[Amps] High Voltage Switching Supply (Bob D.)

[Victor Rosenthal 4X6GP]

I don't know if it's been mentioned yet, but a 'feature' of any supply 
for a microwave oven is that it is designed for a short duty cycle.  A 
"1500-watt" supply will not provide 1500 watts for amplifying compressed 
SSB, CW, or digital transmissions over a period of time of more than a 
few minutes. You would have to derate it and probably provide cooling.

73, Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco

On 05/03/2024 17:09, Bob D. wrote:
> Hi Steve,
> 
> "Well, there's no free lunch... Although these inverters present an
> interesting idea, this particular one uses a flyback transformer to
> generate the HV, which is unregulated and so varies between 2200 and as
> much as 6 kV, the youtube author said at one point in his first video."
> 
> The supplies are tightly regulated.They are regulated for power via current
> sensing on the AC mains side of things. Something like 2% per one article.
> It's what makes that type oven so nice in the kitchen. The one in my
> kitchen can thaw from the freezer without cooking!
> It will melt butter without popping. Best thing is the "sensor reheat"
> mode, It steams vegetables perfectly.
> 
> I am not an EE and welcome any assistance in understanding this thing.
> 
> I think the small IGBT heatsink is possible because the flyback topology
> allows for switching at zero current(voltage).
> 
> So far I've gathered that:
> The cook power setting signal is PWM 220Hz(per the referenced videos) with
> no indication as to delay or hysterisis, if any, in response;
> 220Hz will limit the minimum response time of any voltage regulation
> feedback scheme.
> 
> My thoughts are: That a minimum load and enough capacitance will allow me
> to repurpose the cook power setting and hopefully hold voltage to within
> 10%;
> There is minimal filtering on DC feeding the inverter so 20 uFd should be
> adequate for filtering the 120Hz feed through; If the power control
> feedback response
> is no more than a cycle or so at 220 Hz, the 20uf will be adequate; My
> first task in learning if this will work is to measure the response time of
> the power feedback loop;
> If the existing control loop is too slow, an impractical amount of
> capacitance may be required for ham amplifier regulation.
> 
> 
> 73, -bob ah7i
> 
> 
> Not knowing specs for the black box regulator, I'm doubtful there us any
> approach to learning if this will work aside from cut and try.
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