Hello
How would you put together a 10VDC to 400VDC input to 120VAC / 4KW output inverter ? -To be used with any battery bank you happen to have- Or is there such animal in the market ?

 

4KW at 10 volts is 400 amps. How thick are the wires? Do you have a 400A output How long does the output have
to work for?

 

Here comes another brain fart... Some modern gasoline powered portable generators labeled "inverters" work in a mode am not sure if I understand... Something like at low rpm or even idling; deliver 120VAC, and only when power demand rises, then they throttle up. (If I have it right)

Is that a sort of "any voltage-in - 120VAC out" ? What guts in there can behave/harnessed as a "any volt in - 120V out" ?

A solar inverter yields a constant steady 120VAC out with varying insolation from angle, clouds, haze, dust on panels... What part of the circuitry manages such ? Is not the MPPT, or is it ?

An uninterrupted power supply UPS puts out 120VAC when its battery is 14V or down to 10V. What is the circuitry that harnesses that ?

 

What is the circuitry that harnesses that ?

The inverter generators have an alternator which is converted to DC and then a DC-AC inverter generates that AC.
The alternator likely has a regulator to keep it's voltage relatively constant (similar to a car alternator) as the engine speed changes.
That's how they can throttle down the engine speed at light loads for better efficiency, while still maintaining a constant output AC voltage and frequency.

In all the devices you mention, an inverter that can tolerate some input voltage change generates the AC.
But I doubt it would be practical to make one with the the very wide input voltage range and large power output you would like.

Long live the deciBel!!

 

As Crutschow have mentioned, the generators on these devices you have shown have a field regulator which stabilizes the output voltage as the RPM changes.
Similar to car alternators.

 

Thanks. A field regulator instead of a speed governor explains it. Yes, the width expectations I wrote are exaggerated. 12 to 48V would make more sense. A single solar panel can be 12 to 50V; a string of them can be 40 to 400V with maaany batteries configurations.

 

Thanks. A field regulator instead of a speed governor explains it. Yes, the width expectations I wrote are exaggerated. 12 to 48V would make more sense. A single solar panel can be 12 to 50V; a string of them can be 40 to 400V with maaany batteries configurations.

Many cheap inverters consist of DC-DC converter outputting 400V followed by an DC-AC converter, either sinewave or "modified" sinewave. (To what extent can you claim that a squarewave is a modified sinewave?)
It would, therefore, be theoretically possible for a DC -DC converter to operate from any voltage from 12V to 48V if it were of the flyback type, but most of the ones I have seen circuit for are push-pull types. However, efficiency for such a circuit would not be optimum.

 

To what extent can you claim that a squarewave is a modified sinewave?

It may be close enough if it is a stepped wave where both the RMS and peak voltage values equal that of a sinewave (example below).
That way it should be able to operate a device that requires the RMS voltage such as a heater or motor (with some harmonic losses), or the peak voltage such as a diode-capacitor rectifier.

 

Long live the deciBel!!

What is the level of -13.6 dB digital audio in 600 ohms ?

 

What is the level of -13.6 dB digital audio in 600 ohms ?

Beats me.
If you want to abolish dB, then at least know how it's properly used.
That can't be answered unless you define what the digital signal audio is, and since dB is the ratio of powers, -13.6dB relative to what?