Anotherpower.com Forum
Renewable Energy Questions/Discussion => Automation, Controls, Inverters, MPPT, etc => Topic started by: RFburns on March 28, 2016, 07:08:39 am
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There have at various times been questions surrounding a 3 phase inverter and if this would be possible . I believe that this would be possible using the EG8030 chip (similar to EG8010 but 3 phases) supplied as a board EGS031 . The last time I started thinking like this http://www.anotherpower.com/board/index.php?topic=1087.0 (http://www.anotherpower.com/board/index.php?topic=1087.0) Oztules took up the batton and ran with it coming up with a with a little gem. To get an operational inverter, you need to add driver switch transistors and filters.
The board has many programmable features such as output frequency (50 or 60Hz), output transistor dead band (to prevent switching current pulses), carrier frequency (addresses output filter needs as well as efficiency), 4 operating modes (controls PWM regulation and overload monitoring), and soft-start mode. The board includes monitoring features with over/undervolt and overcurrent, short circuit and overtemp protection. There is also provision for a fan driver, as well as an onboard fault LED and buzzer. Anyway if people are really intrested here is a starting point make of it what you will. RF
Additional info 29/03/16 In case someone has the inclination http://www.aliexpress.com/item/EGP3000W-3-phase-pure-sine-wave-inverter-power-PCB-UPS-EPS-EGS031-SPWM-driver-board-EG8030/1440528984.html (http://www.aliexpress.com/item/EGP3000W-3-phase-pure-sine-wave-inverter-power-PCB-UPS-EPS-EGS031-SPWM-driver-board-EG8030/1440528984.html)
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If you use a three-phase independent mode controller, you can use three independent transformers. Primary organizations they have to connect the star (first terminal to the half bridge, the second - in the middle of the battery), the secondary star, too. It is a flexible regime, but then every trance and half bridge must be ready to accept 100% load.
Balanced three-phase load is more cost-effective than independent adjustment.
I was asked why you may want a three phase inverter there are a couple of answers here - on a farm have three phase motors or have an abundance of solar panels use one phase to the grid tie and get the feed in all the time; two for the house or numerous other combinations.
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hmm this looks very interesting. i have 3 transformers that i have just removed from a 15kw pj that i am re-transformering, those and one of these setups could make for some interesting experiments.
do you think it would be worthwile to make one to run some various workshop equipment or should i just buy some vfd's and drive the motors from them?
Cheers,
Sam
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just buy the vfd and rewire motors to delta from star
Or make a rotary phase inverter for 50 dollars from some relays, caps and a big three phase motor... how I run the 50 ton press and mill etc.
........oztules
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roger that, sound's like a hell of a lot less work too so i am all for that.
oh well im back off to keep winding this transformer now, i think my thumbs and forearms have doubled in size hahaha :D
Cheers,
Sam
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Mmmm so somthing like this? ??? http://www.laserfx.com/Backstage.LaserFX.com/Hobby/PhaseConvert.html (http://www.laserfx.com/Backstage.LaserFX.com/Hobby/PhaseConvert.html) .Is it necessary to reduce the voltage into the motor ? :-\. RF
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thanks for that mate :). i'm doing a bit of reading into converters now.
roughly how is yours setup oz?
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From memory it has about 50uf across the phases, and 1000uf for the start. I used the voltage in the third phase to turn off the start capacitance, and that just leaves the run caps in place.... sort of cap start cap run auto start...
10 hp motor. 1440 rpm.
Easier way is to have a double pole momentary switch that one pole is used to pull a normal stop start arrangement common to all industrial machines, but the second pole is used for start capacitance... hold switch until motor starts, then let go.... this releases the 1000uf, and leaves the contactor intact until you press the momentary stop button ( series with the NO contact with solenoid).... that releases the run contactor.... will check it tomorrow... been a decade since I built it.
Memory is lousy.. tomorrow.....
RF is that for me?? the voltage starts at 240, so the 415v motor in star needs to be at 240 .... so delta it, for the same power at lower voltage, higher amps.
................oztules
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thanks for that. haven't even finished the inverters yet and it's time to start collecting parts for the next project. i think it is a common theme on this forum that we like to punish ourselves haha
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From memory it has about 50uf across the phases, and 1000uf for the start. I used the voltage in the third phase to turn off the start capacitance, and that just leaves the run caps in place.... sort of cap start cap run auto start...
10 hp motor. 1440 rpm.
Easier way is to have a double pole momentary switch that one pole is used to pull a normal stop start arrangement common to all industrial machines, but the second pole is used for start capacitance... hold switch until motor starts, then let go.... this releases the 1000uf, and leaves the contactor intact until you press the momentary stop button ( series with the NO contact with solenoid).... that releases the run contactor.... will check it tomorrow... been a decade since I built it.
Once I get the family visits out of the way in 6-7 weeks time I can start assembling things properly - my Ozinverter is still not in the box and I have to rewire from 24 to 48 volts.
One of my main objectives is to run the irrigation for my walnut orchards from the solar and that means 3kw of 3 phase for the well pump 50m down the hole!
I'll get my mate off round the local scrap yards for the 8-10 hp 3 phase motor and looks like motor start caps of 100uf run about us$2.50 each from aliexpress so I'll just have to see my sparks neighbour for a suitable contactor I can drive with the 24v from the irrigation controller. I like the idea of the 3rd phase volts pulling in a nc contactor to remove the start cap.
Any details that can help out a beginner would be appreciated.
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It would be a lot nicer, and more subject to Frackers controllers, if you simply used a cheap vfd like this
http://www.ebay.com.au/itm/2-2KW-3HP-10A-220VAC-SINGLE-PHASE-VARIABLE-FREQUENCY-DRIVE-INVERTER-VSD-VFD-AUS-/121224071334?hash=item1c398488a6:g:W2kAAOSwgQ9VxGX5
Or a bit bigger.. Then your problems melt away.... no hard starts, full rpm control.. even way faster than design if you tun it higher.
I use one on my salt water desalination unit I built for an outer island... 1.5kw all day. Have run the 1440 motor 1.5kw at 70 hz for hours on end too... much more sensible.
Running the 10hp 3ph motor is ok for industrial things when VFD were expensive. ( 12 years ago).. now they are throw away prices, it makes no sense.
Yes it is the oztules inverter running it all day too, as well as the house there. It has 10kw solar.
How many lpm and what pressure... maybe a pair fof these will be better and autonomous.
We have a few of these here doing 120psi@30lpm.....
http://www.ebay.com.au/itm/4-1000W-110V-Screw-Submersible-Solar-Bore-Pump-Free-delivery-/141879008391?hash=item2108a5dc87:g:uN0AAOSwBLlVJAUe
...............oztules
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How many lpm and what pressure... maybe a pair of these will be better and autonomous.
I have the single 150 mm bore hole 58 m deep with the pump down at 55 m with sensors in the 10000 l tank to refill the domestic water. The 1500 w domestic pump (with pressure tank) supplies the house and stock water and the low flow irrigation but the orchard needs the well pump (4HP) to deliver the 200+ l/m @ 3-4 bar for the 80 nozzles in each 1 acre section (I run 2 at once normally but over pressure by running just 1 section at a time for frost protection in the spring).
The irrigation controller looks after opening a valve from the domestic supply into the irrigation circuit or starting the well pump depending on the flow demand. Assuming the idle current of a VFD is low then I'd start it when the batteries looked OK and use the output to switch the box full of relays that control the pump(s) from grid to VFD. That way I can keep each sub-system isolated for fallback and emergencies (i.e. the next big earthquake!!).
Each circuit on the irrigation has its own 24v AC valve - 22 at the last count :)
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Hi all,
needing an inverter capable of supplying pure sine 3-phase 380V 50Hz from either a DC source or AC single phase as well, I came across the EGS031 and companion board EGP3000W on one of the many marketplaces around.
I've gathered all the relevant schematic and datsheets (pity that most of them are written in Chinese, but this is when Google translator came handy...), ordered the boards, started sourcing components and got myself a custom made 3-phase transformer.
But soon I realized that, despite the fact that a good number of boards (judging from seller's statistics) have been sold, there's no trace around of someone having actually built the 3-phase inverter and willing to share his experience.
Soon after, looking around for further infos / hints I came across this site, and found some competent and active posters although this thread looks deserted from a while.
So, hoping that interest in this subject is still alive, and that, maybe, someone else embarked the adventure of building one or at least is planning to, I'm dusting off this thread, hoping to find some enthusiast to share ideas / doubts about this project.
My priority is to fully understand the right jumper configuration on EGS031 board. While some are obvious, other are not and having not yet completed the circuits, I look forward to get off on the right foot and avoid building a smoke generator ;D
... Anyone answering the call ?
Greetings from Italy,
Roberto
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I've decided to avoid the 3-phase issue altogether and replace the pump with a single phase one since what I have is 15 years old and the debris from the last series of earthquakes likely did it no good at all!
A mate is in the irrigation business and he has a nice solution that uses a flow meter integrated into the headworks from the bore hole to determine when to run - it tries and if it find no flow then it shuts off again!!
Also means that I avoid all the hassle of probe relays in the tank (just had one fail a few weeks ago and spares are not available so had to reposition the tank empty into the tank fill) and just use a differential ballcock.
Still no new shed (costs are spiraling) but hope to move onwards again in a few weeks.
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Hey Roberto
I'm a noobie to this field but I've done a fair bit of reading over the last few months, Im also pretty keen on building a 3 phase inverter using the EG8030 chip as I have not seen cost effective single phase to three phase inverters over 3kw.
We have some 3 phase 10kw plus motors on a dairy farm, Id like to think in future i could build a battery/inverter/grid tie solar system to run these beasts, they would only be started knowing there is going to be enough solar coming in to take the bulk of the load.
After building my first Oztules/Clockmans Single Phase inverter.
My plan of attack would be to wind 3 toroids, build 3 of Oztules/Clockmans power boards, study and understand the latest OZ/Clocks Control board, then re engineer i new control board with the EG8030 chip. From the drawings I have studied it looks identical to the EG8010 just has 3 of almost everything.
Then test, test, test. That would be my cheats way to get to a 3 phase inverter. ;D
So my advice to you read everything and anything on the Ozinverter!!!
Cheers Shane
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Ok then, the hatchet is unburied ;D
But instead of embarking a (possibly complex) re-engineering, and having already ordered the EGS031 and EGP3000W boards, I've opted to take the short way home, assemble the kit and see how it turns out.
This is the -almost finished- circuit based on the updated version of the schematic on post #1. There's an additional board to accommodate the three feedback transformers and now I'm just waiting for the three-phase transformer to power it up and check.
I'll be back soon with the updates!
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So... here we are!
Inverter powered up and running smoothly :D (just a brief initial panicking because, being the multi-turn voltage adjustment trimmer factory preset to almost full travel, on first power up the output voltage jumped abruptly to a worrisome 460V :o)
But after adjustment I got a steady three phase 380V 50Hz featuring a nice sine wave from a 48Vdc input.
Now for the heavy load tests... (as soon as I find some suitable resistor)
Stay tuned!
Roberto
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Hey Roberto, Any update on your load tests?
Cheers Shane
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Nice ! :D
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A couple years ago, I set up a rotary phase converter (50hp) to run a cnc lathe and mill for a small machine shop starting up. It was quite a bit cheaper than the power company. It isnt a perfect solution but it does work.
Input voltage is 245v single phase then power runs through two parallel 80A toroids connected as 35v buck to drop voltage to 210 then 50hp rpc, for 3-phase 208. With the balancing caps it worked real well. 2 months down the road we added a 30kw isolation transformer because one of the cnc inverter designs dumps regnerative braking power between its 208 legs and ground (120v) or supposed to be xcept without the isolation transformer one of the output from the delta rpc is the dreaded wild leg which blew up a drive. Thus the need for isolation.
It has worked ok since with the exception of twice now a run capacitor on the rpc has melted down due to terminal connections i would guess. They have since upgraded the lathe to a larger machine, which required a bit of adjustment to the balance.
Because of the noise and these two cap failures, the boys (the owners) want to get rid of the rpc and use an inverter instead. I will be visiting them tomorrow morning about it.
My opinion is the rpc is way more reliable than an inverter. What do you guys think?? If they insist, would the 30kw inverter in the link below be a suitable choice? Could i simply jumper the 3-phase inputs for single phase input?? May need to add an external rectifier and connect to buss?
Or should i consider the eg031 egp3000w build and connect some large igbts to it to get the 30kw? I think I have some dual igbt packs that would work for this. I would rather have them choose an off the shelf unit so they arent dependent on me. Any thoughts much appreciated!
http://m.ebay.com/itm/TOP-GIN-30KW-40HP-MOTOR-INVERTER-VARIABLE-FREQUENCY-DRIVE-VFD-200-220V-3PHASE-/282251886988?nav=SEARCH