Stepper Motor Drive Subdivision

- Nov 02, 2017-

1 stepper motor is an open-loop servo motion system implementation of the elements to control the pulse, the output angular displacement. Compared with the AC servo motor and DC servo motor, its outstanding advantages is the low price, and no accumulation of error. However, the stepper motor running there are many shortcomings, such as low-frequency oscillation, noise, resolution is not high, but also seriously restricted the scope of application of stepper motor.

The performance of the stepper motor is closely related to its stepper driver, which can overcome the shortcomings of the stepper motor by improving the drive technology. Compared with other driving methods, subdivision drive mode can not only reduce the Stepper Motor stepping angle, improve the resolution, and can reduce or eliminate low-frequency vibration, the motor running more smoothly and evenly.

In general, the subdivision-driven control is the best. Because the commonly used low-end stepper motor servo system without encoder feedback, so as the motor speed increases its internal control current correspondingly reduced, resulting in lost step phenomenon. So the speed and accuracy requirements of the field is not high, its application is very extensive

Subdivision drive is high precision, the subdivision is the driver will be issued by the superior device for each pulse according to the drive set the subdivision coefficient is divided into coefficient pulse output, metaphor stepper motor every turn for 200 pulses, if the stepper motor driver Subdivided into 32, then the stepper motor driver needs to output 6400 pulse stepper motor to turn around. Usually subdivided into 2,4,8,16,32,62,128,256,512 ....

In foreign countries, for the stepper system, mainly using two-phase hybrid stepper motor and the corresponding subdivision drive. But in the country, the majority of users of the "breakdown" is not a special understanding, and some just think that the breakdown is to improve the accuracy, it is not true, the breakdown is mainly to improve the motor performance.

It is described as follows: stepper motor subdivision control is precisely controlled by the driver to stepper motor phase current to achieve, to two-phase motor, for example, if the motor rated phase current of 3A, if the use of conventional drives (such as commonly used Constant current chopping mode) to drive the motor, the motor running every one step, the current within the winding will change from 0 to 3A or from 3A to 0, phase current changes, will inevitably cause the motor to run the vibration and noise.

If the subdivision drive is used, the motor is driven in a 10-segmented state. The motor has a slight change in current within the winding of only 0.3A instead of 3A, and the current changes with the sinusoidal curve. Improve the motor vibration and noise, therefore, the performance advantage is the real advantage of subdivision. As the subdivision drive to accurately control the motor phase current, so the stepper motor driver to have a very high technical requirements and process requirements, the cost will be higher.

that some of the domestic drive to use "smooth" to replace the subdivision, and some also known as the breakdown, but this is not a real breakdown, hope the majority of users must distinguish between the two different nature:

1. "Smooth" does not precisely control the motor phase current, but the rate of change in the current rate of some slow, so "smooth" does not produce micro-step, and subdivision of the micro-step can be used to accurately locate.

2. The motor phase current is smoothed, will cause the motor torque to decline, and subdivision control will not only cause the motor torque decline, on the contrary, the torque will increase

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