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mab1 Senior Member Joined: 10/02/2015 Location: United KingdomPosts: 209
Posted: 09:11am 30 Mar 2023
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Ah, yes! That's the other '150A mppt thread roll your own' by poida; they do seem to be running sort of in parallel ATM.
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418
Posted: 10:19am 30 Mar 2023
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Bryan, I think it will work when you load the driver. Most cheap Nanos use the CH340 chip and the Arduino software does not include a driver for it.wronger than a phone book full of wrong phone numbers
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 12:07am 31 Mar 2023
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I'm use ARM controllers so forgive my ignorant question.
Why is the brain board called a Picoverter when it's using an Arduino Nano, and there is also mention of a Nanoverter.It's all too hard. Mike.
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418
Posted: 12:22am 31 Mar 2023
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I originally wanted to build an inverter controller that did the bare minimum. We worked in the project that came to be the nanoverter.
For my own use I designed and built the picoverter, that used the same code that is loaded into Nano no.1 of the nanoverter.
I found it a large task to build and program the nanoverter. The picoverter takes this well proven code and works just as well and the nanoverter, costs less in parts and is less than 1/2 the size and is fast to build, using easy to find components. So I gave it that name.wronger than a phone book full of wrong phone numbers
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 12:54am 31 Mar 2023
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The Raspberry PI Pico which I think can be programmed in the same Arudino IDE was throwing me. I'll have to find a couple of Arduino NANO online as the local J store has a clone (328 chip) but priced at $30.00.
BTW: Thank you for all the work, time, effort and great info you have started to post to bring this all together. Not enough hours in the day for me to keep up but this sure helps.It's all too hard. Mike.
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 07:53am 31 Mar 2023
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Well finally got upto my shed and the first thing was downloading that driver and found nope no change as the error was access denied so when for a look and changed a few settings and tried again where uploading was close to instant aswell as the upload so now got a nano blinking at me
Cheers Bryan
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 09:21am 31 Mar 2023
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Peter, just programmed the Nano as per your instructions, all good.
I just wanted to point out that on my WIN 11, the driver install says it failed, if anyone gets this message, don't believe it, check with Device manager again as in my case it shows that it DID install and is correctly identified and running.It's all too hard. Mike.
Peter, thank you for the Nano programming instructions just posted the other day, it was very easy to follow. I have just received my ebay order of nanos and programmed one each for the MPPT and Inverter Controllers and after spending a bit of time looking at previous posts I have also located the Variac code and programmed a nano for some experimentation with the power board when completed. I have started ordering the parts and hope to be ready soon but I need some clarification regarding the picoverter design.
Unlike the nanoverter board, I cannot see any current monitoring and control circuitry so I am wondering if this is now considered nonessential for this version of the Inverter or would you recommend adding at least some external circuitry such as the well established current transformer and SCR crowbar method employed in other inverter versions?
Klaus, please feel free to chime in, your experience with this method as used in your picoverter board design would be appreciated, thanks. BTW, please PM me if you still need help programming your nanos as we can easily do that remotely.
Peter, my other question relates to the total amount of capacitance required for the MPPT Controller. The BOM you supplied mentions lots of 1,000uF caps, which could mean up to 9,000uF on the Input and 4,000uF on the Output but I recall your comment in an earlier post regarding the MPPT code being optimised for 9x 450uF caps (4,050uF) on the Input so I am thinking of ordering 8x 560uF (4,480uF) for the Input and 4x 560uF (2,240uF) for the Output. Are these values in the recommended range? Thanks.Cheers Michael
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648
Posted: 08:05am 03 Apr 2023
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The SCR crowbar method works fine. I adjust it initially with the equipment that has the biggest start up current here (abrasive chop saw) and then it was good for everything else. You might need an extra transistor to hold the nano input OFF. PM me if you want the schematic how I did it.
Thanks for the programming offer, would you not require the physical nano to do it?
The capacitor values you quote for your MPPT sound OK to me, I have similar values but they are all recycled from broken inverters. Still have a box full of them .
Klaus, great to hear it's easy to implement the SCR crowbar method. I would like to pursue that so thank you for any assistance you can provide.
I know that many forum members have been very lucky to get hold of a few Aerosharp Inverters for many of the components we all need but I blew a big chance I had a few years ago to buy multiple brand new 2.5KW Inspire Inverters. Silly me, I bought only one and for a measly $80 "just in case" I ever need to upgrade my second 24V "8000CW" PJ Inverter transformer, which luckily has worked fault free over the last 5 years. The first one I bought held up fine with a 5KW load during the brief bench tests but once installed it promptly blew it's FETs after just 1 minute of operation without any load attached to it
Fortunately, I have already extracted the Inspire transformer and unwound the Primary windings and rewound it for 48V operation with some pretty good quality 50mm2 tinned copper cable, which will hopefully be sufficient for my future needs. Of course, a dual stack transformer would have been preferable. At this stage, I have yet to go through the Inverter and recover all the goodies in there for the MPPT and Inverter builds but it should be fun.
As far as programming your nano is concerned, as long as you have it plugged into your PC via a USB cable, we can easily get it done over the Internet today. I will PM you the details in a few minutes.Cheers Michael
Klaus, I just realised I can't PM you so please PM instead and I will get back you asap with the connection details, thanks.Cheers Michael
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418
Posted: 10:21am 03 Apr 2023
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The picoverter design has no current monitoring. I have found that it is not needed. Past tests with a 4 x 4 HY4008 power board, driving a 1.5hp air compressor shows that peak power events are not damaging. I saw 12kW for a few 50 Hz cycles with no problem. I do have a large DC CB on the input and a sensibly sized AC CB on the output of my inverters.
If you want you can make an external SCR overcurrent circuit and have it over-rule the inverter on/off switch, that will work fine. How it will work is the SCR will latch ON, pulling the on/off switch to logic HIGH (5V) and then the soft stop process will commence.
As far as how much caps for the mppt, the board has space for a lot of caps. It allows us to use whatever we have. I found it worked fine with 450uF caps scavenged from Aerosharps. Testing showed I needed about 3 or 4 of these on the input as a minimum or else they get a bit warm. Testing also showed even 10,000uF on the output did not much up the program's behaviour. There is no need for 10,000uF. It can get silly if we think more is better. On the output side, fit 6 x 450 or something. I prefer not too much on the output, there will be a massive battery on it as well.
If we put too much caps on the output it could come to the point where the maximum power point code will not work properly. It waits a little while after each change in power point testing to measure the result. Too much capacitance will effect the accuracy or even the function of this search.wronger than a phone book full of wrong phone numbers
Oops, I just realised you can't PM me either, Klaus.
Poida, if you don't mind could you kindly forward Klaus my contact details when you get a chance so I can help him out with programming the nano remotely, thanks.
Sorry if I have highjacked this post with my dribble.Cheers Michael
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418
Posted: 11:03am 03 Apr 2023
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I can't select Murphy's friend for a PM. I can search and find it. But I can't select it. strange.
And I got the SCR output WRONG. It needs to PULL DOWN to ground the on/off switch input. PULL DOWN to stop it.wronger than a phone book full of wrong phone numbers
Poida, thank you for the info regarding the Inverter's insanely robust operation even without over-current control. It is very encouraging to know but in case of a "surprise" overload I would like to have the option of a faster acting and hopefully gentler way to shut it down compared with the usual delayed CB operation. Easy enough to implement anyway. Thanks for the update re the correct SCR connection.
I had the same concern with overheating of the input caps due to excessively high ripple current when too few are fitted so I will go with 8x 560uF, however I am a little confused by your suggestion of fitting 6x caps on the output though as I can only see room for 4x maximum. I presume 4x 560uF will do the job just fine, yes? Edited 2023-04-03 23:05 by CobblerCheers Michael
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418
Posted: 11:18pm 03 Apr 2023
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4 caps? 6 caps? I guessed wrong. something tells me I am going to make more posts correcting my errors than helping guide people towards a good working build.wronger than a phone book full of wrong phone numbers
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1679
Posted: 12:25am 04 Apr 2023
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No, all is good, I just cut and paste everything you post for each device, I may need a bigger SSD though It's all too hard. Mike.
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 648
Posted: 08:41am 04 Apr 2023
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OK, to stop you worrying about capacitors getting too warm, here are the values I use and they do work:
Input, 4 x 1500uF + 4 x 560uF
Output, 4 x 2200uF/100V
These are secondhand ones that I had on hand. You can add up the values to get the total.
To keep the MPPT cool put it on a decent heat sink and do not scrounge with the choke wire. With my MPPT the choke gets warmest when the output hovers around 40 Amps so I fitted the little fan to suck the heat away from the choke. The heat sink is mostly natural convection cooling. The fan runs only on days above 35 degrees ambient.
Good to know there is a lot of flexibility in the design. That's double the amount of capacitance I was considering on the input and 4 times on the output. Given the amount of caps you have used on the input, I would expect they will stay pretty cool even for extended periods at max. charge current.
The fun part will be making suitable chokes for both the MPPT and the Inverter, which will require a good inductance tester. I am thinking of using the design you posted here:
I will need to spend a bit of time going through the thread to better understand all the inductor parameter calculations and tester requirements. Fortunately, I already have a suitable DSO for the project and that is a major obstacle out of the way.Cheers Michael
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418
connect a lot of caps in parallel. I have about 6 5,000uF or something. The more the better. One nano or Uno, with a simple program to pulse a pin with variable duty width something like 10 to 500 uS. A large FET, again the HY4008 does well. A 10K pulling Gate to Ground. short wires, including a current sensor inline from +ve and the FET's Drain going to inductor. A large fast diode across the inductor terminals to quench flyback. A variable power supply, I use 12V with 1 Amp current limit. The nano pin goes straight to the Gate. The DSO needs two channels. ch1 can be the Gate voltage, use this as trigger too. ch2 is current sensor output. use waveform averaging to get a clean trace
the "i*1" is a place holder so I can change the 1 to be 4, 10 or something when testing large inductances. This uses pin D9 It pulses at 10 Hz and will with the above code give pulses 1 to 1000 uS wide.
The LEM sensors go up to about 50 Amps. You can connect thick wire to shunt them and so get far greater range of measurement.wronger than a phone book full of wrong phone numbers
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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and found nope no change as the error was access denied so when for a look and changed a few settings and tried again where uploading was close to instant aswell as the upload so now got a nano blinking at me 
. 
