IGBT vs MOSFET

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
See the file attached.

A seller said the MOSFET will work instead of the IGBT.

App is a tread mill motor controller.

I on the other hand does not think so. Correct me please.
 

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strantor

Joined Oct 3, 2010
6,782
I don't know the answer. I don't see any reason why it wouldn't work. When I calculate watt loss both, assuming 20A tradmill motor, they are almost identical. I am curious why you think it won't work.
 

t06afre

Joined May 11, 2009
5,934
I would say it is worth a try. They both have about the same switching times. And VGE versus VDS fully on looks also to be compatible
 

ramancini8

Joined Jul 18, 2012
473
IGBT:
I=10A, P=21W
soft recovery diode
non-punch through
short circuit capability (10Us)

FET:
I=10A, P=78W

The IGBT seems to be a better choice, and that is why it is often preferred for motor applications.
 

ScottWang

Joined Aug 23, 2012
7,397
MOSFET STP10NK80ZFP - V(BR)DSS=800V,RDS(on)=VGS=10V,Id=4.5A,0.78Ω.
IGBT IRGIB10B60KD1 - VCES = 600V,IC = 10A,VCE(on)=1.7V.

IGBT Calculation:
R = 1.7V / 10A = 0.17Ω
IGBT VCE(on) = 1.7V, when IC = 10A, W = 1.7V * 10A = 17W

MOSFET Calculation:
Vds = 4.5A * 0.78Ω = 3.51V, W = 3.51V * 4.5A = 15.795W
IGBT to MOSFET Current rate = 10A/4.5A=2.222
Vds = 3.51V * 2.222 = 7.8V
W = 15.795W * 2.222 = 35.096W.

The power dissipation rate of MOSFET to IGBT :
PD_rate = 35.096W / 17W = 2.064

If my calculation is right then the power dissipation of MOSFET is more than IGBT.
 

strantor

Joined Oct 3, 2010
6,782
IGBT:
I=10A, P=21W
FET:
I=10A, P=78W
IGBT Calculation:
R = 1.7V / 10A = 0.17Ω
IGBT VCE(on) = 1.7V, when IC = 10A, W = 1.7V * 10A = 17W

MOSFET Calculation:
Vds = 4.5A * 0.78Ω = 3.51V, W = 3.51V * 4.5A = 15.795W
IGBT to MOSFET Current rate = 10A/4.5A=2.222
Vds = 3.51V * 2.222 = 7.8V
W = 15.795W * 2.222 = 35.096W.

The power dissipation rate of MOSFET to IGBT :
PD_rate = 35.096W / 17W = 2.064

If my calculation is right then the power dissipation of MOSFET is more than IGBT.
You guys are right on. My calculation was out to lunch since I misread the datasheet and did math for 20A @ 0.09ΩRDSon
 

t06afre

Joined May 11, 2009
5,934
So..this is new.

Will it be safe to switch the IGBT for the MOSFET then ?
Nah...not sure any more. I forgot to take the power dissipation into the consideration. It will most probably overheat. Due to insufficient heat sink. As the heat sinks are dimensioned for the IGBT. You should try to find a FET, which is as fast as the IGBT and RDS(on) around 0.17 ohm. Then one suggested will probably work for while then break down
 

ScottWang

Joined Aug 23, 2012
7,397
To see what I posted on #6, and another parameter that you should care about that is frequency.

Comparing every parameters and considering what's your application, and then make the last decision.
 

Thread Starter

R!f@@

Joined Apr 2, 2009
9,918
Well! guess what?

It ran for a half an hour without a load (Empty belt). But as soon as some one got on the belt it suddenly increased speed and KAPOW!
 
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