PD or Iota for my upgrade?

Salvo wrote:
I'm not asking about ac voltage.

I realized that. You were asking about the rectified voltage, which I hadn't measured, but implied by the question was whether there was enough voltage and power, and I'd starting thinking along those lines, too and thought you might be interested in the fact I was running at low AC voltage during the tests. I would have preferred to run at higher voltage, but I need a boost buck transformer or another power line.

Calculation for minimum dc input voltage:
Vmin = (Np/Ns) * (Vreg + Vd) / pwm_max
Where:
Np/Ns is the primary to secondary turns ration of transformer
Np/Ns = 13/2 = 6.5
Vreg = 14.4V
Vd = diode voltage drop and other IR losses = 1V
pwm_max = max duty cycle = 80%

Vmin = 6.5 * (14.4V + 1V) /0.8 = 125Vdc

Thanks, but I was wondering where you got your numbers. for Np, Ns and pwm_maxetc. Are they in the patent or are they just reasonable guesses?

If your input voltage is that low then the only way to fix the converter is to replace the transformer. The transformer requires a lower turns ratio. Or, install a big-ass 120Vac step-up transformer on the front end.

A 120X240 12/24 buck boost transformer rated 750VA will handle 30 amps of 10 or 20% boost - enough for my entire RV with the PD running maxed out and room to spare. I've sourced one for less than $100, but I'm cheap and waiting for one on Cragslist of less than $50. I found a couple at that price but they've all been too big at more than 1KVA and I want one that's as light as possible to carry with me. There's no point buying two.

I've got a Sola constant voltage harmonic neutralized transformer which will hold 118VAC on a 105VAC input, but it's only 1KVA - not enough amperage for the full load of the converter since it's not a buck boost design - it's fully isolated and has to carry the full load on both windings.