Kapanadze Cousin - DALLY FREE ENERGY

verpies · March 31, 2016, 06:54:48 AM

Quote from: MenofFather on March 31, 2016, 04:02:44 AM
He says, that it is better to use a thyristor, then it will be more efficient.

When ON, Thyristors have much higher voltage drop than MOSFETs.
Consequently thyristors convert more electric energy into heat, compared to MOSFETs.

verpies · March 31, 2016, 07:00:13 AM

Quote from: MenofFather on March 31, 2016, 04:28:32 AM
For 1000 volts you can use IGBT transistor. Maybe better than MOSFET and than thyristor.

IGBTs are slower than MOSFETs.
IGBTs have a higher i*v product at slow speeds, though. ...but MOSFETs are more efficient above 100kHz.

Read this.

T-1000 · March 31, 2016, 07:05:25 AM

Quote from: verpies on March 31, 2016, 07:00:13 AM
They have a higher i*v product at slow speeds, though.

About speed in these days, it can go up to megahertz range, see my datasheet link of ST IGBT in my previous post.

The Turn-on delay time + Turn-off delay time is the limit. For STGW40H120DF2 it is 36+161ns which is limiting frequency to 5.07614213MHz.

verpies · March 31, 2016, 07:13:40 AM

Quote from: T-1000 on March 31, 2016, 07:05:25 AM
About speed in these days, it can go up to megahertz range, see my datasheet link of ST IGBT in my previous post.

That's maximum switching speed, not efficiency which Menofather, brought up.
Above 100kHz a MOSFET will be more efficient every time.

Quote from: T-1000 on March 31, 2016, 07:05:25 AM
The Turn-on delay time + Turn-off delay time is the limit. For STGW40H120DF2 it is 36+161ns which is limiting frequency to 5.07614213MHz.

An at that frequency the IGBT will spend most of its time switching while the efficiency is horrible compared to a MOSFET which would have switched long time ago and have been idling ON for a significant fraction of the entire cycle.

T-1000 · March 31, 2016, 07:20:41 AM

Quote from: verpies on March 31, 2016, 07:13:40 AM
That's maximum switching speed, not efficiency which Menofather, brought up.
Above 100kHz a MOSFET will be more efficient every time.
An at that frequency the IGBT will spend most of its time switching while the efficiency is horrible compared to a MOSFET which would have switched long time ago and have been idling ON for a significant fraction of the entire cycle.

Not going to argue with you and will just do little Tesla coil driving tests instead.
And about MOSFETs, for example, the IRFP460 is worse than this - https://www.fairchildsemi.com/datasheets/IR/IRFP460C.pdf
Turn-On delay time 110 ns
Turn-On Rise Time 150 ns
Turn-Off Delay Time 380 ns
Turn-Off Fall Time 180 ns