About MC3PHAC (3 phase motor controller)

[jgoncalves]

I would like to build an inverter to drive a motor, and my first idea was about to use the monolithic intelligent motor controller with an standard IGBT module. But reading the MC3PHAC data sheet, i found out that its synchronous motor frequency is from 1Hz to 128Hz, which is too low for me. If I change the crystal/resonator frequency, will it be necessary to change all the small components values (I mean, capacitors and resistors) that are shown in the data sheet? Do you know about any other motor controller that could achieve a larger synchronous motor frequency?
I hava attached the data sheet.
I really hope someone could help me.
Thanks in advance.

Jgoncalves

Message Edited by jgoncalves on 2007-04-2303:16 PM

MC3PHAC.pdf

Message Edited by t.dowe on 2009-09-01 05:10 PM

[vwdevotee]

Hi.  I'm also looking to modify the example circuit for the MC3PHAc to increase the allowable frequency.  I'm using an induction motor that I need to drive to 400Hz though.  Going back to the original question, by modifying the oscillator frequency can the drive frequency range be changed to 0-400Hz?  Also, does the resistive brake have to be used, or can the dynamic deceleration control be used alone to keep the DC bus voltage below the threshold value?  Thanks for everything!

[gr8electronics]

I am new to this forum stuff, but have recently done LOTS of IC researcch on motor controllers... I think one that may interest you id the IR model IR2131 it says it will go to 400 Hz.

Hope this will help !

Good luck !

[mohammad]

My serial connection I have problems with IC IC send all codes code 0x2b-0x0-0x0 pulled the code, but I'll forward the revers pulled this code 0x2b-0x85-0x86 Have you send the code 0x2b-0xe3-0x10- 0x0-0x10-0x0-0xd Please help Thanks

[admin]

Hi Mohammad,

please help me as i got stucked in sending the commands to the mc3phac controller as it is not responding anything.

please help me anybody...

regards,

Poornima

[metero]

Hi,

I have to make a speed regulator for single phase 220v asynhronius AC motor. The motor has a a start coil, connected via capacitor for phase shifting, and is switched off by centrifugal switch when the speed increase enough. The range of power is from 75 to 2200 watt.

I'd like very much to use MC3PHAC for speed control, but how to use it only with one phase? And may be a separate switch for decoupling the start coil will be necsessery for start and switch it of when the motor wil work with low speed ( say, 10-15 Hz).

I'll be thankful for any advice.

[amaz]

hello...i dun know how u guys can get the PWMs output in standalone mode.I hardly tried for the mode but still could not get the PWMs output.Can i have your configuration to get the 6 PWMs out of MC3PHAC other than stated in the datasheet because i've tried it so many times.

[rocco]

Hi Jgoncalves:

The MC3PHAC was meant to control a 50 or 60 hz three-phase induction motor. It allows speed control for a motor that was designed for one speed (at line frequency). That is why its frequency range is what it is.

So the first question in my mind is: What kind of motor are you trying to control?

If it is an AC induction motor, than operating it above 128 hz will entail more challenges than just the control IC.

If it is a three-phase brushless DC motor, than the MC3PHAC may not be appropriate.

[jgoncalves]

Hi rocco! Thanks for answering!
I am trying to control a 3-phase synchronous motor.
But in the data sheet is write "MC3PHAC is... designed specifically to meet the requirements for low cost, variable-speed, 3-phase ac motor control systems". That is the reason I though it could soulve my problem.
Because what I want is a controller that could generate the 6 PWM signals, but that I could change as much the PWM frequency (what can be done with MC3PHAC) and the electrical frequency.  I though it was between 1 and 128 Hz, cause it writes this range when it explains about speed control.
But I have looked for another options to make this control, and I haven't find anything.
Do you have any other suggestion.

Thanks in advance.
Jgoncalves

[rocco]

Hi Jgoncalves:

I would need to know more of your requirements, as well as the requirements of that motor. The MC3PHAC may work. Do you have a link to the motor specifications? How fast does the motor have to go? How accurate does the speed have to be?

[jgoncalves]

Hi rocco:

I have attached the master thesis about the construction of this motor, you can go directly to the page 29. Actually, it is a motor/generator, but now I am just worried about operating it as motor. It has 14 pole pairs and I would like to achieve a revolution speed of, at least, 1000rpm. To do that it would be necessary an electrical frequency of 250Hz. Using the MC3PHAC, the synchronous motor frequency can be specified between 1 and 128Hz. As I told you, I though about changing the crystal frequency, but I am afraid it is not possible.
Thanks once more.

Jgoncalves.

exjobb.pdf

Message Edited by jgoncalves on 2007-04-2509:11 AM

Message Edited by t.dowe on 2009-09-01 05:11 PM

[rocco]

Hello again, Jgoncalves:

Now I see. The biggest problem I now see is finding the time to read that thesis. This is the type of thing that I can get immersed in. Dang. But that's my problem.

Your problem is finding a suitable control circuit. Your motor is a permanent-magnet 3-phase motor, and the MC3PHAC was designed for an induction motor (no magnets). So it really isn't suitable, as the control algorithms are very different.

The 56Fxxxx digital signal controllers are designed for this, but then you would need firmware. Freescale offers a lot of sample firmware for motor control, but you would still need to pull things together. One big advantage of a firmware approach to control is that it can be expanded to handle the generator functions later, and a pre-programmed motor-controller would not give you that flexibility.

The next important question is whether or not you have a feedback device to help with the commutation. Hall sensors would be the most common method, and the simplest. An encoder or resolver could give you better control, with some added complexity. A sensorless control scheme could lower the per unit cost, at the expense of development effort, but I doubt you want to go there.

You might try operating open-loop, which would be similar to controlling a 3-phase stepper motor. That is close to what the MC3PHAC would have given you. The disadvantage is that it could waste a lot of energy, as the current won't be self-regulating as it would be with an induction motor.

Depending on your control method, I can probably suggest a few controller ICs, or even complete control modules.

[jgoncalves]

Hej rocco,

First, thanks in advance.

Honestly, I don't know that much about DSP, and my first intention was to use it in the future (now, I was looking for a simpler controller to the motor).
But I don't have any other idea about what I could use instead of MC3PHAC.

Talking about your suggestion, I hope you don't care about these basic questions, but a firmware is like the software? Will I need to program it?
For a while I am not thinking about a feedback control, and I agree with that if start working with a digital signal controller it will going to make things much easier in the future. (When you said about controller IC, were you talking about the feedback, weren't you?)

And wich one do you suggest from the family 56Fxxxx? Which is the difference between so many different components?

Janaína.