Stepper and servo motor drive selection application
1 Introduction of the characteristics, advantages and disadvantages of stepper and servo motor
1.1 Introduction of two motors in point control or speed control applications
Stepper and servo motors are mainly used for precise positioning applications, and can also be used for speed control applications. Stepper motors are generally not used for power due to their low efficiency; they are not recommended for torque control due to certain torque ripple. The servo system can be used for torque control, and it is also considered to replace the variable frequency drive for power.
When the stepping motor is used for speed regulation, the control command usually uses a pulse command to adjust the pulse frequency to adjust the speed. Compared with the frequency converter speed regulation, it has the advantages of large low speed torque, easy control start and stop, and short acceleration and deceleration time (under the appropriate voltage and load conditions, the target speed can be achieved in 100 milliseconds). Moreover, the speed regulation range is wide, and under the condition that the load inertia ratio is matched reasonably, an additional speed reduction mechanism is usually not required. The disadvantage is that the operating noise is relatively large.
Servo motor for speed control application has the advantage of short acceleration and deceleration time compared with variable frequency speed regulation. Usually, it can achieve the expected speed in tens of milliseconds, and the speed regulation range is wider. When doing speed control and torque control applications, the control signal suggests using an analog voltage signal.
2 Motor selection and application experience
2.1 Motor drive selection method
Equipment manufacturers can refer to the following methods when selecting the motor:
1) the use environment, the required level of protection, operational noise indicators, temperature rise indicators, etc.;
2) Determine mechanical specifications, load, rigidity and other parameters;
3) Confirm the action parameters: speed, stroke, acceleration and deceleration time, period, accuracy, etc.;
4) Calculate the load inertia and select the motor inertia;
5) Calculate the torque required by the motor;
6) Select the motor with the highest speed to meet the application requirements.
Equipment manufacturer related personnel can obtain this information according to the following division of labor
2.2 Application experience
1) Reasonable assembly connection between motor and load.
2) Pay attention to the heat dissipation of the drive and motor.
3) Optional drive, power supply, reasonable current setting, subdivision.
4) Proper electrical connection and reasonable electrical assembly process.
5) Design a reasonable motion curve.
