Paul & Sabrina's cheap DIY 144v motor controller

[brihoo2k]

OMG that looks exactly like the one I bought on ebay from Nanjing China. Hey Paul here's an idea go to rat shack and but a couple of their bread boards then unbolt the ones off the china board and bolt on the ones from rat shack. Rat shack = radio shack BTW

[MazdaMatt]

When I was in highschool my digital electronics teacher (best class/teacher ever) made us VERY neatly do our breadboarding. If we had wires that arched up off the board, he'd just pull them out and hand it back. I learned to make nice 90* bends to route busses in parallel and keep everything flat. The time spend putting it together always pays off in the troubleshooting in the end.

We also had to use 10 year old abused breadboards... so finding dead spots in the board was pretty common. MAJOR pain in the arse.

[MazdaMatt]

brihoo... ratshack has HUGELY overpriced breadboards. The best thing to do, IMO, is go to an electronics supplier for them. About 1/3 the price of radioshack and quality controlled (unlike ebay).

[MazdaMatt]

I'm just full of posts this morning....

Yesterday at work we had the fellows from Freescale (makers of microcontrollers and sensors, our primary supplier of such things) in for a mini-seminar on "what's new" from them. One of the things they had to show was a new series of motor control "DSC"s. A DSC is like a DSP (Digital Signal Processor) except that it has onboard flash (thereby making it a controller, not a processor). So I looked it up... and it turns out that they have a 100 dollar "demo kit" that comes with firmware. The demo kit is in 2 parts - a control board, and a power board that has a 9v 6W 3-phase BLDC motor attached. So if one were so inclined, one could use this demo kit to develop really sweet control system, then pop off the control board and design a high-powered driver board (*cough*) and connect up to that instead.
The best part is that the firmware comes with all of the control system stuff you could want. It reads Hall sensors to determine shaft position and controlls voltage via pwm to set the speed. It even has overvoltage PWM shutdown protection.
The processors are internally designed to be helpful for designing motor control. One of the features is a special timer that triggers on the rising or falling edge of the pwm. When that timer expires, it will trigger an ADC reading. The purpose of this is to ensure that you are never taking an ADC reading DURING your switching time. You switch the fets, wait a couple microseconds, then autometically read the current sensors. fancy stuff. The PWM module also has full-speed center-align mode, something they didn't have on their previous controllers. LINK:
APMOTOR56F8000 Product Summary Page

I'm going to look more into this... They usually also provide schematics and sometimes board layout files with their demo kits.

[MPaulHolmes]

Since I have to pull all that stuff out, I'm going to try a different layout on a newer, fancier breadboard. Your teacher would be proud of this next one! haha! Atmel also has some u-controllers that only read a/d channels when not switching. It's a nice feature to cut down on noise. Those also have built in features to make SR really easy, but is only available in surface mount. It sounds like the controller you saw is awesome! But what is it about it that makes it for "small" brushless motors? Can't you, as you were saying, just put in a larger power section?

[MazdaMatt]

There is no tie to small motors. It just comes with one in the demo kit. Click the link and you'll see another link on that page to show you the product. It is 2 boards, the bottom one has some puny power electronicsa nd a small motor.

Are all BLDC motors 3-phase? I can't seem to find a direct answer to that question.

edit: oh yeah, that DSC has 6 PWM output lines for controlling 3-phase low-and high-side drive. It also has the ability to swap which PWM registers are controlling which PWM outputs, so you can generate a 6-step BLDC drive by simply rotating which output sees which register set, instead of rewriting each register in sequence.

[dcb]

Is there a cheap development environment option for the MC56F8013 freescale chip?

[Blue Bomber Man]

I don't think they use prisoners for that work, but rather children. Children are preferable because they have smaller fingers to work with.

Unfortunately because of the malnutrition they have very poor eyesight =/

[MazdaMatt]

Oh yeah... they actually charge for their dev evironment... you love Linux... i'm sure there is a linux option - I just don't know anything about it. If you're not aware, it is CodeWarrior that is used as the usual dev environment for freescale products. You can get 30 day trials... usually as many as you want, so it is "effectively" free.

EDIT: Eclipse is the linux free version. Not entirely sure if it supports the DSC's yet - i'd guess it does.

[dcb]

Looks like freescale wants $700 for an optimizing compiler, I think you can buy a decent controller for $700.