Builiding of a complete 6kW PV inverter with MPPT chargers


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-dex-
Regular Member

Joined: 11/01/2024
Location: Poland
Posts: 77
Posted: 08:49pm 04 Feb 2024      

I'm starting a new topic about building a complete solar inverter in which I would like to share the results of my work, and, more appropriately, an account of the construction of a home power system.

As a new member of this forum, at the outset I would like to say hello - I am Mateusz, or simply Mat. In my country I have no one to discuss with about building an inverter, I came across this forum which is a mine of knowledge about building inverters for home brewing.  I went through many topics on this forum. In the meantime, I purchased the OzInverter Book from Leslie R A Bryan albeit the initial admiration for this project passed and I started working on my own circuit. In the meantime, I came across the wiseguy inverter project and it basically meets all my expectations both in terms of power and layout solutions. Why reinvent the wheel? The boards for the inverter are already with me.

I would like to say a big thank you to user wiseguy who helped me a lot and probably if it wasn't for his support I wouldn't have started this project.

The project is to include the construction of an inverter with a continuous power min. of 6kW and a peak of more than 10kW, and the construction of MPPT chargers according to the poida design (150V 45A design) 3-4 pieces.

The system is to work 24/7 and is to be the first source of electricity at home. When the sun goes out and the current in the battery runs out the automatic switch (ATS) will switch to the grid.

The big challenge is to get a steel core for a toroidal transformer. I looked through everything I have at my place and found the core, it came from disassembly, I have two identical ones.






Perhaps power-wise by gluing two together I would achieve the required power, but after calculating the windings it comes out that they will not fit in the window (OD=145mm, ID=65mm, H=80m, 7kg weight) Basically it is 14 small disks glued together. I will save it for later.

I asked a lot of companies making transformers or cores and no one wanted to talk to me, I'm just too small - this was no surprise to me.  But finally one company spoke up and made an offer to inquire.

OD=250mm, ID= 160mm, H=100mm, weight 21kg. Chamfered edges, annealed steel, made of material in grade M095-23P/ETH095-23. that's it!






With CD for size refernece







And for compare sizes two of them





I assume that I would like to get a flux density of 1.4T. I think this is a compromise between maximum efficiency and idle current.
I also assume that I will use 1.8mm wire and 4 layers for the winding. Will this be correct?  This is a solution taken from the OzInverter book, I have access to wires of a different diameter.

I encourage you to participate in the topic and would appreciate any help and answers!