Guru
Joined: 02/02/2017
Location: AustraliaPosts: 1424
| Posted: 12:57pm 03 Nov 2017 |
Oz,
I agree re. Vfb. Just give it something, smooth away the high frequency rubbish and set a trimpot voltage divider to make the inverter give what you want. (I like 230V AC)
When mains drops out, my program will detect no sync and smoothly change to an internally generated 50Hz. The program is an oscillator with frequency and phase driven by an error signal. I will build a ceramic resonator circuit to do the same thing, with a frequency tuning input that when set at (say) 2.5V will produce 12Mhz.
I think there will be no problems at all. When mains reappears, it can resync. The problem exists only when change over from mains to inverter. The other change, from inverter to mains does not create stress in inverter components (maybe household items such as the aquarium pump with it's syncronous impeller or a fridge..) This will not change over when street power is not present.
When playing with the PLL sync system on the bench (at work - shhh, don't tell the boss) I see the output of the PLL remain in sync when I pull the mains sample input out of the ADC pin socket sometimes. The board and program still finds something to sync to, probably from picking up mains hum from the mass of wires I usually have hooked up to the arduino board.
wronger than a phone book full of wrong phone numbers