Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control - Page 7 - Fuel Economy, Hypermiling, EcoModding News and Forum

Weisheimer · 11-13-2009, 05:56 PM

Paul,

It looks like you have the same sensor that

Thunderstruck Motors Web Site

is using on their AC-50 motor that is matched up to the
Curtis 1238 AC controller.
They have a copy of the Curtis manual on the site.

Mark

Christ · 11-13-2009, 08:16 PM

Quote:

Originally Posted by NiHaoMike

Use an encoder wheel with a wider gap or cog in one spot. That's how most crankshaft sensors are designed. I don't think exact position is that critical for induction motors, only switched reluctance or synchronous AC. (In the case of switched reluctance, the motor itself can be used as a position sensor by measuring inductance.)

The ABS sensors (as well as camshaft and crankshaft sensors) I have seen are actually inductive. The sensor circuit applies a high frequency AC signal to the sensor and uses it as part of a voltage divider. The inductance varies depending on whether the sensing coil is over a cog or gap, which changes the impedance and the voltage division ratio.

Hey thanks! Is that how all the ABS sensors work? I just assumed it was laser because there is a little "window" like area, and it quit being stupid every time I cleaned the dirt from the sensor housing in that area.

It just made sense, I guess.

MPaulHolmes · 11-17-2009, 02:15 AM

The motor is here. I wired it for 208-230v operation. I'm basically done with a schematic too. I uploaded one that has a couple errors, but it's super annoying getting it in this format, so i'll just attach it as it is. I think I fixed all the mistakes on my schematic that's still on my computer. Basically, it should be VS3 to motor, VS2 to motor and VS1 to motor, instead of how it is in this picture.

Here's the motor:

I think to keep with tradition, I'll first try to drive 3 LEDs, so they should all pulse gradually brighter and darker out of phase by 120 degrees each. That will be a 3 phase 5v 0.01amp controller! hahaha. Just like the good old days.

Christ · 11-17-2009, 06:34 PM

So, what are you going to drive with that motor? I'm thinking garden cart.

MPaulHolmes · 11-21-2009, 01:44 AM

I programmed the microcontroller for the first time tonight! I made up a basic circuit for in-system programming. I turned on an LED, then I turned on another LED! hahaha. There were several irritating things that happened along the way, but I digress...

I got the encoder installed on the motor. I had to mill a flat plate and JB weld it onto the motor, so there would be a nice surface to stick the encoder. It's perfectly centered, since I ordered a centering tool. I took pictures, but the camera just ran out of batteries, so they are charging right now.
EDIT: THEY ARE DONE CHARGING!
PicKit3 in action! Thank you sawickm!!!!!

Here's the test circuit for in-system programming!

So, how do you program this dang chip anyway? Follow these directions!

Here's the 3 phase AC test motor. Notice the encoder mounted on the motor shaft. It has 512 pulses per revolution:

Next I'm going to get the A/D channels working, and then the pwm working. Then all 6 of them working, and then drive 6 LEDs at the same time (like a 3 phase bridge), and then hook it up to the motor!

I've been deriving the clarke and park transformations to make sure I understand what is going on. It's not bad at all now! I understand! In fact, I found a mistake in the Application Note AN908 that everyone always talks about. They have the wrong transformation for Park! The most important part was wrong! I had actually used that transformation when I used to make really stupid video games. It's a 2D rotation. I'll add the pictures later.

Jack Bauer is using 1200v 1000amp IGBTs! If I can get 6 of those for a 3 phase bridge, that would be some crazy crazy power. Profoundly disturbing power.

MPaulHolmes · 11-21-2009, 02:55 AM

Two Fuji 6MBI450U4-120, 1200V, 450A Trench-FS IGBT's NR - eBay (item 320449646390 end time Nov-22-09 17:30:18 PST)

Please? It's almost Christmas! The sale is for 2 IGBT 6 PACs. That would be enough for 2 AC inverters, about 300v DC 250amp each, since they are rated for 450amp continuous so you derate them a little. I still have a long row to hoe, but I was rather shocked to see that, so I just thought I would post it here. Each one should cost about $800, so 2 for $60 is *pretty good*.

Tweety · 11-21-2009, 06:59 AM

Are those big enough for the final full scale AC controller? Or just a step on the way?

I'm considering a purchase... If I do I'll need an shipping adress as the SOB won't ship outside the US...

Ie, to clarify... If they end up below $80 + shipping as my bid will be, and if they are sized for the final controller, they will arrive at your doorstep, at the end of the auction...

PM me an adress...