Author Topic: testing the egs002 inverter board  (Read 147607 times)

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Offline oztules

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Re: testing the egs002 inverter board
« Reply #225 on: May 08, 2016, 05:46:33 pm »
I don't think it matters much at all, without an electrolyte , there is very little chance of having free ion carriers... as there is no water or moisture available, I just don't see it.

Once you add water, it is a problem, and salt water is a killer.... but dry... I don't think so



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Flinders Island...... Australia

Offline rossw

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Re: testing the egs002 inverter board
« Reply #226 on: May 08, 2016, 05:47:16 pm »
I'm not sure which option would be better. Does anyone have any thoughts?

HASL is inexpensive, and ok for a short period of time, but it does oxidise up reasonably quickly. Soon takes on that "dull" look.
ENIG isn't much more expensive and seems to last a very long time. It is only a thin coating, not terribly resiliant, but nicely protected. Certainly remains nice to solder to for a long time. Has almost no "give" like HASL does though, so not sure how its heat transfer would be by comparison.

Offline Antman

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Re: testing the egs002 inverter board
« Reply #227 on: May 08, 2016, 08:17:59 pm »
Thanks for the input Ross.

I thought to use brass but it's a pretty terrible conductor. Aluminium is good because it's cheap, readily available and easy to work with. If I made a production version I'd just get copper bars cut to shape with all the holes tapped in. I'll more than likely conformal coat the board too.

Offline Antman

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Re: testing the egs002 inverter board
« Reply #228 on: May 09, 2016, 06:23:02 pm »
I've done some more testing and programming on the Arduino portion of the board.

Things i've got going now are...

Thermal shutdown
Thermal based ramping fan control
Fan control based on input current
Input current display
Input voltage display
Input wattage display
3 second overload shutdown current limit
1 second overload shutdown current limit

Just need to add under and over voltage protection now and an extra thermocouple input. Its really starting to come along now ;D

I've ordered a PJ toroidal from Ebay which i should get next week hopefully. Then I can test some high power levels and really give it a run for its money. Does anybody know where I can get a suitable E-core for the idle current reduction?

Here is a short vid showing the functions


Offline frackers

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Re: testing the egs002 inverter board
« Reply #229 on: May 09, 2016, 08:23:31 pm »
Good work there. I have all the bits for my next build and now the walnut harvest has finished I'll have to get started!!

A few questions
  • are you using a shunt or a Hall effect device to measure DC current
  • are you measuring the input volts directly with the AVR or using an external A/D
  • is that one of those cheap I2C interface LCDs you are using

The reason I ask is that I've used the 1-wire DS2438 and DS18B20 for the measurement tasks in all my charge control devices so far and once you have been bitten by the 1-wire bug its so simple to add sensors!!
Robin Down Under (or are you Up Over!)

Offline Antman

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Re: testing the egs002 inverter board
« Reply #230 on: May 09, 2016, 08:55:43 pm »
Hey Frackers

I'm using a 1mv per amp shunt at the moment. This goes to a INA271 high side current amplifier on my power board. There is a screw terminal for connecting the kelvin sense wires from the shunt.

The input voltage is measured by the Arduino through a 10K 1K voltage divider on the power board. It's smoothed by a capacitor to cancel out all the high speed switching fluctuations.

LCD is just hooked up with a ribbon cable. I have no idea how to program I2C LCD's and there is heaps of free pins on the micro anyway.

Talking to sensors through I2C is pretty awesome and I wish I knew more about programming. Im more of a hardware guy. Do you have much programming experience?

Offline frackers

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Re: testing the egs002 inverter board
« Reply #231 on: May 09, 2016, 09:10:31 pm »
Talking to sensors through I2C is pretty awesome and I wish I knew more about programming. Im more of a hardware guy. Do you have much programming experience?

Hmmm - I wrote my first software about 48 years ago. It was on punched card and the done at the local college and was very very simple. I've been earning a living at it for the last 40 years though :)

Take a look at https://github.com/g8ecj/turbine. It may look complex but it has a lot of configuration options, SDcard logging etc. The basics in 'measure' and 'control' should be straight forward to read, the user interface in 'ui' is perhaps tricky to read but it is designed to be a very flexible template for all my "lunchbox electronics" projects. It uses lots of library functions from the BeRTOS system, that I use in preference to the Arduino libraries.
Robin Down Under (or are you Up Over!)

Offline Antman

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Re: testing the egs002 inverter board
« Reply #232 on: May 09, 2016, 10:43:03 pm »
Nice one Frackers. I'll have a good look at it when I get home to my PC.

So does that mean you're the guy that can help with the software on my next project which is a maximum power point tracker? I've already got the hardware designed and works well on a simple Arduino program. Only problem is the bad voltage regulation since I'm limited by the 8bit pwm.

Offline frackers

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Re: testing the egs002 inverter board
« Reply #233 on: May 10, 2016, 07:29:37 am »
Only problem is the bad voltage regulation since I'm limited by the 8bit pwm.
If you're using an AVR mega328p - Arduino Nano type, then use timer 1 as its 16 bit and even in Fast PWM mode 7 it uses 10 bits and mode 14 I recall is 15 bits.

I must admit that a lot of my project are now moving over to the stm32 series with the 72MHz clocked ARM core. The f103 boards can be had for US$2 or less and have up to 6 compare units on some timers with programmable dead time and complementary outputs to do full bridge operation. Pretty easy to use as the BeRTOS and Arduino libraries now support them or you can use the ST Micro supplied HAL and startup code generated from the stm32cubemx 'wizard'. What I'm enjoying is the debug tool only costs another US$3 and allows breakpoints, tracing etc from a full GUI such as Eclipse (with the sw4stm32 plugin).
Robin Down Under (or are you Up Over!)

Offline Antman

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Re: testing the egs002 inverter board
« Reply #234 on: May 11, 2016, 04:39:39 am »
Hey Frackers

The problem is I need a 60 Khz PWM and the Arduino doesnt have the power to do it without dropping the resolution. Those STM32 boards are awesome and that chip is so powerful compared to the Arduino. Ill order a few tonight:)

Offline billy

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Re: testing the egs002 inverter board
« Reply #235 on: May 11, 2016, 06:53:41 am »
Hey Oztules,
Just woundering what your currently using to heat your water for showers and dishes, sorry a little off topic.


Thx

billy

Offline billy

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Re: testing the egs002 inverter board
« Reply #236 on: May 11, 2016, 01:58:34 pm »
Here's the oz controll pcb I did on my 5x10 CNC.


Billy



Offline oztules

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Re: testing the egs002 inverter board
« Reply #237 on: May 11, 2016, 04:38:17 pm »
Amazing router work there... never seen a routed board before. Thanks for that

I use a normal 130ltr hot water unit for water heating. It is time clocked to come on at 10am, and clock drops out at 4pm.... usually runs for 2 hours in the am, and usually 30 mins top up in the afternoon before the timer shuts down....basically the same as the original night rate hot water heaters did... but opposite times of the day.

It is heavily insulated beyond the original urethane stuff it has originally.... They loose a massive amount of heat in their original guise.

On another place that has a proper commercial inverter ( victron thing ) he does not have the power that I have in my inverters, so we put a capacitor in series with the line voltage, that cuts his element power from 2500w down to only 1000w or so ( about 100 to 150uf or so from memory). This stops his victron from having a fit, and lets his batteries see a lower amp drain........ so the Peukert effect is better for him too..... just another over priced toy those victron things.... for all the money he spent on the victron, he cant start a 3hp motor .... just silly.

As expected the VA is high on the AC side, and would indicate that you are wasting power.... but the battery drain is much lower, and  reflects the 1000w only, as most of the VA is out of phase ( voltage and current ), so the 1500w lost as a vector thing, not as a real loss.... ( wattless current).... better than using triac switching to achieve the same thing.... that would bother the inverter greatly.



.................oztules

Flinders Island...... Australia

Offline billy

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Re: testing the egs002 inverter board
« Reply #238 on: May 12, 2016, 06:48:59 am »
thanks Oztules,

this board is inverted so i have to make it the right way, oh well it was just a test anyways.

As per your water heater,  is that not going to kill your batteries? If I run mine it really pulls the amps , and I only have it set at 92, and using one of your inverter at 24 volts , maybe I should try that capacitor.

Billy

Offline Antman

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Re: testing the egs002 inverter board
« Reply #239 on: May 12, 2016, 07:21:44 am »
Some extra mosfets and a heatsink arrived today so I put them together for testing.

The heatsink is a little undersized I think but it should do the job with fan cooling. From my testing so far most of the heat is lost in the transformer anyway. At 45 amps the heatsink goes to around 15 degrees above ambient without fan cooling. The PCB warms up a bit since its only 1 oz copper.