How to Adjust the Speed of the Stepper Motor

With the rapid development of electronic technology, the performance index of frequency control of motor speed can reach up to or even exceed the system of DC motor speed regulation. By adjusting the pulse frequency of the input driver and subdivision parameter, the speed of the stepper motor can adjust. The control of speed is the step number of the stepper motor in a unit time.

1. Change the Number of Pole Pairs

Advantage

(1) No additional slip loss, high efficiency.

(2) The control circuit is simple, easy to maintain, low price.

(3) Cooperate with stator voltage regulation or electromagnetic slip clutch, smooth speed regulation with higher efficiency can obtain.

Disadvantage

Stepless speed control can not realize, and due to the limitation of motor structure and manufacturing process, only 2-3 types of step speed regulation of pole pairs can achieve. The scope of speed regulation is very limited.

2. Frequency Control

Advantage

(1) No additional slip loss, high efficiency, the scope of speed regulation is wide.

(2) For the applications where the low load operation time is long, or the start and stop are frequent, the purpose of saving energy and protecting motor can achieve.

Disadvantage

(1) The technology is relatively complicated.

(2) The price is relatively high.

3. Commutator Speed Control

Advantage

(1) It has a simple structure of AC synchronous motor and good speed regulation performance of DC motor.

(2) At low speed, using power supply voltage. At high speed, the back EMF of the stepper motor is used for natural commutation, which is very reliable.

(3) No additional slip loss, high efficiency, which is suitable for start-up and speed regulation of high speed and large-capacity synchronous motor.

Disadvantage

(1) The over-load capacity is low, and the original motor capacity can not be fully utilized.

4. Cascade Speed Control

Advantage

(1) The slip energy generated in the process of speed regulation can be used for feedback.

(2) High efficiency.

(3) The capacity of the device is proportional to the speed regulation range, which is suitable for 70%-80% speed regulation.

Disadvantage

(1) Low power factor.

(2) Harmonic interference.

(3) No braking torque at normal operation.

(4) Suitable for loads in single quadrant operation.

5. Stator Voltage and Speed Control

Advantage

(1) The circuit is simple, the device is small, and the price is cheap.

(2) It is convenient to use and maintain.

Disadvantage

(1) The speed regulation scope is small.

(2) High-slip motors are required, such as torque motor.

6. Electromagnetic Slip Clutch Speed Control

Advantage

(1) Simple structure, small control device capacity, and low value.

(2) Reliable operation and easy maintenance.

(3) No harmonic interference

Disadvantage

(1) The speed loss is very large, the maximum speed of the output shaft is 80%-90% of the synchronous motor.

(2) In the speed regulation process, the slip power is all converted into the loss of heat energy, the efficiency is low.

7. Rotor String Resistance and Speed Control

Advantage

(1) Low technical requirements, easy to master.

(2) Low equipment cost

(3) No electromagnetic harmonic interference.

Disadvantage

(1) Cast iron series resistance can only be adjusted in steps. If the liquid resistance is used for stepless speed regulation, the maintenance is very high.

(2) The additional slip energy in the speed regulation process is all converted into the loss in the form of heat

(3) The speed regulation scope is not large.