Author Topic: The dual primary coil idea  (Read 3816 times)

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Re: The dual primary coil idea
« Reply #16 on: March 21, 2017, 14:26:24 pm »
i´m happy to tell you that the problem is now solved... i found that this chip is open collector output so it need a pull up resistor on the output... 1k will give 12ma using 12v supply.. i had to substitute the chip because i think i burned the first in the way..

the circuit works perfectly and generate waveforms in sync with different pulses widths. .

for that i had to add a uf4007 diode to the charging path from pin 3 to the resistor capacitor network on the 555 timer.. 
 
i found out also something new and interesting.. i was observing some ringing on the output of the mosfet driver and i tried to add resistors everywhere but i found that adding a small capacitor as load on the input side of the driver killed the ringing immediately... i tried 1nf .. but i will try some smaller caps too .. this ringing would make the end of the pulse cause false trigering of the mosfet or igbt... i thought of the capacitor because i thought the ringing was coming because the igbt was not yet present but surprisingly even adding a capacitance to the output the ringing wont stop only if add on the input part...

« Last Edit: March 21, 2017, 16:20:13 pm by sebosfato »

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Re: The dual primary coil idea
« Reply #17 on: March 21, 2017, 18:40:33 pm »
part list and schematic for who is interested...

Here you see the full schematic and part list... i call this circuit Dual Sync Pulse Width Frequency Generator..D.S.P.W.F.G.,  because is just what it does..

the capacitor that filters the ringing is in parallel with a 1k ohm resistor.. and it cause a slight delay in the turn on of the driver.. but is not important for what i´m trying to do... it has this delay because the resistor connected to the vcc 1k takes a time to let the capacitor voltage rise above the threshold of the driver.. but its ok since it prevent ringing totally! i have to find some smaller caps to try if still cut the ringing while take less delay

the output with igbts arrangement i will post later... with some waveforms...

it works pretty well and now i just need to wind some primaries to test the theory!

the pcb i made with the tracks on top so i dont need to make holes i just solder the components over it..

« Last Edit: March 22, 2017, 03:43:35 am by sebosfato »

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Re: The dual primary coil idea
« Reply #18 on: April 13, 2017, 21:57:38 pm »
Are you trying to make the alternating pulsed DC like I have done in the attached image?

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Re: The dual primary coil idea
« Reply #19 on: April 17, 2017, 07:54:18 am »
Hello Tony

The idea of this circuit is to create two pulses that start at same time with same frequency but have independent variable pulse width

My idea is to get this pulse combined in two split primaries being in opposite phases

The objective is to try loading a coil with current but having zero magnetic flux on the charging time

I'm almost done to start the tests but didn't turned it on yet