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Forum Index : Electronics : Inverter building using Wiseguys Power board and the Nano drive board
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KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 07:25am 30 Aug 2024
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For those not up to speed:
I think Cpoc means the 2 stage control switching:
This is gives the option of having only one half of the Inverter running at low power demands in order to lower the Idling current.
I know you want to see that working, and the board is on the bench ready to be populated, I am going to include it in my build, you never know, I might use it one day, the AC output connection block is already setup is for it.
But alas it's still a day or two away I really need to get the inverter in its current state, which is in dual high power mode, fully off grid and unattended running, for that, I need the safety monitors finished first.
BTW the 2stage board is the same physical size as the nano controller board.
But you are 100% correct it's a real brute of a design now, and the Nano controller is running sooooo sweetly _ Edited 2024-08-30 17:28 by KeepISIt's all too hard. Mike.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78
Posted: 09:11am 30 Aug 2024
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Take your time no rush…however I am not the only one that wants to see the second stage running.
When I first proposed the idea of the 12KW inverter I was never expecting the second stage being a part of this project.
I just needed a 12KW inverter design and not two separate 6KW inverters. It was because I wanted to use my MiG welder that uses about 8KW of power.
Then wiseguy not only said that is was possible to parallel 2 X 6KW units with a single nano controller main board but he would even develop a second stage pcb that would cut the idle power in half when the inverter was at idle.
I was totally fine with the idle power at 50w to 60w of power consumption. So this has well surpassed my expectations with even lower idle consumption use. Edited 2024-08-30 19:29 by Cpoc
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 09:57am 30 Aug 2024
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This inverter is a 12kW inverter, I can't test it at 12kW until I have all protection finished.
When I add wiseguys second stage board, it will then be switchable back down to 6kw, and only if I ever needed a lower 24 watts of Idle power, instead the 48 watts idle power as it is now.
Like you, I'm fine with around 50 watts as well, but you never know when you might have to makes the batteries last a bit longer, it could be handy to save every last bit of battery power in emergency situations.It's all too hard. Mike.
wiseguy Guru Joined: 21/06/2018 Location: AustraliaPosts: 1156
Posted: 10:47am 30 Aug 2024
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Here is a picture of the second stage control board from 2 aspects. Note I have not installed the connectors or op-amp for the peak reading circuit as I really just wanted to test the control functions.
Note the Main relay does not switch 30A it closes and opens with minimal current flow, the second stage drive is enabled and disabled to avoid high current relay switching. The smaller relay in series with the NTC anti surge resistors only passes a single cycle of current ~ 8A max with 2 x 15R NTCs and then only if it is switched at the worst possible time, thereby driving the second toroid into saturation. The current quickly reduces over the next few hundred milliseconds to normal magnetizing current. Note the smaller relay can be upgraded to a 10A or 16A type with the standard DIL footprint instead of the SIP type I used, the board accepts either type.
Q1-Q4 are backwards for the silkscreen as I used different FETs to the BS170s that have a different pinout - the outside pins are reversed. Edited 2024-08-30 20:49 by wiseguyIf at first you dont succeed, I suggest you avoid sky diving.... Cheers Mike
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78
Posted: 11:52am 30 Aug 2024
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Wow that is a lot more complex than I thought it was going to be.
Amazing job wiseguy truly a work of art and with no nano code needed just pure electronics.
This is going to be one hell of an inverter that not only can you swap out parts if needed but that you can also replace individual components.
For us old guys with grey hair that our eyes don’t work so well this is a God send due to not having any SMD parts that are so small that I cannot even see them.
However I still need my old man glasses when I will assemble these boards. Edited 2024-08-30 22:05 by Cpoc
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 06:33am 31 Aug 2024
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I spent the morning building and installing my independent two peak DC current trip boards, they worked perfectly, I now have an indicator to show which Power board tripped - I'm not sure it will unless I have a fault.
Only the AC trip board and 2Stage PCB left to do.
Were are now off grid again, running on this beast, a stinking hot day BTW.
I decided to try the Inverter killer load, a 3.2m high external housed woodworking dust extractor. With 3.5 seconds of sustained 580A 100hz DC input startup current peaks.
It started, I know because I heard it start and run, the inverter did nothing, I'm sure it said, dust extractor! what dust extractor?
Each DC input meter peaked at 280A - which is nothing to each stage.
The workshop Aircon and other loads are running at 1.7kW, that didn't bother it all, with the extractor up and running, we started a 2m high Band-saw.
As I type this, my wife has been constantly stopping and starting the Bandsaw, normally about 470A surge each time on a single inverter, but here, Peak meters never reached 270A each. Dust extractor running, air con blasting me with cold air in my closed off part of the workshop.
For the past 50 minutes the Inverter has been running like this at 3.5 to 4.6kW:
Both Toroids are COLD, they have increased in temperature by 1 deg, still at room temperature, everything inside the inverter is basically cold! unbelievable.
This new assisted convection airflow system is seriously impressive and totally silent, the Inverter location is at an ambient temperature of 32°, and I have the Toriod fans set to start at a relatively low 39°, they will not start today.
The Inverter is whisper quite under all loads.
It appears as though the AC output voltage is hardly dropping under these loads, something I was hoping for with the two Toroids, but I have not had a chance confirm this with a DSO, that can wait until it's fully built.
IMHO This dual inverter is sooooooo effortlessly Impressive, a superbly refined Animal.
I've been working with wiseguys designs for way over a year now, and already new how powerful the design is, but this Inverter appears to be way more then just the sum of two of the inverter I was using just a day or two ago.
_ Edited 2024-08-31 16:36 by KeepISIt's all too hard. Mike.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78
Posted: 08:29am 31 Aug 2024
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This is great news. Looking forward to my build when all the bugs have been squashed. So far this has way exceeded my expectations. Amazing work to all the devs.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 06:38pm 31 Aug 2024
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The Inverter ran all night - there was no discernible difference in battery consumption over night - nor should there be given the size of the batteries.It's all too hard. Mike.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 04:32am 01 Sep 2024
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Just a quick update, I spent the day with the DSO, comparing the DC input current waveforms.
I can confirm that at 510A combined DC input, both Inverter stages show EXACTLY the same current sharing at 255A each, right from when the load first starts and throughout the entire 3 second startup waveform, they are exact mirror images, current load sharing is 100% from Idle to whatever you can throw at.
The total current draw is 40 to 60 amps less then starting this load with the single Inverter version.
I still haven't captured the AC voltage under this load, but I bet it's holding higher, I was so busy with the two Current sensors. BTW the peak current meters on the front panel both registered just under 260A each as well, I went through and really got those meters calibrated together.
Edit
When I said I got those meters calibrated together I meant I calibrated each to indicate exactly the same current for a given Hall Current sensor output voltage, which for my meters, is the sensor output voltage corresponding to the full scale reading of 600A DC. _ Edited 2024-09-02 08:06 by KeepISIt's all too hard. Mike.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 02:03am 02 Sep 2024
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There is not a lot of difference between the old single power stage inverter waveforms and the dual power stage inverter waveforms.
Dual: AC holds it's wave shape when a 13kW load dumped on it. Single: drops a bit more, has a big disruption at load start, can skew slightly.
Dual: AC recovers to set output in a few cycles. Single: Takes up to twice as long to get close to full AC.
Dual: AC current waveforms are very good (half total current in each stage). Single: Almost matches, pretty impressive as it's hitting a full 540A DC input.
Thoughts: This just highlights how powerful a single wiseguy inverter is.
It means that a dual stage inverter could easily handle over 1000A peak DC input
I had to rewire the cabling to the Hall sensors - I had a lot of switching noise on one sensor.
I had gone to great lengths to keep 53V and AC sensor signals out of the cabling, even running a separate 5A 3-pin plug in cable from 53vdc input bus, precharge resistors and Kilovac coil enable line directly to the power switch.
Anyway, I made the change last night and tested this morning - YES fixed.
I have two BNC connectors for two 500A Hall effect current clamps for easy monitoring of DC input currents for each power stage with a Digital Storage Scope, those sensors are accurate to over 750A each.
The BNC connectors are hidden behind the front panel, I thought this was this best solution as the font panel simply lifts forward to gain access, and the front panel can sit back against them when testing or capturing startup data.
The messy cables and Veroboard on the bottom right of the cabinet are for the last of the sensor indicators and AC current trips.
Nano control board, a tiny fan to keep air circulating through the control cabinet.
20 seconds after the pictures above were taken, here is the upper cabinet on the bench ready for adding the last AC current sensors indicators. _ Edited 2024-09-02 12:07 by KeepISIt's all too hard. Mike.
analog8484 Senior Member Joined: 11/11/2021 Location: United StatesPosts: 108
Posted: 06:22pm 02 Sep 2024
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And the idle power is < 50W!?
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 09:54pm 02 Sep 2024
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I finished the two AC latching current trip indicators and the Over Current drive signals to the Nano controller master current trip indicator and reset switch.
All the OC trip Boards are shown in the following photo, the above dual AC board (large Veroboard) combines with a board for two Peak DC input OC indicators and Master OC drive, and two boards for fast attach slow decay drive signals to the control-panel meters, each displays peak DC current into the two power boards.
The only thing to do now is to build and test the optional 1-stage/2-Stage control board on the Inverter.
I've decided that with my usage and random high transient startup loads, I won't be including this board in my build, leaving the Inverter hard wired as a constant high power Dual-Power-board and Dual-Toroid Inverter.
Just to clarify again the reason for using a 2-stage board:
The 2-Stage board allows you to connect or disconnect the 2nd stage toroid and drive based on system power usage (adjustable on the 2-Stage board).
To do that, we must be able to control the 2nd stage power on/off with the inverter running.
When the second toriod is switched in parallel, there will likely be a very high inrush current into the UN-powered Second-stage Toriod, this must be reduced.
The 2-Stage board employs a timed soft inrush current circuit for parallel connection of the inactive 2nd stage toriod secondary across the running 1st stage Toroids active secondary AC output.
FYI. If you were to stop the inverter, connect the 2nd secondary in parallel with a switch, then power up the Inverter, the Nano controller would simply soft start both power stages together normally, and there would be no need a 1/2-Stage board.
This auto dual-power mode (it does have manual override as well) will be important in some systems to help reduce long term low power running conditions and allow half the Idle power in the inverter under these conditions. _It's all too hard. Mike.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 10:13pm 02 Sep 2024
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The inverter starting the BandSaw.
Blue: AC on the Mains some distance from the inverter
Magenta: Power stage 2 current
Yellow: Power stage 1 current
Start up current 235A on each power stage, total peak input 100Hz waveforms of 470A.
The lower waveform currents are identical, just a bit more noise on the lower.
Zoomed in on the initial startup. The slight humps on the left of the screen are the normal Inverter load running currents of around 600 watts each (1.2kW) prior to powering the BandSaw.
BTW This 2 meter high BandSaw is not a big load when compared to other workshop equipment.
_ Edited 2024-09-03 09:31 by KeepISIt's all too hard. Mike.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 04:34am 03 Sep 2024
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One of the final reasons that forced me into trying a Dual inverter was a large Bosh Compound Slide Saw we had acquired.
It tripped the single inverter every time I tried it.
So I jumped in and started this build, I finally realize the reason it tripped the single Big Inverter every time.
This stupid thing was right at the safe limit I had set for my single Inverter, it had a peak DC input of almost 600 Amperes
Here is that Bosh Drop saw on my new Dual Inverter:
I'm only showing the output from one AC current Sensor, the other power board and toroid Sensor is exactly the same. Both at 297A.
The total DC input to the Dual Inverter is 595 Amperes. It just laughs at it.
Blue trace: AC output.
Zoomed to start up of the Drop Saw, scale is different from an earlier start up test.
_ Edited 2024-09-03 14:36 by KeepISIt's all too hard. Mike.
nickskethisniks Guru Joined: 17/10/2017 Location: BelgiumPosts: 458
Posted: 07:02am 03 Sep 2024
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Just amazing! My build will be something to work on this winter.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 08:33am 03 Sep 2024
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Thanks, I'm feeling a bit frazzled thought after being in zombie mode for the past 5 or 6 weeks of constant building, but was it worth it, oh hell yes.
For a long time now I've been so impressed with wiseguys single power stage inverter, I've built and tested various controllers also designed by wiseguy, and recently upgraded to wiseguys Nano controller board, but this Dual power stage and dual Toroid Nano controller version is just .... WOW!
It's great to see a few of us on the forum planning to build this beast, I hope it all goes to plan for you _It's all too hard. Mike.
Cpoc Regular Member Joined: 28/05/2024 Location: PortugalPosts: 78
Posted: 09:37am 03 Sep 2024
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Is it possible to also have the pcb for the over current protections as well.
I really like having all of these protection systems in place.
I see that in your build you have diy pcbs in your build however a finished pcb for us amateurs would be better.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 11:32pm 03 Sep 2024
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For Dual AC over-current protection, all you need do is duplicate the input adjustment of the Nano controller:
On a small board, put a socket like J4, put a 200 ohm burden resistor across the socket, a 5k pot and a 1k resistor across the 200ohm and a diode (like D6) then connects to the "EXT Trip" input on the Nano.
Make two circuits like that for the two power board AC trip.
The current sensor on J4 now goes to the Combined AC output lead, D6 is removed and that sensor will now only display the total AC output current from the two power stages of the Inverter on the LCD.
For separate DC input Over-current tripping for each power board, using the same or similar sensors as mine, the same circuit as above but without the 200 ohm burden resistor can be used.
All four (AC an DC) would be connected to the "EXT Trip" input on the Nano.
Mine are slightly more complicated as I also duplicated the Latch Q1 and Q2, part of the circuit, I use this to drive four LED's that Indicate which AC or DC power board circuit caused the over-current trip.
I can draw the complete circuit if required.
If you want the peak DC current meter displays, then the two DC trip circuits above are not needed, just use the two Peak circuits and connect the Over-Current connections to the "EXT Trip" input on the Nano along with the two AC OC outputs.
On the subject of the Peak DC meter circuit, I'm hoping wiseguy does not look closely at one of the DC peak input current boards
I took a hacksaw to one of his 2Stage PCBs, and neatly cut out that part of the board
It's shown in my post of "07:54am 03 Sep 2024" about 5 posts back, it's the neat little green PCB. I have to do another one to match _ Edited 2024-09-04 09:34 by KeepISIt's all too hard. Mike.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 02:18am 04 Sep 2024
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It's all too hard. Mike.
Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1021
Posted: 08:42am 06 Sep 2024
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Some of us have built more and taken longer, but they are all good.
Your Inverter should run all you need I reckon, I like the way it all turned out I have been thinking about airflow around everything and the ease of taking it apart for service if needed, probably run for years, occasional dust clean etc. Cheers Aaron Off The Grid
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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it's still a day or two away 
I really need to get the inverter in its current state, which is in dual high power mode, fully off grid and unattended running, for that, I need the safety monitors finished first. 
fixed.
I have been thinking about airflow around everything and the ease of taking it apart for service if needed, probably run for years, occasional dust clean etc. 