dc-dc boos converters

Belfior

dc-dc boos converters
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So I wanna buy a device that will allow me to get voltages from 10-400V for cap charging mostly.

I can't remember if product links were allowed on this forum, but it is here just so you can see the data provided with the product.

https://www.aliexpress.com/item/32705909982.html

It seems to use some kinda ZVS to get he voltage up from 6-16V to even 400V, but is it pulsed DC that comes out or are those caps there to even it out to "kinda" smooth voltage?

The info says the operating freq is75kHz, but is that really how the output looks like?

I do want to get high frequency positive HV DC pulses, but can this one deliver that?


Lynx

Re: dc-dc boos converters
« Reply #1,  »
Quote from Belfior on May 26th, 02:30 AM
I do want to get high frequency positive HV DC pulses, but can this one deliver that?
Judging by customer reviews (scroll down the site you linked to) it should be possible for you to get HV DC pulses from this if you omit the output capacitor. Frequency of the pulses are unknown though, ballpark estimate would be between 40-50 kHz.

Belfior

Re: dc-dc boos converters
« Reply #2,  »
Ok it seems this kinda "surgery" is most likely just going to kill the PSU.

I might have to get a ZVS driver and then use it with or without the flyback coil to get desired voltages. I would really need just DC impulses and I would like to be able to set the duty cycle and voltage. I do not know if HV PWM modules exist.

I gotta take some HV sine wave and use diodes to get positive pulses, if everything else fails. Rate of change will not be the best though.

This might still be an option and I found one just like it in my boxes. Even has a flyback coil from some TV I believe

https://www.aliexpress.com/item/32799690496.html

Lynx

Re: dc-dc boos converters
« Reply #3,  »
As I understand it you'd like to have a square wave generator with variable duty cycle at voltages ranging from 10 to 400VDC, for the purpose of charging capacitors.

Personally I'd first rectify the output from my variac powered 230/400V transformer to show 400VDC when connected to two 3500 µF / 350V capacitors which in turn are connected in series, resulting in a overall capacitance of 1750 µF capable of with standing a total voltage of 700VDC.

After that then I'd use a DIY OP amp PWM Circuit to switch a suitable FET on/off which in turn switches the capacitors at hand to whatever voltage you'd like them to be charged to.

Here, some inspiration (scroll down to squarewave generators) https://www.nutsvolts.com/magazine/article/op-amp-cookbook-part-3

patrick1

Re: dc-dc boos converters
« Reply #4,  »
wow that ali express find is good value, - -what you need though sounds like my home made psu for my newman build, -

i have the output from a MOT recifiyed and charging MOT cap,  - it goes good bang, and never breaks.

input of the mot is the standard primary, split into 2,  and being pulsed with 555 / decade counter. -    and the power from that, comes from the knobs on the front of the supply,  volts and current. ;-D.  which are altering the parameters of an lm723 charging a cap, from a mains transformer.

more of less like my video of upgrading it a few days ago ;-D   https://www.youtube.com/watch?v=RqkOercaqOM

Belfior

Re: dc-dc boos converters
« Reply #5,  »
Yeah well that dc-dc booster already has controllable output of 10-400V DC and like Lynx suggested I could just use a MOSFET to pulse that.

Maybe IRFP460, 220Ohm resistor on the gate and drive the gate with CMOS signal from a signal generator. My signal generator can only do 10V CMOS, but the datasheet shows it can turn the MOSFET on with 10V.
Re: dc-dc boos converters
« Reply #6,  »
I do have a MOT coming in, so that might be the next step, if this contraption blows up...
Re: dc-dc boos converters
« Reply #7,  »
I think it is very peculiar, that I can buy what ever electronics from the internet, but variable freq, duty cycle, or  PWM HV DC module I cannot find. I need to lump together 3-4 items to get what I want.



Lynx

Re: dc-dc boos converters
« Reply #8,  »
Quote from Belfior on May 31st, 01:56 PM
I think it is very peculiar, that I can buy what ever electronics from the internet, but variable freq, duty cycle, or  PWM HV DC module I cannot find. I need to lump together 3-4 items to get what I want.
That's the sign of being on a path to something completely different, when there's no readily available mass produced off the shelf devices to be had anywhere that which meets your demands ;-)

patrick1

Re: dc-dc boos converters
« Reply #9,  »
Quote from Lynx on June 1st, 01:35 AM
That's the sign of being on a path to something completely different, when there's no readily available mass produced off the shelf devices to be had anywhere that which meets your demands ;-)
good point, - this was my problem with the newman motor power supply, - requires Adjustable, current limited 0 > 1000v @ 200ma  ... so just like all of my problems, - i cut up a MOT

Belfior

Re: dc-dc boos converters
« Reply #10,  »
well completely different is something this free energy stuff seems to demand.

HV DC gives you the most "rate of change" and that is what you should be using.

You guys have been a great help!

Matt Watts

Re: dc-dc HV Boost Converters
« Reply #11,  »
Belfior,

Dig around here.  You may find something of interest.  I picked up a nice little 12 to 40k volt unit to use as an air ionizer.  Works splendidly.  The kit version will save you a few coins too.