Open Source Microconverter

[JohnPoole]

I was exploring what efforts, if any, have been made in the realm of open source for microconverters. I found this set of blog entries made over a span of 3 days. I thought if anyone else is interested in what has been done in terms of open source, this post might be a good place to start with.

https://sustburbia.blogspot.com/2015/10/micro-solar-new-approach-to-increasing.html (Saturday, Oct. 3, 2015)
Part 1: https://sustburbia.blogspot.com/2015/10/a-micro-solar-inverter-based-on-arduino.html (Oct. 3, 2015)
Part 2: https://sustburbia.blogspot.com/2015/10/an-open-source-micro-solar-inverter.html (Oct. 3, 2015)
Part 3: https://sustburbia.blogspot.com/2015/10/openinverter-open-source-micro-solar.html (Monday, Oct 4, 2015)
Part 4: https://sustburbia.blogspot.com/2015/10/open-inverter-getting-draft-design-into.html (Tuesday, Oct. 5, 2915)
Part 5: https://sustburbia.blogspot.com/2015/10/open-inverter-part-5-more.html (Oct. 6, 2015)
Part 6: https://sustburbia.blogspot.com/2015/10/open-inverter-part-6-thinking-allowed.html (Oct. 6, 2015)

--- start edit: added Parts 7 & 8 below ---
Part 7: https://sustburbia.blogspot.com/2015/11/open-inverter-part-7-in-search-of-sine.html (Sunday, November 8, 2015)
Part 8: https://sustburbia.blogspot.com/2016/01/open-inverter-part-8-general-purpose.html (Thursday, Jan 21, 2016)
-- end edit --


If the concept of an open source hardware solution interests you, raise a hand by way of reply. I just started searching in this area and perhaps I'll find some other interesting attempts.

 

[Warpspeed]

WTF ?
People have been successfully designing and building their own home built inverters and MPPT solar controllers for decades.
You are really on the wrong Forum for that my friend.
People here only seem to be interested in connecting up cheap Chinese boxes.

Try The Back Shed Forum.
Take a look at Poida's MPPT solar controller using a Nano.
The famous Oz inverter, up to about 5Kw, pure sine wave PWM transformer inverter.
Above 4Kw, the Warpverter, pure sine wave transformer inverter.
Everything open source and freely available, plenty of help and advice from Forum members there too.
Its a complete waste of time presenting anything technical like that here, I have already tried.

 

[curiouscarbon]

thanks for the heads up about those learning resources

 

[JohnPoole]

WTF ?
People have been successfully designing and building their own home built inverters and MPPT solar controllers for decades.
You are really on the wrong Forum for that my friend.
People here only seem to be interested in connecting up cheap Chinese boxes.

Try The Back Shed Forum.
Take a look at Poida's MPPT solar controller using a Nano.
The famous Oz inverter, up to about 5Kw, pure sine wave PWM transformer inverter.
Above 4Kw, the Warpverter, pure sine wave transformer inverter.
Everything open source and freely available, plenty of help and advice from Forum members there too.
Its a complete waste of time presenting anything technical like that here, I have already tried.

@Warpspeed suggested The Back Shed per the above. A search on their site using their Google search facility for their web site did not return any results using the criteria '"open source" microinverter" (but did include a page full of 4 Ads suggested by Google). https://www.thebackshed.com/home.php I haven't yet followed the specific leads @Warpspeed suggested.

I'm looking for something akin to the Enphase QI 8 and I am interested in attempts to provide an open source [readily documented] solution that mimics the functionality of the QI 8.

 

[curiouscarbon]

i havent checked that other forum out yet, and this forum is my favorite for no ads, but finding low level DIY projects with documentation here can be a bit challenging. not that it always has to be that way, many people are working hard just to properly assemble premade components into a properly designed and operating system (myself included)

but any discussion here would be happily read by little old me

endless sphere has some discussion about low level design but most of what i saw had to do with motor controllers because of the EV focus there

 

[curiouscarbon]

also maybe check out greatscott on youtube for more diy project info

 

[Warpspeed]

@Warpspeed suggested The Back Shed per the above. A search on their site using their Google search facility for their web site did not return any results using the criteria '"open source" microinverter" (but did include a page full of 4 Ads suggested by Google). https://www.thebackshed.com/home.php I haven't yet followed the specific leads @Warpspeed suggested.

I'm looking for something akin to the Enphase QI 8 and I am interested in attempts to provide an open source [readily documented] solution that mimics the functionality of the QI 8.

Probably because open source usually refers to software.
Microinverter is not a commonly used term either.
Try again using the term "inverter" although on reflection, a large central home built inverter is probably not what you are looking for.

Exact key words can be very useful, but you also need to try different variants or combinations.

 

[ncsolarelectric]

@Warpspeed suggested The Back Shed per the above. A search on their site using their Google search facility for their web site did not return any results using the criteria '"open source" microinverter" (but did include a page full of 4 Ads suggested by Google). https://www.thebackshed.com/home.php I haven't yet followed the specific leads @Warpspeed suggested.

I'm looking for something akin to the Enphase QI 8 and I am interested in attempts to provide an open source [readily documented] solution that mimics the functionality of the QI 8.

I bought 10 IQ8+ inverters, built a system, passed final inspection, and received permission to operate. I jumped through all the hoops for the full (4) Enphase Certifications for installation, IQ8, Storage, and Design. I might get to turn my system on this week. (Note to DIYers, you need a certified Enphase installer or you can't turn on the inverters. No way, no how. They don't allow it.) I would love to find an alternative that can do what the IQ8 can do, but without all the red tape. I've already got some things in the works.

Hoymiles HMS microinverters have Export Management control. (see their YT channel) So with a minimum load (TBD), they should be able to operate in parallel with a microgrid, given an off-grid inverter with paralleling capability and a split-phase transformer to give us a neutral. Howver, Idk if this works yet. I haven't tested it. I'm about to order the microinverters, meter, and DTU-Pro-S, and then an EG4 Inverter and Battery to make this test happen.

I am now an official dealer for Hoymiles, so if you want to try this with me, please give me a shout-out. I'll be happy to add your order to my own and get you an incredibly low price on microinverters and a tiny markup for me so I can keep doing what I'm doing. One of these days, I need to edit my videos and put them on YT. I'm slacking. Thanks.

 

[JohnPoole]

I completed my first review of WarpSpeed's suggestion. His suggestion is kind of like drinking from a firehose.

Conclusion: The Back Shed forum has a lot of low level/ hands on activity experimenting with inverters. Really good stuff and something more technical that what I am seeing in this DIY Solar Forum. I did not find anything akin to microinverters.

I'm wondering: has anyone broken down an Enphase IQ 7 or 8 just to document what's inside &etc. What are the components? I'm tempted, as I love to tear things apart to understand what's going on inside. As a child, one of my favorite books was the set The Way Things Work.
I read somewhere, maybe a 10K Securities & Exchange filing for Enphase, that there are hundreds of patents involved with their technology. I'm suspecting that obfuscation, to the extent of building their own chip, is being used to protect their investment in a technology which may not be all that magical.

Here are my notes:
---------------------------------------------------------------------------
Warpspeed wrote:
Try The Back Shed Forum.
Take a look at Poida's MPPT solar controller using a Nano.
The famous Oz inverter, up to about 5Kw, pure sine wave PWM transformer inverter.
Above 4Kw, the Warpverter, pure sine wave transformer inverter.

1) Poida's MPPT using a Nano [Arduino nano]
2) Oz invert <5Kw
3) Warpverter, >4Kw

1) Poida's MPPT
search against user podia, term "MPPT". 2 results:
A) https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=12027 "150V 45A MPPT - roll your own"
05:20pm 24 Mar 2020
22 post on page 1 of 39 pages. One person posting towards the end hinted it took him a couple of hours to read everything. This topic is becoming a major tome.

About:
Warpspeed
Guru
Joined: 09/08/2007
Location: Australia
Posts: 4406

"buck converter" -- what is? A lot of terms and acronyms used by people doing electronics. Glossary?

B) https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=10683 "buck converter for mppt"

2) Oz invert
search using "Oz Inverter", Subject only and Post only, produced same 1 result:

Book, "MAKING A 6kW OZINVERTER"
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=8710


3) Warpverter
search using "warpvert" produced 8 results:

Forum Subject Started
Electronics WARPVERTER with 3 transformers 2021-09-30 14:57:07
by Haxby - 2 posts
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=12699

Electronics Transformer choice for 300V WARPVERTER 2020-09-05 18:03:01
by Haxby - 2 pages

Electronics Mack-OffGrid -- 100 Volt -- WARPVERTER 2019-06-24 22:02:46
by mackoffgrid - 18 posts Note: 3 phase
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=11493

Electronics Mack-OffGrid’s 26.5 Volt WARPVERTER 2019-06-20 11:56:01
by mackoffgrid - 4 pages Notes: Huge framed
https://www.thebackshed.com/forum/ViewTopic.php?TID=11481&P=1

Electronics stm32_WARPVERTER 2019-04-21 10:17:10
by mackoffgrid - 9 posts, link to https://github.com/mackelec/StepInverter/tree/master/stm32WarpVerter
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=11323

Electronics WARPVERTER Simulator 2019-04-15 17:31:27
by mackoffgrid - 16 posts
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=11313

Electronics Micro controller driven WARPVERTER 2019-03-27 14:15:51
by poida - 10 pages
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=11266

Electronics WARPVERTER brains: Tony’s Implementation 2019-03-12 04:35:15
by LadyN - 9 posts
https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=11219

WarpSpeed [Tony] " Experimental sinewave inverter designs" at https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=10432
7 pages

 

[Warpspeed]

Here is Australia microinverters are not a popular thing, we tend to build dc systems here, feeding into one giant inverter.
In fact until I found this thread I had never heard the term microinverter before.
Apologies for my confusion and ignorance, but its not something I can really help you with.

Large inverters, huge inverters, giant inverters, definitely, but not microinverters unfortunately.

 

[BradCagle]

You can use the EGS002 pure sign wave controller module to build inverters.

I have a few. Maybe some day I will build a string inverter with one. Could utilize high PV voltage instead of implementing a hi frequency converter.

 

[JohnPoole]

@Warpspeed, au contrare. What you and your pals at The Back Shed have done is very helpful. Thank you very much for your initial posting and suggestions, it's opened an area to me that merits further investigation. My assessment is you're getting down to the nitty gritty, smoothing the curves for the since wave and etc. All the microconverter does is reduce the size and harness a microprocessor to accomplish the same end result. Kind of a "nano" version of what you have accomplished.

Also, open source hardware is a new and developing area. If you are not already familiar with "the guy with the Swiss Accent", I commend to you 400+ videos (another firehose), of Andreas Spiess at https://www.youtube.com/c/AndreasSpiess. Andreas is currently working on a communal solar project, if anyone could make the tie-in to your technological achievements and microprocessors, it's Andreas.

I really do not like the idea that solar power, which can mean a matter of life and death in a disaster area, is being buried into a morass of technology. I think there needs to be a movement to take the learnings of The Back Shed and integrate it with the new emerging technologies, e.g. Raspberry Pi Zero 2, which can provide whatever digital power would be needed. The problem is most people are not willing to make the intellectual investment when they can order something from Amazon made in China. And then they cry when it breaks and there's nothing they can do about it but complain.

 

[Warpspeed]

There is just something special about building your own home, or building a boat, or building a hot rod for example.
Its very creative and a wonderful journey of self discovery, and an achievement to be proud of.

And you are right, in a disaster situation, when the grid goes down, the mobile phone stops working, or the SUV refuses to start, many people just become totally helpless. Being able to "fix stuff" is definitely becoming a lost art.

A lot of commercial equipment these days is deliberately designed to not be repairable, planned obsolescence, the throw it away and buy a new one mentality.
Building your own solar controller or inverter is not going to save any money, but what you have built yourself, you both understand and can repair, which might become a very valuable asset in coming times.

 

[houseofancients]

@Warpspeed, au contrare. What you and your pals at The Back Shed have done is very helpful. Thank you very much for your initial posting and suggestions, it's opened an area to me that merits further investigation. My assessment is you're getting down to the nitty gritty, smoothing the curves for the since wave and etc. All the microconverter does is reduce the size and harness a microprocessor to accomplish the same end result. Kind of a "nano" version of what you have accomplished.

Also, open source hardware is a new and developing area. If you are not already familiar with "the guy with the Swiss Accent", I commend to you 400+ videos (another firehose), of Andreas Spiess at https://www.youtube.com/c/AndreasSpiess. Andreas is currently working on a communal solar project, if anyone could make the tie-in to your technological achievements and microprocessors, it's Andreas.

I really do not like the idea that solar power, which can mean a matter of life and death in a disaster area, is being buried into a morass of technology. I think there needs to be a movement to take the learnings of The Back Shed and integrate it with the new emerging technologies, e.g. Raspberry Pi Zero 2, which can provide whatever digital power would be needed. The problem is most people are not willing to make the intellectual investment when they can order something from Amazon made in China. And then they cry when it breaks and there's nothing they can do about it but complain.

i very much like andrea's channel

 

[12VoltInstalls]

this post might be a good place to start with

Welcome to the forum.

problem is most people are not willing to make the intellectual investment when they can order something from Amazon made in China. And then they cry when it breaks and there's nothing they can do about it but complain.

While I agree that post-modernists and those of all ages contemporary to millennial and post-millennials have become intellectually lazy, your statement is a bit myopic.
Intellectual shallowness is even a part of the driver for our societal problems with race, gender, and mass killers: the ability to observe, learn, think, and conclude is missing and at an accelerating occurrence so ‘we’ discuss symptoms and surfaces rather than the depths and causes of our problems.

most people are not willing to make the intellectual investment

That’s only part of it. There’s also stages of life. I rebuilt my first transmission without instructions in the late 1980s, taught myself Java script, html, and graphics work in the 90s, spent 30+ years learning business practices, learned to weld, blah blah blah

I’m about to turn 57. Job/time demands sorta prescribe that I buy working things or at least subcomponents. I’ve forgotten most of what little I knew about programming. Time, time, time… But anyways- I also buy things to accomplish my goals because I started discovering 10-15 years ago that I no longer required myself to conquer everything. If I needed a carburetor for a weedwhacker it no longer offended me to spend $50 on a new one versus 3 hours of fleeting time to get the bad-gas ethanol crap out of the old one; I figured my time I can’t get back is worth at least $50/hr so I not only gained a couple hours but I “saved” $100. Just one way I put it in perspective. I haven’t become lazy, I just don’t have to prove myself constantly anymore nor do I have to outdo ‘other people’ I would criticize for being consumers. No one will remember when I was uber-cheap and uber-frugal (not positively anyway) but they will remember I was there when they needed me or wanted me. Workaholicism is a sickness one can beat.

And I’m not unique- the stages of life come, and we start to value the shortness of time we have left more than total self-reliance. So we sometimes buy rather than self rely. The time we gain is most often worth the expense.

I’ve been tempted with a few arduino projects but I’ve prevailed against it. I have nothing to prove, I can distribute my 60-hour time better by buying some things so I can actually do other things of value.

Not everyone that buys gadgetry is lazy or unwilling to challenge themselves. We’ve just learned to not have to conquer everything anymore, or thst time is precious and life is fleeting.
Nevertheless I’m still looking forward to my next off-frame jeep project and building a pilot house on my 19’ project boat. That’s been sitting for three years .

 

[Vigilant24]

I completed my first review of WarpSpeed's suggestion. His suggestion is kind of like drinking from a firehose.

Conclusion: The Back Shed forum has a lot of low level/ hands on activity experimenting with inverters. Really good stuff and something more technical that what I am seeing in this DIY Solar Forum. I did not find anything akin to microinverters.
....

John,
Thanks very much for taking the time to put together the brief notes on the "major bits of interest" at The Back Shed forum. It was a real time saver for me.

Warpspeed, you and the the others at The Back Shed have certainly been busy over the years with some great projects. I'm learning a bit more about "Clockmanfr"'s Oz Inverter. I'd like a simple 12VDC-->115VAC LF inverter. Wow--that's some project. Probably beyond my ability and "time budget", but just to know it is being done is a good thing. Thanks to you for steering folks to that board.

Mark

 

[Warpspeed]

The Oz inverter has been around for a great many years, and its slowly evolved into a very mature and well proven design.
Its not a "microinverter" unfortunately, that concept is not at all popular here in Australia, its virtually unknown here.
We do all our power combining with dc, and then run a single main large inverter.

 

[JohnPoole]

I commend readers of this thread to my posting on the Open Energy Monitor Forum

Open Source Microinverter: Epilogue?

On June 27, 2022, I ordered an Enphase Q8+ microinverter through Amazon Prime for $164.99. The component shipped from Miami, FL, and arrived July 2nd via United States Postal Service (“USPS”) in a USPS box. I wanted to dismantel the microinverter to see what was on the circuit board and learn...

community.openenergymonitor.org

 

[Warpspeed]

An excellent write-up John.
You are quite right, its a complex thing to do, and unless there is a very specific reason, just not worth all the trouble.

I have recently designed an ultra simple mppt solar controller that is entirely hardware, no microcontroller, no software. It just uses a single readily available low cost pwm controller chip. Its very spartan with absolutely no frills, but it does work very well. If it ever does blow up, very easily repairable.
It maintains a constant solar panel voltage (set with a potentiometer) and charges a battery up to a set charging voltage. That is really all that is necessary.
Ideal for lithium, not really appropriate for lead acid.

The only difference between this and a "smart" software driven mppt controller, is that the software finds the max power solar panel voltage.
With this, you have to adjust the voltage yourself manually. But as the rating plate fitted to every solar panel tells you the maximum power voltage, that is not really a disadvantage.
Even if you don't know the max power voltage of your panels, its simple to just to tweak the potentiometer up and down for maximum charging current during bulk charging.
There will be a definite maximum. Its not really a sharp peak, but a very broad hump, and adjustment is not in the least bit critical.

I doubt if there will be any interest shown at all here, Folks on this forum seem to be more into buying Chinese boxes than home building anything.

 

[Doggydogworld]

The only difference between this and a "smart" software driven mppt controller, is that the software finds the max power solar panel voltage.
With this, you have to adjust the voltage yourself manually. But as the rating plate fitted to every solar panel tells you the maximum power voltage, that is not really a disadvantage.

How does it adjust as Vmp changes with temperature, solar intensity, etc.?