Micro-Inverter that support MicroGrids / GridMG / Frequency-Shifting

[dognose]

Hey guys,

I’m running 2x 8kWp Solar-Arrays, one beeing 30° South on the upper roof, one is 0° on the lower roof (easy access).

During winter we have snow fall, and freeing the upper pv (3 story tall building) is a bit dangerous, so that one usually ends up in a snowy sleep from time to time. The 0°-Array can be easily freed with a leaf-blower, however that angle is far away from “ideal” during winter times.

So, to add a bit of winter support to my system, I have the following opportunity:
behind the fence of our lawn (east-side) we have a ramp with an angle of 45 - 55° towards east. It is technically our lawn, but ofc unused due to angle.

This makes a nice spot for east-facing, steep angle PV which could be valuable during winter time.

However, the following considerations almost exclude the usage of DC-coupled MPPTs.:

• Even if that is our lawn, it could be theoretically accessed by anyone, especially children from the neighbor hood.
• So, building Strings with > 120V is nothing I would do for safety reasons.
• Just 2 panels in series isn’t enough to provide the required DC Level for any MPPT during HOT times (using a 48V battery, so minimum of ~ 55V would be required)

So, that barely only allows the usage of one or multiple Micro-Inverters, utilizing one Panel per input and beeing mounted in a “access protected area” within our fencing where the actual conversion to AC can happen inside a proper housing. (So everything “out of the fence” is ~ 30-50V)

So, what I’m looking for is a Microinverter Model that is able to work with Frequency-Shifting as well. Unfortunately almost no documentation outlines that, so maybe someone is using Microinverters and can confirm that “Model XY” is able to reduce it’s output based on Frequency-Shifts of the multiplus?

Ofc. doing the unnecessary DC-AC and AC-DC conversion will reduce overall efficency, but here, safety > efficency . Also that array could focus on sustaining existing AC-Loads, while the DC-Coupled 0°-Array could fully be used for battery charge to minimize the impact off conversion-losses.

(ps.: I’m not afraid of theft or vandalism, i’m living on the country side, biggest crimes here are people not sorting their trash accordingly or not snow shoveling their part of the sidewalk in the early morning )

[lxonline (LX)]

@dognose
Have you looked at enphase micro inverters?

[dognose]

@lxonline

Have you looked at enphase micro inverters?

Yes, but these are a bit “too micro” for my taste. (One per panel, directly wired to a 230V-Connection, if I understand that system correctly)

And the Main Design-Idea of running 230 VAC from Panel to Panel would be the opposite of my thought to avoid high voltage close to the array, but to keep that inside a access restricted area.

[chrigu]

Im using a Hoymiles HM300 to feed from a battery to grid. Thats its grid profile that it came with:

[chrigu]

So for you the most interesting is this

Im reading this as:

Up until 50.2Hz it will not limit its output power.
From 50.2Hz upwards, it will derate 40% per Hz, i guess with no delay
Going back down from the derate, it will ramp up the power again at 0.16% per second

[dognose]

Thx for the detailed answer, I checked the Hoymiles inverter, they look like an option.

Do you know if the (optional) DTU unit is required at all? To me, it reads that this is mainly for infotainment purpose, but I would use a regular wired meter to measure production anyway.

Tried to ask their support if all features can be configured / used without that DTU stick, but the language barrier seems to be to big to understand my question.

[chrigu]

The inverter works out of the box, no DTU required.

Im not sure about the functionality of the original DTU. Im using an open source version, ahoyDTU. Theres also another available, openDTU. Both require an ESP32/8266 and a NRF24L01+ RF module

Im using it to set the inverters power as well as reading out its values over MQTT. Im not sure if its possible to control more things, or adjust the settings visible in the grid profile for example.

[m_ach (Michael Achenbach)]

With the openDTU/AhoyDTU and https://github.com/henne49/dbus-opendtu the Hoymiles microinverters will be visible in your GX device.