How to AC Couple & Frequency Shift a SolarEdge SE5000H-US

[robwolff3]

Posting this on how I got AC Coupling with my SolarEdge SE5000H-US and my MPP LVX6040WP hybrid inverter to work together. Since I didn't see consolidated information on this anywhere online.

The other day I tried testing a grid down situation with my MPP to see if it could charge my LiFePo4 48v batteries from the AC Coupled SolarEdge. The SolarEdge is on the loads side of my MPP with my other critical loads and the MPP is configured for AC Coupling. Popping the grid breaker on my MPP the SolarEdge resets and after 5 minutes of seeing power on the loads side of the MPP the SolarEdge will start producing power. I noticed pretty quickly that above 3,000w the MPP starts frequency shifting but the SolarEdge was not reducing its power. At around 4,000 watts the MPP frequency shifted all the way up to 61Hz, then the SolarEdge throws a fault and stops producing power. It seems the SolarEdge is producing too much AC power for the MPP's loads side. After a couple of moments the MPP will come back down to 60Hz and the process will repeat if you let it.

I got into the settings of my SolarEdge inverter but didnt see the P(f) settings option referenced in the SolarEdge documentation I found. Through trial and error I figured out changing my County & Grid mode from "US 240V" to "US/Rule21 240V" in inverter started to listen to frequency shifting. And through tweaking some of those options I got the most output with the MPP.

Now when my SolarEdge get up around 4,000w it reports a "throttled" through monitoring and decreases its output in accordance with the frequency shifted.

Warning - Seek guidance from a solar installer or a licensed electrician before modifying the settings on your SolarEdge inverter. Follow all local electrical code and grid operating rules for your region.

Modifying the Settings on your SolarEdge Inverter​

In order to set your County & Grid mode to "US/Rule21 240V" you must be on CPU version 4.4.70, Check the California Electric Rule 21 pdf in the references section below for exact versions.

If you need to update your firmware you must use the SetApp option below. Otherwise you can edit your settings with either option below.

Editing the configuration through WIFI and a web browser​

• Enable wifi direct on the inverter by switching the red toggle switch on the inverter to "P" position for less than 5 seconds.
• Connect to the inverter access point like you would for a normal WI network. The wifi password is published at the right side of the inverter. If your having trouble connecting to the wifi network try a different computer or smartphone.
• Open up a browser and go to http://172.16.0.1

Updating the firmware and editing the configuration through the SolarEdge SetApp​

To use the SetApp you must first create an installer account. As far as I can tell anyone can.

• Go to the SolarEdge website, create an account as an "installer". Follow the prompts and you should now have a SolarEdge installer account.
• Download and login to the SetApp on your smartphone.
• Follow the on screen prompts to update your firmware or edit your SolarEdge inverter's configuration.

Settings I use to Frequency Shift​

• Under Country & Language set Country & Grid to US/Rule21 240V

Initially I noticed the SolarEdge was limiting its power to around 3,000w which seemed lower then what the MPP was handling before. I noticed many of the Power Control options were changed under the Rule 21 mode. I went through and changed many of them back to the normal grid settings as I don't live in California.

• Reactive Power - CosPhi
  • CosPhi - 1
  • CosPhi(P)
    • P0 - 0 - 1
    • P1 - 0 - 1
    • P2 - 50 - 1
    • P3 - 100 - -0.95
    • P4 - 100 - -0.95
    • P5 - 100 - -0.95
  • Q(U)
    • P0 - 50 - -4.12
    • P1 - 97.83 - -4.12
    • P2 - 97.83 - -4.12
    • P3 - 102.17- 4.12
    • P4 - 102.17- 4.12
    • P5 - 120 - - 4.12
  • Q(P)
    • P0 - 0 - 0
    • P1 - 25 - 0
    • P2 - 50 - 0
    • P3 - 60 - 0
    • P4 - 70 - 0
    • P5 - 100 - 0

With Reactive Power set to CosPhi I noticed my SolarEdge throttling higher closer to 4,000w and that seemed to work well with my MPP.




References

• SolarEdge Instruction - California Electric Rule 21
• SolarEdge Inverters - Power Control Options
• Victron Energy - Integrating with SolarEdge
• Github - home-assistant-solaredge-modbus

 

[solar8484]

So, where is MPP docs for AC coupling LVX6040WP?

When does the LVX6040WP start and stop frequency shifting? Battery SOC setpoints? AC voltage setpoints?

Also, what's the max frequency shift? Are the settings adjustable?

 

[robwolff3]

So, where is MPP docs for AC coupling LVX6040WP?

When does the LVX6040WP start and stop frequency shifting? Battery SOC setpoints? AC voltage setpoints?

I have found no info or docs on AC coupling with the LVX6040WP except for the diagram and statement on the MPP website that it supports it. Through trial, error and monitoring what the MPP does I have been able to figure out its AC coupling behavior for the most part. I plan on writing up a post on my usage and helpful information on the LVX6040WP in the next couple days. Need to finish the last few loose ends of this project first.

 

[Hedges]

I didn't realize MPP supported AC coupling.
Good to see that feature becoming widespread.
Could become a huge market; lots of GT PV out there, and an economical battery solution for grid-backup may be popular.

I assume it can also do time of use shifting, good for people who find themselves on NEM 3.0?
New installs might use it for PV as well, so AC coupling more for existing GT PV installations.

MPP Solar Inc » SPLIT PHASE LVX6048WP (IP65)

www.mppsolar.com

"One important advantage of using the LVX6048WP is that one can easily convert a On-Grid system into a true Hybrid (grid-interactive with battery backup) easily by simply adding LVX6048WP into the existing system and “couple” its output with the on-grid inverter by programming a menu setting."

http://www.mppsolar.com/manual/SPLIT%20PHASE%20LV/LVX6048WP%20manual-20221213.pdf

Page 40 "AC output coupling"
Page 57 "Output Frequency Range 47.5 ~ 51.5 Hz or 59.3~ 60.5Hz"
That is NOT sufficient to do frequency-watts curtailment of PV production. Probably goes higher.

 

[BenW]

Why did you use "Reactive Priority" over "Power Priority"?
I see that your current limit goes to the 7071.87 amps just like mine on about anything that is done with Setapp. I always return that to what my system is designed for. Don't know if it matters.

 

[robwolff3]

Why did you use "Reactive Priority" over "Power Priority"?
I see that your current limit goes to the 7071.87 amps just like mine on about anything that is done with Setapp. I always return that to what my system is designed for. Don't know if it matters.

Honestly I don't have a good reason. I was having a hard time finding documentation that explained these options and terminology. That's just what I managed to get working. Would you suggest Power Priority?

 

[solar8484]

Does the MPP shift frequency above 61Hz? That's a relatively low limit as some grid-tied inverters require 62Hz+ to fully turn off.

Given that it's a 6KW inverter it should be able to handle well above 4KW of power from the the SolarEdge without frequency shifting when the batteries are not full.

It seems odd that the inverter doesn't provide settings for battery SOC/voltage or frequency shift range for AC coupling.

 

[robwolff3]

Does the MPP shift frequency above 61Hz? That's a relatively low limit as some grid-tied inverters require 62Hz+ to fully turn off.

Given that it's a 6KW inverter it should be able to handle well above 4KW of power from the the SolarEdge without frequency shifting when the batteries are not full.

It seems odd that the inverter doesn't provide settings for battery SOC/voltage or frequency shift range for AC coupling.

You're right and I realized after doing all of this that I had my battery AC charger amperage limited to 60a. With it increased to 120a I suspect it will be able to take all of the solar when the batteries are not full like you suggest. I can set my battery float and absorption voltages fairly easily. AC coupling on the LVX6040WP is not really documented at all (yet?) so that I just figured out through trial and error. It seemed to frequently shift above 61hz but the solar edge always shutdown at 61hz or so, never makes it to 62hz.

 

[BenW]

Honestly I don't have a good reason. I was having a hard time finding documentation that explained these options and terminology. That's just what I managed to get working. Would you suggest Power Priority?

From my experience it seems that Reactive Priority is more of a California grid thing. It could reduce inverter power if voltage gets too high. The country code I'm using (USA 240V no neutral) doesn't give an option to go to Reactive Priority.

 

[Hedges]

Makes sense that could help for load dump situation and a battery inverter that can't readily switch from inverting to charging batteries. Takes time to frequency shift, so has to absorb the extra for some seconds.
People have said HF inverters have difficulty with reversing, although I don't understand what about the architecture and why.
I'll be trying volts-watts at some point. I've used frequency-watts of a couple modes, but have an application where frequency won't change and need to curtail power.

 

[robwolff3]

@BenW I dont even see an option for Power Priority, where would that be in the menus? Under Reactive Power Priority I have "Active Priority" and "Reactive Priority".

 

[BenW]

Under the "Reactive Power" screen you show a "Priority" and "Reactive Priority" to the right with a > after it. Click on "Reactive Priority" and see if it gives choices. Reactive Power Priority is enabled by default when setting the appropriate USA Rule 21 country code. "Active Priority" is what you are looking for. I mis-spoke when I said Power Priority.

 

[BenW]

I wish the Sol-Ark 12K I have would be able to "Throttle" my Solaredge inverter using frequency like your MPP does! Maybe they'll get there someday! Seems like it would be just a software update.

 

[Hedges]

And I don't get why it doesn't. Off-grid it will raise frequency. That throttles output of inverters with frequency-watts. The shift takes a couple seconds to AC loads don't get too disturbed.
The difficulty may be how these HF architecture inverters deal with switching between source/sink power from AC, all the while being source of frequency and voltage.
But I think some such as Schneider, Skybox, PowerWall, Sunny Boy Storage are able to do so.
Any difference in hardware? Or just firmware?

To make them play nice as they work presently, can you reassign > 50% of PV panels to DC coupling?
(Wonder what the RSD "keep alive" is for SolarEdge optimizers? Otherwise, you would need to replace with something like Tigo RSD, for which keep-alive transmitter is sold separately.)

 

[artieb78]

Hi there. I have a relatively new solar install and I'm seeing this throttling happen, but I don't want it to happen.

My system is 6 kW, inverter is rated 5.052 kW in the PGE interconnection confirmation. I have one Tesla Powerwall 2.

Once the solar production gets to 4.1 kW, the inverters starts throttling. It continues to do that until the production gets back below 4.1 kW in the afternoon, and then runs smoothly again. It does this even if the battery is not even close to full. It also does this even if I have a big load on the system (such charging an EV).

I live in CA and am on grid "US/Rule21 240V".

How do I get it to stop doing this? I want to get the full production in the middle of the day and not be throttled. I also don't like the wear and tear that it puts on the inverter when it has to turn off/on continuously for several hours every day.

 

[400bird]

Is the grid connected when this happens?
What specific equipment do you have, other than the power wall?

If you have a powerwall, what does the installer say about this behavior? Seems like they're warranty should be involved?

 

[Hedges]

How do I get it to stop doing this? I want to get the full production in the middle of the day and not be throttled. I also don't like the wear and tear that it puts on the inverter when it has to turn off/on continuously for several hours every day.

If the inverter is delivering less power, not switching on and off, it is less wear and tear than full power.
If due to thermal derating, then that is degrading.

But yes, you want full output. I still don't know what is going on.

What brand and model inverter?