# 1 MegaWatt DC controller dream



## Hollie Maea (Dec 9, 2009)

I think Evwest is still trying to find someone to buy their Shiva. That would probably be the easiest way (though finding $11,000 might not be easy). Thus said, what brushed motor could do 3000A for 65 seconds?


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## dkubus (Oct 10, 2019)

Agreed that's the challenging part however the use of multiple motors opens up loads of possibilities regarding wiring configuration and therefore voltage/amperage handeling abilities. Plus the ability of the controller is there to have "headroom" from over heating and catastrophic failure mode at say 1,500-2,000 Amp "continuos" abusive racing use. The idea isn't to run at 3,000+ Amps for more than a second or two of course and "spread over multiple motors" all equipped with super cooling ability for short bursts. I currently have (in my road car) a Soliton1 and I do really like it! But I'm not keen on spending thousands of dollars on a big bad-ass controller from Evnetics as they are no longer able to support it and assist the development or repair if we ever damage it. I'd rather do the hard work and be able to "back ourself" so that we can add the features we need/want... plus then it's possible we can assist others have amazing power too?... 





Hollie Maea said:


> I think Evwest is still trying to find someone to buy their Shiva. That would probably be the easiest way (though finding $11,000 might not be easy). Thus said, what brushed motor could do 3000A for 65 seconds?


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## Duncan (Dec 8, 2008)

I'm using a P&S IGBT controller - I think it's good for 1400 amps - but I'n limiting it to 1200 amps

This uses three IGBTs - I don't see any reason why you could not use six IGBTs - or bigger ones 

I'm a mechanical engineer (so I could be wrong) - but the genius level trick that Paul used was that each IGBT has a meter of cable before the three connect to each other - this means that the usual problem of the three IGBTs have slightly different closed resistance and the current then going through one of them and not the other two is eliminated

The IGBTs bolt to a thick aluminium plate - on mine I drilled it and pass water through it to keep it cool


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## dkubus (Oct 10, 2019)

Hi Duncan, thanks for joining in here. I was hoping you would. Exactly what I was thinking might be the best way forward. The one meter cables are of what size and do they pose any heating problems? Efficiency is of course important too but my main questions regarding the P&S board is what's the control interface options for it like? If I ran 6 igbts then should I run two P&S boards? Or twin up three pairs of igbts? 2,400A would be great!!

Thanks again for joining in. 🙏



Duncan said:


> I'm using a P&S IGBT controller - I think it's good for 1400 amps - but I'n limiting it to 1200 amps
> 
> This uses three IGBTs - I don't see any reason why you could not use six IGBTs - or bigger ones
> 
> ...


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## Duncan (Dec 8, 2008)

This is Paul's website

https://www.pandspowerelectronics.com/shop

I'm sure that he will be able to help you


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## dgilbert (Jul 24, 2018)

I used the P&S control board with another IGBT driver (2 actually) to drive 6 x400A IGBT. Current limit is set at 1200A. I've been running 170V but will be 220V or so next year.
And built another very similar with 4 IGBTs set for 800A.


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## dkubus (Oct 10, 2019)

Hey Dgilbert, they sound like great setup's you've put together! And they should have loads of safety margin too. I'm also considering attempting to try and stay under 50% of each IGBT's rated abilities (if I can get hold of enough meaty units to use)...? 

Would love to see some pics of your setup if your willing to share? How configurable is the control boards firmware? Is there plenty of options for settings of battery/motor voltage & current limits etc? 

Cheers for joining the conversation, really gives me hope that my goal might not be as crazy as I first thought. 🤘🤘👍👍

Merry MegaWatt Christmas 🎁😜



dgilbert said:


> I used the P&S control board with another IGBT driver (2 actually) to drive 6 x400A IGBT. Current limit is set at 1200A. I've been running 170V but will be 220V or so next year.
> And built another very similar with 4 IGBTs set for 800A.


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## brian_ (Feb 7, 2017)

Duncan said:


> I'm a mechanical engineer (so I could be wrong) - but the genius level trick that Paul used was that each IGBT has a meter of cable before the three connect to each other - this means that the usual problem of the three IGBTs have slightly different closed resistance and the current then going through one of them and not the other two is eliminated


While this wouldn't eliminate the potential imbalance situation, it would reduce the severity (perhaps to the point of eliminating the problem) by making the IGBT closed resistance a less significant part of the resistance of each output current path - slick idea. 



dkubus said:


> The one meter cables are of what size and do they pose any heating problems?


I would hope that this configuration would not increase the overall output wiring resistance, but that's only an educated guess. Ideally (for balance) the individual (one per IGBT) output cables would be matched in length, and all run all the way to the motor terminal or a point very close to it, with a total cross-sectional area comparable to what would be used as a single conductor.


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## brian_ (Feb 7, 2017)

dkubus said:


> Agreed that's the challenging part however the use of multiple motors opens up loads of possibilities regarding wiring configuration and therefore voltage/amperage handeling abilities.


The obvious possibility is to use one controller per motor. That allows you to scale up the power by increasing the number of controllers (from one to two), instead of by increasing the capacity of a single controller to a level which is difficult to build and to find. It does have the inherent cost disadvantage of duplicating the logic portion. It also eliminates the possibility of switching the motors from in series with each other at low speed to in parallel with each other at high speed... but is that a practical option anyway?


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## dkubus (Oct 10, 2019)

Yes it would be good to put a single controller per motor however the application I have in mind means the advantage of twin motors with various contactor configurations will be of more benefit for the initial launch torque, and minimizing the voltage stress on the brushes too. 

Mike. 

[/QUOTE]
The obvious possibility is to use one controller per motor. That allows you to scale up the power by increasing the number of controllers (from one to two), instead of by increasing the capacity of a single controller to a level which is difficult to build and to find. It does have the inherent cost disadvantage of duplicating the logic portion. It also eliminates the possibility of switching the motors from in series with each other at low speed to in parallel with each other at high speed... but is that a practical option anyway?[/QUOTE]


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## Duncan (Dec 8, 2008)

Hi

I am very unconvinced about the advantages of being able to change parallel/series - with a modern high voltage controller I think the advantage evaporates

Two (or more) controllers strikes me as a very sensible idea

The Logic board is cheap - the expensive parts are the IGBTs and the big capacitor

So you would need the expensive bits anyway!!

I'm thinking about two of the P&S controller I'm using - one for each motor

You can see the "brain" card there at the front - there is also a 24v supply card that mounts above that 
Then it's just the three IGBTs and the huge round capacitor - and the current sensors

You can see the long output leads I mentioned 

https://ecomodder.com/forum/showthr...cheap-diy-144v-motor-controller-6404-689.html

This link takes you to the conversation I had with Paul when he sent me the controller - it arrived a bit bashed up


1400 amps is probably all you want to feed each motor anyway!


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## dkubus (Oct 10, 2019)

Any ideas if these or similar might be the way to go ??

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com.au/ulk/itm/192701402023

3600A 😜 1200 volt max! 



dgilbert said:


> I used the P&S control board with another IGBT driver (2 actually) to drive 6 x400A IGBT. Current limit is set at 1200A. I've been running 170V but will be 220V or so next year.
> And built another very similar with 4 IGBTs set for 800A.


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## dkubus (Oct 10, 2019)

That's a sweet setup, and I'm thinking you may well be correct regarding the value of contactor switching etc.. unfortunately my second WapP9 is stuck in transit (merry Christmas).. so I can't test the "torque per Amp" experiments I have in mind prior to deciding on a final configuration. 

I was recently given a box of 20 x 1000V DC link caps that I was thinking should all team up in parallel real well into one mother of a DC link Cap. (20x 100uF)... 

Very experimental of course but this is a race car project after all so experimenting is the fun bit. 🤘





Duncan said:


> Hi
> 
> I am very unconvinced about the advantages of being able to change parallel/series - with a modern high voltage controller I think the advantage evaporates
> 
> ...


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## kennybobby (Aug 10, 2012)

dkubus said:


> Any ideas if these or similar might be the way to go ??
> 
> https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com.au/ulk/itm/192701402023
> 
> 3600A 😜 1200 volt max!


That is just a diode module, no gate or transistor.

Mouser has a 1200V, 800A single IGBT module for ~$150, FZ800R12KE3.


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## dkubus (Oct 10, 2019)

Hey cheers Kennybobby, I'll check that out. I got a little excited when I saw it listed as an IGBT 🤷‍♂️🤦‍♂️



kennybobby said:


> dkubus said:
> 
> 
> > Any ideas if these or similar might be the way to go ??
> ...


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## dkubus (Oct 10, 2019)

Hi Kennybobby, how would these go? 

https://au.mouser.com/ProductDetail...=sGAEpiMZZMshyDBzk1/Wi3HsWEt5/iIsxEP0C45rDQ8=

https://au.mouser.com/datasheet/2/196/Infineon-FZ1600R17KE3-DS-v02_00-en_cn-464842.pdf




kennybobby said:


> dkubus said:
> 
> 
> > Any ideas if these or similar might be the way to go ??
> ...


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## kennybobby (Aug 10, 2012)

Those are massive indeed, maybe 3 or 4 in parallel could handle the current.

It is not a trivial task to take a design and scale it up to the level you want. And this is just the controller. What motor can handle that power? And what batteries can supply that energy?

It sounds like you need a Shiva controller, designed and built by experts in motor drives. 

https://www.evwest.com/catalog/product_info.php?cPath=1&products_id=148


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## dkubus (Oct 10, 2019)

I originally didn't go into details regarding the motors or battery as this was a "controller topic" I'm pretty new here so please excuse my ignorance. I'm learning how to post etc (I still don't get how my posts always look different with regard to "replying or quotes"... here goes... bellow ⬇



kennybobby said:


> Those are massive indeed, maybe 3 or 4 in parallel could handle the current.
> 
> I'll keep researching ideal components then but I know that these are available here in Australia so these might be a good choice.
> 
> ...


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## Duncan (Dec 8, 2008)

Hi
The high current end is very important - Paul (of P&S) does know what he is doing
He learnt a lot from his earlier 500 amp controller

The ring capacitor on my controller has it's connections to the IGBTs in the form of copper sheet - and this is something to do with the inductance!

Which is why if I was going to do as you are I would be using his design - and his control board in the form of two controllers

The SHIVA looks awesome and is probably a level above the P&S in sophistication

But it is five times the cost and no longer supported

Hill climbs here (South Island) are gravel with big trees and big drop offs - I don't have the balls to use my car at full power in those conditions

Back in the UK "Sprints" were great fun - I used to have a twin cam mini

Here we do something similar - But I don't have the maximum speed for the fast ones - I had my mini up to about 130 mph 
The fastest I have taken my device is 93 mph at the 1/8th mile drags
100 mph would probably be OK - beyond that will overspeed my 11 inch Hitachi too much


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## dkubus (Oct 10, 2019)

Hi Duncan, yes Hillclimb racing is a little difficult for "normal trackday or drag racing" enthusiasts to contemplate sometimes. The risks far outweigh the rewards but of course like anything it becomes an addiction. Luckily for me our Hillclimb racing is more like Tarmac Rally stage racing on closed public roads. Only difference is that we run multiple times up the one road in the course of a racing weekend. Top speeds are normally around 150-170km per hour. Many of our "tracks" now have barriers and cliff protection due to insurance companies refusing to cover event organizers otherwise. 

Once I hear back from Paul, I'll be able to make better assessment of my ideas for the capacitor design (I do intend to use sheet copper too) I've opened my Soliton1 (had a loose two pin plug on main board that was causing random shut-down) and I was really impressed with the copper sheet layout with insulative intermediate sheet. After giving the offending pins a slight bow the plug was firm to replace and has never faulted again so far. (It's a good internal design). 

Being in NZ you'd have a good understanding of being isolated from the "world" (USA) and the desire to stick with components and suppliers that can and will support you. 

I know what I want to do, and I appreciate that it's not going to be easy or straightforward. However this isn't a 3 phase beast of sinusoidal wave forms etc. it's a big series wound "motor's" pair (or more) if I melt something first go.. lol 

I still think DIY is the only way for this goal. And I'm sure Paul will be able to help me achieve my goal. Once Christmas holidays are over I'm sure he'll respond to my original email via his web page. 

really looking forward to this. 👍

Mike.


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## brian_ (Feb 7, 2017)

dkubus said:


> I'm pretty new here so please excuse my ignorance. I'm learning how to post etc (I still don't get how my posts always look different with regard to "replying or quotes"... here goes...


I think this is what you intended:



kennybobby said:


> Those are massive indeed, maybe 3 or 4 in parallel could handle the current.





> I'll keep researching ideal components then but I know that these are available here in Australia so these might be a good choice.





kennybobby said:


> It is not a trivial task to take a design and scale it up to the level you want





> 100% agree with you on that one! This is why I started this conversation, there's much more experience and knowledge here than I currently posses on the topic and as a DIY guy I'm keen to learn (probably the hard way) but learn all the same.





kennybobby said:


> And this is just the controller. What motor can handle that power?





> There will be a minimum of two motors (I have room for more in this vehicle design) if required.





kennybobby said:


> And what batteries can supply that energy?





> Battery will be 100Ah (5Ah x 20P Lipo pouch cells) power density cells not energy dencity chemistry. More than likely 88S and more than capable of 30C continuous (till exhausted) with minimal sag. (Hillclimb racing is like drag racing but with corners and normally one mile in distance up a 10-20% grade of mountain road).





kennybobby said:


> It sounds like you need a Shiva controller, designed and built by experts in motor drives.
> 
> https://www.evwest.com/catalog/product_info.php?cPath=1&products_id=148





> Whilst I love the idea of the Shiva and I truly enjoy the Soliton1 I have in my daily driver unfortunately Evnetics is no more and I'm not keen on spending money on a device that will have no backup support. On the other hand if I spend double, triple or more getting a controller designed and built that works well then by the time I have been able to achieve that goal, I'll definitely be equipped to support it and keep it running and perform any future modification I ever dream up....
> 
> That's why I'm here in this diy forum. Cheers for all of the help and guidance so far. I really appreciate it.
> 
> Cheers Mike.


It's way too late for me to be up to explaining how to format posts for this forum.


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## dkubus (Oct 10, 2019)

Cheers Brian 👍👍


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## dkubus (Oct 10, 2019)

Warp9 number 2 just arrived 🎁🎁 woohoo 🙌 Once I have them coupled up I'll start on some experiments with wiring configuration. Another step forward.


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## Duncan (Dec 8, 2008)

Hi
You are from the "West Island" AKA Australia?

Have you read 
https://www.diyelectriccar.com/forums/showthread.php?t=185897&highlight=autocross

This thread?

Galderdi is having difficulty with the motorsports authorities in Australia - might be worth contacting him


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## dkubus (Oct 10, 2019)

Yes I sure am in Australia, "CAMS" (our motorsport governing body) can be difficult with things they don't understand that's for sure. I've been Hillclimb racing for about 25 years and remember my first run in with them regarding a "non approved roll bar" in my fiberglass bodied tarmac racing buggy, I removed it and the let me race! 🤦‍♂️🤦‍♂️ Absolutely crazy lol.. 

Cheers I'll check it out and reach out to him if he needs any help 👍👍🤘

Mike. 



Duncan said:


> Hi
> You are from the "West Island" AKA Australia?
> 
> Have you read
> ...


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## brian_ (Feb 7, 2017)

dkubus said:


> 👍👍🤘


Nothing to do with EVs...
Mike, I assume that you are putting emojis (emoticons, whatever...) in your posts with some mobile device. The codes which result mean nothing to the forum or to browsers, so instead of getting "thumbs up" and similar graphics, all that is displayed in some cases is strings of hex codes. They work in the special mobile browser view that I see on my Android phone (in Chrome), but not in the "desktop" browser view on a Windows PC (also in Chrome). This is a quirk of the forum operator's software, not the fault of a user, but you might want to be aware of it.


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## dkubus (Oct 10, 2019)

Cheers Brian I appreciate the heads up. 

Mike. 



brian_ said:


> dkubus said:
> 
> 
> > 👍👍🤘
> ...


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## dkubus (Oct 10, 2019)

I've been so flat out with work that not much has occurred regarding the Hillclimb EV project, however I've now at least got the two WarP9 motors together in the same space and just waiting on an incorrectly supplied taperlock bushing to be replace next week so they can be joined.


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## dkubus (Oct 10, 2019)

Dual motor testing has been done (12v only) measuring Amp draw Vs rate of acceleration (internal fan & bearing drag and inertia forces only) I've tried all configurations I could think of plus some that were from the netgain motor manual listed as "experimental" (they were not useful in my opinion). 
Hooking up fields in series and then linked in series with the Armatures in series-or-parallel "option" seemed like the best two configurations attempted. Looking forward to some dyno testing as soon as I have this lot linked up to some wheels and a chassis! 

Hope everyone's projects are going well.


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## dkubus (Oct 10, 2019)

New direction with this controller design now has me getting rather excited about the abilities of SiC based MOSFET devices, they look like they will be much suited to working in parallel for massive power potential. So far designing around the SOT-227 miniBloc versions as the beefy connection method looks most up to the challenges of motorsport. Have any of you guys used these before? 

I hope your all well and keeping out of the way of this horrible Covid19 disaster. Wishing all the best to everyone around the world. I'm staying home and will just work on my controller design.


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## mikejh (Nov 20, 2008)

Hey Mike,

Another far-west west islander here... 

I like your idea of the SOT-227 SiC Mosfets although I can't say I have used them. Considering them lately although their current capability still seems low. The SOT package is also lead limited to 200A too.

I started working on my controller years ago with standard SOT mosfets but as usual I have procrastinated and gotten side tracked for years and never finished it. Still dreaming of building an EV and now it's probably cheaper to buy one.

This was back before IGBT's and laminated bus bars were doable for the DIY's so I went the easier route and liked the isolated nature of the SOT's. Through hole mosfets and PCB's just didn't seem to cut it for me, although there has been plenty of success stories.

My plan was always to scale this design after prototyping, both in current (longer bus bars, more SOT's) and voltage, but as time goes on I can see all the flaws in this design. Long bars = inductance, electrolytic caps too much ESR, not enough ripple current capability etc. etc.
But easier for me to mill a copper bar than bend a large copper sheet.
Is the Soliton copper or ali? Sorry, just re-read your post saying it was copper...

Laminated bus bars and ring caps are definitely the way to go to keep inductance and ringing to a minimum, and the SOT package doesn't lend itself to the laminated design as easily as the SP6 IGBT blocks.

Then there's the current sensing. The LEM HASS 600 can go up to 1100A full scale and I think the HTFS800 can go to 1200A but that's about it for the nice single rail sensors. (I think) Never liked the idea of the SO8 sensor that gets stuck on the cable and the calibration varies with the distance from the cable. Seems less than average...

My prototype uses 4 x IXFN230N20T Mosfets (230A @ 200V) so 800A max and I was planning on 150v initially.
Could swap these out with IGBT's or SiC mosfets when they get a bit better and change the caps for higher voltage. Seems like 143A is max for the SiC's in this package at the moment?

Anyway, good luck with your design. I'm interested to see your progress.

Stay safe.

Mike


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## dkubus (Oct 10, 2019)

Hey very cool Mike, looks almost exactly like my cad model so far except that instead of electrolytic caps I'm using 1000V film caps (100uf each x15 in total) 

Otherwise the only difference is that mine is flipped upside down compared to your photograph so that the cooling plate is at the top of the controller. 

So far my design is based on the hass600 x3 (one for each brick of the modular design). I'll eventually be running 27 sot227 blocks in total ( 3x 9 blocks) each block will have 5x 100uf 1000V film caps. (This is based on my soliton1 having 500uf ring cap). Hopefully my set-up will work just as well "per module" giving me a total of an easy 3000A capability. Yet to be seen??

I'll never need to push the sot package's anywhere near 200A each due to how many ill be using in the design, im still however working on the driver circuit design options... (not fun for a mechanical guy).

I've recently re designed (yes all over again for about the 11th time).. so that my connections get positioned opposite sides of each 1000A module so that hopefully it helps equally distribute the power flow amongst the sot's more evenly? Plus I'm thinning down my rails and placing them even closer to my plates that carry the caps. Hopefully this helps all that black magic stuff. Lol

Would love an opportunity to talk with you via a phone call considering you're in Australia too and obviously have a similar interest in this stuff. 

I'm currently waiting on components to arrive for first scale test of design. 

Cheers for jumping in and sharing your photos and experiences so far. 

Cheers 
Mike.


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## mikejh (Nov 20, 2008)

Those modules look great.



> Hopefully this helps all that black magic stuff. Lol


I'm sure it will be fine. Some people have success with some real spaghetti messes so it's gotta be better than that. 

One reason why the Soliton "gets away" with the reasonably low capacitance is because of the very low inductance that is afforded with the laminated bus and even the ring cap itself. The cap has so many connections in parallel that it drops the resistance right down too meaning high current capability, and better able to absorb those inductive spikes rapidly before they do any damage. With your film caps your're mostly there anyway.

If there is a way you could feed the bars from the centre that would help in lowering the L as well.

That said if you are using 1700v Sic mosfets then there is probably a fair bit of headroom above DC link voltage that might prevent them from getting hurt, even if the spikes are a little larger than you would like.
With a 400v supply even 800v of inductive kick back wouldn't hurt anything.... much. 

One of my problems in taking too long to finish my design is learning more and thinking I should just can it and change to a ring cap, laminated bus, and IGBT's... but then I think if I just press on i'll probably learn more by running it than just thinking about the theory... of which I am no expert. 

Yeah drivers will be a worry.
Not sure which mosfets you are using but mine have something like a 47nF gate capacitance, meaning you need a high current driver to turn them on *fast*. 9 in parallel is gonna need some serious currents....
One benefit of the IGBT blocks is 600A Ic and only one large input capacitance. 49nF in the case of the APTGT600A60G.

I'm using the IXYS 30A drivers (one per mosfet) but unfortunately I don't think they can take a negative vss for fast turn off. I certainly didn't design for it either. Starting to question my choice there... could be overkill. 
Of course you don't want to turn them on too fast either as you have to wait for the reverse recovery of the high side, but you can tune that with the gate resistor.

Mike


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## dkubus (Oct 10, 2019)

My capacitor choice was based on being given these caps from a charging station rebuild. (Replacement caps went in even though these ones are fine).. the Soliton Jr (600A) controller uses similar individual 3x 150uf caps attached in the same parallel copper sandwich lamination bus (like my design uses) so my optimistic hope is that I'll be ok with 500uf high current film caps attached to my laminated bus plates? I do have enough room to fit one more 100uf cap if I delete my internal dual contactors per module. This would then mean the total goes up from 1500uf to 1800uf for the full controller, each cap is rather large and has 8mm studs for connection so im not sure if this equates to "as good as" the ring cap in the soliton1 or not? What is the advantage of the big round ring cap especially considering that in the soliton1 the igbts are placed at the end of the controller rather than directly above and (adjacent to) the capacitors and bus plates in my design?... my distance between any one cap terminal and the source of any pulse and or power source is much shorter (upto 20 times shorter) than in the soliton1 or soliton Jr. (Or perhaps I'm missing something)? 

I agree that centralised power supply to each feed rail would be preferable however its extremely difficult to package. I'll give it a go though as it might mean i can shorten the overall packaging.. maybe?.. (redesign number 12,13,14 coming up)...

The main reason I'm not going with IGBT's is that apparently they don't parallel very well in comparison to MOSFET's so with my lofty Current goals I wanted good parallel behaviour. Plus one thing I've discovered is that with my current road-EV (running my soliton1) its more efficient to drive with a semi-aggressive throttle use and then coasting, rather than driving with light throttle. I can only assume that this is due to the igbt modules having the same or similar losses at all current loads and therefore they are more efficient at higher power than they are at extremely small current demand (most of the typical driving cycle). For this reason I'm optimistic that with a large amount of SIC Mosfet devices in parallel with a ridiculously low RdsON should yield amazing efficiency at typical "light" driving loads and when using high current be "almost as good as" igbt modules (if they were capable of 3000A) and of course high current won't be required for very long as there are other limitations (motor meltdown and legal speed limits) etc. 

Driver tuning via resistance etc is all the parts where my mechanical brain starts to hurt lol...

Thanks again for jumping into this discussion and for all the great info. As always wishing everyone well during these testing times. 

Mike.


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## mikejh (Nov 20, 2008)

Yeah I think you'll be fine with the number of caps you're running. The internal contactors sound good too, I didn't see those. 
Good score on the caps.  Those are still good for high current being film caps and decent connections. I think the ring cap is all about packaging and suitability for mounting to the laminated bus design. Another plus is that it usually sits on the same heatsink as the power modules so has some cooling as well. Makes for a large controller though.
Ive often thought those caps like yours would be great but weren't great for mounting/packaging, but it looks like you have that sorted with your design.

Your design is certainly well thought out and I would go with it as is. Change it later if you find a reason.  You might find the caps will cover any slight inductance change you would get by shortening the bars.

Yes, agree with the IGBT paralleling issues. Guess they just became the go to device for high voltage before the SiC's were available. If only we could have the SiC's an similar package and current capability.  Oh and a reasonable price. 

Damien Maguire has some good videos on his controller builds and I think he talks about tuning the gate resistors. I think it's mostly about finding that sweet spot between slow turn on (excessive heating) and ringing/noise generation.

Not sure if you have seen the attached document but there is some good information there that might be useful. Getting a bit old now though. Think it was 2012.

Mike


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## Duncan (Dec 8, 2008)

The problem with IGBT's not sharing was solved by Paul (of P&S) by simply using a length of cable on each one
Brilliantly simple


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## mikejh (Nov 20, 2008)

Duncan said:


> The problem with IGBT's not sharing was solved by Paul (of P&S) by simply using a length of cable on each one
> Brilliantly simple


Yeah I remember seeing that. What does that do for inductance though?

Actually, I realise that adding the length of cable is intentionally adding inductance/resistance for current sharing, but what does it do for voltage spikes?

Guessing the voltage spikes only happen when the inductance is on the battery side of the controller and the extra cables just look like a motor with higher inductance?

Likely to make the high side fets/diodes work harder?

If the controller sees higher inductance then it will have to deal with higher flyback?

Mike


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## dkubus (Oct 10, 2019)

Yeah I'm also not convinced that this method can be called "solved" as it seems that most people using IGBT modules in this way purposely limit their current to around half of what the igbts should easily be able to cope with if they were being used on their own. That's at best a good and creative work around but not a cure. 

I think that its quite possible that the igbt modules were the popular option as they were the first player to emerge with both high voltage and high current carrying capacity in a nice convenient package. 

I'm starting to believe though that the use of a large number of SIC sot227 (or similar) modules allows a massive heat shedding area (comparatively speaking) to that of an equivalent current carrying igbt solution. 

Again all of my design ideas so far are only based on theory and data sheets that could be optimistic and therefore i could be missing the point entirely. 

I still think that with my design being constructed from three modules that I'll still be running three sets of cables, not for inductance reasons but rather ease of connection and routing plus more copper cross section in total to carry the current and also shed any heat that may be made at the extreme end of the current limits ive set for this project. (3,000A)

On the battery side I'm still torn as to weather or not ill run three sets of cables or just perhaps two sets attached to a pair of power rail bus bars? Will depend probably on what i can make fit in this tiny car. As the controller design is rather massive so far. 

If its possible i hope to mount the controller to the motor assembly and have the motor side cables with very minimal length. 

Again all depends on room back there. 

Mike.


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## dkubus (Oct 10, 2019)

mikejh said:


> Yeah I think you'll be fine with the number of caps you're running. The internal contactors sound good too, I didn't see those.
> Good score on the caps. 🙂 Those are still good for high current being film caps and decent connections. I think the ring cap is all about packaging and suitability for mounting to the laminated bus design. Another plus is that it usually sits on the same heatsink as the power modules so has some cooling as well. Makes for a large controller though.
> Ive often thought those caps like yours would be great but weren't great for mounting/packaging, but it looks like you have that sorted with your design.
> 
> ...


I'm not sure why but the attached document you mentioned isn't attached or at least i can't find it?

Cheers 
Mike.


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## mikejh (Nov 20, 2008)

Hey Mike,

Not sure if you are viewing this on a PC or not but I can see it on the post at the bottom. It's a PDF.

Maybe download via this link instead:
https://www.ixys.com/Documents/AppNotes/IXAN0009.pdf

This one is similar but might be a later revision.
https://www.ixys.com/Documents/AppNotes/IXAN0010.pdf

This one maybe not so useful...
https://www.ixys.com/Documents/AppNotes/IXAN0011.pdf

They have some good information for calculating required drive current, gate resistors and power dissipation in the drivers etc. for a given gate charge and drain current etc.

Mike


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