230 khz with a brick (halfbridge Drsstc)

Reaching, Tue Sept 05 2006, 12:44AM

hey, heres my new drsstc 8 which im working on for a month. it uses a gca200aa60 igbt brick with very fast turn on times (i got this brick for a pack cigarettes and 5$ cheesey ) the last few weeks i had no time for this lil monster but now the work is full in progress, .the secondary fres is 226khz and the halfbridge signal looks perfectly. the brick is driven by a single pair of mosfet driver ics and a usual gdt with 10/25 turns. the driver draws around 200mA with highest on time and bps of 340 . this small drsstc uses secondary bottom feedback with overcurrent protection (had problems running those small drsstcs with primary feedback) secondary measures only 7,5cmx22cm, toroid 6x20cm, case 18,5x18,5x10 . i tried some things out to make a nice front panel and here is what i came up with. i printed my eagle made frontpanel on a foil and put it in between a 2mm plexi sheet screwed on the side of the case, voila a nice looking frontpanel cheesey

here are a few pics, its soo cute
Link2
Link2
and heres the complete electronic (note, low inductance bridge designa and ,ohh whats this, yeah 2 400volt tvs tongue )
Link2
i hope i can get first light within this week, unbelievable that this is my 8th drsstc im building
forgot : primary is 7 turns 6mm copper tubing (strikerail is not finished)
mmc 3 wima mkp10 220nF 1,6kV in series total of 73nF 4,8kV DC. the brick can handle 400A pulsed current
Re: 230 khz with a brick (halfbridge Drsstc)
EDY19, Tue Sept 05 2006, 12:50AM

second link isn't working, but it looks good! It will be interesting to see how a 226kHz brick works smile
Re: 230 khz with a brick (halfbridge Drsstc)
Self Defenestrate, Tue Sept 05 2006, 03:01AM

Reaching wrote ...

(i got this brick for a pack cigarettes and 5$ cheesey )

You aren't in jail, are you? wink Looks pretty nice. Hope that brick stay cool.
Re: 230 khz with a brick (halfbridge Drsstc)
Reaching, Tue Sept 05 2006, 09:32PM

first light today! i got around 20cm discharges at full power, yeah not very good but i know where the failure is. the case is very small so i needed a very small transformer and got one out of my boxes, but i think this lil guy is way to weak for this job, you can hear the fan running slower while increasing the on time dead but for now it works and im happy that i didnt kill something except a switch which couldnt whitstand the charge current (3A is totally underrated, note i charge the 500yf lytic cap directly without a resistor) mhhh, maybe its the lytic that limits the power?
Re: 230 khz with a brick (halfbridge Drsstc)
Marko, Tue Sept 05 2006, 09:40PM

Firstly I also got puny arcs from my halfbridge DRSSTC; with best tweaking I got no more than some 40cm sparks with only 125nF MMC.

I need a fullbridge and bigger MMC (MKP possibly, I'm afraid I'l just kill those MKT's I stuck in there)

What voltage are you running at? With only 73nF MMC I think you will need to use the brick's voltage rating for some decent sparks!
Re: 230 khz with a brick (halfbridge Drsstc)
Reaching, Tue Sept 05 2006, 09:53PM

one possible problem is shielding, but i never shielded drivers with secondary feedback which im using here, only had problems with primary feedback so far

voltage on the bridge is 309Volt
mhh, i can enlarge the mmc but i think i have to find a compromise cause my secondary fres is very high,