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Forum Index : Electronics : 3Phase Inverter Needed
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| Cpoc Regular Member  Joined: 28/05/2024 Location: PortugalPosts: 97 |
This is why I am a big fan of open hardware designs. Would be nice to have a 3phase inverter design that we can repair ourselves. Problem with current designs is they are all balanced inverters I need a unbalanced design that can run both single phase and 3 phase loads. When you put 3 X single phase inverters in 3phase mode now they are unbalanced design. |
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Revlac Guru  Joined: 31/12/2016 Location: AustraliaPosts: 1207 |
I remember have an issue with 2 of the (small) 3 Phase Gensets I had, If one phase was loaded more the voltage would be driven high on the other two outputs due to the AVR, the other large genset could run without any issue. So an AVR on each phase independent? and a current sensor on each phase For a DIY 3 Phase inverter, there's a lot more to it, just My thoughts on this so far. Cheers Aaron Off The Grid |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
The solution is not easy but unbalanced 3phase is the way to go. Its how most manufactures do it including Victron. They connect 3 single phase inverters and the first one is master the other 2 are slaves and sync them up. This way the loads can be unbalanced with no issues. This is the solution I am asking for if its possible. We already have half of the solution done with the current Wiseguy design and firmware. The current firmware would need to to updated for 3phase support and all 3 inverters would connect to a master controller that would keep all 3 inverters synced up. So in theory you can have 3 x 12k units with 6 transformers or 3 times 6k unites with 3 transformers. If this is not possible then I will go with the Luxpower setup because its a lot less expensive than the same Victron setup. The 12k units have a very impressive spec sheet. |
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| analog8484 Senior Member  Joined: 11/11/2021 Location: United StatesPosts: 173 |
Agreed, Luxpower is definitely better than Voltronics. But its idle consumption is still 2-3x that of similar power capacity leading LF inverters (e.g. Schneider, Victron, etc.). So, depending on the situation, more PV and batteries could be required. Another thing to keep in mind for tight spaces (e.g. boat), these HF inverters can be quite loud under load with jet engine level fans. |
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| analog8484 Senior Member Joined: 11/11/2021 Location: United StatesPosts: 173 |
Thanks for the info. That's interesting ... I am guessing the control loop does not monitor and adjust for DC bus voltage level. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
Agreed the Luxpower SNA 6000 are very load and do not have conformal coating and in a marine environment will not last the test of time. The 12K is way over spec they can do 10K continuous not worried about the extra panels to power them up. Would use Tigo optimizers does well in shade and high voltage as they have rapid shutdown and make having 300v pv very safe. I would mostly go with 3 X 12K units as they are very silent and I would never overload them at all. The fans barely run at all. In the US they are expensive over here in Europe can be had for 1500 Euros that is with tax and shipping included.Tax here is like 20 to 24 percent. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
As for space I have the space to install them way above the waterline on the bridge-deck so no issues there for either solution. I did find the single phase compressor for the chiller at the same price so the only thing I cannot run is the 3 phase mig welder that can stay on land and I can keep a 200A DP mig welder on the boat for emergency repairs. A question for Wiseguy if I go with your design and stick with single phase is it possible to add another 6k transformer. The AC compressor consumes 1k to 5K of power and the hot plate consumes 3k of power plus the hot water tank consumes 2k of power. Was wondering since the 12K works in hardware parallel with only 1 controller can you add another power board and transformer and chokes for a total of 18K. Idle power would be only 75 watts total and you can add your relay circuit to power down the third transformer when you do not not need more than 12K single phase. That solution would work for me. AC charging is not needed. As for MPPT would use your design as well. The firmware would need to be updated for Lithium profile as I am sure that would not be to difficult to do. Solar panels under 150V volts are not an issue and no tigo optimizers are needed. Just an idea. |
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| nickskethisniks Guru Joined: 17/10/2017 Location: BelgiumPosts: 467 |
Could you give an example of "current design"? What you need is that each phase has it's own feedback loop, like Poida allready had incorporated in his 3ph code. The way I see it ( to start al little bit of discussion  )What victron and other brands are doing by using 3 single phase inverters to create a 3ph is probably to complex for us and would bring in more points of failure, I don't see the need and it would add extra cost and in my opinion less reliable. Allthough a sync input is allready on the wiseguy controllerboard and technically could sync with a signal from a Master board, a firmware update will be needed. But also an extra revision of the controllerboard, you will want to shut down the board when something happens with interrupt speed and you only have 2 on a nano wich are allready taken. The masterboard will then need to have also all kinds of measuring/metering stuff to have 1 LCD meter with all readings and this would bring extra wiring susceptable to emi and maybe extra sensors. We only need 1 controllerboard, this would also support only single phase operation when needed, 3ph appliances would probably need to be put after a dedicated contactor/relay in case 1 phase is failing or is not needed. Unbalanced and balanced is something for a 3ph transformers, but this is not the case when using 3 different H-bridges and transformers. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
You are correct 3phase is very complex so I am leaning toward single phase. There are are few mig welders that can do at least 250A in single phase and that is what I would need. As for the chiller I have found the single phase replacement I need. 12K may not be enough unless I am managing power needs which I really do not want to do. Would like to know if we can add one more transformer for an 18K load. All single phase. 12K with two transformers always on and the third transformer on the relay circuit so if need more than 12K for short period the last transformer would turn on. Would still need a firmware update but that should not be too difficult. At 18K would have all the power I need with no power management needed. Wiseguy can answer this if his hardware design can support this. It would be all running an a single controller up to 18k single phase. |
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wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1227 |
I am now ~ 2-3 weeks from home so will confirm then. Pretty confident that a third transformer and progressive start-up too if desired should be no problem. If at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
Thanks Wiseguy that would work for me. That would be a perfect setup. That would be a perfect solution. I also contacted Luxpower and they said their inverters and not to be used for marine use as the warranty would not be honored. I had a feeling about that. Very few manufactures allow their products to be used in marine environment. Victron has great gear but way to expensive and when the warranty period expires good luck trying to have your gear repaired. They tell you its too old and buy another one. The one thing I do not like about Luxpower is that it is cloud connected which means they can brick your inverter from very far away. The hardware is useless without the firmware. Deye inverters has already done this. All of this cloud based crap is not good. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 938 |
All very interesting to see where this is leading. I like the idea of a staged output. If you are aiming for 18k and staying single phase, why not consider a Warpverter. There's apparently no limit to the size you can design for, so maybe wind for 20k and cruise away.  Mine is good for 15k and idling power is only 35W. If I was to build another I would design for 20 or 25k ... and definitely use IGBT modules and not worry about mosfets with their extra complexity. Would be heavy, but super simple ... and a handful of spares would keep you confident you wont get caught out. In 20 months mine has clocked over 18MWh, so it can definitely deliver the goods. Cheers, Roger |
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KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1948 |
You have likely noticed that I've had my twin power stage running at up to 14kW and cycling between 8 to 12kw for an hour or so morning and night, similar loads to you except the Air-con being an inverter is much lower consumption once the temp is reached, they sometimes run all night and day, hot water is around 3.4kW. I've had everything running at once, including the JUG at 2.3kW and Toaster in the mornings. I'm using the High current Driver option on the controller that wiseguy included on the later boards, but obviously you need to know for sure with the third switched power stage, hopefully wiseguys answer will give you another option. . Edited 2025-11-13 10:00 by KeepIS NANO Inverter: Full download - Only Hex Ver 8.1Ks |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
Warp inverters are very strange but they work for a land setup but not so much for a boat marine setup. They are very heavy. The 3 inverter setup will work great. 90 percent of the time only 2 transformers will be on. Only when alot of power is used all at the same time because I do not want to manage my energy the third transformer will turn on and can handle loads up to 18k continuous. That set up works for me. 18k is alot of power. I am waiting feedback on a mig inverter that can do 350A and supoorts both single phase and has 3 phase power supplies with double pulse. 350A is more than enough for all my needs. When you pass 350A its only available in 3phase power. The one I was going to buy was a 500A 3phase model. I do not need that much power. Also I have a case that will support all 3 transformers, chokes, power boards and controller. Its 600mm X 800mm and that should fit everything. Its in ABS plastic case with a steel backing plate. |
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| Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 97 |
I believe Wiseguy setup will work. Having that extra transformer is more of an insurance as I will not do any power management. 12K is more than enough for all my loads buy having the extra 6K available to auto switch when needed would be perfect. I believe a firmware update would be needed so it would turn on the third transformer when loads pass 12k and not 6K. I have all the parts already in his latest design unless their has been new hardware changes that I am unaware of. |
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