The follow on to Power MOSFETs, will most likely be:- "Insulated Gate Bipolar Transistors (IGBTs)

[Andy-Mat]

A Spike in EVs Means a Spike in Insulated Gate Bipolar Transistors (IGBTs)
by Jake Hertz
Although as far as I am aware, they are not yet in general usage in e-bike controllers, it may not be long in coming, so if you are one of those people who is always interested in staying up to date, you might find this interesting to follow:-

A Spike in EVs Means a Spike in Insulated Gate Bipolar Transistors (IGBTs) - News

The Insulated Gate Bipolar Transistor (IGBT) has been a key player in the development of electric vehicles. What makes them so valuable?

www.allaboutcircuits.com

Best wishes
Andy

 

[Woosh]

we won't see IGBTs in controllers because our normal power MOSFETs are more energy efficient than IGBTs at 36V-48V range.
IGBTs come into interest when your batteries are over 200V.

 

[Andy-Mat]

we won't see IGBTs in controllers because our normal power MOSFETs are more energy efficient than IGBTs at 36V-48V range.
IGBTs come into interest when your batteries are over 200V.

I anticipate further improvements in that area over the next few years....as do the people designing with them today!
Time will tell, as development work carries on, nothing gets fixed into stone....
You may find this document informative with regard to future developements:-

Regards
Andy

 

[Woosh]

from your link:

(The power scale is log)
You can see that MOSFETs are very efficient in the power band 50W-5kW where e-bikes live.

 

[Andy-Mat]

from your link:

(The power scale is log)
You can see that MOSFETs are very efficient in the power band 50W-5kW where e-bikes live.

I feel that you are completely overlooking future developments completely. I, and many others, take a great interest in such future (just around the corner?) possibilities.
Perhaps you are just fixed on today, but at least you show the interesting graphic showing how MOSFETs and IGBT devices, already "overlap" considerably even today!
Why don't we discuss this (civilly) again in say 12 months?
Andy

 

[Woosh]

MOSFETs have lower ohmic resistance than IGBTs. Wherever high voltage capability is not a critical factor, MOSFETs are cheaper to make, switch faster and waste less heat.

This graph compares 30A IGBT (red) against 31A MOSFET (SJMOS, grey)

 

[sjpt]

MOSFETs have lower ohmic resistance than IGBTs. Wherever high voltage capability is not a critical factor, MOSFETs are cheaper to make, switch faster and waste less heat.

This graph compares 30A IGBT (red) against 31A MOSFET (SJMOS, grey)

I don't think there is argument about the situation as it is today; more discussion about what it may be in a few years time.

 

[Woosh]

In my days (60s), SCRs and NPN power transistors were the only switching devices available. MOSFETs were just invented but mainly low power, not the power MOSFETs we have in our bikes though. IGBTs were invented in the late 70s so it's about the same maturity as power MOSFETs.
Unless we go for much higher voltage and current, the controllers we have today are pretty much matured designs.
Silicon devices will continue their progress, getting smaller, carrying larger loads, waste less heat etc but like motor winding codes, their fundamental 'sweet zones' are still the same.
Think of house frames. You can build a bungalow with steel frame but would you want to do that?

 

[Andy-Mat]

MOSFETs have lower ohmic resistance than IGBTs. Wherever high voltage capability is not a critical factor, MOSFETs are cheaper to make, switch faster and waste less heat.

This graph compares 30A IGBT (red) against 31A MOSFET (SJMOS, grey)

A low "ON" resistance is always better, wasting less power, and I am quite sure that the "inventors" of many other electronic components remain busy to achieve just that.
Since building my first RC control system, transmitter and receiver in 1956 (or 55, I forget!), I have watched (and learned) over the years, just how much progress has been made in all things electronic.
I learned "Never say nay!" for instance.
"Moore's law" is a shining example for us all, of progress in such things.... Moore's second law works for me as well!
Have a great day, I am!
Andy

 

[Woosh]

here is a summary comparison between the two types, MOSFET vs IGBT for a 500W switching device, similar to e-bike controllers.

https://www.infineon.com/dgdl/Infineon-IGBT_or_MOSFET_Choose_Wisely-Article-v01_00-EN.pdf?fileId=5546d462533600a40153574048b73edc

If you use IGBT, you need to add the reverse body diodes to handle back EMF. That takes PCB real estate. Mosfets in current controller designs are simpler, cheaper, waste less energy, have positive thermal coefficient and better on almost every count except short circuits. If you are worried about on state resistance, it's only 0.02 Ohm for 30A that go into the motor coils. If it were more, there would not be any need for the shunt resistor in the first place.

 

[Andy-Mat]

here is a summary comparison between the two types, MOSFET vs IGBT for a 500W switching device, similar to e-bike controllers.

https://www.infineon.com/dgdl/Infineon-IGBT_or_MOSFET_Choose_Wisely-Article-v01_00-EN.pdf?fileId=5546d462533600a40153574048b73edc

If you use IGBT, you need to add the reverse body diodes to handle back EMF. That takes PCB real estate. Mosfets in current controller designs are simpler, cheaper, waste less energy, have positive thermal coefficient and better on almost every count except short circuits. If you are worried about on state resistance, it's only 0.02 Ohm for 30A that go into the motor coils. If it were more, there would not be any need for the shunt resistor in the first place.

Dear Whoosh,
further development work has not stopped yet!
It goes on continuously.
We may all get a surprise in the next 12 - 24 months!
I am going to simply wait for such work to come to fruition....
Have a great weekend, I am!
Andy

 

[vfr400]

Dear Whoosh,
further development work has not stopped yet!
It goes on continuously.
We may all get a surprise in the next 12 - 24 months!
I am going to simply wait for such work to come to fruition....
Have a great weekend, I am!
Andy

See if you can put your time and electronics expertise to better use. If you want a project, see if you can find out why if you replace a solid state or wire shunt with a piece of 14g battery wire with the same resistance, the controller doesn't work.

 

[Woosh]

see if you can find out why if you replace a solid state or wire shunt with a piece of 14g battery wire with the same resistance, the controller doesn't work.

no idea. Can you explain?

 

[vfr400]

no idea. Can you explain?

Say you have a .05 wire shunt, unsolder it and solder in a 10cm length of 14g braided wire that also has 0.05 resistance. The controller doesn't work. The original idea was to get a more accurate way of adjusting your current with the length of the wire. I've used 10cm of 14g wire as a shunt for my wattmeters, and it works perfectly.

 

[Andy-Mat]

See if you can put your time and electronics expertise to better use. If you want a project, see if you can find out why if you replace a solid state or wire shunt with a piece of 14g battery wire with the same resistance, the controller doesn't work.

Guessing only, but probably the heating effect, no matter how small, causes the wire to react differently to the original shunt. You did not mention which metal(s) were in the original wire, or the replacement.
True quality shunts are made to have as little resistance change from temperature effects as possible.
Some are coil wound on the inside, which means a certain tiny amount of inductance as well, which might also be "checked" in some way.
The usual metals for for resistances is either :-
Constantan or Manganin, both are generally used in potentiometer resistance wires and shunts. Constantan is a copper-nickel alloy usually consisting of 55% copper and 45% nickel. Its main feature is its resistivity which is constant over a wide range of temperatures.
You may need to replace like with like!
Some are embedded in porcelain or similar, to further iron out any possible temperature changes.
I hope this helps a little.
Andy

 

[RossG]

Temperature coefficient, Andy got it right.

 

[vfr400]

Guessing only, but probably the heating effect, no matter how small, causes the wire to react differently to the original shunt. You did not mention which metal(s) were in the original wire, or the replacement.
True quality shunts are made to have as little resistance change from temperature effects as possible.
Some are coil wound on the inside, which means a certain tiny amount of inductance as well, which might also be "checked" in some way.
The usual metals for for resistances is either :-
Constantan or Manganin, both are generally used in potentiometer resistance wires and shunts. Constantan is a copper-nickel alloy usually consisting of 55% copper and 45% nickel. Its main feature is its resistivity which is constant over a wide range of temperatures.
You may need to replace like with like!
Some are embedded in porcelain or similar, to further iron out any possible temperature changes.
I hope this helps a little.
Andy

The controller only sees the voltage difference. It doesn't care what changes it.

If the question was, "Sometimes I get a max current of 15.01 amps and another time, it's 15.02 amps, and now that I put a copper wire shunt in of the same value, it varies from 14.99 to 15.06 amps", what you wrote might be an explanation.

I think you're going to have to turn up your internet research skills to maximum to get this one.

 

[Woosh]

maybe something to do with the way your 14 gauge flexible wire is manufactured.
Maybe its flexibility is obtained by twisting the conductor around a flexible string. If that is the case, the length of wire you use forms a small solenoid whose impedance increases with the frequency of the current flowing through it, causing the voltage to rise much more than the shunt it replaces.

 

[RossG]

Clue ... the wire shunt in a controller is not made of copper.

 

[vfr400]

maybe something to do with the way your 14 gauge flexible wire is manufactured.
Maybe its flexibility is obtained by twisting the conductor around a flexible string. If that is the case, the length of wire you use forms a small solenoid whose impedance increases with the frequency of the current flowing through it, causing the voltage to rise much more than the shunt it replaces.

Then it wouldn't work as a shunt for the wattmeter, but it does.