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Forum Index : Electronics : My attemps to make an ozinverter

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arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 04:05pm 01 Jun 2019
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Hi Everyone.

I'm new on this forum, so, excuse me.

I've just read all ozinverters projects made on this forum and been looking for the forum since December but never posted anything.

So i went ahead and registered myself so i can try to help and be helped on my try to make my own ozinverter.

Actually, my system have 12x 320wp panels on the roof:


Here is the DC / AC protection boxes:


Here is the on grid system, each ongrid inverter is connected to a single 320wp spare solar panel up the roof:

Madness have a circuit that can limit those ongrid inverters, i will be buyin some of the boards from him so i can limit my grid tie system. They are advertised for 600W, but can't handle even 500W.



Those inverters have the cooling stage modified and some capacitors added to avoid ripple. I warn everyone that has those inverters to take care on islanding. Since i have some compressors here, they kept working after an energy loss and they were generating about 290V on the house. I'm using now a small circuit from china to avoid islanding on those.

Here is the fantastic solar controller from 'fangpusun'. It handles up to 80A or about 4.4kW. It is cheap and very well made clone from the known Outback Solar brand. I've just changed the cooling on it and removed the original chinese capacitores and added some Nippon brand caps. Rock solid working since 2 years ago.



Here is the best part on my opinion. The Maxwell Ultracapacitors. Each cap have 350 Farads (or 350.000.000uF). They have been taken from some wind generators that we have on northeastern of Brazil.

Those things are beasts.




The winds generators that this caps came from are like this ones:


I've been able to push 100A @ 56V of current with almost no voltage loss over a big-ass resistor i had on water and had to stop after some seconds because the wiring can't handle all the current. Those caps are excelent to avoid using the battery bank during the day.

The caps handle the system during the day, and can handle cloud for about 10 minutes without switching to lithium back.

The system voltages are:

> 60V = Capacitor bank handles up
< 46V = Lithium bank gets switched up

The relay boxes i will be making (waiting them to arrive from eBay) will switch on the lithium bank during the night or extremely rainy days (when the voltage drops to less than 46V).

Here is my 13s Lithium battery bank, currently with something like 15kW of energy stored. But i will be growing the battery bank soon to something like 50kW.



Here is an overview of the system:



The system is currently turned on, but without generating any power, since all my off grid inverters are destroyed.

I've been using for about 1 year three APC 3000XLI nobreaks taken without cost for the company i work. All of them, destroyed one by one because of the peaks my system have. The transformers are on perfectly fine condition and i will be using them for this new inverter project.

I've been using 2 Magnum inverter's 4400W 48VDC, but they failed in some months of use. They have been returned to Magnum, fixed and sold since they can't handle my system.

Now i will try to make the famous ozinverter and finally, avoid the magic smokes when i push 10kW+ from it.

This system, when ready, will give energy to our house and my mother house that is near me.Edited by arthur8 2019-06-03
 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 04:30pm 01 Jun 2019
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Here is the transformers taken from the APC nobreaks:

I've tested them on the 220v AC line and been able to push about 4kW from each group of two transformers and they get a little warm.




The problem with those is the inrush current. When i turn they up, their field magnetization in rush current where able to turn off a 16A Class C circuit breaker.

So, i'm creating a soft start circuit based on this circuit:



The circuit turns on a big resistor with 0.5 or 1 Ohm in series with the transformer and after 3 seconds (can be adjusted increasing the capacitance to something like 10.000uF) it turns on the transformer.




It worked.

The idea over this is to turn on transformer groups #2 and #3 without destroying the mosfets. It is something like the soft start the guys use on the egs002 overtemp.

The group #2 will be turned on (softly, using the soft start circuit) according to the temp of the transformer group #1.

Also, the group #3 will be turned on according to the temperature of group #2.

Something like that:

Edited by arthur8 2019-06-03
 
renewableMark

Guru

Joined: 09/12/2017
Location: Australia
Posts: 1423
Posted: 11:30pm 01 Jun 2019
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Welcome to the forum mate.

Impressive setup you have!

I have that same fangpusen 80A unit, it's been fantastic.

Have you heard things about the caps having problems or just replaced as a precaution?
Cheers Caveman Mark
Off grid eastern Melb
 
brucedownunder2
Guru

Joined: 14/09/2005
Location: Australia
Posts: 1362
Posted: 12:25am 02 Jun 2019
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looks good ,Mark. and Arthur .

Gee, thinking of John(Oztules), he has done so much for this forum ,a big "thank-You John". from all of us .

Ilda, my "handbrake" will be taking stuff over to Arthur ,when she visits Mum in a couple months-Mums 103 ,so very important to go visit .

Ok, nice stuff Arthur ,

Bruce.
Bushboy
 
hugocamaras
Newbie

Joined: 12/04/2019
Location: Brazil
Posts: 12
Posted: 02:21am 02 Jun 2019
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Fala Arthur! Belez mano? Mundo pequeno né? Agente se encontrar num forum estrangeiro...

Tenho acompanhado esse forum à algum tempo e fiquei muito animado com esses caras aqui... Eles desenvolveram projectos maravilhosos e publicaram para qualquer um que queira replicar. Muito bom mesmo. Caso queira trocar umas figurinhas, me chame no Whatsapp (33)988161426. Grato, Hugo.
 
brucedownunder2
Guru

Joined: 14/09/2005
Location: Australia
Posts: 1362
Posted: 02:58am 02 Jun 2019
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All,

Hugo is talking to Arthur ,


Hugo is commenting on the wonderful forum of "the back shed" .

He is very complementary of the projects being designed and the members participating in their builds and the help being shown by all.

He is living in Brasil and follows our forum . I think he will not mind me explaining his post.

Bruce
Bushboy
 
hugocamaras
Newbie

Joined: 12/04/2019
Location: Brazil
Posts: 12
Posted: 03:22am 02 Jun 2019
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Thanks, Bruce. I apologize for writing in Portuguese.
But, yes ... I am very grateful for everyone who has brought their knowledge to this forum and shared it to everyone who seeks this knowledge about building investors much more advanced in features than commercial investors!
I have been researching these investor projects on Internet forums for some time, but the projects I found in this forum and the brilliant minds that developed them, "I NEVER FOUND ANYTHING I HAVE FOUND WITH WHAT I FOUND HERE IN THIS FORUM!"
 
BenandAmber
Guru

Joined: 16/02/2019
Location: United States
Posts: 791
Posted: 03:36am 02 Jun 2019
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103 years old that's wonderful just think of the wisdom

 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 09:01am 02 Jun 2019
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  renewableMark said   Welcome to the forum mate.

Impressive setup you have!

I have that same fangpusen 80A unit, it's been fantastic.

Have you heard things about the caps having problems or just replaced as a precaution?


Hi Mark!

This controller is a beast, highly recommended.

I have an friend that have the 60A version and he is using it stock since 1 year ago. I don't think that in the sort therm, you will have any problems with the stock caps.

But i think brand caps are so cheap and to prevent any issue, i've replaced them and i can recommend doing it if is something possible for you.

If anyone need help at this process, let me know. But it should be easy, since the fangpusun chassis have a good spare space.
 
renewableMark

Guru

Joined: 09/12/2017
Location: Australia
Posts: 1423
Posted: 10:00am 02 Jun 2019
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Thanks Arthur, BTW getting one of these Ozinverters to run 10Kw may be a big ask, might be a better idea to split that load between two units.

Some of us here are building the Cascade type of unit that Warpspeed has designed, they are more suitable for large scale production, as the switching is at 50hz so the fets have an easier time rather than 23khz for PWM.
Cheers Caveman Mark
Off grid eastern Melb
 
Revlac

Senior Member

Joined: 31/12/2016
Location: Australia
Posts: 274
Posted: 11:41am 02 Jun 2019
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Hi Arthur
You have done well getting it all together, nice set of batteries too.
I also run a battery bank similar to yours, and currently running 13s 160p so about 2080 cells, More would be better.
Has been running the house for some time, voltage is 53.3v (4.1 per cell) and low voltage cutout is set at 46v.
Anyway keep at it mate.
Cheers Aaron
Off The Grid

 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 12:21pm 02 Jun 2019
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  brucedownunder2 said   looks good ,Mark. and Arthur .

Gee, thinking of John(Oztules), he has done so much for this forum ,a big "thank-You John". from all of us .

Ilda, my "handbrake" will be taking stuff over to Arthur ,when she visits Mum in a couple months-Mums 103 ,so very important to go visit .

Ok, nice stuff Arthur ,

Bruce.


Hi Bruce,

I can't thank you more for your (and Ilda) kindness. I really hope that you get better soon and if you would visit Goiânia/Goiás someday, let me know.

It would be an pleasure to receive you, my friends, here.

Oztules is an extremely smart person and i have a lot of admiration
for him.


Thanks again, friend.
 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 12:23pm 02 Jun 2019
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  hugocamaras said   Fala Arthur! Belez mano? Mundo pequeno né? Agente se encontrar num forum estrangeiro...

Tenho acompanhado esse forum à algum tempo e fiquei muito animado com esses caras aqui... Eles desenvolveram projectos maravilhosos e publicaram para qualquer um que queira replicar. Muito bom mesmo. Caso queira trocar umas figurinhas, me chame no Whatsapp (33)988161426. Grato, Hugo.


Oi/Hi Hugo,

Sure. Contacting you over whatsapp.
 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 12:48pm 02 Jun 2019
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  hugocamaras said   Thanks, Bruce. I apologize for writing in Portuguese.
But, yes ... I am very grateful for everyone who has brought their knowledge to this forum and shared it to everyone who seeks this knowledge about building investors much more advanced in features than commercial investors!
I have been researching these investor projects on Internet forums for some time, but the projects I found in this forum and the brilliant minds that developed them, "I NEVER FOUND ANYTHING I HAVE FOUND WITH WHAT I FOUND HERE IN THIS FORUM!"


Yes, Hugo.

That is what we need on Brazil, more helpful people like the people on this forum.

This forum is fantastic.
 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 12:58pm 02 Jun 2019
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  BenandAmber said   103 years old that's wonderful just think of the wisdom



I agree. My wife's grandpa is 93. Just incredible.
 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 01:02pm 02 Jun 2019
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  renewableMark said   Thanks Arthur, BTW getting one of these Ozinverters to run 10Kw may be a big ask, might be a better idea to split that load between two units.

Some of us here are building the Cascade type of unit that Warpspeed has designed, they are more suitable for large scale production, as the switching is at 50hz so the fets have an easier time rather than 23khz for PWM.


Hi Mark!

Thanks for giving me this option. We still have some time since Bruce wife will get to brazil.

I didn't know of those cascade inverters. I've tried to tind the topic but i've just find poida's topic: https://www.thebackshed.com/forum/forum_posts.asp?TID=11266

Could you please guide me to the topic so i can take a look?

Thanks for the help!
 
arthur8
Regular Member

Joined: 08/05/2019
Location: Brazil
Posts: 69
Posted: 01:17pm 02 Jun 2019
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  Revlac said   Hi Arthur
You have done well getting it all together, nice set of batteries too.
I also run a battery bank similar to yours, and currently running 13s 160p so about 2080 cells, More would be better.
Has been running the house for some time, voltage is 53.3v (4.1 per cell) and low voltage cutout is set at 46v.
Anyway keep at it mate.


Hi Revlac,

I will, maybe, rewind the battery bank to 14s to increase a little the system efficience.

But my cutout points are:

low: 3.30v
high: 3.95v

Thanks friend!
 
ltopower
Regular Member

Joined: 08/03/2019
Location: United Kingdom
Posts: 64
Posted: 05:24pm 06 Jun 2019
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Wow, very impressed with the capacitor setup. I think it is the first home power pack I have seen with that many supercaps.

You say each is 350F and by the looks of it you have around 588 caps, so at 2.7V charge you have about 330Wh of capacity ?

What voltage range do you run the capacitors over ?


Another option for getting 10kW output is to use a standard inverter build and then attach one or more grid tie inverters that has a CT and feedback (typically used for a zero export setup)

So you end up with :

OZ Inverter --CT------------ House / demand
| |
2kW Grid Tie Inverter ---|
|
2kW Grid Tie Inverter ---|


The Oz would handle the initial switching load change and then the grid tie units would then add supply and back off the Oz Inverter to handle the faster changes.

This is the setup that I intend to have for the house, using a 10kW inverter to only ever supply 5kW and the other 2x2kW units providing an overall continuous capacity of 11kW.
 
ltopower
Regular Member

Joined: 08/03/2019
Location: United Kingdom
Posts: 64
Posted: 05:30pm 06 Jun 2019
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Here is a rough outline.... the text did not qork quite as intended..


 
LadyN

Guru

Joined: 26/01/2019
Location: United States
Posts: 408
Posted: 07:44pm 06 Jun 2019
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arthur8, have you found links to the various Warpverter related information here?

If not, please let me know.

I started by creating a post that was meant to consolidate these links but this forum does not let one edit older posts that have been replied to, so that first post is now incomplete as I cannot update it anymore.

The Warpverter can be used to scale from a few kW to many kW without changing the fundamental design.

The biggest painpoint with the Warpverter, which is currently blocking all of us who are in the U.S. is the availability of cheap transformers - an issue that's just not a problem for you since you have way more than what you will need.

The ozInverter focuses all its power on one single transformer, while the Warpverter spreads it across multiple ones with each stage decreasing the THD and increasing the power output.

It's also a low freq. design - makes things easier to follow, diagnose and maintain.
 
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