Interesting royer HF circuit
Andrea87, Sat Nov 11 2006, 06:37PMToday I've tried to build up a little royer/zvs/mazzilli's circuit or what you want to call it, and taken it without any problem up to 1.4MHz (by now!). I've used as fets a couple of FDH27N50 from Fairchild, charged up by a little 270Ohm gate resistor, to keep the gates from having a slow charge. All the circuit have been built up on a very tiny circuit board, now I need to try with a lil more voltage on and with the right freq.
First pic: complete assembly, 4T coil with 10cm diameter, and 4.4nF cap bank rated at 4kV
Now just the tiny oscillator, notice the yellow caps and the samsung 1000µF low esr cap, needed to deliver enought fast burst of current to the gates or to the LC circuit
and at last the third pic, showing the circuitry, the two 12 volts zeners and the fast diodes (by now I'm using MUR240 ones). If anyone wants the pcb, I've designed it with eagle, I will post there the pcb file.
more news coming soon, and also a test of the circuit with the new tc secondary or... what about a mini RF royer TC?
Re: Interesting royer HF circuit
..., Sat Nov 11 2006, 06:58PM
Ahh, the good 'old mizzilli
I still don't fully understand it and likewise I have a hard time making it do what I want, but I have managed to push 1kw+ at 50khz. I still haven't figured out how to change its frequency, I tried changing every component (except the series inductor) to no avail. Oh well, it it works it works ;)
Looking at yours, I am going to say that you will need to rethink that primary before you try to get any decent amount of power out of it. The skin depth at 1mhz is tiny, and you will be running huge rms currents; not a good combination.
If you can get any decent amount sparks out of a TC with it, I would say that you have a considerable edge over th class-E crowd
..., Sat Nov 11 2006, 06:58PM
Ahh, the good 'old mizzilli
I still don't fully understand it and likewise I have a hard time making it do what I want, but I have managed to push 1kw+ at 50khz. I still haven't figured out how to change its frequency, I tried changing every component (except the series inductor) to no avail. Oh well, it it works it works ;)
Looking at yours, I am going to say that you will need to rethink that primary before you try to get any decent amount of power out of it. The skin depth at 1mhz is tiny, and you will be running huge rms currents; not a good combination.
If you can get any decent amount sparks out of a TC with it, I would say that you have a considerable edge over th class-E crowd
Re: Interesting royer HF circuit
Colin 99, Sat Nov 11 2006, 08:10PM
Looks interesting!
I see that your heatsinks are very small. If I feed this circuit 36 volts from some batteries, My much larger heat sinks get warm. I'm using some 20N60 IGBTs also from fairchild.
You can change frequency by changing the value of the resonant capacitor across the flyback primary. I found increasing it from 0.68uF to 1.36uF made a big difference in output. Also adding a capacitor across the battery terminal makes a difference too, I used 2uF polypropylene, I haven't tried an electrolytic yet, I happened to have the 2uF handy.
You L1 inductor might saturate considering that it's a toroid and this circuit can pull 10 amps.
I used an air inductor (lots of wire)
Shaun
Colin 99, Sat Nov 11 2006, 08:10PM
Looks interesting!
I see that your heatsinks are very small. If I feed this circuit 36 volts from some batteries, My much larger heat sinks get warm. I'm using some 20N60 IGBTs also from fairchild.
You can change frequency by changing the value of the resonant capacitor across the flyback primary. I found increasing it from 0.68uF to 1.36uF made a big difference in output. Also adding a capacitor across the battery terminal makes a difference too, I used 2uF polypropylene, I haven't tried an electrolytic yet, I happened to have the 2uF handy.
You L1 inductor might saturate considering that it's a toroid and this circuit can pull 10 amps.
I used an air inductor (lots of wire)
Shaun
Re: Interesting royer HF circuit
Andrea87, Sat Nov 11 2006, 08:53PM
That circuit is tremendous, I've made too an inverter for my indheat projects that were able to put out over 1kW of power... looks pretty good also considering its cost.
the frequency is given by the primary LC circuit, let's say the working inductor and the big cap / mmc. lower the cap or the inductor and you'll get a higher freq.
that primary is just for test, next ones will be made from good copper tubing (still need to find it
) and some serious mmc and well cooled fets.
Atm I've wound a very little secondary with 0.25mm wire, about 440 turns on a 35mm carton + tape pipe, for about 2.4MHz of fres... let's see tomorrow what I can do :D
edit: here is the pcb
these are two images, 1st is the setup I've used, second the board, wich is 37x43mm
and at the end the cadsoft eagle file:
(.brd inside rar file, 3kb)
Andrea87, Sat Nov 11 2006, 08:53PM
... wrote ...
Ahh, the good 'old mizzilli
I still don't fully understand it and likewise I have a hard time making it do what I want, but I have managed to push 1kw+ at 50khz. I still haven't figured out how to change its frequency, I tried changing every component (except the series inductor) to no avail. Oh well, it it works it works ;)
Looking at yours, I am going to say that you will need to rethink that primary before you try to get any decent amount of power out of it. The skin depth at 1mhz is tiny, and you will be running huge rms currents; not a good combination.
If you can get any decent amount sparks out of a TC with it, I would say that you have a considerable edge over th class-E crowd
Ahh, the good 'old mizzilli
I still don't fully understand it and likewise I have a hard time making it do what I want, but I have managed to push 1kw+ at 50khz. I still haven't figured out how to change its frequency, I tried changing every component (except the series inductor) to no avail. Oh well, it it works it works ;)
Looking at yours, I am going to say that you will need to rethink that primary before you try to get any decent amount of power out of it. The skin depth at 1mhz is tiny, and you will be running huge rms currents; not a good combination.
If you can get any decent amount sparks out of a TC with it, I would say that you have a considerable edge over th class-E crowd
That circuit is tremendous, I've made too an inverter for my indheat projects that were able to put out over 1kW of power... looks pretty good also considering its cost.
the frequency is given by the primary LC circuit, let's say the working inductor and the big cap / mmc. lower the cap or the inductor and you'll get a higher freq.
that primary is just for test, next ones will be made from good copper tubing (still need to find it
) and some serious mmc and well cooled fets.Atm I've wound a very little secondary with 0.25mm wire, about 440 turns on a 35mm carton + tape pipe, for about 2.4MHz of fres... let's see tomorrow what I can do :D
edit: here is the pcb
these are two images, 1st is the setup I've used, second the board, wich is 37x43mm
and at the end the cadsoft eagle file:
(.brd inside rar file, 3kb)Print this page