Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-23-2011, 12:24 PM   #601 (permalink)
EcoModding Lurker
 
Join Date: Aug 2011
Location: Michigan
Posts: 32
Thanks: 3
Thanked 27 Times in 10 Posts
Heh, it's interesting that you found this thread. I have had your website bookmarked for a long time. Yeah, I've now blown up the controller twice. I think this makes my average about 60% since I've successfully tested with no blow ups like three times and blown it up twice. Luckily this last time was just a transistor, gate resistor, and a few diodes. I'm using $25 surplus 200A IGBTs right now so that explosions are less sad.

Here's my thoughts on my last blow up (which I unfortunately did not film at all.... stupid!):

I ordered a 50A 800V three phase rectifier off of ebay and used it connected to 240V single phase as my power source. Since I had precharge capacitors installed they were able to smooth the voltage to about 339V at rest. Unfortunately I never got to testing how much voltage fluctuation I was getting. However, I was only testing a 2HP motor unloaded so I doubt that the amperage was too high. I did have an oscilloscope running at the time. I put a probe on one of the three phase outputs to the motor while testing. I could see really large spikes on the output. They looked very short, perhaps like 1us. Here is where I wish I really wish I had video because all I can go on now are vague recollections after the fact. I'm not sure if the spikes were because A. I somehow managed to use IGBTs with no freewheel diodes. I doubt this because any reasonable half bridge should have them but I'll check B. using a rectifier would have caused the input voltage to be very unstiff and maybe that caused some issues C. I had way too long of a connection between the capacitor bank and the bus bars. I knew that was naughty but was hoping to get away with it. One thing is sure though, I had way too much inductance on the input side of the controller. D: Maybe my leads from driver to IGBT are too long. I mean, the wires are like 2.5" or something but maybe that's still too much. Or maybe something was getting induced on the lines. I might be able to shorten the leads even more.

Regrettably I didn't test for many of my guesses above. It blew up before I could. Well, it's fixed again and I'll keep at it.

Quote:
Originally Posted by etischer View Post
Your first spin video is just like mine =) I blew up my IGBTs too =)
<<URL removed>>

Now, two years later, I'm running closed loop vector control, and have racked up almost 30k miles!

It's great to see other people take on a such a project. I wish you luck.
Here's a link to my inverter project: <<URL removed>>

It's my first post, and I'm not allowed to post URLs yet =( You can google etischer and find my electric vehicle webpage.


Cheers
-Eric.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-23-2011, 01:30 PM   #602 (permalink)
EcoModding Lurker
 
Join Date: Nov 2010
Location: San Francisco Bay Area
Posts: 3
Thanks: 0
Thanked 1 Time in 1 Post
My best guess is:

C. I had way too long of a connection between the capacitor bank and the bus bars. I knew that was naughty but was hoping to get away with it. One thing is sure though, I had way too much inductance on the input side of the controller.

This could also be why you were seeing large voltage spikes on the scope.
  Reply With Quote
The Following User Says Thank You to etischer For This Useful Post:
CollinK (10-23-2011)
Old 10-23-2011, 03:15 PM   #603 (permalink)
EcoModding Lurker
 
Join Date: Aug 2011
Location: Michigan
Posts: 32
Thanks: 3
Thanked 27 Times in 10 Posts
Yes, that's my guess too. I've since shortened the links and I think I'll try to make them even shorter. I know that the less distance and inductance between capacitors and bus bars the better. Chalk this one up for knowing better and trying it anyway...
  Reply With Quote
Old 10-24-2011, 01:04 AM   #604 (permalink)
Master EcoModder
 
JasonG's Avatar
 
Join Date: May 2009
Location: Charlotte NC / York SC
Posts: 728

05 DMax - '05 Chevrolet 2500HD
90 day: 18.48 mpg (US)
Thanks: 114
Thanked 55 Times in 51 Posts
Are your leads cable?
May I suggest using flat bar from the caps to the IGBTs, I know its a pain to fabricate but it will kill the inductance.

BTW etischer, I haven't kept up. Didn't know the AC was up and running. Nice !
Since your post count isn't up yet http://etischer.com/awdev/
__________________



I can't understand why my MPG's are so low..........
21,000lb, 41' Toy Haulers are rough on FE!
  Reply With Quote
Old 10-26-2011, 07:55 PM   #605 (permalink)
EcoModding Lurker
 
Join Date: Aug 2011
Location: Michigan
Posts: 32
Thanks: 3
Thanked 27 Times in 10 Posts
I was using bars across the IGBTs. The batteries where connected through a contactor to the busbar. The capacitors, though, were connected to the bus bar with 2 or 4 gauge wire. It was way too long too. What a recipe for disaster! I've since bought a 66uF 800V film cap that can handle 100Arms. It is now bolted directly to the bus bars. My calculations suggest that this should result in a total of about 15V ripple at 100Arms AC ripple current. However, I also got some 1500uF 450V elcos. I might try to get bars long enough to put one or two of those on the bar too. That will make the bar sort of long though. I suppose the real question now is, what sort of ripple might the busbars experience? If I run a motor up to 250Arms then what equations should I use for the AC ripple at the caps? From what I can gather it seems that the AC ripple of a three phase system should be approximately half of the Arms to the motor. This would give me about 125Arms at the caps at peak output. Additionally, I might want to clamp the ripple voltage to less than 15v so I'll need more caps because of that too. So, I think I'll need a bit more than just my 66uf film cap but maybe not until I start really loading the motor. I'm reading that elcos in the system were mostly used in VFDs because they input rectified mains voltage and thus have very ripply voltage input. A battery is very stiff and constant so it seems like tons of capacitance is no longer needed. Instead, the caps in that case are just to deal with the ripple current and to decouple the IGBTs from the batteries.

I have a ton of PDFs about this whole situation but I certainly wouldn't reject suggestions either directly or for other PDFs or books I might want to read.
  Reply With Quote
Old 10-26-2011, 09:48 PM   #606 (permalink)
AC-DC enthusiast
 
mrbigh's Avatar
 
Join Date: Nov 2009
Location: Long Island, NY
Posts: 282

Dual-PWR PHEV - '04 Toyota Prius

Kopper - '79 Bradley Bradley GT-II
Thanks: 122
Thanked 54 Times in 37 Posts
IGBTs/Cap mounting

And here is my approach to the IGBTs and Capacitor mounting














__________________
. .. .. . .......
Prius Absolutum Dominium . ..........KOPPER
PHEV conversion since Dec 2006.. . .... .Future EV
. . . . . . . .CALCars # 27. . . . . . . . . . ..on the works now !!
. . . . . . . . . . . . . . . . .. . ........
  Reply With Quote
The Following 3 Users Say Thank You to mrbigh For This Useful Post:
Electroddy (10-23-2012), LouMan (10-28-2011), madmike8 (10-26-2011)
Old 10-26-2011, 11:44 PM   #607 (permalink)
EcoModding Lurker
 
Join Date: Jun 2011
Location: Tennessee
Posts: 16
Thanks: 4
Thanked 1 Time in 1 Post
That's pretty impressive looking... I like it!
  Reply With Quote
Old 10-27-2011, 12:08 AM   #608 (permalink)
EcoModding Apprentice
 
dave koller's Avatar
 
Join Date: Feb 2010
Location: Northern Wisconsin
Posts: 137
Thanks: 32
Thanked 38 Times in 23 Posts
mrbigh

Nice!!!
__________________
Dave ...
  Reply With Quote
Old 10-27-2011, 12:16 AM   #609 (permalink)
EcoModding Lurker
 
Join Date: Nov 2010
Location: San Francisco Bay Area
Posts: 3
Thanks: 0
Thanked 1 Time in 1 Post
Make sure your bus bars don't rub through the vinyl insulation on your capacitors! You might also verify the vinyl insulation is rated for your bus voltage.
  Reply With Quote
Old 10-27-2011, 08:41 AM   #610 (permalink)
Master EcoModder
 
Join Date: Apr 2009
Location: Charlton MA, USA
Posts: 463

EVVette - '71 Chevy Corvette Coupe
Thanks: 31
Thanked 180 Times in 94 Posts
Looks great MrBigh!

How did you end up bending those curves on the bus bars?

-Adam

__________________
www.EVVette.com - 1971 Corvette Coupe Conversion to all Electric!
www.AdamBrunette.com - Machining, CNC, Robotics and Electronics.

You can download RTD Explorer for the Cougar controllers at www.EVVette.com
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Paul & Sabrina's cheap DIY 144v motor controller MPaulHolmes Open ReVolt: open source DC motor controller 7350 07-28-2021 06:32 AM
Paul & Sabrina's Cheap EV Conversion MPaulHolmes Fossil Fuel Free 542 11-12-2016 10:09 PM
Contest! Name Paul & Sabrina's controller MetroMPG Forum News & Feedback 120 10-22-2011 02:59 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com