I'm working on a PFC input stage built around an ADP1047. The input is 230 volt 50 Hz, the output 385 volt DC and the maximum power
is supposed to reach 2100 Watt.
It's working quite nicely up to a power level of about 800 Watt. If the load is increased any further the output voltage begins to sag, still
with an excellent power factor, until it hits peak input voltage. Adjusting the voltage loop filters seems not to help. I observed the
Voltage Loop Output Register 0xFE38 and found the following behavior:
at idle: 00100000
300 Watt: 00101011
600 Watt: 00110110
900 Watt: 00111110
I think that's odd, I expected that register to show around 0 at idle and approach 11111111 when the output voltage starts to sag.
Any ideas would be appreciated!