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

[Janis]

If we want to see EV on fire Higher Voltage is perfect He He...

[Janis]

Yes some frends from Ogre town are going EV to Dackar: OSC Race Car Engineering — OSCar, Rally Raid & Racing

[JRoque]

Hi.

Yes, higher voltage is better... for the controller and that's about it. It's not so good for when you need to attach your peripherals to the pack like your DC-DC since there are no cheap ones for higher voltages. Charging your pack can only be done with a boost converter and it's complexity, expense and losses. Your pack will be considerably heavier than a low voltage pack when using prismatic cells like we do. Do a quick check on this and you'll see. This means that any efficiency gains for higher voltage will be lost in extra battery pack weight. There are more cells to check or BMS and more interconnects to buy and maintain. I'd say ~350V bus is a good compromise.

EV controllers are not servo/position drivers. The loss of the "encoder" will not default the controller to spin up the motor out of control. Or at least it's not... hmmm... "best-practice" for the software to spin the motor in all directions if it can't see shaft feedback. That used to happen in the early days when servo controllers were all hardware. Ever seen an IBM mainframe printer feed a whole box of paper in 45 seconds? But yes, LED feedback on this application is not that good.

That's good progress, Paul! Hopefully David hasn't given up on this plans either.

JR

[thingstodo]

Originally Posted by JasonG

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

Or a 20hp for ~$1200

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 !!

Hi Jason,

10 HP and 20 HP are too low to get my S10 up to highway speed. I need 30 HP for 60 mph, prefer 40. I'd like 90 HP for short periods so that acceleration is decent.

I'm following this thread with much interest, but I am also trying to source a surplus industrial VFD to do as you suggest.

The (failed) VFDs that I have dissected have all had sense resistors to give the voltage input on the control board the appropriate range. These have all been 5 - 15 years old and do not have a way to disable low voltage levels. Changing the sense resistor to make the VFD sense a voltage that is in range is the method I want to try.

I'm not familiar with what it takes to mod an industrial VFD to make it reliable as a traction drive - I guess I should read up on that topic.

I like the idea of DIY so that it can be fixed - industrial Drives cost a LOT to fix. But I'm not sure that I'm good enough at assembly and testing to make something reliable.

[jackbauer]

Agree with JR. High voltage is great up to a point. I wouldn't personally want anymore than 200v in a home converted car. You know me Paul. Just point me at it and i'll igbt it

[MPaulHolmes]

Originally Posted by jackbauer

You know me Paul. Just point me at it and i'll igbt it

Dude just verbed IGBT!!!

[ChiefsBuggy]

Paul,

Seems like you started down the IGBT path and are now working on a MOSFET power section? Are you looking for a cheaper Power section or is there some other characteristic you are designing for?

I plan to be first in line to buy a kit when its ready. I've finished my 1966 Boss Bug dune buggy... all it needs is motor and controller. Motor is targeted to be an AC-50 from HiPerf (no curtis controller thank you).

Your dedication and tenacity is inspiring. I feel like I know you pretty well after reading posts in this and the big open revolt forums!

Jim

[lechancel]

I plan to be second in line to buy a kit when its ready
Regis

[jackbauer]

I will be zero in line! That way i'm before first!

[ChiefsBuggy]

Originally Posted by jackbauer

I will be zero in line! That way i'm before first!

Ok, but no letting your friends cut in line and no negative numbers.