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

[JasonG]

Originally Posted by MPaulHolmes

I'm very interested to see the difference in price. Cheap IGBTs can be found mostly on Ebay, but not a certain steady supply of new parts. And they are the clear winner at higher voltages, but there aren't a lot of people out there that seem to want to put 300v worth of batteries in their car. Or maybe that's just me. haha. If you can have all the advantages of AC, like regen, and a motor that runs a million miles with no brush changes, and the advantages of DC like lower voltage components, which are sometimes cheaper, and not dying instantly if you touch the batteries. We'll see though. I think the mosfet based one can be done for a few hundred dollars, but would be limited to like 144v or maybe even less if you do much regen.

The igbt one seemed to have an "all new parts" cost of around $2500 if that one open source AC controller price can't be improved upon much.

Don't get me wrong Paul, I love what you're doing and understand the "built this myself mentallity"

Why build one for that much when an 10hp off brand retails for ~$700 http://www.driveswarehouse.com/Drive...p_10=&x=38&y=2

Or a 20hp for ~$1200 http://www.driveswarehouse.com/Drive...p_10=&x=26&y=9

A good ABB drive sells through supply houses for about the same. Just check the specs to see if (a) it can run off of a common DC bus and (b) if you can turn off the "low input voltage shutdown" feature. These tend to go together, this allows you to run it with your batteries feeding straight into the common bus.

In an early post you stated you saw them for $8-10K. I wouldn't expect to pay that until I crossed the 250hp level. I don't think you'll fit that in a Metro !! (4'L 3'W 2400lbs )

[bennelson]

My friend Tom built a 300 volt AC Dodge Neon.
He used a stock AC drive from some decommissioned factory.

The problem is that those drives are not designed with a car in mind. There are a lot of "little things" that had to be taken into account to make the drive really work for a car application.

He's an electrical engineer, and enjoyed the challenge. For the average guy, it would be a lot of work to make all the little tweaks for it to all work.

With an open source build, everything can be designed in right from the start.

[MPaulHolmes]

Also, the control board doesn't care what power electronics you use. And the same goes for the driver to some extent. With good surplus igbts, you can do 250HP for under $500 I think. And 10 HP is close to the same price. It's the same way with DC controllers. A Homemade 72v DC controller costs like $300 to build, and new it's only like $500 or $600, but similarly, you can make a $400 144v 1000amp controller, or pay around $2000-$2500.

[MPaulHolmes]

Oh I had it all set up in the garage, and then I had to take it all apart so I could finish other stuff that was more pressing. I need more room!!! It's a day long event to get things set up for whatever thing I'm working on out there. And now it smells like dead rat because I put poison out there since they kept stealing all our apples. I saw one run along the garage door top, and it was about 14 or 15 inches from head to tail. An ROUS, if you will. Before seeing them, I didn't think they existed.

[pedjag]

Paul, here's another open source license that is probably more relevant to Hardware products.
The TAPR Open Hardware License

I think at the very least it provides a base for other contributers to add on to the product and keep track of changes as it develops etc.... without losing the core product to "Da Man" by ensuring all of its documentation is distributed as Open Source with a legal license... in addition to other benefits.

Anyway just my thoughts.....

[Cyruscosmo]

They do exist!

An ROUS invaded our shop once long ago. It defeated numerous traps designed for the “Big Ones” leaving only a tuft of fur. In response to numerous thefts of lunch’s three boxes of Ritz crackers and a shoe, “not exactly clear about the shoe” but I am sure it was to show its displeasure at loosing the aforementioned tufts of fur to puny traps which clearly seemed to annoy it.

I was not happy at having one of my work shoes chewed so me being the imaginative soul I am and with a shop full of tools I built a “Trap”.

Not just any trap mind you, this one was solid steel and came in at close to 20 pounds when done. This trap was designed for an ROUS and was made from a 6X6X.025 chunk of square tubing 18 inches long. One end was closed by a 6X6X.025 plate fitted into slots with a locking mechanism so that the trip arm could be baited and the other end was fitted with a 6X6X.025 square plate that slid into a pair of milled slots. When the ROUS went for the bait “a generous helping of peanut butter held in place by a stainless steal screen” the trip arm pulled a pin from a spring loaded wheel which rotated to develop enough momentum to pop the trigger on the spring loaded sliding front door.

The first time we came to work and found the trap had been triggered the guy I work with decided to take a look at the culprit. He got an empty metal trashcan and up ended the trap over said trashcan and pulled the door open before I had a chance to explain something very important to him.

He was expecting to see a rather large “ish” rat drop into the trashcan and since I didn’t have time to explain that I did not build the trap to “kill” I took a step back. I was not sure what he was thinking till the ROUS dropped out of the trap hit the bottom of the trashcan with a thud and jumped straight up at his face. The surprise was well worth the time I took building the trap when a HUGE rat came back up out of the trashcan rebounded off his chest and ran off across the parking lot.

I laughed so hard a came pretty close to pissing myself and from the look on his face when that rat looked him in the eyes I am pretty sure he did.

From that point on he filled the trashcan with water and dropped the whole trap in “without opening it first”.

[drbobwoolery]

For a previous financially successful "open source" venture in a totally different realm, view _Sita sings the Blues_ and dig into the associated blog. Nina Paley produced this animated feature in 4 styles, and gives it freely for personal or commercial use. She claims to have gotten more money return from donations and her (non-exclusive) products than a mainstream sale contract could yave yielded. The issue of derivative works is particularly thorny: Disney owns Snow White, the talking wooden puppet, etc. through the copyright on derivative works.

[lechancel]

hello,i have finish my axial flux motor 3 phases will you continue help with your sheap controller ?
i need too a digit rpm to read number of turns ,not an optical somebody as idea
Régis

[MPaulHolmes]

A resolver is a mechanical device that's very robust and isn't optical. I'm not going to get anything done on this though until I'm done with the 1000 amp prototypes. My garage isn't big enough.

[etc]

What is the status of this project? Will there be an open source inverter before they are cheaply commercially available? Is there a current parts list? I would love to start building an AC system, my DC kits are just enough to get you hooked.

Keep up the great work Paul!
Brian