Half-bridge SLR transformer driver / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Half-bridge SLR transformer driver

Move Thread

LAN_403

Plasma Lover

Tue Jan 27 2009, 11:15PM

Registered Member #1911 Joined: Mon Jan 05 2009, 06:30PM
Location: Salem, Oregon, USA
Posts: 165

Hello Everyone,

I've recently come into the possession of a double-U core with inside measurements being about 3" by 5" and outside core measurements being about 5" by 7 1/8".

I am trying to learn how to drive a transformer wound on such a core.

I have one IGBT brick rated at 100A and 600V and it's a Fairchild FMG2G100US60 - The way that it was described to me was as a 'Dual IGBT Brick'.

I also have eight STGW30NC60WD IGBTs, which are rated at 30A 600V and produced/sold by STMicroelectronics.

I understand how a transistor works and how to use one, but I don't understand what the ratings mean and what the tolerances mean, and I don't know how to build a circuit to drive one. Is there any way that you might be able to help me with this?

What I need help with is, specifically, making a driver. What I've been told is that a driver consisting of the Fairchild transistor is my best bet, as it has a higher current capability and is also capable of half-bridge use. (I'm not sure exactly what half-bridge is, but I was wondering if it has anything to do with half-wave)

I was wondering if anyone could help me learn how to integrate the Fairchild brick into a Series Load Resonant (SLR) switching topology.

I'm not a complete HV noob; I understand how to build a SGTC and how to build a transformer and the rules of capacitors and transformers (basically, I could pass all the tests being proposed in the 'New Forum' thread).

Feel free to use any terms with me you like, if I don't know it, I'll ask for clarification.

Berni

Wed Jan 28 2009, 05:54AM

Registered Member #1132 Joined: Mon Nov 19 2007, 06:15PM
Location: Slovenia
Posts: 84

Well you should check google to find what are transistor H bridges. Basically one transistor pulls the output to positive and the other to negative and then they have to be turned on at opposite times, if they turn on at the same time it shots the supply over it and that might blow the transistor.

For makeing one of these you will also need a bulky capacitor on the output. Its should have a 600V rating and its better to use a lot of smaller caps than 1 big one. The big currents and frequencys are very demanding on the capacitor and it gets hot. I used 10 small 47nF caps to make one big 470nF cap, it still gets quite warm but not too much.

Plasma Lover

Wed Jan 28 2009, 12:12PM

Registered Member #1911 Joined: Mon Jan 05 2009, 06:30PM
Location: Salem, Oregon, USA
Posts: 165

I've already googled H bridges, but I don't know how to make all the components go together. I don't know how, for Steve Ward's CCPS, to make the output of the TL494 the proper amperage and voltage to drive the transistors. I don't know how to make the delay in the driver signal for each transistor.

Berni

Wed Jan 28 2009, 03:33PM

Registered Member #1132 Joined: Mon Nov 19 2007, 06:15PM
Location: Slovenia
Posts: 84

Well most people found that using just a GDT(Gate Drive Transformer) without trying to make any delays works fine.

rp181

Wed Jan 28 2009, 09:46PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

wow! that core is just like the one i just sold! =p
Look at steve ward's mini SSTC circuit. That uses the method of a 555 pulsing into 2 UCC's (one inverting, one non inverting) to make a alternating pattern.

Plasma Lover

Wed Jan 28 2009, 11:33PM

Registered Member #1911 Joined: Mon Jan 05 2009, 06:30PM
Location: Salem, Oregon, USA
Posts: 165

rp181 wrote ...

wow! that core is just like the one i just sold! =p
Look at steve ward's mini SSTC circuit. That uses the method of a 555 pulsing into 2 UCC's (one inverting, one non inverting) to make a alternating pattern.

Wouldn't it work to just make a resonant driver like in a flyback? Or am I just being way too hopeful? I mean, it would make it much more simple, just like a SSTC tuning setup driving the IGBTs with the frequency from an antenna recording the frequency output of the secondary coil.

teslacoolguy

Thu Jan 29 2009, 12:10AM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

naa, you cant do that because tthe transformer doesn't give out interference like a sstc does. What you can do is just make a fixed frequency oscillator in the 100khz range driving a full bridge of igbt's. You would be hardswitching the transformer but you will still be able to pull multiple kw out of the secondary if made properly. See uzzor's thread about his hard switched hf hv transformer.

more if what you want is on the second page but tons of info in that thread.

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob