Hi,
We are developing one new digitally controlled grid connected inverter in which everything is controlled by an ARM microcontroller instead of the old ones that we produced where everything was controlled with analog devices.
The problem is that we make a sinusoidal modulation of the output voltage that in open circuit works perfectly but as the inverter works in parallel with the grid, injecting current to this one we got one comparison system between the injected current and the desired current (created from one table) and one PID feedback loop.
The result of all this is that we are injecting distorted current with oscillations and we can't get the right parameters to stop those oscillations.
Anyone could help in order to find some documentation of regulation algorithms or solutions of similar cases?
Thanks
Bernat