Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control

[wehzeh]

Ok. Let's make sure we coordinate via github so nothing gets lost and we can support the various generations. If you toss me the code for the new features I can make sure we're all on the same page.

I already have a feature edit that's ready for release: command aliases. Example:
instead of "current-sensor-amps-per-volt" you can just type in "csapv" and it has the same result. all the old commands are intact, the aliases just save you annoying typing. i'm also working on adding sin/cos encoder support.

[ricemodder]

Originally Posted by wehzeh

Ok. i'm also working on adding sin/cos encoder support.

That sounds interesting, what is that? I'm working on something that is possibly similar. Built in resolver?

[wehzeh]

Originally Posted by ricemodder

That sounds interesting, what is that? I'm working on something that is possibly similar. Built in resolver?

It's almost a resolver but not quite:

http://www.rls.si/fileuploader/downl...ic_encoder.pdf

That's an example of the one built in to my motor (DLC-28 e.g. Motenergy ME1302). It only takes V_dd, GND, and Shied (always optional, amirite?) and outputs 2 lines: sinusoids offset by 90 degrees with an aplitude of 3/5*V_dd.

In theory, it should be as simple as probing the pins with an ADC read (they output analog voltage) and doing some reverse trig to see where we are. It's a good middle ground in the whole encoder/resolver thing--the tight resolution of a resolver with some of the simplicity of an encoder.

[ricemodder]

Originally Posted by wehzeh

It's almost a resolver but not quite:

http://www.rls.si/fileuploader/downl...ic_encoder.pdf

That's an example of the one built in to my motor (DLC-28 e.g. Motenergy ME1302). It only takes V_dd, GND, and Shied (always optional, amirite?) and outputs 2 lines: sinusoids offset by 90 degrees with an aplitude of 3/5*V_dd.

In theory, it should be as simple as probing the pins with an ADC read (they output analog voltage) and doing some reverse trig to see where we are. It's a good middle ground in the whole encoder/resolver thing--the tight resolution of a resolver with some of the simplicity of an encoder.

I'm finding you can compute the instantaneous position but it is a hell of a challenge to be precise with no lag.

I'm thinking you need to incorporate motor expected inertial max/min change.

Losing wind in my sail.

Let me know how it goes.

[MPaulHolmes]

I think I figured out yesterday why the driver boards may have failed for Eclipse but not me, and also why the previous board, with the built-in resolver to encoder chip didn't work. Basically, I've always programmed the attiny (even the surface mount one) before soldering it in (I have a cool little thing that grabs surface mount legs so you can put one in, program, and then remove). I had thought programming in system wouldn't be a problem, but what i didn't think of was, when the attiny is unprogrammed, the 2 "outputs" are inputs by default, so the 6 drivers' 12 input pins are left floating, so they could be high or low. Well, if one is randomly high, and another is randomly low, the driver output will have a constant DC load of about 2.7Ohm at 24v!! Needless to say, the little chip 6amp driver would quietly fail in that case the first time you turn on the board to program the ATTiny.

I didnt' see that happen because I always programmed the attinys before soldering them (just sort of randomly, since I had programmed several and had them laying around).

The fix is to add a weak pull down resistor on the 2 ATTINY push pull pins to ground. LIke 47k or whatever. Then, all the drivers are off while the attiny gets programmed.

[MPaulHolmes]

Wow! I can now use the little 15watt supply too with those 2 pull down resistors added. It must be that the attiny, even programmed, (due to the delay of like 50mS or whatever), starts out dead, comes alive, but after like 60mS, there's already been time for large surges through the push pull drivers, so that I've had to use the 50watt 12v in, 24v out power supply for powering the board. Now it can use the tiny 15 watt! Oh joy.

[Astro]

Originally Posted by MPaulHolmes

I got a new board made! I just want to mention that I have really appreciated having Astro's controller for testing. I"m going to solder him one of the new boards.

The board looks amazing. Well done.

And the longer you have the controller the better it gets so i will definitely not be rushing you.

Originally Posted by MPaulHolmes

This one includes voltage monitoring, a 2nd temperature, and also a brake regen "throttle". And it's all 1206 and 1210 suface mount resistors and capacitors. No 0603 this time.

Mmmm.... Regen. Love it. My daily commute is about 30 minutes of traffic lights each way so regen will certainly make a difference.

Originally Posted by MPaulHolmes

I would take a picture of a couple of the boards that are almost soldered, but my stupid apple phone is a daughter of debauchery, and needs to be flushed down the toilet.

I know the Apple pain. My girls have Ipads and recently i thought. I'll download all the photos off of them as they were getting a little full. Yeah, right. What you want to take your photos out of appleland?!? Not allowed. Ended up having to pay for an app that acted like a web server that served up an archive of all the photos to a browser on a real PC. Talk about convoluted.

[ricemodder]

Originally Posted by MPaulHolmes

Wow! I can now use the little 15watt supply too with those 2 pull down resistors added. It must be that the attiny, even programmed, (due to the delay of like 50mS or whatever), starts out dead, comes alive, but after like 60mS, there's already been time for large surges through the push pull drivers, so that I've had to use the 50watt 12v in, 24v out power supply for powering the board. Now it can use the tiny 15 watt! Oh joy.

Improvements - that's great to hear. Is it possible this could happen on our rev 1 boards during the startup of the controller since the attiny starts up in a float condition?

[MPaulHolmes]

Yes, exactly. A pull-down on the 2 ATTiny pins on the original board should allow the control board to be powered by a 15watt supply rather than the larger 50w supply.

[thingstodo]

Originally Posted by MPaulHolmes

Yes, exactly. A pull-down on the 2 ATTiny pins on the original board should allow the control board to be powered by a 15watt supply rather than the larger 50w supply.

Is that for both the DC Controller and the AC Controller?