Open Source DC microgrid

[VooteleAer]

I have been thinking about designing an open source DC inverter system, that could be DC microgrid capable. Each functionality would be implemented on separate module, sharing common high voltage (400-500V) DC bus.
So ,the modules could be:
- Battery to common bus (containing also bms functionality, could be even bidirectional topology so it could charge battery from the bus)
- MPPT to common bus (solar panel input, wind turbine input etc)
- Common bus to battery charger (can be used to charge e-bikes for instance)
- Common bus to H-bridge for generating 230V AC
- Common bus to DC grid (various voltages, according to Current/OS - Defining Standards for Direct Current Microgrids, also incoprorating precise grid voltage/current measurement and some sort of communication protocol. Powerline data adapters do exist, but aren't very suitable at this point. We have been testing HomePlug adapters and couldn't get more than 3 devices to network in real outdoor environment. We have been testing high voltage coaxial cables in our lab and they are a viable option - safe (positive wire embedded in center, surrounded by ground wire, also they can be used for high frequency communication without any sgnificant RF pollution. The idea was to provide BOTH power and high speed network in single cable. Ethernet over Coax would be maybe suitable technology.
- Controller module. This is where all the smart features would residue. Maybe Raspberry PI mated to some special carrier PCB. Web interface for managing all the settings, real time data dashboards etc. MQTT communication with external Smart Home (Home Assistant) systems.

Each module would have some sort of small controller embedded, which speaks CANbus, for instance.

And the main ideology would be -all those designs would be available to anyone along with schematics, gerber files etc so anyone can order their own from JLCPCB and similar services.

 

[A-DamW]

Open Source DC microgrid

I've been wanting to explore and build something like this.

I think most of the hardware and software is available at this point, maybe Home Assistant and the right hardware could work.

 

[VooteleAer]

I'm building the battery module prototype right now. IT will be in 2U rackmount case, LFP 18650 cells 16S, right now I just use two DC-DC converters for charging and discharging, 100balance bms, ESP32-C3 based controller with ESPHome software.
The DC bus will be 400V, wihich, turns out, is fairly common voltage in various server and other electronic equipment power.
The boost converter just needs to have Droop Current Sharing feature, which means the output voltage is fixed, but has current dependant voltage curve.

 

[CountingCoulombs]

I'm building the battery module prototype right now. IT will be in 2U rackmount case, LFP 18650 cells 16S, right now I just use two DC-DC converters for charging and discharging, 100balance bms, ESP32-C3 based controller with ESPHome software.
The DC bus will be 400V, wihich, turns out, is fairly common voltage in various server and other electronic equipment power.
The boost converter just needs to have Droop Current Sharing feature, which means the output voltage is fixed, but has current dependant voltage curve.

So this might be a little out of scope for the power range you're looking at but I was on a project where we built a micro grid using old EV batteries. We used these bidirection DC/DC converters to form a high voltage bus from a company called Advantics. They still sell that DC/DC (+50kW!!!) but its nonisolated which for a battery to a dc bus is not great since you can have some scary uncontrolled releases of energy if your dc/dc fails BUT they have started to sell a bidirection ISOLATED DC/DC which is so awesome and I really want to buy one to play with! Catch is... they're expensive and not like a consumer product (but that's never stopped me )

Bidirectional Isolated DC/DC converter

This bidirectional DC/DC transformer operates at very high frequencies allowing it to reach an impressively high power density. It is perfect to add isolation to your application, or even as a transparent add-on in preexisting topologies, while keeping bidirectionality and high efficiency.

advantics.fr

 

[A-DamW]

I have been thinking about designing an open source DC inverter system, that could be DC microgrid capable. Each functionality would be implemented on separate module, sharing common high voltage (400-500V) DC bus.
So ,the modules could be:
- Battery to common bus (containing also bms functionality, could be even bidirectional topology so it could charge battery from the bus)
- MPPT to common bus (solar panel input, wind turbine input etc)
- Common bus to battery charger (can be used to charge e-bikes for instance)
- Common bus to H-bridge for generating 230V AC
- Common bus to DC grid (various voltages, according to Current/OS - Defining Standards for Direct Current Microgrids, also incoprorating precise grid voltage/current measurement and some sort of communication protocol. Powerline data adapters do exist, but aren't very suitable at this point. We have been testing HomePlug adapters and couldn't get more than 3 devices to network in real outdoor environment. We have been testing high voltage coaxial cables in our lab and they are a viable option - safe (positive wire embedded in center, surrounded by ground wire, also they can be used for high frequency communication without any sgnificant RF pollution. The idea was to provide BOTH power and high speed network in single cable. Ethernet over Coax would be maybe suitable technology.
- Controller module. This is where all the smart features would residue. Maybe Raspberry PI mated to some special carrier PCB. Web interface for managing all the settings, real time data dashboards etc. MQTT communication with external Smart Home (Home Assistant) systems.

Each module would have some sort of small controller embedded, which speaks CANbus, for instance.

And the main ideology would be -all those designs would be available to anyone along with schematics, gerber files etc so anyone can order their own from JLCPCB and similar services.

Possibly relevant?

Inverter Huawei I23002G1 / I23003G1 - Embedded Telecom Power (ETP) - 48V 42~58V 3000w

Hello all of you, Short introduction from my side, I am an electrical engineer / electronics developer / firmware programmer from Austria who likes to deal with all kind of electrical components / electronics / battery storage systems ranging from very small power levels (uCs) up to very large...

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