Paul & Sabrina's cheap DIY 144v motor controller

[amazuki]

thanks ian, I have visited the site. For the control board, power board, casing and hardware#1 they added to A$1000 multiply by xchange rate of 2.87 becomes M$2870. I am afraid I cannot afford it for now. Got to start saving right away.

[amazuki]

btw so far I have spend less than M$1000 on donor car, used motor 48V 7.5Kw, 4X12V lead acid battery, diy mechanical controller and wiring.

[MPaulHolmes]

Maybe something like these bad bad bad boys:
I wish I had the money to use these instead...
The panasonic ts-ed caps should last quite a few years though, since they don't get too hot.

The ESR (equivalent series resistance) creates heat inside the cap while current is rushing in and out. Heat is bad. Those bad boys from above have an equivalent series resistance of 4 mOhms, which is really really really low. The panasonic ones have an ESR of like 250mOhm I think.

The ripple current rating is basically how much current can rush in and out of the cap without it overheating. The bad bad bad boys above can take a very large amount of ripple current each, so like 10 or 20 in parallel would have an extremely high ripple rating. (like 500 amps or something) You only need like around 5% of the max current for ripple rating, so they say. 50% is the worst case scenario.

Originally Posted by bigh

Hey Everyone,
I don't have the logic side done as yet, i'm waiting on the next incarnation that will include CAN, but i've got a need to order some parts for my ebike from Digikey, and I figgured I may as well order the powerside capacitors at the same time.

I need some help with Capacitor selection. I've got 4x Powerex CM400DU-12F Modules which i'm going to be using for the build. I have a target voltage of 288v+, which will require 400v+ caps.

adamj12b has said he's using Panasonic TS-ED caps. 6 for each IGBT, 560uF each 400V.
(The Australian Electric Vehicle Asn: IGBT Group buy for open source controllers)

But before I purchase the same caps, I'd like to understand how we select apropriate capacitors. The Soliton1 advertises that it has: "Cutting edge capacitor: State of the art ultra low loss 600V film capacitor. No electrolytics to dry out and fail!"

What kind of film capacitor would they be talking about - I checked wikipedia, and there is a plethora of film caps.

I asked on AEVA what properties I should look for in higher voltage caps, and MCUDogs gave the response: "It's the cap properties, ESR, ripple current and temperature. "

Now i'm asking why these properties?

I'm assuming we want a cap that will operate in high temp environments.


on a side note, I'm going to look at a donor car tonight... oh the excitement (1992 Toyota MR2)!

Thanks,
Haydon

[sawickm]

Originally Posted by bigh

The Soliton1 advertises that it has: "Cutting edge capacitor: State of the art ultra low loss 600V film capacitor. No electrolytics to dry out and fail!"

What kind of film capacitor would they be talking about - I checked wikipedia, and there is a plethora of film caps.

Haydon,

A while back I looked into the Capacitors that Soliton Controllers used.

They are using CORNELL DUBILIER TYPE 947C Film Capacitors. I am not sure of the capacitance value that they are using. Their high-voltage and high-current ratings allows one or a few of them to replace a whole bank of aluminum electrolytic capacitors.

Don't be shocked on the cost of them, one (1) capacitor will cost you between $125 - $225 depending on it's capacitance value.

-Mark

[adamj12b]

Originally Posted by sawickm

Haydon,

A while back I looked into the Capacitors that Soliton Controllers used.

They are using CORNELL DUBILIER TYPE 947C Film Capacitors. I am not sure of the capacitance value that they are using. Their high-voltage and high-current ratings allows one or a few of them to replace a whole bank of aluminum electrolytic capacitors.

Don't be shocked on the cost of them, one (1) capacitor will cost you between $125 - $225 depending on it's capacitance value.

-Mark

Actually, the lower capacity ones have higher ripple current. You want the highest ripple current as you can afford.

The maximum ripple of the controller will be full current (500A for the normal controller) at 50% duty cycle. You will want a % of this total to be able to be available in the caps. Ive heard mixed percentages, between 5 and 25% but 50% wouldn't hurt. Just make the caps run cooler.

Also, the film caps last longer. They are rated for 5000 hours at 85°C.

Here is one that Im looking at for my IGBT controller....too many decisions....Digi-Key - 338-1398-ND (Manufacturer - 947C361K801CAMS)

$102 each and 72A RMS ripple current.

-Adam

[edown]

I think some of you are being a little over concerned about the capacitors, I just use 3 old 4400uf 300V screw mount 85C caps. They never even get warm. I just got them off ebay for about $3 each. And I can’t believe I will have this set-up long enough to worry about there life span. Anyway, that’s my 2 cents worth.

[Tesseract]

First off, I've been following this thread off and on since it started. Paul is hilarious, and I am actually kinda touched that you all pulled it off... even if lots of the dirty work was actually done by Fran Sabolich

However, you all might not realize just how small the market is for DC motor controllers for DIY EV conversions. We estimate somewhere in the 100-500 per year range.

And there were three companies, two of which are uppity upstarts (EVnetics and NetGain Controls) battling it out with the venerable and entrenched Zilla (which appears to be on hiatus, at least temporarily) for this market. So, this is a very competitive business and every advantage counts. When I see open speculation about what IGBTs or capacitors, etc., are used in the Soliton1 it frankly makes my stomach churn. Some people (e.g. - Dan Fredericksen) think they are entitled to know what components are used in these controllers, even though it took people like me or Otmar Ebenhoech hundreds of hours, and often times thousands of dollars, to arrive at the choices made.

So, I simply ask that you folks not speculate so much on what's inside the Soliton1 because, well, making it is how I make a living, and not even a remotely lavish one at that. If EVnetics is going to be a financial success then it will be from making other products besides EV motor controllers.

Originally Posted by MPaulHolmes

The panasonic ts-ed caps should last quite a few years though, since they don't get too hot.

Depends on how much ripple current they are exposed to, at what percentage of their voltage rating, and at what ambient temp. Why don't you collect some operating data from people driving around to get a better idea of how much ripple the capacitors actually see "on average". Plug that into the Arrhenius equation to see how that, and the ambient temp, affects the lifetime. Remember - you don't get to use both temperature and frequency multipliers at the same time!

Originally Posted by MPaulHolmes

You only need like around 5% of the max current for ripple rating, so they say. 50% is the worst case scenario.

That is an oft-cited rule of thumb but hell if I know how someone came up with it. Design for 50% ripple current and you don't have to worry. Design for 25% if you can guarantee that the capacitors will never be operated long enough above their rating to develop an internal hot spot that exceeds 105C (or 85C, though such has no business inside a motor controller). At only 5% ripple, though? Man, that's like Russian Roulette.

Also, you need to make sure that each cap sees its fair share of the current (and same with each MOSFET/IGBT and FWD). The tool usually employed for testing this is an expensive one, though: a Rogowski coil current probe. Good layout/wiring practices goes a long way towards solving this problem before it even has a chance to crop up.

This, btw, is one of the main reasons Kelly controllers blow up so often.

Originally Posted by sawickm

A while back I looked into the Capacitors that Soliton Controllers used.

And the survey says?

Originally Posted by sawickm

They are using CORNELL DUBILIER TYPE 947C Film Capacitors....

BUUZZZZ. Nope... but the 947C series is a pretty good guess. Not the best choice for this particular application - aimed more at the dc link function in mains-fed inverters - but not a terrible one.

Originally Posted by edown

I think some of you are being a little over concerned about the capacitors, I just use 3 old 4400uf 300V screw mount 85C caps. They never even get warm. I just got them off ebay for about $3 each. And I can’t believe I will have this set-up long enough to worry about there life span. Anyway, that’s my 2 cents worth.

The part of the capacitor that gets hot is the very center, and it's a long way - thermally speaking - from the very center to the case... in fact, the internal temperature limit is reached with as little as a 5C rise of the case.

Perhaps you won't use the controller long enough to matter - that's entirely possible - but sometimes the failure happens within seconds or minutes, especially if your layout results in one capacitor taking the brunt of the ripple current.

[MPaulHolmes]

Hi Tesseract! It's true, I am hilarious! hahaha. I've learned so much from Fran, it's not even funny. Also, the guy that made the control board (he wanted to remain anonymous) has been a huge help to me. He and Fran taught me just about everything I've learned about circuit design, which isn't much (but that's not their fault).

Thank you for the Rogowski coil current probe recommendation. I've never even heard of such a thing! It would be very interesting to see how everything is being shared inside there. First I need to make myself a controller for testing. I still don't even own my own. That's messed up.

[bigh]

Originally Posted by Tesseract

First off, I've been following this thread off and on since it started. Paul is hilarious, and I am actually kinda touched that you all pulled it off... even if lots of the dirty work was actually done by Fran Sabolich

Completely agree

Originally Posted by Tesseract

So, I simply ask that you folks not speculate so much on what's inside the Soliton1 because, well, making it is how I make a living, and not even a remotely lavish one at that. If EVnetics is going to be a financial success then it will be from making other products besides EV motor controllers.

Damm i just lost a massive post.

Hi Tesseract, sorry It wasn't my intention to reverse engineer the Soliton1. I was intruiged as to "Cutting edge capacitor: Special purpose high reliability/low loss 600V film capacitor. No electrolytic capacitors are used in power stage. "

When i asked which type of film cap was being used, i was referring to the types of film caps listed in Wikipedia , not which make, model and spec the one used in your controller is. I'm looking to learn what my options are and select what the best option for my purposes is. Ie high voltage long lasting, and easy to hook up. The fact that your controller used no electrolytic caps is very interesting, as I found the rated lifespan of the electrolytics to be very poor.

Sorry if i caused you anguish, I completely understand why you'd feel that way, as I don't think I expressed myself very well..

I very much appreciate your posts on here and endless-sphere.

[dave koller]

Capacitors are "over-rated" ......
and with that - on with the show.... Oprah is watching......