The board arrived in Melbourne about 3 1/2 weeks after ordering
http://www.aliexpress.com/item/Free-shipping-1pcs-1800W-5500W-DC12V-24V-36V-48V-to-AC-220V-pure-sine-inverter-board/32637730780.html?spm=2114.30010308.3.44.ut8jCV&ws_ab_test=searchweb201556_9,searchweb201602_5_10017_10005_10006_10034_10021_507_10022_508_10020_10018_10019,searchweb201603_6&btsid=d7e2931a-fdd2-404a-ab4a-c692c960a062and see the photos that show the condition out of the box and 2x bubble wrap. It copped a few whacks in transit.
I hooked it up to the 1.5kW Aerosharp transformer with a nominal 20 turns primary.
When a 145uH choke is inserted in series with the torriod primary, I get a nice 0.3A idle current at 26V DC supply.
I have not tested it at any sort of high current yet. I need to get suitable primary cable first.
The extra wire coming out of the EG002 board goes to C24 on the IFB input to the EG8010.
This wire seems to be driven via a few inputs which are combined via a relay:
- too low input voltage
- too high input voltage
- too high current output
- too high current sourced from supply.
as sorted out by the LM324 opamp
When delivered, the board needed a bit of fiddling with the low voltage cutout trimpot for it to work. I can't make the high voltage cutoff work, nor the high current cutoff.
Maybe when I have a more realistic test scenario things will start to come together.
I have found it runs very nicely at the low power output of my test setup (only about 50VA into a halogen desk lamp).
The manufacturer (or reseller or whatever) supply a 5uF cap to place across the 240V secondary. I found this to be too large, drawing about 0.6A at 26 V input.
A 0.47uF makes it draw 0.3A
Interestingly (for me at least) I found I could use a salvaged choke from the 1.5kW Areosharp inverter, by unwinding about 1/2 turns from one side and using that as the
primary side 145uH choke to reduce the high frequency hash from the PWM. This, coupled with a 0.47uF 250V X2 cap on the secondary is all I need for a very clean sine wave output.
I chose 20 turns as a start point seeminly at random. I have a 0-40V 5A supply that I intended to use in initial testing.
This has been quite good when finding what voltage range the bourd can run.
The 1.5kW transformer is 0.7V RMS/turn, so the 20 turns = approx 14V RMS
This is about 20V peak and I would first think that all I need is supply 20V and it will run OK giving 240V RMS output.
In practice I found the lowest it would run is 23V and it runs quite fine all the way to 40V. This means the EG002 controller board can modulate the SPWM from 100% down to about 50% or less.
This testing now gives me a good idea of how many turns are needed for the primary when ensuring large margins of safety for low voltage dropout.
Onward and upward now. Time to get some decent 50A primary cable and hit it with a 1.5kW load when driven by a small 24V battery bank. Will it emit the magic smoke?