Paul & Sabrina's cheap DIY 144v motor controller

[mani9876]

Hey!

I've been new here, but that's a really amazing project!
I read a lot in the wiki, and on google about that.

Am I right, that regenerative braking isn't possible? Is it planned that it should be able to do that in the future?

Another question is, about the 1kA and 500A question, in the wiki there are different versions of that, but there is always used the same amout and types of MOSFETs, so where is the difference?

Thanks a lot!
Best regards
Manuel

[MPaulHolmes]

There have been a few 1000amp prototypes I've tried that haven't done so well. haha. I'm not sure which ones are on the wiki, but it would probably be good if they weren't there. The driver board I think is good, and the control board might be OK, but the power section, specifically where the TO-247 mosfets get their backs soldered right to a bus bar... That's a problem.

[mani9876]

Thanks for the reply Paul!

But what do you think of regenerative braking?
It should be possible to use it even with our series - wound motors.
Like some controllers available from the companys like Curtis, ....

Have you ever thought of this?

[MPaulHolmes]

I've heard there are issues with series wound motors if the motor doesn't have interpoles (whatever those are). I think it has to do with the brushes being advanced. The soliton hasn't implemented it in their software, even though they have the hardware, I believe. I also remember Otmar (zilla) going through quite a process to get it working, but it wasn't at all simple. Even then, I'm not sure how practical it was.

[mani9876]

Hello Paul.

I also saw that problems with our series-wound motors. Not easy at all you're right.
So we should wait till AC Motors get cheaper I think.

Paul, what happens if the MOSFETs in your self designed controller blows, and dies as a shortcircuit, this should end up in full speed, or have you designed a fault control for that?

[Greg Fordyce]

Hi mani9876, I've been running Paul's 500 amp controller for nearly 2 years and 10k miles (16,000 km) in a Daewoo Matiz Greg's 1999 Daewoo Matiz

The controller gives good performance in this size car. As far as regenerative braking, a series wound DC motor is a great traction motor but a very badly behaved generator. But most people don't need regenerative braking so I wouldn't let that stop you from doing a conversion.

I'm using a NetGain Impulse 9 motor and it is very good, only just fits into the Matiz. But another option that you should investigate is Kostov motors in Bulgaria. Being in the EU they will have a shipping cost advantage over the Netgain and also for me the dollar-sterling exchange rate is pretty rubbish at the moment which really pushes up the price of the Netgain motors over here.

You are right about the risk of a short circuit in the controller causing a potential run-away situation. But this risk is the same for any controller for this type of motor. You need to install a Big Red Button to disconnect the pack in emergencies.

Regarding interpoles, I don't really understand them either, but the Kostov motors have them as standard. Apparently due to the interpoles you can keep the brush timing neutral, normally for voltages above 120 volts you would advance the brush timing. In order to do regenerative braking you need neutral brush timing. I only know of 2 controllers on the market that do regen on a series DC, Zapi and Kelly Controls. The Zapi are sold as off-road controllers only (ie forklifts) with a max 120 volts. I suspect the reason for this is something like a fork lift will be operating at slower speeds which means lower motor voltage (motor and pack voltage are not the same, motor voltage is determined by rpm and limited by pack voltage). In a road vehicle motor voltage is higher and this is where you get problems with regen braking and controllers going bang.

[mani9876]

Hi Greg!

Sounds fine, that you use this controller such a long time!

Another thing I thought about, has anyone made something like an EMC test? Here in Austria, all components has to be EMC tested, or at least we should be absolutely sure, that nothing happens

I ask that, because the filtering isn't done very well, because it's just the capacitors which filters the pwm on the high voltage side. Has anyone problems?

[mani9876]

Hello again

Has someone got the schematic and board files of the Version 2C ? The link on the wiki is broken.

What's the difference between 2C and 2D, it seems that anyone uses the 2C version?

Manuel

[z_power]

Manuel,
send me pm with your email address, it's ~100kB pdf so I can send it to you via e-mail.
Mike

[Greg Fordyce]

Mine's the 2C version, consider it the 'stable' release.

I haven't done or had to do any EMC testing, but I can tell you the radio won't recieve AM/MW/LW and FM can be a problem in weak signal areas. Try and find someone in your local area who has done a conversion, they will know what needs to be done to get your vehicle legal and on the road. EV photo album is a good place to start with a geographic search.

Edit: I suspect that the motor brushes also contribute a lot to EMC.