hi @JaniEronen !
sorry I was so busy with the other thread that somehhow I missed this… I do not hav no drawing but here the setup is described short and sweet.
The control loop is not easy to describe (in fact it is not only one…).
Inputs:
- grid power
- SoC
- MPP operation mode
- domestic hot water
- battery voltage
- battery current
- gradient of load change / pulsing of load
Outputs:
- inverter setpoint(s)
- charge voltage
- dom hot water heating (3 stages, 50Vdc)
Priorities:
- zero consumption
- accu 80/85% SoC (at least during summer)
- dom. hot water hot
- surplus feedin (up to certain level, officially I’m restricted)
SoC control done in a simple extra loop limiting the charge voltage in case, otherwise charge voltage ‘curve’ from BMS
The power control loop is quite complex since it acts e.g diffferently to different gradients of load and on switching/pulsing loads depending on winter or summer. the algorith is several hundred of lines of code.
You are right, the grid meter signal is some kind of slow, but in Germany we are restricted to 400W/s gradient so you can not 100% compensate a kettle getting switched on anyway. The 1.4kW pid expresso machine pulsing in sub-second frequency is even harder (impossible with 1 Hz grid info), this is why I’m doing different in summer/winter. The MPP operation mode also reacts quite slowly on a 280Ah battery, but in general it works quite well even i’m still working on it…
but the original question was how to get the inverter doing what I tell it. this we figured out in the meanwhile (ESS mode 3) and we also managed to keep the solar chargers charing when an ess mode 3 inverter connected to the Venus OS (this took 4 complete days and the only solution seems to be a small Venus mod, I think there is a bug…)
thanks Alex @alexpescaru I will have a look at the linked stuff even we got a lot further in the meanwhile 