EG8010 + Areosharp?

[RFburns]

So I have been stripping down a couple of 3KW Aerosharp's and see they use an IGBT (PM50B5LA060) that has an opto driver board already nicely made so was wondering if anyone thought that driving this with a EG8010 would work? -This would only be suitable for a fairly small inverter due to the IGBT current spec being rather low? (I am not saying it would be as easy as it sound's; some data sheet trolling and reverse engineering would be required)

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[oztules]

It had crossed my mind..... but as you say, low current.... maybe if you run it at 96vdc it would be worth the effort..

Those 3kw units are deceptively heavy.... really heavy.... nice transformer cores too.

What drive circuit are you going with?
If I give it a go, I may go with isolated supplies on  the  high side driver, simple totem on the low........ similar topology to the PJ Isolated 15v supplies are very very cheap, so save me making a pwm supply myself..... although I may still do that anyway too.


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

[RFburns]

Yes they are heavier than they look (Aerosharp)

Maybe a simple pre converter to 350v dc (alot of  UPS's seem to use this step up stage - push pull ) and than into the H bridge would make the IGBT more useable . The isolated supplies are so cheap its not worth making them (some of those little buck converters are going for $1 and will run down to 4.5v and do a couple of amps) .But for a start I think I will get the PJ boards and go the tried and proven method; already have enough 1/2 - 3/4 done projects ,so just thinking out loud with this post I guess(but I have ordered some EG8010's so if the mood takes me...). Stu

[oztules]

Once you start to pre boost to 320v or so, you have lost all the advantages of the LF inverter topology. I would never build a hf inverter, as it is just an inverter... and a poorly regulated one at that.

When you have to rely on the energy storage of your HV caps and the throughput of your step up stage, we find very limited surge.... and straight away we have made running many highly inductive devices problematic... like single phase induction motors of any size etc.
The big advantage of lf inverters is that you have the entire battery as the surge energy storage, so you can be running a  pretty heavy house load regime, and still start a compressor or boil a 3kw jug, while the water pump turns on and run the welder etc etc etc.

You also forgo the advantage of using reverse grid tie, which is very handy too, and allows for huge house loads during the day, without even loading the inverter up.... your 3kw aero sharps are perfect for this..... like running air conditioning all day while the aero sharp actually runs it and charges the batteries all at once.... so no....not step up for me.

I have made a small 3ph BLDC motor drive from a mc33033, and it had a pwm power supply to simplify the high side drive, and provide a isolated supply to both the three high side drivers, and the low side too. It totally isolates the drivers from spurious stuff in the power supply, which is god when you start using lots of power... so I gravitate to this sort of thing, and thats also why I like the PJ controller. It can be making a mess of the battery line, while the control is effectively totally isolated form the hash at 15kw and beyond in the surges.

So I will probably go that route, and leave the current pump style to the others.
I have the eg810 to play with, but may never get there... I have so many inverters now from experimenting, and they are all 6kw plus.... makes it hard to justify really, but curiosity is still there.

here is my bldc driver board with the 3842 pwm power supply. 5 outputs, three for the high sides, and two for house keeping and low side.



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

[RFburns]

Great reply Oztules, answers a lot of questions for me!  (and also explains why there are so many POS on the market) and as inverters are not where I normally play I value your feed back.

I notice not much use is made of IGBT's in these; is this purely cost or drive problems? .Heavy industry seems to have gone here with most VF drives useing these (guess you still can't beat physics though and the heat sink will remain the same size) and as I said earilier
 "But for a start I think I will get the PJ boards and go the tried and proven method; already have enough 1/2 - 3/4 done projects ,so just thinking out loud with this post I guess"
but enjoy tossing ideas around. Thanks for sharing your brushless drive given me lots to think about.Stu

[oztules]

......well.........Actually the bldc was  fairly poor performer. It was designed to drive bldc water pumps off solar directly. It did this... but only up to 800w..... but the chinese do a better job of it for less than I can build one for... just buy a bike one and modify the input to behave as a quasi mppt....... better than my unit, and easy as hell..... but a good learning curve... I tell myself... anyway.

Have just  finished a board to use on any motor control topology, including VFD units....so now I can control any number of parameters... like max speed, pressure, mppt, current, acceleration flow rate etc etc..... and use someone else's power stages.... cheap and easy and versatile...better way for me to go I think.... next step is micro computer control... out of my comfort zone..... but looks the way forward.

Will really try to do part2 of the inverter story very soon.. this one used aero sharp carcasses too.

Probably cost and low voltage keeps the little fets up there.... hard to beat .003R@180 amps...600 amps surge...........100v..... even if the thin wires can't possibly handle it, apparently the silicon can....so very hard to beat price wise, and there may be little to gain in reliability.... for .006r you pay only 50-60 cents a piece ( supposed to be .003.... but tested out at .006-.007Rds on.... cant grizzle really.

I have not worked with igbt devices, so don't know their foibles or good things, apart from them being tougher perhaps... but still insulated gate, so it must be the bipolar part that is tuff... I don't know.



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

[BeckWick]

Can you please share the electronic hardware required for this system?
What are the specifications of the components?
Also what is its working temprature range?

[oztules]

which hardware?

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

[RFburns]

Just in case Google brought here and you are looking to build an inverter using the EG8010 please see this topic http://www.anotherpower.com/board/index.php/topic,1116.0.html