Author Topic: testing the egs002 inverter board  (Read 32522 times)

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Offline oztules

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testing the egs002 inverter board
« on: January 05, 2016, 12:55:16 AM »
Had a bit of free time to play with the EGS002 board recently... and this is as far as I have had time at this stage
Did a quick circuit board to match the PJ h bridge board and one I cobbled together to test initially.
The board looks like this
ila_rendered

Is  as simple as I can do for a pre run.

Here it is running a 40 watt load

ila_rendered

It was the only filament globe I had

ila_rendered

There is only 1 fet per bridge as in this:

ila_rendered

I also built a little h bridge to test initially which worked fine too:

ila_rendered

It will be noted I made it compatible with the PJ connections so  if it worked I could just plug in the pj... it did.

the output looks like this @ 240v:

ila_rendered

As you can see, my scope could not handle the output, so I turned it down a bit to 180v or thereabouts to se it complete

ila_rendered

Later added 200 watts of resistor, and the thing behaved exactly the same.

The fet stayed cold during this, so it looks like time to use 6 fets/bank, and use the main battery bank, and a bigger transformer to see how well it drives more fets.

If the transitions stay within a decent band, it may require no more drive than the board supplies.. I can hope.....

ila_rendered


So the test was fine, and when I get time I will expand on it.

My preference is for isolated supplies for the high and low switching... but will see how this goes first.
I ran it as low as 68vac up to 260vac, seems completely stable all the way up and down.
The 56vdc power supply is only 300w, so I went as far as I dared for the first runs.
These boards can be bought for as little as $7-$8 each from aliexpress if you want to play cheaply.

Did not get a chance to test current limits obviously, but the temp limiter works ( put it against 200w resistor).It self resets when I took the temp probe away from the resistor just fine.
Soft start works well. Starts under the 240w load no problem, smooth and clean wave. Frequency stable, and amplitude climbs to set point nicely.

Very interesting unit to start out with. I suspect you could get 600 or more watts with a single fet h bridge with 48v unit.

Edit..... I know it is hard to see the globe.... it blends in with the background well.





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

Flinders Island...... Australia

Offline ClockmanFrance

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Re: testing the egs002 inverter board
« Reply #1 on: January 05, 2016, 02:39:48 AM »
That's really Nice!

Offline RFburns

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Re: testing the egs002 inverter board
« Reply #2 on: January 06, 2016, 01:22:00 AM »
Great stuff Oz! :) .This looks like it will make a nice roll your own solution for the driver boards allowing great flexibility depending on its load ability ; did you get any of the LCD's that couple to the EGS002?, not that there is a lot of useful info from it.
Get With It ,Get Over It , Get On With It ...Or Leave

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Cheap and fast wont be reliable.
Reliable and fast wont be cheap.

Offline oztules

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Re: testing the egs002 inverter board
« Reply #3 on: January 06, 2016, 03:52:48 AM »
No LCD from them, although I have plenty of lcd screens i could use I suppose.

It does look to be very useful, and if it turns out that it is stable with all kinds of loads, it may well be a good replacement for the power jack control card.

Easy to draw up the PJ fet card with a few more bits on it to improve it 's layout, and get a few printed in double thickness.
I do like the idea of separate cards.

This would make a very very cheap high power unit..... no idea how good it will be until we give it a proper trial, but going my yesterdays tests, it does look good.

How it handles the current transients I don't know. The PJ is good in that it gives you 3 x power for 12 seconds, then gives up, not sure how much this will do before it gives up etc etc. Keen to find out, but too many folks with problems to solve the last few days.... need to work on the big windmills here tomorrow to track down some problems there with their direction electronics....always something.

Island life is perfect, but sometimes hectic as well....


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

Offline RFburns

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Re: testing the egs002 inverter board
« Reply #4 on: January 13, 2016, 04:01:40 PM »
Recovery time under load should be good 1-3 cycles max, this board will provide surge performance to the point that undervoltage on pin 9 is detected (2.75v) lifted from the data sheet (see below);  I would guess that provided your FET's are up to it and supply line voltage does not drop it should be good, will look forward to your further tests. Stu

Quote
To prevent output voltage is too low or too high when supply to the load, EG8010 has integrated
overvoltage and undervoltage protection. Overvoltage protection is set at 3.15V with 300mS delay.
Undervoltage protection is set at 2.75V with 3S delay. When either situation happens, depending on
pin (9)PWMTYP’s setting, EG8010 will set the level of SPWMOUT1 to SPWMOUT4 at “0” or “1”,
and shut down all power MOSFET to decrease the voltage to zero. Eight seconds after overvoltage
or undervoltage protection activates, EG8010 will turn on power MOSFET for 100ms to
re-determine output voltage. If overvoltage or undervoltage issue still exists, EG8010 will repeat the
process above every eight seconds. If EG8010 runs regularly for more than one minute, it will zero
the counter of overvoltage and undervoltage. However, if EG8010 does not function regularly after
five 8-second cycle, it will complete turn off the output of SPWM unit. It needs a hard reset to start
again.
Get With It ,Get Over It , Get On With It ...Or Leave

Cheap and reliable wont be fast.
Cheap and fast wont be reliable.
Reliable and fast wont be cheap.

Offline oztules

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Re: testing the egs002 inverter board
« Reply #5 on: January 13, 2016, 11:16:36 PM »
I have been far too darn busy for the last few weeks... and the salt water RO machine has taken me longer to do the electronics and computer programming for.. it is always too long between playing with the programming, and I forget all the syntax, and spend too much time wondering why it wont work as I wanted.. or even compile etc... wish I was better at this stuff.
Now have a arduino nano with 30 wires coming away from it... then wondering where they all go .....etc. etc.

I will get to it...if you don't get there first, then you can tell me....

Where does the time go....


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

Offline oztules

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Re: testing the egs002 inverter board
« Reply #6 on: February 12, 2016, 04:15:58 PM »
Finally got some time to play (* albeit small).
Wound 25 turns onto a 3kw aerosharp torroid to get a 48v transformer to drive a bit harder... looks like this:
ila_rendered


Then a 2100w stove element , and we get this:
ila_rendered


Voltage was this
ila_rendered


Current this:
ila_rendered

test unit looks like this:
ila_rendered

Ok, things we found out.
The unit ran quite cool considering 40 amps over only 2 fets per bridge for 10 mins. :)
The voltage was controllable, very smooth. :)
The current control worked.... but there was a problem.     :o  When I used a welding transformer ( EI type) the current feedback seemed to  work fine, but the torroid blew the thing to bits when I  then  turned the pot to make the current sense more acute and make the  current regulation start....instant fusion reaction actually, and fire bombed the fets.... the smoke was well and truly released. :(

So it looks like another system of current shut off is necessary for big torroids... thats the only reason I can see for the blow up..... other ideas welcome.
It seems that the shut down current control must change the frequency or some other rapid wave change problem that the transformer reacts badly too... don't know, but will try to find a reason.... more fets must die in the name of progress I think..... :-[

Torroids are very good, but take no prisoners... they are electrically stiff.

Apart from that, the little test was impressive to say the least. A 3 second soft start was good, the current regulation was good, the voltage rock steady throughout, mostly happy... but would be ecstatic if the current control had not have blown 8 more fets to hell.... with more to come I can bet.

Anyone else been playing with these things yet?


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



Flinders Island...... Australia

Offline RFburns

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Re: testing the egs002 inverter board
« Reply #7 on: February 12, 2016, 06:47:47 PM »
Me think's its pin nine set to turning on the bridge resulting in FET smoke (or maybe for a torroid the dead time needs to be extended?). I have all the bits but havn't done anything yet (to hot to go out to the shed on days off) From the data sheet

"Pin IFB measures the output load current for overcurrent protection detection. As the current sampling and feedback circuit shown in figure 8.1a, pin IFB’s reference peak voltage is 0.5V and overcurrent detection time is 600mS. If current is higher than inverter’s lad current by some reason, EG8010 will set the electrical level of SPWMOUT1 to SPWMOUT4 at “0” or “1” and shut down all
power MOSFET to decrease the voltage to zero depending on pin (9)PWMTYP’s setting. This function mainly protects power MOSFET and the load. Sixteen seconds after overcurrent protection
activates, EG8010 will turn on power MOSFET for 100ms to re-determine load current. If overcurrent issue still exists, EG8010 will repeat the process above every sixteen seconds. If EG8010
runs regularly for more than one minute, it will zero the counter of overcurrent. However, if EG8010 does not function regularly after five 16-second cycle, it will complete turn off the output of SPWM unit. It needs a hard reset to start again. If in some scenarios the starting current is relatively high and it takes longer timeto start, which overcurrent protection is not suitable, Pin IFB can beconnected to the ground."

9 PWMTYP I
PWM type select
“0”: positive polarity PWM type,MOSFET on when SPWMOUT is high
“1” positive polarity PWM type,MOSFET on when SPWMOUT is low
Best configuring pin according to driver device and referring to the typical
application schematic below, otherwise will result in both sides of MOS
tubes conducting at the same time.

and dead time could be an issue with a stiff inductor

Pin DT1, DT0 controls the dead time. Dead time control is one of the important characteristics
of power MOSFET. Lack of enough dead time will result in the damage of MOSFET due to
conduction. If the dead time is too long, it will lead to distortion of waveform and overheating of
MOSFET. Figure 8.5a is EG8010’s four dead time control settings.“00”= 300nS. “01”= 500nS.
“10”= 1uS. “11”= 1.5uS.

Just my 2c worth. Stu
Get With It ,Get Over It , Get On With It ...Or Leave

Cheap and reliable wont be fast.
Cheap and fast wont be reliable.
Reliable and fast wont be cheap.

Offline oztules

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Re: testing the egs002 inverter board
« Reply #8 on: February 13, 2016, 02:27:38 PM »
Thanks Stu.
I have pondered those bits of the data sheet for some time.
 I will use the big EI tranny again, to check if this is really the problem.

It looks like it is unipolar operation on my boards.... which is another problem with the EG002 boards for me.

This means the high switch on one side is working in  high frequency, and one side is 50 hz...... I want to switch the high side on both bridges at 50hz, and this will make the driver much simpler.

As it is, the 50hz high side using the current pump is sloppy, and bleeds off too quickly. It cant maintain current for long enough unless you use a bigger cap on the charge pump..

Add this to the current regulation with torroids, and I think it will be better to just buy the chips for a few dollars and make my own board.

So I want 50hz high side switching, a small circuit that will unambiguously shut the thing off, or maybe a nano arduino to monitor, and make decisions on time and action.
I want isolated high side power supply..... so really there is nothing on the commercial offering I need to use ... apart from the crystal and chip..... don't want their drivers either.

I will persist with the tests on these boards, but feel i will probably move on at some stage and go it alone.


Hope the weather cools so you can do some tests of your own.


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

Flinders Island...... Australia

Offline oztules

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Re: testing the egs002 inverter board
« Reply #9 on: March 12, 2016, 12:31:15 AM »
The big EI tranny works fine........ with the current control ..... although only barely surviving in fact.... lots of noise on current shut off... and the scope gave the reasons why.

So it appears that the IFB pin on the board goes to not just the ifb pin on the chip... which would shut it down properly, but also to two differential amplifiers. These intercept the signal from the  CT, and then process it. One signal goes to the inhibit of the driver chips, and one to the inhibit of the main chip.

What this really means, is there is a short period where three things are competing for the right to shut the thing down on an over current event.... this leads to a train of small pulses from one of them, that causes the disasters with the torroid.... which one....... I don't care! ... the system has to go.....

I don't know how others have circumvented this behavior, but I decided to use the temp input as the over load input instead, and get rid of the other offending signals completely... ie effectively short the ifb signal pin out, and instead, use the CT output and  send it to the temp input.

The good thing about the temp input, is the moment it goes above 4.3v, it shuts down instantly... no train pulses to be seen.. so it causes no problems with either the torroid or the big EI transformer...... the other beauty of it, is that it is programmed to restart with a 3 second soft start...every time, not like the unit does form low voltage etc etc.... this suits the torroid fine..... and it also means you dont make changes to  the commercial board, they stay interchangeable and complete.

I am also using this input for the on/off, as it never fails to soft start.

Cooling will be done by my system anyway, so no loss of usability, and you can still use this input as the temperature shut down as well if you so choose to have a doomsday heat shut off.

Currently designing a from scratch board, with isolated driver voltages for the high side, and so that  also means pwm control of the DC side.... safer from spikes in the battery line, and also the egs8010 chip is only a few dollars anyway.... so the complete boards will be very cheap, with opto drivers for high and low.. this means a blow up will only take out the optos and fets.... never the board..... I like that sort of thing... especially for testing.

These things are unipolar in the type i bought, but the 50hz is on both a high side switch, and a low side switch.... not what I expected.

The high frequency high side switch gets warmer than the 50hz high side switch,( as expected ), but for this little 3kw unit, will be fine.. little heat even at 2-2.5kw, and thats with lousy fet drivers driving two fets per leg running 40-50 amps or so The commercial driver chips are not up to the 50hz, as they sag badly with the pump system on the high side drivers. They seem to be only able to handle 2 fets of the 4110 type, as the capacitance is quite high on the gates for hex fets.... not sure I'm game to use 3 or 6 fets per leg on these.

The other thing is that measuring newer PJ boards, they are bipolar outputs, so the opto's are driving the high side at 20khz just fine... I'm sure on the original one I played with, it was unipolar, and the high side was only 50 hz... maybe I was wrong.....

( unipolar runs 20khz for the spwm modulated legs and fundamental frequency for the other two ( 50 hz square waves ), the bipolar uses spwm modulation on all four )


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

Offline frackers

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Re: testing the egs002 inverter board
« Reply #10 on: March 12, 2016, 03:55:28 AM »
That's some great info - I've a couple on their way and I plan to get one of my logic analysers onto one early on to see what sort of signals are floating about!!

I've been playing with the STM32F0 and STM32F1 series micros a lot recently and am about to start a project with the better M4 core STM32F3 series that has DSP capabilites (fast 64 bit multiple and accumulate and saturated arithmetic for example) and clocks at 72MHz but with 3 PWM timers that can run from 144MHz there is a lot of scope for high resolution operations. The development board is NZ$20 and includes the programmer/debugger. So much nicer to have debugging via an IDE instead of a few dodgy printfs or waggling pins on an AVR :)

Now the power transformer construction is understood I'm more inclined to experiment as I rather doubt I could blow it up if I tried!! MOSFETs are cheap although driving 12nF of gate capacitance on each of 5-6 hexfets but the Toshiba optos seem a good bet provided I can get my head round the high side supply design.

I think there might be life in the old git yet ;)

Robin Down Under (or are you Up Over!)

Offline oztules

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Re: testing the egs002 inverter board
« Reply #11 on: March 12, 2016, 06:14:09 AM »
Nearly finished designing the board. There is no circuit as usual.......
You are welcome to reverse engineer it or modify it using protel pcb software.

The 3842 pwm stage is done with three isolated 12v outputs, the opto section is done, just waiting for the chinese to send me the tiny adapter boards that will allow me to use the 8010 like a  normal 32pin  chip and so  just plug the eg8010 adaptor into mine... and etch it.....

Bought these http://www.aliexpress.com/item/HOT-New-IC-EG8010-8010-EG-QFP32/32435098232.html
and this http://www.ebay.com.au/itm/301708635193?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

You can buy small ( like a small relay sized) isolated pwm things for modest outlays also... like this http://www.ebay.com.au/itm/DC-DC-Converter-Isolated-Power-Module-In-10-16V-Out-12V-4-Pins-for-Auto-Car-Boat-/121569486627?hash=item1c4e1b2723:g:7iYAAOSw4UtWR~DP
Not too sure how many fets they could drive... duty cycle would probably allow them to do it ok.... or use two etc...... simpler than winding a tiny hf transformer like I have.

I do like the robustness of the unit I have done on my previous bldc controller board..... we'll see how this goes.... I am pretty confident in it's ability to perform actually.

I may use a scr to trigger the o/current on the temp pin, and have a hard start from o/load only... not sure yet.


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

Offline frackers

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Re: testing the egs002 inverter board
« Reply #12 on: March 12, 2016, 01:56:59 PM »
Nearly finished designing the board. There is no circuit as usual.......
You are welcome to reverse engineer it or modify it using protel pcb software.

Thats a shame - I not only don't have access to Protel, I don't have access to Windows to run it!!

Quote
The 3842 pwm stage is done with three isolated 12v outputs, the opto section is done, just waiting for the chinese to send me the tiny adapter boards that will allow me to use the 8010 like a  normal 32pin  chip and so  just plug the eg8010 adaptor into mine... and etch it.....

Bought these http://www.aliexpress.com/item/HOT-New-IC-EG8010-8010-EG-QFP32/32435098232.html
and this http://www.ebay.com.au/itm/301708635193?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Good idea - my eyesight and hand-eye coordination are degrading at an equal rate and my homemade PCBs wouldn't be up to SMD reliably

Quote
You can buy small ( like a small relay sized) isolated pwm things for modest outlays also... like this http://www.ebay.com.au/itm/DC-DC-Converter-Isolated-Power-Module-In-10-16V-Out-12V-4-Pins-for-Auto-Car-Boat-/121569486627?hash=item1c4e1b2723:g:7iYAAOSw4UtWR~DP
Not too sure how many fets they could drive... duty cycle would probably allow them to do it ok.... or use two etc...... simpler than winding a tiny hf transformer like I have.

A scan of AliExpress got me to these guys http://www.aliexpress.com/store/1302754 who have a suitable 6w range that can take 72v on the input - not too cheap though :(

Quote
I do like the robustness of the unit I have done on my previous bldc controller board..... we'll see how this goes.... I am pretty confident in it's ability to perform actually.

I may use a scr to trigger the o/current on the temp pin, and have a hard start from o/load only... not sure yet.

Keep us updated, with the parts problems for the PJs it is always handy to have another arrow in the quiver!

Robin Down Under (or are you Up Over!)

Offline oztules

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Re: testing the egs002 inverter board
« Reply #13 on: March 12, 2016, 05:23:41 PM »
I run protel for windows.....on LINUX under wine....
New software is downloadable for free as a test for 30 days or so..... from arrium now. ( bought protel)... don't know if it runs under wine.

Will do a pdf of it when finished.

I expect any 48v PJ board would be suitable... just change CT network ( 1 resistor and maybe swap the heavy 15kw CT.... different thickness primary is all I think)... so should be parts available if you need them.

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

Offline frwainscott

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Re: testing the egs002 inverter board
« Reply #14 on: March 13, 2016, 12:47:25 AM »
what if you used an over-wound toroid (less iron) so it is closer to saturation,somewhat as a bottleneck,or an r-c filter between the board and toroid,or just a choke or possibly both. I think if you can slow the current drop or rise. I don't think it would effect anything else much,but it might stop the implosion of the 4110's. I'm just thinking if you get the right buffer between the board and the toroid it should buffer it ,possibly enough to stop the surge. Feel free to correct my thoughts,as i dont know much.......  Frank