Uploaded April 2024 | Updated September 2026, 2 weeks ago
First testing of another buck circuit for a future QCW using a couple old FUJI bricks. I have a bunch of used ones so it would be great if they work alright. I figure an old brick from a legit manufactured VFD might be about as good as a newer one from aliexpress.
For this circuit I just needed to source the LC inductor cores, couple film caps, and the driver circuit. Every other part came from old blown up VFD's.
Every now and then you might be able to find an old drive just sold for parts and if you're lucky you will get working IGBT's and a 3 phase bridge rectifier as well as the bus capacitors.
I need to test this at higher power once I have it cleaned up and better 'finger protected' but I think I pushed brief 5000W peaks or so.
While that's not very much in QCW testing terms that resistor was getting too hot in that short time so I need to find something else.
This is by just driving this IGBT at a little under 15V+ and 0v. Ideally I would have some negative gate drive at closer to +18V/-10V but these IC's were all I had to make it work at the time.
To finish this circuit I need to just add a little 24V coil contactor for pulling in the DC bus input on the NO output of the relay controlling the discharge resistor. That will keep an incoming charge from occurring the same time the discharge resistor is in line. I'm waiting on some more IXDD614CI's then I'll put together the SSTC driver board.
First testing of another buck circuit for a future QCW using a couple old FUJI bricks. I have a bunch of used ones so it would be great if they work alright. I figure an old brick from a legit manufactured VFD might be about as good as a newer one from aliexpress.
For this circuit I just needed to source the LC inductor cores, couple film caps, and the driver circuit. Every other part came from old blown up VFD's.
Every now and then you might be able to find an old drive just sold for parts and if you're lucky you will get working IGBT's and a 3 phase bridge rectifier as well as the bus capacitors.
I need to test this at higher power once I have it cleaned up and better 'finger protected' but I think I pushed brief 5000W peaks or so.
While that's not very much in QCW testing terms that resistor was getting too hot in that short time so I need to find something else.
This is by just driving this IGBT at a little under 15V+ and 0v. Ideally I would have some negative gate drive at closer to +18V/-10V but these IC's were all I had to make it work at the time.
To finish this circuit I need to just add a little 24V coil contactor for pulling in the DC bus input on the NO output of the relay controlling the discharge resistor. That will keep an incoming charge from occurring the same time the discharge resistor is in line. I'm waiting on some more IXDD614CI's then I'll put together the SSTC driver board.
