Selection method of stepping motor and stepping motor driver
Stepping Motor, as an executive element, is one of the key products of mechatronics and is widely used in various automatic control systems.
With the development of microelectronics and computer technology, the demand for stepping motors is increasing day by day and has been applied in various fields of national economy.
Although stepping motors have been widely used, stepping motors cannot be used under normal conditions like ordinary DC motors.
It must be composed of double ring pulse signal, power drive circuit and other control systems before use.
Therefore, it is not easy to use stepping motors well. It involves many professional knowledge such as machinery, motors, electronics and computers.
Selection method of stepping motor and stepping motor driver: 1.
Judging how much torque is needed: Static torque is one of the main parameters for selecting stepping motor. When the load is large, a large torque motor is required. When the torque index is large, the motor shape is also large. 2.
Judging the running speed of the motor: when the rotating speed requirement is high, the motor with larger phase current and smaller inductance should be selected to increase the power input.
And a higher supply voltage is used when selecting the driver. 3.
Select the installation specifications of the motor: such as 57, 86, 110, etc. , mainly related to torque requirements. 4.
Determine the requirements for positioning accuracy and vibration: judge whether subdivision is needed and how much subdivision is needed. 5.
Select the driver according to the current, subdivision and supply voltage of the motor.
Stepping motors can be divided into reactive stepping motors, permanent magnet stepping motors, hybrid stepping motors, single-phase stepping motors, planar stepping motors and other types from their structural forms, hybrid stepping motors are the main stepping motors used in our country.
The operation performance of stepping motor is closely related to the control mode. From the control mode of stepping motor control system, it can be divided into the following three categories: open-loop control system, closed-loop control system and semi-closed-loop control system.
Semi-closed loop control systems are generally classified as open-loop or closed-loop systems in practical applications.
1. Reactive formula: the stator has windings and the rotor consists of soft magnetic materials.
Simple structure, low cost, small step angle, up to 1. 2 °
However, the dynamic performance is poor, the efficiency is low, the heat is large, and the reliability is difficult to guarantee.
2. Permanent magnet type: the rotor of the permanent magnet stepping motor is made of permanent magnet material, and the number of poles of the rotor is the same as that of the stator.
It is characterized by good dynamic performance and large output torque, but this kind of motor has poor precision and large step angle (Generally 7. 5 °Or 15).
3. Hybrid: Hybrid Stepping Motor combines the advantages of reactive type and permanent magnet type. Its stator has multiphase winding and rotor is made of permanent magnet material, there are a plurality of small teeth on the rotor and stator to improve the step moment accuracy.
It is characterized by large output torque, good dynamic performance, small step angle, but complex structure and relatively high cost.
According to the stator winding, there are two-phase, three-phase and five-phase series.
The most popular is the two-phase Hybrid Stepping Motor, which accounts for more than 97% of the market share. The reason is that it is cost-effective and works well with the subdivision driver. The basic step angle of this kind of motor is 1. 8 °
/Step, with the upper half-step driver, the step angle is reduced to 0. 9 °
, With the subdivision drive, its step angle can be subdivided by 256 times (0. 007 °/Micro step).
Due to friction and manufacturing accuracy, the actual control accuracy is slightly lower.
The same stepping motor can be equipped with different subdivision drivers to change the accuracy and effect.
Tags: stepper motor, stepper motor driver, Related reading: Factors affecting the price of stepper motor, three-phase stepper motor and driver current subdivision drive TAG stepper motor driver