# NEED HELP Matching Three phase IGBT Inverter module with driver IC



## major (Apr 4, 2008)

Hi Tyler,

On the IGBT controllers I have used, gate voltage is +15 for on and -8 for off. Gate resistors are a fixed value and sized (ohm wise) to get the switching speed you want. The gate looks like a capacitor to the driver circuit which needs to be charged to turn on and then discharged to turn off.

Regards,

major


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## tgrandahl (Jan 24, 2009)

Thanks Major,

I read through an application note IR published, it explained how the boot strap circuit works on the high IGBT's. This helped some things "click" into place.

I felt comfortable enough to order a few parts to play with.

some IR21362 IC's to drive my IGBT module and a IRAMS10UP60A just for kicks that the application note was written for.


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## yarross (Jan 7, 2009)

tgrandahl said:


> Looking at the basic characteristics I notice that the IGBTs have a Vge threshold of about 6V and a max Vge of +/- 20V. The IR2136 claims a gate drive supply range of 10V to 20V, well over the threshold and right up to the max.


Typical gate drive voltage is 15V. For this power it's feasible to use unipolar driver, but negative bias will help keeping IGBTs off in noisy environment, especially when you don't have Kelvin emitters.


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## Morf (May 29, 2009)

Hi TGrandahl,

It has been a while since your parts purchase for an inverter. Since I am about to do some something similar, I wonder if you would pass along any pitfalls you encountered that might enlighten some of the rest of us. I have an Oswald PM Synchronous that has big torque. It is rated at 92 amps, with max amps at 170. It is watercooled and so goes the planned inverter. I am looking at an inverter made for windmill use made by Applied Power Systems of Hicksville, Ny. The engineer there was willing to spend time with me to help lay out the inverter. So he sent a photo of two, which set off some controversy about the duty numbers that would relate to a vehicle on the road. 

I might have Applied P S do the control component when I get to it, with good reason since I now am clear about how much more there is to know about such a build, more than I bring to the project. I also went through the Fairchild Data Archives. How did that work out for you? Was it thorough or did it leave a lot to your skill level? Thanks,


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## coulombKid (Jan 10, 2009)

I too have been working on a 3-phase drive. My old gen-II IGBTs claim they don't need negative gate drive (but it won't hurt). Some driver chips incorporate this feature (AVAGO et al). The rated switching speed limit for mine is 20 Khz but I've seen gen-III chips by IR that are thermal rated up to 75 Khz maximum switching speed. The Rg spec you see is a mandatory resistor between your charging circuit and the IGBT gate lead. Without this resistor you will charge the gate too quickly and cause damage. Some drives use a different value resistor for the discharge circuit. A lot of this info is available from Micro Chips AN documents. The EE from OZ on this board is a whiz at this stuff.


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