Primary current waveshape

[Bakr]

Hello Everybody
Please see the attached ciruit.
I'm designing 5Kvdc 32uF capacitor charging circuit using typical flyback circuit with 12V battery. There is 555 timer to switch mosfet and then the primary of flyback transformer. At secondary side, there is a series of ten (600 Volts ) diodes, then the capacitor.
Both GNDs are same.
On examining primary current waveshape, I notice there is not a linear ramp, at first ramp goes up then falls towards zero, it again goes up (higher the previous) then falls towards zero and so on. But during this period transistor is full in saturation, I do not see anything except DC level.
Please help me to solve it.
Does anybody tell me hap can I improve its efficiency so that it charges faster.

Sample.zip

[audioguru]

Hi Bakr,
Your transformer is a high-Q resonant circuit that probably "rings" at a very high frequency. You can take advantage of this (like a TV's HV supply and a car's spark coil) by tuning the transformer to the oscillator's frequency with a capacitor in parallel with the primary. Around 22nF should do it.
The only way to charge the 32uF capacitor quicker is to increase its charging current, which means a higher current into the primary and a bigger core to avoid saturation of it.

[steven]

nicely put audio guru ive got plenty high voltage circuits here but the high voltage capacitor chargeinging circuit useing a flyback transformer is something that intrests me to, but like bakr likes is to charge a cap faster, and i like to try it to but i dont have higher voltage caps to try it with, but got plenty photo flash caps to play with , this reminds me of the photo flash cap sharger circuits in cameras the unidentified diode i changed to a uf4007 and it changed the frenquency of it well you can hear that sound changeing like its speeding up i think, i have a untested prototype circuit different than bakr s but havent tried it out yet

[steven]

ive uloaded good circuit schematics that all seem to use high voltage capacitor charger circuits in them to bakr s topic chargeing of a capacitor, thats the best i can do to help him, i hoped he would find new ideas in them to help him in chargeing of a high voltage capacitor more faster, my exsperiments before that relate to high voltage capacitor chargeing was with the photo flash units of cameras but i got stuck on it due to lack of info i can find on the transister the d975 and d965, the substituites for these if theres any , so my exsperiments was limited , but in the circuit of an ignition coil driver circuit i have biult so many of, the author gives some details on it being used as a capacitor charger but fails to add the circuit modifications to do that with , so untill i start more exsperiments with it pending on the availiability of better hv caps ill just hang in there till i get there then ill upload it for bakr

[steven]

in the topic of generators i was able to charge a parralell stack of 16x 630 volts capacitors really good from the high voltage multiplier circuit powerd from ma microwave oven motor generater, the capacitors were charge via a 1m resister from the high voltage multiplier circuit, but when i increased the parralell capacitor stack to 20. i should of increased the feeder resister to higher than 1m as i blew the capacitors, but with the right voltage limiting useing a flyback transformer output, may be a good idea to try in chargeing them caps up faster to , . with the microwave oven motor / generater i would only have to rotate it half way backwards and forwards a few times, then touch the 2 output wires from the capacitor stack output, together, like touching a screw driver to the terminals of a high voltage photo flash capacitor, when charged then i get a big pop .

[Kevin Weddle]

If your regulator is not working properly then you might have an RL type circuit. Also the PW of the driving signal will allow for discharging of the inductor. But I think that if you are getting weird voltages then it is probably your regulator that is at fault.