XT-350 conversion using hybrid car parts

[nki]

greetings endless spheroids,
lurker nki here to contribute some findings and progress. I've spent the last couple months working with a friend to develop a control board and some code to speak to the gen 2 Prius inverter. It is an interesting motor controller option as working inverters can be had for $150 on ebay. Each contains a small (~20kW) and a large (~40kW) three phase bridge in the inverter brick as well as other goodies like a big ole inductor, a gigantic film cap, a 1kW 200V->12V DC/DC converter, and a really nice and friendly boost converter brick.

We used a motor from a Mercury Milan hybrid. Sadly it didn't come with an accompanying transaxle or position sensors so a custom housing and a rotor position sensor had to be made for it.

Knowing that the obvious place to put used hybrid car drivetrain components is on dirtbike shaped objects, I began staring at craigslist. After weeks of hit and miss (more like miss and miss) browsing, I managed to find a friend selling a rather ancient XT350 for parts. Perfect.

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so hey there,
hope all's well with you. thanks for reading. We're still working out bugs in the control code. Everything worked fine on the bench but of course it performs differently under real load where the current demands are higher.

 

[Nobuo]

that looks promising, what are more or less the peak power desired?

also what kind of batteries are you planning to use?

thanks for sharing!

 

[nki]

Hi Nobuo,

peak power - I'm mostly trying to figure out the limits of the car parts here, not really shooting for any power range. During early testing, we used the generator half of the brick out of fear of blowing it up. Eventually, we hit its current limit. The brick has overcurrent protection and shuts down the gate drive when it detects too much current. No hard numbers on this yet due to overshoot in the current loop. We switched over to the motor half of the brick which has a higher current limit, but we're still able to trip it into overcurrent. We need to figure out where the shutdown threshold is and tune the current loop to come in a bit under that.

Both the prius inverter brick and boost module have been very nice to work with so far. fully electrically isolated with goodies like current and voltage sensing. I guess overcurrent shutdown is a feature too as long as it keeps us from blowing up the brick.

Batteries - not sure. Many S, not too many P as the components really want a few hundred volts. There isn't a ton of room but I think that'll be OK. I think EREV is the way to go on this one. I'm working on a chainsaw->pmsm->3ph rectifier for recharging the pack-to-be on the go. If I can get a kW or two out of my 40cc chainsaw, it will be enough to cruise at 25 or 30 as long as there's gas in the tank.