The closed loop control mode of NEMA 17 closed loop stepper motor can be roughly divided into two types:

1. Keep the phase relationship between excitation flux and current consistent, so that it can generate electromagnetic torque that can drive load torque. This control method of motor current is the same as that of brushless DC motor, which is called brushless drive mode or current closed loop control method.

2. The power Angle closed loop control method is used to control the phase Angle of excitation flux and current when the motor current is kept certain. Power Angle refers to the phase Angle of mutual attraction between the magnetic pole of the rotor and the excitation phase of the stator (or the rotating magnetic field axis of the stator of the synchronous motor can also be considered). This power Angle is smaller at low speed or light load, and larger at high speed or high load.

NEMA 17 closed loop stepper motor advantages

A. With the increase of the output torque, the speed of both decreases in a nonlinear manner, but the closed loop control improves the torque-frequency characteristics.

B. Under closed loop control, the output power/torque curve is improved because, under closed loop control, the excitation conversion of NEMA 17 closed loop stepper motor is based on the rotor position information, and the current value is determined by the motor load. Therefore, the current can be fully converted into torque even in the low speed range.

C. Efficiency-torque curve is improved under closed loop control.

D, using closed loop control, can get higher running speed than open loop control, more stable, more smooth speed.

E. Using closed loop control, the stepping motor can be automatically and effectively accelerated and decelerated.

F. Quantitative evaluation of the rapidity improvement of closed loop control over open-loop control can be made by comparing the time through a certain path interval in step IV.

G. With closed loop drive, the efficiency can be increased to 7.8 times, the output power to 3.3 times, and the speed to 3.6 times.

The performance of the NEMA 17 closed loop stepper motor is superior to that of the open-loop drive stepper motor in all aspects. Step motor closed loop drive has the advantages of step motor open loop drive and dc brushless servo motor. Therefore, closed loop control stepper motors will be widely used in position control systems with high reliability requirements.