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

[e*clipse]

Yup; the rotor itself is pretty little: 6" in diameter and 2.5" long. However, it's very integrated into the system and has some crazy strong magnets. (I've got one in pieces sitting on my desk)

Originally Posted by MPaulHolmes

So, the motor is inside there??

[freebeard]

So, the motor is inside there??

heh, heh, he.

e*clipse -- Thanks, I alerted my buyer. The Highlander Hybrid isn't on the compatibility list. I wonder what the differences are.

Will these work with the Open Revolt controller?

[MPaulHolmes]

Sure, if you use 1200v IGBTs, and 650v worth of batteries (or a boost converter on the front).

Hey, how should we do regen? In a perfect world, the throttle would be a wig wag, where you twist forward to command positive torque, twist backward to regen. But this is a crazy messed up world. So, what do we do instead? haha.

[e*clipse]

??? Buyer ???

Here is a direct ( I edited some uneccessary stuff out ) quote from that 2nd E*bay listing. Now, I would agree that E*bay listings are terrible sources for technical information, but I've seen this same information in other places, including department of energy test data. Also, one of the three I own is from a Lexus, the other two are from a Toyota. If you lined them up next to each other, you honestly couldn't see a difference.

2006 LEXUS RX400H REAR DIFFERENTIAL IN GOOD CONDITION WORKS FINE WITHOUT ANY PROBLEMS

Donor Vehicle
Model LEXUS RX400H
Year 2006
Mileage 98099 Miles (0 = not available or unknown)
Stock Number AA0094
Store Number 1

Notes
This part will fit these makes and models with these options

HIGHLANDER 06-07 elec (hybrid), rear (4WD)
HIGHLANDER 08 elec, rear (4WD)
HIGHLANDER 09-13 electric, rear (4WD)
LEXUS RX400H 06-09 elec, rear (AWD)
LEXUS RX450H 10-13 electric, rear (AWD)

Ok, now regarding whether the controller will work for a 3 phase Permenant Magnet/ reluctance motor design instead of the 3 phase induction motor it's designed for? I don't know - that's Paul's responsibility. - LOL!

Just kidding Paul -

Short answer - the controller hardware is the same (except for the points Paul just mentioned - thanks, Paul!) , except for the motor position feedback, which is a resolver on the MGR. Translators exist, which is what I'm going to use for the first prototype. Eventually I want mine to run directly off the resolvers. I've got about 1/2 the code for that working. There are a lot of application notes out there from Microchip and other companies that will confirm this. HOWEVER, the code will be different because in the BLDC - type motor the rotor follows the magnetic field developed by the stator exactly. In the induction motor, there is a phenomenon known as "slip." Basically, the rotor lags the magnetic field by a little bit; this creates movement between the magnetic field and the rotor coils, which creates the stator's magnetic field.

To me, the BLDC type motor is pretty straight forward. The induction motor is pure black magic - voodoo. That one device puts Tesla in the beyond genius category.

Originally Posted by freebeard

heh, heh, he.

e*clipse -- Thanks, I alerted my buyer. The Highlander Hybrid isn't on the compatibility list. I wonder what the differences are.

Will these work with the Open Revolt controller?

[e*clipse]

Some quickee user-input (regen) thoughts:

We probably could do a wig-wag like thing like this: The 1st 1/4 of the throttle pedal depression goes from most regen > least regen > nothing. Then the last 1/4 > full throttle depression is least throttle > most throttle. You'd have to learn to drive with "coasting" being foot on the throttle. Also, if you ever took your foot off the throttle, the car would start full-regen braking. Hmmm, that could be bad, like downshift braking without intending it...

I think this could work unless regen requires some power to operate, in which case it may be a power leach when the car is not moving. However, it may be possible to do an override based on whether the car is moving or not.

Another method ( My Honda Insight ) Two different inputs, on on the brake pedal, one on the throttle. The throttle is straight forward. The brake allows the regen to work in that "dead zone" where the pads haven't touched the rotors yet and aren't doing anything. I would still want my brakes to respond quickly, like a normal car, so I wouldn't suggest an extended "dead zone."

Originally Posted by MPaulHolmes

Sure, if you use 1200v IGBTs, and 650v worth of batteries (or a boost converter on the front).

Hey, how should we do regen? In a perfect world, the throttle would be a wig wag, where you twist forward to command positive torque, twist backward to regen. But this is a crazy messed up world. So, what do we do instead? haha.

[MPaulHolmes]

Ya, FOC is easier with a permanent magnet DC motor. You command the field current to be 0 (since it's already there! Since they are magnets! haha. Or you can command negative field current, which fights against the magnets, field weakening). You need the rotor flux angle, which as e*clipse was saying, is exactly the same as the rotor angle. You have to find the angle's starting position, and save it for all eternity in the EEProm, but it's not a big deal. Computing the rotor flux angle with an ACIM is evil. But you do it, and hurray, it works. You need an index pulse with a permanent magnet motor (assuming an encoder), but don't need an index pulse with ACIM.

I should come clean. I only made a single throttle A/D input. I think that could work with a single throttle as you described. Or maybe you could flip a switch that would regen as much as possible? Like connected to the brake? Either regen or not regen?

Maybe zero throttle could be zero regen, and the first 50% of throttle is regen, where 50% throttle is zero regen, and *almost zero* throttle is max regen, but with a built in delay, so it wouldn't start to regen unless you wanted it to. So it would have time to drop throttle to zero if you wanted to coast without losing your momentum? Man, everyone hits the brakes when they want to slow down. That could take some getting used to.

[Astro]

Originally Posted by MPaulHolmes

Hey, how should we do regen? In a perfect world, the throttle would be a wig wag, where you twist forward to command positive torque, twist backward to regen. But this is a crazy messed up world. So, what do we do instead? haha.

Paul, as there are going to be several people driving my EV i would like it to mimic the ICE setup as much as possible.

So when cruising if you start to lift the throttle there should be a ramp up to a level of regen that mimics the ICE engine braking. It would be nice if the amount of regen used to mimic the ICE engine drag was configurable to get the right feel.
Then just use a pressure sensor on the brake line to detect any pressure and ramp the regen based on that pressure so that a light pressure gives light regen and as pressure increases we get to full regen. Full regen on the brake pedal should be reached just prior to the brake pads engaging the disk/drum.
So the car would feel just like a standard ICE vehicle except you would get the benefits of regen (extended range and little brake wear).

That way we won't be fighting habits of a lifetime and for other drivers the vehicle will seem perfectly normal.

Edit: Also by only using a small amount of regen on the accelerator we avoid having to worry about managing the brake lights. The brake lights would still just use the standard switch on the brake pedal.

[e*clipse]

These position sensors were mentioned in the EV tech list. The hall-effect ones are really bomber complete with a sealed connector! You can also specify what angle range you want them to work in. The ones I'm interested in are the RTY series. Yes, they're a bit on the spendy side ($40) but they solve all the problems reliability problems in one nice clean unit. You can also get them in a "wig wag" output format.

Check out page 5 in this document:
http://sensing.honeywell.com/index.p...ment/1/re_id/0

Here's the data sheet for the RTY series:
http://sensing.honeywell.com/index.php?ci_id=147803

No, I don't have any connection to Honeywell.

So one might be able to do something where from 0.5V > 2.5V is either increasing or reducing regen and no throttle. Then from 2.5V > 4.5V is increasing throttle with no regen. It would probably be smart to build in a "dead zone" around 2.5V.

Are all the AtoD inputs for the microcontroller used up (the DSPic)? I mean, it might be nice to have an extra AtoD input for whatever silly thing the builder thinks of..

- E*clipse

Originally Posted by MPaulHolmes

I should come clean. I only made a single throttle A/D input. I think that could work with a single throttle as you described. Or maybe you could flip a switch that would regen as much as possible? Like connected to the brake? Either regen or not regen?

Maybe zero throttle could be zero regen, and the first 50% of throttle is regen, where 50% throttle is zero regen, and *almost zero* throttle is max regen, but with a built in delay, so it wouldn't start to regen unless you wanted it to. So it would have time to drop throttle to zero if you wanted to coast without losing your momentum? Man, everyone hits the brakes when they want to slow down. That could take some getting used to.

[MPaulHolmes]

There is one more A/D. How would the brake be a variable signal? I've only heard of pressure switches, but not linear things, so more pressure gives a "more pressure" output. Are there 0-5v brake signal things? We would have to add a little RC filter, and connect to the unused A/D with a wire. Not a big deal.

The dang Index, QEA, QEB are hogging 3 of the A/Ds unfortunately. I had used a 40 pin thru hole dspic30f4011 because the tqfp or whatever they are called chips are hard for most people to solder.

I wonder if it would be mechanically possible for the brake to pull the throttle one way (regen territory), and the gas pedal to push it the other way.

EDIT: OK, I found a brake pressure switch. Basically a throttle. ground, 5v, and 0-5v as a function of PSI.
http://www.bimmerfest.com/forums/sho...d.php?t=592136

[Astro]

Paul, how about this one. Only GBP 18.99
BMW Audi Seat VW Bosch ABS Brake Pressure Thrust Sensor 0265005303 8E0907597 | eBay



Pretty cheap.
The output curve shows the output in the 0-5v range so likely the supply is also 5v but i havent found that out for sure yet.


Here is the MKS web page, the sensor is the second bottom one, part number 0265005303.
MKS Autobusiness, special components for special needs - Products