EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: VanMarco on March 18, 2022, 12:34:10 pm
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Hello!
I am planning to build a "pure sine wave" inverter to power some things with solar.
I plan to do 2 stages. 1st stage, regular 12v to 350v square wave, second stage, 350v to 220v sine via a egs002 module.
now i did a sketch of the 1st stage side, and i am not sure if it's wrong.
Output A and B will go to SG3525 driver circuit, not pictured yet.
Is there anything essentially wrong?
(https://i.imgur.com/oyW5PPU.png)
thanks in advance
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What kind of inverter topology are you aiming for? There are many different ways of making a sinewave inverter. The most popular ones:
A) Generate a positive and negative high voltage DC rails using SMPS, followed by a half bridge PWM switcher (similar to class D audio amp).
B) PWM the main SMPS step-up transformer in such a way as to obtain a rectified sine wave at the output, and follow that up with a H-bridge IGBT switch on the output to be able to "flip" each half of the sinewave on the zero crossings to obtain your positive and negative going peaks.
C) Full bridge PWM switching a mains frequency step-up transformer, obtaining the high voltage output sinewave in essentially one step.
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I think it qualifies for A)
some similar to this for the 1st stage
(https://i1.wp.com/www.how2electronics.com/wp-content/uploads/2019/08/12V-to-220V-Inverter.png?ssl=1)
Thank you!
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A good starting point: https://sound-au.com/project89.htm
To adapt it for your application, redesign the output section for higher voltage.
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I made a new schematic, i still need to finish the output. Do you like it?
thanks
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It is unusual to see what appears to be two transformers, after the bridge rectifiers, in parallel. It is very difficult to match two separate transformers exactly, so one will tend to carry more load than the other. If you want to use two transformers, it is better in series, but what is really better than two is one suitably sized transformer. If I have misread your intentions I look forward to your explanation. :)
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hmm, i want to add more transformers and mos groups in order to have more W output.
this module on ali is a lot like what i plan to do, without the side-boards https://www.aliexpress.com/item/32985499596.html (https://www.aliexpress.com/item/32985499596.html)
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This article: https://www.facilitiesnet.com/whitepapers/pdfs/SchneiderElectric_111711.pdf (https://www.facilitiesnet.com/whitepapers/pdfs/SchneiderElectric_111711.pdf)
talks about paralleling transformer secondaries, which is related to what you are intending to do. The advantage you have is that the bridge rectifiers will prevent circulating currents, but not the load sharing mismatch if there is any. What is your intended configuration after the bridge rectification?
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Huh? an old CD4047 driving your MOSFETs? That's going to be some sloppy drive, isn't it?
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IR2153 makes a nice oscillator driver for this application. I used to buy these on a board with FET and heatsinks for $7 shipped look up 300W inverter board. Now they are more expensive and you don't know what you will get, sometimes SG2453.