"Could you explain ,why you would take a primary voltage of 26v,when the battery voltage is 48v ?And whats meant by tighter dynamic,range ?"
We need to generate a 240v sine wave, and to do that with dc we need to remember that the 240v is a rms value ( root mean squared )... so we need to multiply by 1.414 ( root 2) to get the real peak AC wave form voltage.. ie 1.414 x 240= 340 volts or more. We need to overcome sag in the secondary and primary, inefficiencies, and have room for high and low power outputs. The dynamics of the system, is how much variation is required to get the job done. A static system has no change, a dynamic one has change. We need to go from 0 watts out to over 14000 or more.... thats a big range... and it all occurs from the pulse WIDTH modulation of the spwm wave. The fundamental wave is static, not dynamic, but the spwm is very much on the move.... dynamic.... this width must change dramatically to create the sine wave, then the widening of those pulses to drive ever bigger loads.... and back to zero again.... thats the dynamic range required.
Ie the wimpy little pulse width required for idle voltage is simply scaled up ( width) as we need more power from the same waves.( Why it can go over 14000watts is beyond me.... it is truly amazing)..... but you can't get there unless you have enough over head in the transformer windings and ratio. If the software peaks out at a certain pulse width, then thats where you stop.......regardless of the feedback. If the width range is larger ( more dynamic) then you can push harder.
So a say 48v/70v idea would yield a primary voltage of 32v... but this gives no room for driving it much over unloaded voltage... so we need some head room... so 30 volts works okj, 28v works better...... 26 is getting a bit to low for me, but fine for most units. I tend to use 28v or thereabouts. My transformers are tight enough, ( leakage and synchronous losses), that that extra few volts is enough to drive well over 60 amps@ 240v in the secondary, and into a 5hp induction motor for start up... it is probably a bit more than that, but my current meter is a little slow to catch it I suspect.
Put another way.........
The Power jack seems to have the software with a wider dynamic range ( zero to something higher than the 8010 in width) , the 8010 has a lessor range. To make up for this, we use an even wider turns ratio, so that it takes less pulse width to get a higher voltage under load..... now we can see why we need a much lower "voltage" primary than 48v. A 48v winding just won't get anywhere near the voltage you expected.... ie 48vac rms is actually near 70v peak...... putting 48v into a 70v system will not get the job done at all.... So 48vac rms gives 70v peaks to work with the transformer, and 48v dc gives..... well just 48v...... so the output would be in the 160 volt rms range... with 240v peaks....... if we have a sine wave output....not what you expected is it? A normal AC voltmeter will read that as 160vac
Now..... if we had a square wave , then we would use a normal 48:240 transformer... thats 5:1 so our 48v gets to 240v rms just fine.... but it is just a square wave. So your transformer gut feeling was correct, but only for square waves from a switched DC source..... going from switched DC to sine waves is a bit different than the old multivibrator, now you need to look at the peak voltage required to get an equivalent AC RMS voltage.... suddenly were back to 340v peak again.... minimum ( losses need to be looked after too)
The current feedback in the boards I left the gerbers for, use both the IFB and the 2110 shutdown pins.
Ross explained the CT business as well.
.........oztules