How to remove waves when Fronius Inverter is clipping?


#1

Hello from sunny & hot Melbourne.

Seeking the expertise of the community to help me resolve a problem i just can’t seem to work out.

In summary, when my inverter is outputting max capacity, the Power Generated line on the chart is rippled and not smooth. The only way i’ve managed to fix this is by disabling the log data push. However, when I do this, consumption and power used becomes incorrect.

These are the settings I am using to push to PVOutput.

Fronius Push to PVOutput Meter
/service/r2/froniuspost.jsp?sid=sid&key=key&v6=Voltage_AC_Phase_1&auto=1

Fronius Push to PVOutput Inverter
/service/r2/froniuspost.jsp?sid=sid&key=key&dayenergy=1

Fronius Push to PVOutput (Log)
/service/r2/froniuspost.jsp?sid=sid&key=key

Any help would be appreciated.

Many thanks in advance.

Regards,
Andrew.


#2

Hi Andrew, i have a similar set up to you, is your inverter the Australian spec or the international version,i have the international version as its a true 5 KW unit the Australian version is only 4.6 Kw also i see that you are not displaying the average power line, the only time i can see what you are seeing is if i go straight into the inverter read outs with fronius web ,then i can see a small wave line like yours but its only between 5030 and 5050 watts not over a hundred like yours,hope this helps you Jim.
Jims maxim jinkos 6625
yes same fronius push to pvoutput inverter as you,i do not us the log or meter push,have a look at my system for a more in depth look perhaps,

have you updated the inverters firmware to the latest version that came out last month, jim


#3

Hi jimdcollie,

Yes, Its the international version - 5kw. Regarding average power, I can see this column when logged in.

Do you have the same push settings?


#4

Before worrying too much about push settings - have you set your system up in Fonius’s SolarWeb system to see if the waves aren’t real?

I have the 6kW version, and when clipping I see the inverter really is cycling slightly at the top - and watching the little display on the front of the inverter confirms it cycling around 6040 KW in my case.
This is my inverter output displayed within SolarWeb, you can see the ripples at the top there:

and an expanded view of the top shows the ripples more clearly.

Perhaps your ripples are also real rather than an artifact, although they are a bit larger in relative size?


#5

The ripple is most likely an artifact related to the control circuitry involved in protecting the inverter from being overloaded. Circuit design could minimize this control effect but the least expensive circuitry is probably a tradeoff on cost of the inverter which will also meet the design requirements of the inverter’s output.


#6

I Have the wavy lines even when my inverter isn’t clipping, it’s caused by the hourly update cycle as they aren’t there until this process runs.

https://pvoutput.org/intraday.jsp?id=4988&sid=27734&dt=20190202&gs=0&m=0


#7

The ripple is caused by the PVOutput hourly log calc as I explained here https://forums.whirlpool.net.au/thread/2634198?p=22#r428


#8

Ah - I just checked, and I’m NOT using the hourly LogData push, so I don’t have the magnitude ripples your’re seeing, courtesy of @bulletmark’s explanation above.
I’m not missing any of the 5-minute samples, which is what the LogData entry is designed to fill in.
Try disabling the hourly LogData push, and see if you actually have any skipped measurements - you may be able to do without it.


#9

Aliasing.

Averages over longer time samples are OK but shorter sample period timing not aligning causes artificial variability in reported power output where it may not exist, or increases the variability in reported power where some natural variability does already exist.

Same thing happens with hub based cycling power meters, where the torque samples are averaged over 1-second intervals but the power production occurs over variable duration crank revolutions - it results in more variable power output trace than is occurring in reality.


#10

Hi,

I live in Perth and have a Fronius 5.0-3-M [ Firmware fro28500 ]. Watching the LCD display on my inverter I see that that MAX power output moves around quite a bit between around 5.0kW and 5.05kW during the time of peak production - I have 6.6kW of panels. The ‘ripple’ shows up on both PVOutput and my solarweb account. So it represents the actual inverter output and not some artefact of the logging process - for me at least. I have attached a screen grab of my solarweb output from a few days ago - a cloudless day.