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Re: IGBT Recommendations

Original poster: "Daniel McCauley" <dhmccauley@xxxxxxxxxxxxxxxxxxxxxxxxxx>

Typically, the 600V IGBTs will work fine for most low to mid power DRSSTCs. There are several different types available by Fairchild, IXYS, and some others. The ones Terry is using for his SISG are excellent choices as well. However, with the TO-247
package, you will really need to be smart about how to heatsink them.

As far as audio modulation goes, typically, low side modulation is performed by pulse width modulating the gate drive signal to the bridge. High side audio modulation is a bit more difficult, although would probably give much better audio quality. You could either modulate it with a switching device linearly (such as in conjuction with a push-pull audio transformer on the DC bridge voltage) or even use a MOSFET or IGBT and pulse width modulate that. There are many different ways to do it. I would recommend low side first
though since its easiest to implement.

Hope this helps . . .

Daniel McCauley
Check out "DRSSTC : Building the Modern Day Tesla Coil" Book
Available now at http://www.easternvoltageresearch.com

Does anybody have any recommendations for an IGBT to use in an ~1800VA DRSSTC?
On a DRSSTC is it better to go with a higher voltage to get lower losses due to I*I*R? On Richie Burnett's page, his experiments with a DRSSTC (driven by MOSFETs) showed that when the bridge is fed with a half wave from a half wave rectifier, the TC buzzes at 60 Hz and when it is fed full rectified power, it buzzes at 120 Hz. If you place an IGBT on the power rails feeding the bridge, could you make the TC play music by pulsing power to the bridge through the IGBT to feed the bridge a wave form of a specific frequency to make the coil "buzz" out the music so to speak?

          audio signal                    |
                  |                            |
 -________IGBT_____________ |