Hello, I am Dan from Minnesota, USA. I am new to the OEM site, but am very intrigued by the work that has been done. I am deploying a substantial solar site with Schneider Electric XW+ inverters, MPPT 60-150 charge controllers, 48VDC battery bank, battery monitor and ComBox. I intend to use this to power our property and to utilize as a platform to test add-on monitoring and related devices. I am a Mechanical and Software Engineer, and have much experience with Electronics but am not an EE. I am a proponent of Open Source, and am very excited to see the broad spectrum of OEM projects.
I would like to float the idea of an Open Source PV Module level device with modular capabilities like:
PV Module Energy Monitoring (of course)
Rapid Shutdown
DC Optimization
Very much like what TIGO is doing, but as an Open Source/Architecture suite that can be utilized with any vendor. Also to enable the expansion into new functional capabilities like Curtailment. Some of the motivations behind this are:
Module Level Monitoring is very compelling
Ability to retrofit Rapid Shutdown in existing installations
Optimization can be a value add if expanding/reworking an installation
Improve performance of partial shading conditions
There are some big challenges like high DC voltages, certifications and things I can’t even imagine right now. But I wanted to throw this idea against the wall and see what sticks. I look forward to any thoughts the community may have.
As a starting point, here are some high level goals/requirements:
Design or source a standard module level device enclosure:
Robust enough to handle exterior use, potentially be certified
Permit daisy-chaining of modules up to 600 VDC minimum, perhaps 1000 VDC
Provide capability to plug in swappable electronics modules
Provide ability to mount weather-tight MC4 connectors or PV wire stubs
Provide sufficient enclosure volume and connector ports/stubs to accommodate single or dual module versions
Module level receiver
Suitable to handle dozens, possibly 100’s of modules
Enable PV Module level monitoring
Swappable electronics module
Comparable functionality to emonDC
Enable Rapid Shutdown
Swappable electronics module
Satisfy NEC 2017 Rapid Shutdown requirements
Enable DC Optimization
Swappable electronics module
Solar Edge or SMA style DC optimizers, but open source, usable with any string inverter
Develop swappable module to perform Curtailment
New concept to eliminate dump loads, or facilitate AC coupling
Ideally, the individual swappable modules above could be integrated into a single module, but new functionality would likely be a piecewise evolution. The pluggable architecture permits easy migration to incorporate new functions and upgrades as the electronics evolve.
Communication between the module level devices and receivers may need to be a mixed bag of technologies, depending on the functional needs and technical implementation constraints. Wireless, Powerline and/or dedicated communication network are all options at this point.