FET resource page for MEV/HEV applications.

[grindz145]

It probably wouldn't hurt to add 4110 and 4115s to the list as well just to have a complete reference including the top tier legacy components.

Luke, this thread is exactly why its worth spending my time on this forum. Thanks

 

[dangerzone]

When you get above around 120 to 150V it doesn't really make sense to use FETs, as the losses start to rise dramatically due to the high Rdson (9.7mOhm in this case). If you ran this FET at a modest 60 to 70 amps, then the voltage drop across the FET is going to be around the same as an IGBT, and an IGBT will hold that sort of voltage drop for higher currents and work at higher voltages.

This is the reason that the Prius PMBLDC motor controllers use IGBTs and not FETs, they are better at high voltage, high current than FETs (at the moment).

For lower voltages, where you can get FETs with a nice low Rdson, then FETs make sense. For example, the Ixys Hiperfet modules that LFP, Bigmoose and I have just bought have an Rdson on around 1.8mOhm, work at 100V max and will handle up to 680 amps. That low Rdson means that the voltage drop across the FET (and hence the losses in it) won't reach IGBT levels until the current gets up to around 350 amps or more.

You can drive big IGBTs the same way as big FETs, as their gate drive requirements are similar. The main difference is that, because they have a bipolar transistor switching element they have a fairly fixed voltage drop when hard on that is pretty much the same as a diode, around 0.6V at low currents, rising slightly as the current increases. This makes them lossy for low power applications, but great for high voltage, high current applications.

Jeremy

Jeremy, what kind of a controller would you recommend for a 30kW (up to 60kW peak for 1 minute) BLDC motor as the EMRAX electric airplane motor..?

http://www.enstroj.si/Electric-products/emrax-motors.html

The Piktronik controllers for the 200V/300V and 200A use they recommend are in the 7kg to 16kg range, is there any way to make a lighter/better one with some other FETs..?

 

[Jeremy Harris]

You're seriously into IGBT territory at this power level, definitely not FETs.

I've no expertise in really high power controllers, but having read the book on the challenges the Toyota team faced when building a similar power controller for the Prius, I don't for one moment think that it's going to be easy to build a lightweight controller at this power level.

Jeremy

 

[dangerzone]

You're seriously into IGBT territory at this power level, definitely not FETs.

I've no expertise in really high power controllers, but having read the book on the challenges the Toyota team faced when building a similar power controller for the Prius, I don't for one moment think that it's going to be easy to build a lightweight controller at this power level.

Jeremy

Well, it seems Luke is on the right way, these Sevcon controllers seem to have some similar FETs inside:

http://www.sevcon.com/PDFs/G80%20Datasheet%20G801109B.pdf

 

[Jeremy Harris]

Well, it seems Luke is on the right way, these Sevcon controllers seem to have some similar FETs inside:

http://www.sevcon.com/PDFs/G80%20Datasheet%20G801109B.pdf

I've never seen inside a Sevcon, but the two I've seen weren't big enough to have housed the Ixys FETs that Luke and I have inside. Also, the Sevcon isn't a 200/300V rated controller as you enquired about, it's 116V max, which is still just inside FET territory. My guess is that the Sevcon is like pretty much all others and uses an array of smaller package FETs inside.

If you want to operate up at 200 to 300V, then, as I said before, you're definitely into IGBT territory; FETs will simply be too lossy at these high voltages. If you are happy to bring the voltage requirement down to around 80V, then the biggest of those Sevcon controllers you linked to would handle about 17.6kW continuous, well short of your 60kW requirement. It's thermally limited in its current handling capability, so would handle 44kW for two minutes, but this is still well below your requirement. The I²R losses in things like wiring, the controller, the motor and the battery internal resistance start to get very high when you lower the voltage and increase the current to get this sort of power. Your original desire to operate at 200 to 300V makes a great deal more sense than running at the 80V maximum of this Sevcon unit.

Jeremy

 

[dangerzone]

Well, it seems Luke is on the right way, these Sevcon controllers seem to have some similar FETs inside:

http://www.sevcon.com/PDFs/G80%20Datasheet%20G801109B.pdf

I've never seen inside a Sevcon, but the two I've seen weren't big enough to have housed the Ixys FETs that Luke and I have inside. Also, the Sevcon isn't a 200/300V rated controller as you enquired about, it's 116V max, which is still just inside FET territory. My guess is that the Sevcon is like pretty much all others and uses an array of smaller package FETs inside.

If you want to operate up at 200 to 300V, then, as I said before, you're definitely into IGBT territory; FETs will simply be too lossy at these high voltages. If you are happy to bring the voltage requirement down to around 80V, then the biggest of those Sevcon controllers you linked to would handle about 17.6kW continuous, well short of your 60kW requirement. It's thermally limited in its current handling capability, so would handle 44kW for two minutes, but this is still well below your requirement. The I²R losses in things like wiring, the controller, the motor and the battery internal resistance start to get very high when you lower the voltage and increase the current to get this sort of power. Your original desire to operate at 200 to 300V makes a great deal more sense than running at the 80V maximum of this Sevcon unit.

Jeremy

Thanks Jeremy, great info.

 

[dangerzone]

Did anyone on ES ever try to use the 6FET controller with some of those high power IGBTs..? Capacitors, gate drivers and diodes would also have to be changed, copper rods would be better than cables and a whole lot more would have to be adjusted for high power, but has anyone done a bit more than just have the idea..?

 

[Arlo1]

Did anyone on ES ever try to use the 6FET controller with some of those high power IGBTs..? Capacitors, gate drivers and diodes would also have to be changed, copper rods would be better than cables and a whole lot more would have to be adjusted for high power, but has anyone done a bit more than just have the idea..?

jeremy made up some of the stuff and he droped the idea then I got a couple 6 fet bords to try it with so jeremy sent me what he had.
I have been to buisy to make any progress but I do hope to sometime soon.

 

[dangerzone]

Did anyone on ES ever try to use the 6FET controller with some of those high power IGBTs..? Capacitors, gate drivers and diodes would also have to be changed, copper rods would be better than cables and a whole lot more would have to be adjusted for high power, but has anyone done a bit more than just have the idea..?

jeremy made up some of the stuff and he droped the idea then I got a couple 6 fet bords to try it with so jeremy sent me what he had.
I have been to buisy to make any progress but I do hope to sometime soon.

Which IGBTs did you plan to use..?

 

[Arlo1]

Did anyone on ES ever try to use the 6FET controller with some of those high power IGBTs..? Capacitors, gate drivers and diodes would also have to be changed, copper rods would be better than cables and a whole lot more would have to be adjusted for high power, but has anyone done a bit more than just have the idea..?

jeremy made up some of the stuff and he droped the idea then I got a couple 6 fet bords to try it with so jeremy sent me what he had.
I have been to buisy to make any progress but I do hope to sometime soon.

Which IGBTs did you plan to use..?

Sorry I have the big 100v mega fets.
I might try igtbs in the future but never ordered them.

 

[dangerzone]

Sorry I have the big 100v mega fets.
I might try igtbs in the future but never ordered them.

Oh, well, I was actually thinking of using the 'brain' of the 6FET controller and some of those brick like IGBTs on copper rods along with larger capacitors and different gate drivers...

 

[liveforphysics]

Sorry I have the big 100v mega fets.
I might try igtbs in the future but never ordered them.

Oh, well, I was actually thinking of using the 'brain' of the 6FET controller and some of those brick like IGBTs on copper rods along with larger capacitors and different gate drivers...

IGBT's only hurt performance until you get to higher voltages.

 

[Arlo1]

Yup like 1000v?

 

[liveforphysics]

Yup like 1000v?

Yep. At 1000v, IGBT's are the logical choice.


They are actually the logical choice over 200v, however, it's illogical to pick a system voltage in this range, as the MOSFET's all suck, and the IGBT Vf penalty is going to be a pretty large percentage of your power going into waste heat.


Logical ranges for EV voltages are 72v-96v (or up to 150 if you don't mind having a controller twice the size), and then greater than 300-400v, but picking something between 150v and 300v is kinda the fail voltage zone.

 

[dangerzone]

Yup like 1000v?

Yep. At 1000v, IGBT's are the logical choice.


They are actually the logical choice over 200v, however, it's illogical to pick a system voltage in this range, as the MOSFET's all suck, and the IGBT Vf penalty is going to be a pretty large percentage of your power going into waste heat.


Logical ranges for EV voltages are 72v-96v (or up to 150 if you don't mind having a controller twice the size), and then greater than 300-400v, but picking something between 150v and 300v is kinda the fail voltage zone.

Yes, actually, the Emrax motor is running in the 240V-300V range, it is efficient, reliable and light, if it's good for any aircraft it would certainly be good for a motorcycle. So, FETs are definitely out of the question and their controllers have IGBTs, one of such controllers is even only 7kg heavy. Yet there is another 'heaviness', the price in Euros for such a controller...

Cars run at over 200V, motorbikes too, do you have any idea which IGBTs would be good yet cheap enough for such a 6FET controller coversion, for the 200V to 300V range..?

 

[liveforphysics]

Yes, actually, the Emrax motor is running in the 240V-300V range, it is efficient, reliable and light, if it's good for any aircraft it would certainly be good for a motorcycle.

Actually... it's the most simple and light duty job a controller can have to power a propeller.

If I had to make a crude rule of thumb, I would say a controller for an aircraft could be 1/5th the size for a given power level as a controller for a motorcycle.

This is because the torque load of a prop increases at the square of RPM, so the only situation where controllers struggle (low RPM high-load situations) doesn't really happen.

 

[boostjuice]

This is because the torque load of a prop increases at the square of RPM

Cube.

 

[Biff]

This is because the torque load of a prop increases at the square of RPM

Cube.

Luke is right, Torque goes with the square, power goes with the cube

-ryan

 

[boostjuice]

Dammit :x

 

[Arlo1]

I love it Cause last I checked luke aint wrong very often. :wink:

 

[Arlo1]

VMM 1000-01 its a 100v 1000 amp fet. Three of these should show collossus who is boss! Of course with some nanao techs :wink:
http://media.digikey.com/pdf/Data%20Sheets/IXYS%20PDFs/VMM1000-01P.pdf

 

[boostjuice]

$822 just for the bare FETs....bargain.....Sevcon's dont looks so expensive afterall.

 

[Arlo1]

$822 just for the bare FETs....bargain.....Sevcon's don't looks so expensive afterall.

Sevcons are well made but still use lots of T220 fets which no mater what you do they never share current well. Did you price out a programer for a sevcon?

 

[c_a]

Semikron SKM400GAL

1200V/400Amps

http://mobile.semikron.com/imps-semikron/products/data/cur/assets/SKM400GAL12E4_22892314.pdf

I have two at home

 

[amberwolf]

Aren't those IGBTs, rather than FETs?

Also, $300-$400 and up *each*? Yowza