Author Topic: testing the egs002 inverter board  (Read 32521 times)

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Offline oztules

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Re: testing the egs002 inverter board
« Reply #390 on: October 14, 2016, 12:38:47 PM »
Thanks Antman,.... nice and tidy and .... well everything mine woudln't be really.

.......oztules
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Offline Antman

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Re: testing the egs002 inverter board
« Reply #391 on: October 16, 2016, 03:18:13 AM »
No worries OZ. Happy to help.

So I've spent a few hours making changes to the schematic so I can start modifying the board. Things I've done are

#Changed LCD from parralel to I2C. Much less wiring
#Added extra I2C port for other I2C devices like a real time clock and an external ADC I want to try
#Broken out all spare ports onto standard headers so they can all be accessed like a normal arduino
#Added diodes to the ADC ports so they cant be blown with over voltage
#Added an on board buck converter for the control circuit that accepts voltage up to 90 volts
#Cleaned everything up properly

Things I need to do are

#Work out the best way to add the Isolation transformer so there is no issue with earthing. I want to do this off board to save real estate. OZ do you have a schematic of how you did this? I was struggling to work it all out.
#Test using an external ADC to do the current and voltage measurements. I plan on using an ADS1115 16 bit ADC instead of the INA271 current sensor. The INA271 is really off when the board is drawing under 3 amps. Id love to be able to see the Idle current accurately and display efficiency on the LCD. I have an ADS1115 module in the mail from china but it is taking ages.
#Peter wants to be able to show all of the output readings through the Arduino. We can use a meter like the link below and either count pulses or communicate directly through RS485. We would be able to voltage, current, power factor, frequency and many more.

Does anyone else have any suggestions of things to add before I start routing it? The sky really is the limit with Arduino these days



Offline oztules

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Re: testing the egs002 inverter board
« Reply #393 on: October 16, 2016, 04:44:52 AM »
See pcb below
The  14v tranny goes into the diodes, into the divider of 7k5, and  1k8 and 500r trimmer... result is filtered with 4u7, and through a 100r to pin vfb with a little 104 cap as well.

ila_rendered

You already have too much  info for my ... lack of style... so I will stay out of that.... if I have volts and watts, I'm happy really...


.........oztules
Flinders Island...... Australia

Offline Antman

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Re: testing the egs002 inverter board
« Reply #394 on: October 16, 2016, 06:46:51 PM »
Thanks OZ. I'll look into the tranny and modify my circuit to suit. I need to find a tiny transformer so I can fit everything on the board.

Offline oztules

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Re: testing the egs002 inverter board
« Reply #395 on: October 17, 2016, 12:37:14 AM »
I only used a tranny as I had them handy, and wondered how I was ever going to use them after 20 years or so.......

But an opto isolator will do just as well, and there is your space saving.



.........oztules
Flinders Island...... Australia

Offline Antman

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Re: testing the egs002 inverter board
« Reply #396 on: October 17, 2016, 12:44:24 AM »
Hmmmm never used an opto isolator before. I'm guessing it would just go between the trim pot and VFB pin. Ill have to do some research into this. I still haven't fully worked out why the isolation is necessary but was going to sit down and work it all out properly.

Offline Antman

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Re: testing the egs002 inverter board
« Reply #397 on: October 20, 2016, 04:57:42 AM »
I've decided to go with a PCB mount transformer for the isolation since its rugged and I know it works from OZ's experience.

I havent done much with the board because I was waiting to get a ADS1115 ADC module in the mail. I want to use this for current measuring because it is so much more accurate than the Arduino nano. It can also measure current in both directions which will really come in handy. There will be spare ports for other shunts such as charge current.

All the experimenting has been on a NodeMcu which is a WIFI enabled device. I've been sending data to the cloud so I can read it remotely which is very cool.

My inverter creates terrible noise that drifts by around an amp on the arduino. I tried some rough software filtering at first but it didn't do much. After some reading I learned about some simple hardware filters. I just put a 10K resistor in series with the ADC port and added a 10 uf cap between ADC and GND. Noise is down to around 100ma. I'm sure if software filtering is added this can be brought down substantially. I'll probably go with this for current measurement in the final design. internet connectivity might have to wait till the next revision ;)

Offline peter

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Re: testing the egs002 inverter board
« Reply #398 on: October 21, 2016, 07:06:35 AM »
Antman
have a look at http://www.analog.com/designtools/en/filterwizard/
Maybe play with a few high order filters. I liked the 3rd order filter but only because I wouldn't be building it.
The Analog design tool will help you choose more realistic but very good performers compared with the RC LP filter.

peter

Offline noneyabussiness

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Re: testing the egs002 inverter board
« Reply #399 on: October 24, 2016, 05:36:52 AM »
Hey antman, try polling the adc numerous times (10- 20) and then average the results... a "for loop" is good for this.....

Eg.
for (int i; i = 0; i < 20; i++){
static int voltsinRaw = analogRead(adc1) ;
};

Then just divide the result by the test amount..

voltsinraw = voltsinraw / 20;

Another example is the official "smoothing"

https://www.arduino.cc/en/Tutorial/Smoothing

I think that right... its late...

Offline Antman

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Re: testing the egs002 inverter board
« Reply #400 on: October 24, 2016, 04:03:05 PM »
Peter

Thanks for the info on the filters. I've been testing the ADS1115 for the last couple of days on my Nodemcu by logging it to thingspeak. Voltage and current readings are more than stable enough without software filtering.

Noneyabussiness

I tried adding together 10 different ADC readings in a way more complicated way than you describe due to my lack of programming skills. It works very well with stable readings. I think i'll go ahead with the ADS1115 as the current and voltage monitoring device. Now I can move forward with the board design.

Offline Antman

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Re: testing the egs002 inverter board
« Reply #401 on: October 24, 2016, 05:26:43 PM »
For those of you interested I started a new thread on the data logger I've been testing the ADS1115 with. Once finished they will be very handy to have for monitoring of solar systems. I've always wanted to know whats happening at home while I'm stuck at work. Now I can just log onto my phone and see everything in real time.

With the thingspeak interface you can even set it to send you a Tweet when your voltage drops to or reaches a certain level.

http://www.anotherpower.com/board/index.php/topic,1204.0.html

Offline noneyabussiness

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Re: testing the egs002 inverter board
« Reply #402 on: October 31, 2016, 02:25:18 AM »
Would any of you fine Gents/Ladies like me to do the code to control the eg8010 board via serial, via arduino... seems pretty straight forward. .. (lol famous last words...)??

Offline Madness

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Re: testing the egs002 inverter board
« Reply #403 on: November 01, 2016, 03:50:14 AM »
Hi noneyabussiness.

I would appreciate the serial connection to the EG8010, if nothing else it will be handy to be able to turn off the low voltage shut down for testing.

Offline noneyabussiness

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Re: testing the egs002 inverter board
« Reply #404 on: November 03, 2016, 06:13:07 AM »
Not sure if there is a "low voltage shutdown" off command, unless im reading the datasheet wrong.... you maybe could control the "VF " via serial and override the hardware one... it rises liner at 19.6mv per bit from lsb on the feedback command..u would ether have to do the binery math or hex to fool it to thinking its above the threshold. ... :-\ ill see what i can rig up...