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How to determine the pwm frequency of DC motor drive
- Dec 06, 2018 -

How to determine the pwm frequency of DC motor drive

How to Determine the PWM Frequency Driven by DC Motor——Personal Comprehension in the Improvement of Dream Car

In the article "The dream car is strong and healthy", it is mentioned that the new motor can not work normally under the original driver. This article will detail the original.

First, the cause of the problem

This problem was encountered when I first involved the DC motor drive. I could go through all the information and didn't give me a perfect answer, because I always thought that the PWM frequency should be selected according to the characteristics of the motor.

The characteristics of DC small motors vary widely. Generally, the motors of remote control toys are usually less than 1A. This is to reduce the cost of the drive circuit. It is usually driven by 8050 and 8550.

The motors at the remote model level are different. Their target is speed, so the motor usually has 10A or even tens of amps. The reader can search for the ESC for the model (electronic governor, also PWM control mode), those The indicators are 50A, 90A, 130A, etc. The first time I saw them are "halo"! Look at the photos, which one is not a bunch of MOS tubes in parallel? So the price is not cheap, usually hundreds of thousands.

Generally, the geared motor used for industrial control is not. Because of the large reduction ratio and the voltage is generally 12V, the current is usually very small. At several hundred milliamperes, the normal working is only a few tens of milliamps. This is because they Low power consumption is required to increase reliability.

The discussion of the PWM mode of motor control seems to be more for the second category. Because PWM control is more important to the remote control model. Remote control toys generally do not regulate speed, and the H-bridge is only for reversing. Since the industrial control has a very low speed after deceleration, the speed regulation is no longer urgently needed, and the direct-on-off control can meet most of the requirements.