Gate driver datasheet for IGBT

[Jeroen Humasol]

Would i be able to use this capacitor: http://be.farnell.com/epcos/b32524r3106k000/cap-film-pet-10uf-250v-rad/dp/2468908 as the high voltage 10µF capacitor in the circuit above?

 

[Alec_t]

No. If your input voltage is 220V RMS, that has a peak voltage of 311V. Your cap should be an X2 type rated for at least 350V.

 

[Jeroen Humasol]

Sorry stupid mistake, this one is rated at 400V, but won't it have troubles with the 10kHz switching frequency of our IGBT? http://be.farnell.com/kemet/r60mr51005040k/cap-film-pet-10uf-400v-rad/dp/2446302

PS: i made a separate post because i'm going a bit off topic here: https://www.electronicspoint.com/threads/electric-load-controller-high-voltage-capacitor.277964/

 

[Alec_t]

won't it have troubles with the 10kHz switching frequency of our IGBT?

Are we still talking about C7 in your post #20 schematic?

 

[Jeroen Humasol]

jup we are, if you have any idea for a better circuit that would also be helpfull. We just discoverd that by using this circuit our currents through the capacitor would go up 20A wich is way to high for any capacitor to survive :'(

The goal of the circuit is just to be able to continuosly dissipate power. So that we can dissipate 5kW if we want but as well 4737,7W for example. We would do this by using PWM.

 

[dorke]

If I understand correctly ,
you are trying to modify the load of an AC generator(220V RMS) using PWM.
The load goes from 0 to 5KW.

If so,
I would drastically change the solution to be:
A 400V/25A TRIAC driven by a zero-crossing opto-triac as the driver.
It will simplify everything,be cheaper,and will provide opto-isolation safety.
I think we can help you with that as well...

 

[Jeroen Humasol]

Hi dorke, first of all you've been a tremendous help so far thanks for that!

You're completely correct that is what we wanne do. The old model used triac's but what this model did was using like 8 dumploads of 800W and then it switched them on discretely. So you couldn't ajust the dumpload more precise as +-800W. That's why we started this whole PWM thing. We hope that it will expand the lifetime of our turbine because the load is more constant.

In the old model they used optocouplers as drivers, but this is also implemented in our new system because the driver that we use has an optocoupler inside of it. So we already have the opto-isolation. As you probably noticed i'm not an expert in this kind of stuf . So i was just wondering is it even possible to use TRIAC's for PWM? Are they fast enough? In fact it's not really the IGBT that is the problem, it's that huge capacitance C7. Right now we bought 5 of them on farnell for 50€ and this is at once half of the cost of the total device. So if you have a solution for that be my guest

 

[dorke]

Hi Jeroen,
I think more information is needed about your "Turbine"/generator.
What is it ?How is the operated?what drives it?

What are it's Voltage/frequency/current ratings?
Any control of them automatic/manual?

What is the purpose of the C7 cap?

About TRIACs,
Well they are intended for the purpose of switching and controlling mains generated circuits.

If your case is a 50/60HZ,240V,high current circuit to be controlled than TRIACs are the natural choice.

And one more thing ,
why do you need a 10Khz PWM when in fact 50/60Hz one is what is needed?