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Forum Index : Electronics : Parallel operation of inverters
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| nickskethisniks Guru  Joined: 17/10/2017 Location: BelgiumPosts: 411 |
Maybe already mentioned but the following idea looks so simple (in my head) if you have some spare time and motivation.  Running 2 different inverters in sync like commercial ones are a no go, you will need good programming skills and knowledge in control loops. All ideas I have in that direction will also kill the surge capability. So the simplest thing you could do is: Use one main board (with a bufferstage, like a mosfetdriver for example) to create the pwm pulses and feed those to the powerboards, the powerboards need the mosfetdrivers also on the board, for tight gate drive use totem pole or dedicated mosfetdrivers like sugested. Now each powerboard runs in sync, each powerboard is then connected to it's individual transformer and choke. Then after the transformer (secondary?) put them in parallel, or even better in series like KeepIS did. Keep an eye on the right polarization! Now, in series the current is equal true the transformers secondary, if the transformers power rating is different you can play with the winding ratio. For example if transformer A is 2000W and transformer B is 3000W, then transformer A will have 100 secondary windings and transformer B will have 150 secondary windings, primary windings will be the same but with another wire cross section. Edit: primary windings will not be equal with different power ratings, so still need to tweak that, but you get the idea... and probably can calculate to get you in the right direction. With parallel it will be more trial and error and there might be more circular current in the system. My idea is that you can keep the number of primary windings the same (if the core is the same otherwise not), and play with the number of secondary windings to match the power outputs. I think if the winding ratio is the same, it might be possible you don't need to tweak al lot, normally a bigger transformer will always have thicker wires, and lower resistance and impedance because it will also have less number of windings. So the bigger transformer will already be supplying more current then the smaller transformer in a natural way without doing much. I see lot's of fun with winding those transformers. If you don't like to wind much, because the 110/230V winding is most likely on the inside. You can add some windings and put them in series with the 110/230 windings, depending on the polarization you add or subtract some volts. Just an idea, not practically proven (yet  ).Edited 2024-01-26 08:19 by nickskethisniks |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 378 |
Hi Nick, thanks for the explanation. I am curious as to why you suggest two different transformers. I was thinking that as both my power boards are identical that I could parallel the outputs of them and just feed one big transformer. Is that likely to blow the boards up? I was thinking if both power boards were run by the same 8010 board then they would be able to be paralleled. Or am I looking for membership of the smoked mosfet club. Pete |
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| nickskethisniks Guru Joined: 17/10/2017 Location: BelgiumPosts: 411 |
I don't know actually, it was late and looked cool. :) It's probably something I want to try. A little bit like the warpverter but with synced pulses. It's handy when you don't want to wind a lot, little transformers are less heavy to wind, maybe something to keep in mind. It also would make something modular and expandable. You can make a Nice estetical looking inverter. You can parallel both bords with an inductor, So each board An inductor and then parallel. This should improve the current sharing during the switching transients. If you Will wind a transformer from zero you can provide 2 primary windings each going to its powerboards and inductor. Edited 2024-01-26 16:46 by nickskethisniks |
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Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 427 |
Yes, also been thinking about shareing the FET drivers output to two indvidual power boards and two smaller torroids. Not going to happen this year as i am rather busy with other projects, but sure sounds like a crazy fun project, especially using smaller torroids. lol  Everything is possible, just give me time. 3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v. |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1783 |
I guess it takes several parallel inverters to feed this transformer! Big Transformer |
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