How to remove waves when Fronius Inverter is clipping?

jimdcollie · January 30, 2019, 10:49pm

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

melbdude82 · January 29, 2019, 10:32am

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?

willisave · January 29, 2019, 3:00pm

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?

lwsmiser · January 30, 2019, 10:38pm

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.

djos1475 · February 2, 2019, 9:30pm

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

bulletmark · February 3, 2019, 7:04am

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

willisave · February 5, 2019, 6:13am

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.

wattmatters · February 7, 2019, 4:37am

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.

grannos · February 8, 2019, 6:22am

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.

bobosch · June 15, 2022, 3:58pm

Any news here? I facing the same issue. I upload the data from a Fronius Symo 15.0-3-M, exactly as described in Push Services — PVOutput documentation . Intresting: When calculating power from the string voltage and current, there are no waves…
Purple: Calculated power from Voltage and Current String 1 *
Orange: Calculated power from Voltage and Current String 2 *
Green: pvoutput.org original “Power Generation”
*: Extended Data Rule: v11 = v7 * v9; v12 = v8 * v10
With voltages in v7/v8, currents in v9/v10

Bobs Garage 18.120kW

grannos · June 17, 2022, 8:25am

Hi. The POWER values calculated from the individual strings will be DC power whereas the POWER values uploaded via v2 using the API is an AC power value. It is possible that the ripple only appears on the mains side of the inverter. The ripple could be a response of the inverter to rising / falling mains voltage ( hysteresis? ) - I don’t know enough about how inverters co-operate with the grid.

At peak production do you see the output power exceeding the nominal maximum output of your 15kW

Grannos

bobosch · June 17, 2022, 10:46am

I made an overlay with solarweb.com from this day:

The ripples are not there in this view (but maybe they smoothing the graph)
On a sunny day like this the panels get to hot and I don’t reach the maximum, on this day the maximum was 13.5 kW. On cloudy days (like the 30/05/2022) pvoutput wrotes a peak on 1:00PM of 15.264kW, while the inverter log shows a maximum of 15.146kW. solarweb shows at 1:00PM on this day 15.17kW

grannos · June 18, 2022, 1:58am

Hmm. My mistake. I only see the ripples when my inverter is running at its maximum output i.e. 5kW whereas in your situation there is significant ripple much of the time and most importantly when your inverter is running at less than its maximum.

If the ripple is ‘real’ it could represent some sort of response by your inverter to your local grid. If you take a closer look at the AC output data using SolarWeb is there anything odd showing with respect to GRID voltage & GRID frequency? Does your grid operator impose any sort of output limiting?

G.

bobosch · June 18, 2022, 6:13pm

IMHO the ripples are a) calculation error on pvoutput or b) the inverter sends other data to solarweb as in the push services…

I copied some values from both services - maybe solarweb uses an average value

Time     pvoutput (kW)  solarweb (kW)
12:00:00   13.056         12.97
12:05:00   12.924         13.05
12:10:00   13.164         13.08
12:15:00   12.912         13.04
12:20:00   13.2           13.12
12:25:00   13.08          13.21
12:30:00   13.296         13.21
12:35:00   13.176         13.31
12:40:00   13.416         13.33
12:45:00   13.26          13.39
12:50:00   13.416         13.32
12:55:00   13.152         13.29
13:00:00   13.476         13.39
13:05:00   13.26          13.39
13:10:00   13.44          13.35
13:15:00   13.176         13.31
13:20:00   13.44          13.35
13:25:00   13.212         13.34
13:30:00   13.44          13.35
13:35:00   13.164         13.3
13:40:00   13.356         13.27
13:45:00   13.116         13.25
13:50:00   13.356         13.26
13:55:00   13.092         13.23
14:00:00   13.272         13.19

No, no output limiting (except the 15 kW…) And CosPhi is always 1. In the extended output of solarweb I can see reactive power (only some watts), AC voltage and AC current, but seems all normal

bobosch · June 18, 2022, 6:26pm

The ripples are only visible when the output power does not change much. On a cloudy day I can’t see it, too.

grannos · June 20, 2022, 2:02am

What PVO push string(s) are you using in your Fronius? Can you post them sans API key? Are you using the optional LOG push?

https://www.pvoutput.org/help/push_services.html#log-data-push-parameters

Plotting the data that you supplied it certainly looks like some sort of smoothing. Hopefully someone else on this forum with more knowledge than me would care to comment. I imagine that there are a few in that category!

grannos · June 20, 2022, 2:03am

Also. What version(s) of the firmware are running in your Fronius Symo and its Datamanager card?

bobosch · June 25, 2022, 10:09pm

SolarAPI v1 - CurrentData - Inverter (5 min)
/service/r2/froniuspost.jsp?sid=90803&key=xxx

SolarAPI v1 - Logdata - Data (1 h)
/service/r2/froniuspost.jsp?sid=90803&key=xxx&v7=Voltage_DC_String_1&v8=Voltage_DC_String_2&v9=Current_DC_String_1&v10=Current_DC_String_2

Datamanager card
Circuit board version: 2.4E
Software version: 3.21.4-1

Fronius Symo 15.0-3-M
Software version:: fro33151.upd
Control unit RECERBO: V0.3.27.2
Power stage set SYMO _PS: V1.9.5.1
Filter PC board SYMO _FIL: V1.0.0.1
Country setups: V0.0.116.10

bulletmark · June 20, 2022, 10:01pm

@grannos, I have already explained above (4 years ago) where the ripple comes from.

grannos · June 22, 2022, 2:37am

Hi @bulletmark thanks for the reminder. I wasn’t aware though that @bobosch was using a LOG push until his immediate previous post.

Hi @bobosch. If you take a look at @bulletmark’s post to https://forums.whirlpool.net.au/thread/2634198?p=22#r428 you will see that the ripple appears to be caused by the LOG push. Can you disable the LOG push ( for a day or two ) to see if this removes the ripple?

Grannos.