated from the A phase to the B phase, the winding of the B phase is excited to be OFF. At a certain moment when the B phase is stabilized, the A phase excitation consumes the kinetic energy of the rotor with the A phase brake, and then gives Phase B is excited and stops at the B phase stable point. Therefore, as shown in the above figure, the rotor without overshoot is gradually stopped. At this time, the moment when the brake excitation current starts and the braking time greatly affect the braking effect. Therefore, in order to achieve the braking effect, it is necessary to feed back the speed or position signal of the rotor for closed-loop control to determine when to make the brake reverse excitation.