Greetings,

I'm building control panel for 5 BLDC motors.

My question are:

1. Can BLDC be controlled with PWM?
I ask this because brushless DC motors are electronically commutated. So in fact I'm messing up allready electronic pulses that drive originally coils.

2. If they can be controlled with PWM, which PIC to use?
PIC 16f628 has only one PWM channel and 16f876 two channels, I need 5 that have diffrent signals on it, in the same time.

3. Well I want to control all 5 motors and since I never used PWM in PIC, does PWM work in background like TMR0?
Because I want to have graphic percentage of speed of all 5 motors on LCD. Also pushbuttons need to be read for control of motors, all in the same time.

Thank you.

 

Hardware PWM is entirely in the background, you simply set it to the value you want and leave it.

PWM control of brushless motors is entirely dependent on the particular motor concerned - obviously the best way is to control it via it's own electronic control system.

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http://www.winpicprog.co.uk

 

Uuuu, thanks for quick response.

Thank god that PWM is in background!

It's no secret I think to control 12V BLDC in PC, they are sensorless.
Yes definitely direct control of coils would be best, but I want to make "Plug'n'Play" device, so there is no need for additional changes on the BLCDs.

 

Standard PWM driven, H-bridge driver circuits will not work with multi-phase brushless DC motors. There are usually 3 phase windings that need timing between the windings via a speed sensing feedback. The good news is that the radio control hobby industry has well designed brushless motor driver units that interface via standard hobby servo PWM. They come rated (and priced) for a their maximum current rating.

Lefty

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Measurement changes behavior

 

I'm not trying to implement H bridge, because I don't need both direction, anyway they have internal diode that protects electronic circuitry from wrong polarity.

If I buy complete circuit than I won't learn anything, well that's no good.

 

Understood, I just meant that we need to know more about your brushless DC motors, how many wires does each have? voltage and current requirements? etc.

Lefty

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Measurement changes behavior

 

Well, they are working on 12V DC, 2 wiress, it's specified 0.15A, speed 2500 revolutions per minute, no sensor for speed(revolutions per minute).

But I will solve 'outside' circuitry, problem are above questions.

Thanks