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

[TheSGC]

I have been way too lazy during my break, but now I am finally getting around to designing an AC controller for my ACGTX20. I am going to start ground up with IGBT modules and designing the power section. I have a few single IGBT modules, CM600HA modules but I haven't decided it I want to use that type (I would need 6 total) or get dual modules to keep the controller small. I guess it really depends on if I ever get paid.

I have been reading a good chunk on VFDs, and my Circuit's class this semester is dealing with AC circuits, so this should be good.

I am still working on getting a Solectria controller to analyze, and I need to figure out how the Encoder on my motor works before I can do any of the dsPic designing.

[NiHaoMike]

Originally Posted by williamson

But not one 60 hertz motor has any expectation of staying together at any higher speed. Or, for how long? I would think anyone going into AC drive should find a motor rated at at least 5000 rpm, to avoid the constant shifting, or, EXPECT to shift. Kindest regards to all, williamson

I found the following article about using induction motors as generators:
Induction generators: What can go wrong? | Electrical Apparatus | Find Articles at BNET

Don't induction generators need an overspeed capability, for mechanical integrity, beyond what's available in a standard motor? At least one engineer has made that claim. The answer, however, is no. Although the latest NEMA standards are somewhat ambiguous, MG 1 Part 30 allows "maximum safe operating speeds" (for typical standard motors 250 hp and below) ranging from 125% to 200% of synchronous RPM. For brief periods (two minutes) with the machine de-energized, as for a running generator that's electrically disconnected, even higher speeds are allowed by the standards. Special capability for generator operation neither exists nor appears necessary.

[ElectricZX2]

So this is my first post on ecomodder....I have a '98 ZX2 with a 9" GE forklift motor and controller. Paul and friends, I'm very impressed with your work on the DC motor controller and have gotten through most of the thread. I'm planning to build your 1000amp DC controller when it comes out , as I'm currently limited to 108volts by my controller (Have 3 more bats itching to get in the car). Anyways, I thought you guys might be interested in this motor...pretty heavy, but hey, they do make a warp 11 .

Emerson 20 Hp. Electric Motor 3PH 3500 RPM NEW Surplus - eBay (item 370299978293 end time Mar-01-10 10:08:48 PST)

[MPaulHolmes]

How do you mount that type of motor to the bell housing of a transmission? It looks like a perfect motor, I'm just worried about mounting it. Do they even make AC motors that are meant to be bolted by the face to something? My DC forklift motor had 6 holes in the face where I could use six grade 8 bolts to clamp it down with like 60 foot*pounds per bolt.

[adamj12b]

Originally Posted by MPaulHolmes

How do you mount that type of motor to the bell housing of a transmission? It looks like a perfect motor, I'm just worried about mounting it. Do they even make AC motors that are meant to be bolted by the face to something? My DC forklift motor had 6 holes in the face where I could use six grade 8 bolts to clamp it down with like 60 foot*pounds per bolt.

If you look at the pictures of the motor, you will see 4 bolt holes that are tapped. You would use these to bolt to the adapter plate, but you also would need to fabricate mounts to support the motor by the large foot on the bottom. This motor is too heavy to be supported by the transmission. They tell you so add supports to the warp 11 as well, as it weighs about 230lbs which is too much to hang off the transmission.

-Adam

[ElectricZX2]

My 9" GE is actually hung from the original motor mount attached using plate steel to the rear motor face. There is actually no transmission "adapter" but the shaft coupler from the original forklift drive system was bolted/welded to the clutch-transmission coupler (now clutchless ). A couple of the motor output face bolts were connected to a couple of the transmission holes with steel strips, but they aren't the primary strength points (the motor kind of just hovers in the transmission mouth). Like Adam said, it seems like you could make some pretty simple connections using the original engine mounts. In my case I would just hang it upside down from the foot, but I don't know how it would work in a VW....
Nice vette project Adam!
-Luke

[hybriddriveguy]

Originally Posted by jackbauer

Just thinking out loud here but what about adapting a prius transmission as an ac ev motor? isnt it a sealed unit with two ac motors and a diff? .......or mabey i'm just loosing it......

I have a friend that has been working on modifying the Prius inverter. These transmissions would make a clean conversion for most front wheel drive applications. I think having a generic controller that would work with them would be ideal.
There is a simple modification that will join the two motors together and allow about 75hp with a peak hp of about 90.

[bigh]

thinking out loud: i wonder if it would be possible to make a controller board that could use either a DC or AC power stage, kind of like a universal motor logic board. Being in software myself i'd love to see a reusable module that just plugs into a high power section.

but would allow for higher runs on the controller section, as the design would be the same.

probably not possible, i'll put it down to to one of Haydon's(me) hair brain schemes.

edit: after looking a bit more at how Paul's going to do this i think its not possible. i'll shut up now and return to lurking :P

[speedy6963]

What ever happened to this project ? dead ?

Originally Posted by MPaulHolmes

Let's face it, AC is better than DC! An AC motor will last forever, since there are no brushes to wear out. You get regenerative braking for free, which both recharges the batteries, and saves the brake pads! And the new lithium batteries can absorb huge currents. The main problem is cost. What a shocker!

With Field Oriented Control, you get to control the torque of an AC motor with a PI loop, like with a DC controller. This makes it very well suited to EVs. It's sort of confusing, but I've been reading about and I'm learning.

A high powered 3 phase AC inverter with field oriented control can cost $8000-$10,000. There already exists an open source inverter that has a parts cost of $2500. I would like to drive the price down further, and also it just sounds fun! hahaha. I've got very good help too. It will happen.

One thing I hope to do is take advantage of the surplus IGBT market once a process comes together, so people can make their own very cheaply. I would like to see the parts cost be under $500 for an inverter that will get a car on the freeway. Also it will have regen.

Also, the parts count isn't THAT much higher. There are no free-wheel diodes like in a series wound DC controller, but you need a 3 phase bridge, which is 6 IGBTs (or 6 banks of mosfets or whatever).

I'll first do a small one, that can drive a 1/2 HP 3 phase AC motor rated for maybe 220v/440v. Then I'll scale it up. I will probably do a more expensive scaled up version, then try to make it cheaper. My electronics background is not good, so I have to keep it simple.

Here's what I need:
Most of it is from Digikey/Mouser I think.


I should come up with a parts list of what I need to get moving! If anyone wants to donate to get those parts, I won't stop them. As usual, I get payed on the 10th, and am broke on the 11th. hahaha.

[dremd]

What parts are you short? I'd like to help make this happen, but I have no skills.