Author Topic: testing the egs002 inverter board  (Read 147570 times)

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Offline Sandramar

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Re: testing the egs002 inverter board
« Reply #465 on: October 11, 2017, 11:42:22 am »
Frackers,

Thanks for sharing, that is a good looking Toroid.Do you know the kind of steel strip  material ?
I'm glad you wind it with 1/3 hp motor, I have a 1hp ac servo motor with controller and I was wondering if would be enough for long time term, but now i do know is possible.
Did you use an oven for the core annealing process ?

Thanks very much once again

Sandra
I didn't know it couldn't be done, so I did it

Offline frackers

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Re: testing the egs002 inverter board
« Reply #466 on: October 11, 2017, 07:47:21 pm »
No idea what the material was - the donor cores are at least 30 years old (and likely over 50 years), probably current transformers for 11KV distribution grid monitoring. They were rescued from a 45 gallon oil drum that was half full of water in the scrap yard and chosen because their simple construction meant they could be split down easily. They are not ideal, hence the higher than optimum idle current but can't beat the price (NZ$10 each).

Robin Down Under (or are you Up Over!)

Offline Sandramar

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Re: testing the egs002 inverter board
« Reply #467 on: October 11, 2017, 08:43:08 pm »
Well ,
Good for you , difficult to beat that price.  8)

I'll begin my journey  with "Non Oriented " and see how that goes.
Finally I'll get my DIY Spot Welding Machine a worthy  task

Tks
SM
I didn't know it couldn't be done, so I did it

Offline Phaedrus

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Re: testing the egs002 inverter board
« Reply #468 on: October 28, 2017, 05:40:54 am »
Here are a few screen shots taken from that zip file


Been meaning to do a proper write up on the inverters now, but Clockman has done a handy job of that, so I have not bothered, but will some day.
I will firstly try to do a decent story that will make it easy to copy the control box that I now use for the solar charging...but time in an issue.

However I will try to get it done, and maybe ..... maybe.....

(Attachment Link)

Hi Oztules,
The attachments seems to have been deleted.Any chance you could post them again?
I have spent a week reading all the posts here,just waiting for my eg board to arrive.Thanks a lot guy esp. Oztules.
Cheers
Thomas

Offline oztules

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Re: testing the egs002 inverter board
« Reply #469 on: October 28, 2017, 07:29:34 am »
Must have been in the system crash.

Here are the gerber files of the control and power board I used for the pcbway manufacturing of them

There are two component changes in value that improves things a bit.

The 1n cap at the pin 16/17 on the 8010 changes to 22n and the 4k3 between the 100r and the 10k goes to become 1k.

Also that board has no off on... it is hard wired on  via pin 6 of the 8010

 To achieve an on/off switching effect simply get the pin 6 of the 8010 sub board, and push it up not down into the socket. Then the pwr on/off at the bottom of the board provide 5v and 0v via a switch to the now floating pin 6. Pin 6 is the off on switch for the 8010.


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

Offline tunde

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Re: testing the egs002 inverter board
« Reply #470 on: October 29, 2017, 06:01:28 am »
thanks Steve.

Here is a mosaic of the control board for those interested.

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

Hi Oztules great work there and thanks for your selfless contribution.

Two questions please.

1. In your new control board design I could see that you re not only shutting down the 8010 but also shutting down the IR2110s too via
    the SCR (as i could see a top layer track on the board linking to the shutdown pins of the FET drivers by pullig them high just like the
    IFB input of the 8010. Please confirm my suspicion?

2. Recently in oe of your many posts across the platforms, i read that (wish i could quote the thread) but u said " you will be changing
    the way the drive signals goes to the FET gates; that the PWMed signals(20khz) will go to the low side FETs and the squared (50hz)
    will go to the high side mosfets. please confirm this as well and can you explain a little on this?

Thanks.


Tunde

Offline rossw

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Re: testing the egs002 inverter board
« Reply #471 on: October 29, 2017, 07:03:40 am »
that the PWMed signals(20khz) will go to the low side FETs and the squared (50hz) will go to the high side mosfets. please confirm this as well and can you explain a little on this?

I didn't see the original post you're quoting, but this would make oh so much more sense to me.
The high-side was typically either P-channel FETs (which are slow, and the high frequency would be the least-efficient signal to use for them), or have additional drivers required (which add variabilities of delay, and/or make the drive more difficult, especially drive current to turn the FET on or off QUICKLY).

So in either case, driving the low-side fets at the highest frequency, leaving the relatively easy low-frequency on the high-side, makes a lot of sense to me.

Offline Phaedrus

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Re: testing the egs002 inverter board
« Reply #472 on: October 29, 2017, 07:05:03 am »
Quote
Quote
2. Recently in oe of your many posts across the platforms, i read that (wish i could quote the thread) but u said " you will be changing
    the way the drive signals goes to the FET gates; that the PWMed signals(20khz) will go to the low side FETs and the squared (50hz)
    will go to the high side mosfets. please confirm this as well and can you explain a little on this?
Thanks.
Tunde
Check Reply #375 from Oztules.Maybe helpful.

Thomas

Offline oztules

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Re: testing the egs002 inverter board
« Reply #473 on: October 29, 2017, 08:58:53 am »
Tunde.
I never got around to changing a few tracks, as it works so well as it was, I did not bother to change it.
The highside spwm heat sinks do get hotter than the low side for the reasons Ross eluded too, but not enough to get my attention.

So laziness won through. It is incredibly successful as it is.

Yes, the current limiter shuts down the 8010, and the 2110. I wanted instant shut down if it was invoked. Remember it is set up in the 12-14kw area on my units, so if it blows, I wanted it to happen very quickly, rather than rely on the 8010 software.

It is important you don't allow the 2110 to come back on  on it's own for any reason, other than a soft start where it is already on before the software starts to turn on.

You don't want any circumstance where there can be an errant pulse width into a "cold" torroid. The back emf is incredibly high.

Yes I am a lazy slob. I did mean to change to spwm on the low sides only.

As Ross has eluded to, it makes sense to switch the 50hz square wave on the high side, as it makes the switching constraints easier to deal with.
The high side requires driving the fet gate-source with a voltage that will exceed the 48v bus.... by 12v or so. We need this, as when the high side fet is turned on, the drain and source are at the same potential, with RDS on in the milliohms level... but we still need the gate to be 12v above the source to stay turned on hard in the conduction range for the fet to stay in the switched range, rather than the linear part of the conduction curve.

The fet is a very high impedance input ( insulated gate) but with a rather decent capacitance. This means that we need only very small current to switch it on, if we don't need to do it quickly..... but the slower we switch, the more losses we suffer in the linear section of the curve. We want to get past this from 0 to 12v instantly if we can. This means charging the gate up very very fast, which necessarily means decent drive current, at a potential higher than the DC bus.... so driving it is not as simple as the low side driver, where the 12 signal is 30 or more volts less than the DC bus, and so easy to get .

If we are switching very quickly at high frequency, we have a lot of transitions to deal with , and our switching losses will come from here... so it makes sense to switch the high side at the lowest frequency, and the highest duty cycle... ie we switch once in a 100th of a second... and thats it, rather than once in a 20 thousandth of a second.. we will suffer many times the losses with the 20khz signal, and so it makes sense to do this at "normal"voltages  on the low side of things.

I get the 12v above the bus from a voltage pump arrangement on the high side driver, and the less it has to do the better..

As it turned out, it works much better than I imagined, and so I have not bothered to do the simple changes that I should have done to keep the high side switching at the slow speeds.. So one high side switches at  low fundamental frequency, and one at high spwm frequency.

You can change that on your design if you like..


......oztules

Flinders Island...... Australia

Offline Phaedrus

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Re: testing the egs002 inverter board
« Reply #474 on: October 29, 2017, 02:33:17 pm »
Quote
The high-side was typically either P-channel FETs (which are slow, and the high frequency would be the least-efficient signal to use for them), or have additional drivers required (which add variabilities of delay, and/or make the drive more difficult, especially drive current to turn the FET on or off QUICKLY).

I hope I am not being utterly clueless (wont be the first time),but arent all the MOSFETs in the H Bridge , N Channel ? I saw the circuit in the EG 8010 datasheet and the Chinese circuit diagram a member had posted,and both have N Channel FETs ?
Thomas

Offline rossw

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Re: testing the egs002 inverter board
« Reply #475 on: October 29, 2017, 04:12:04 pm »
Quote
The high-side was typically either P-channel FETs (which are slow, and the high frequency would be the least-efficient signal to use for them), or have additional drivers required (which add variabilities of delay, and/or make the drive more difficult, especially drive current to turn the FET on or off QUICKLY).

I hope I am not being utterly clueless (wont be the first time),but arent all the MOSFETs in the H Bridge , N Channel ? I saw the circuit in the EG 8010 datasheet and the Chinese circuit diagram a member had posted,and both have N Channel FETs ?
Thomas

Nowdays most designs use only N-channel FETs, correct. This is due largely due to higher cost of P-channel, lower specs of P-channel, less availability and choice of P-channel, combined with more ready availability of efficient and inexpensive high-side drivers and benefits of reduction in different parts.

But an H-Bridge in itself doesn't dictate the use of a particular device, it's an ancient design concept.

Offline oztules

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Re: testing the egs002 inverter board
« Reply #476 on: October 29, 2017, 05:16:30 pm »
Yes in my design, they are all nfets... thats why we need a voltage higher than the 48v bus to turn them on and keep them on.
I use HY4008 fets.

oztules
Flinders Island...... Australia

Offline Sandramar

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Re: testing the egs002 inverter board
« Reply #477 on: November 06, 2017, 03:16:19 pm »
Must have been in the system crash.

Here are the gerber files of the control and power board I used for the pcbway manufacturing of them


.,........oztules

Oztules,

In attachement W21223ASJ13_CAM%20for%205000AW.zip I Noticed you have 5r6 instead of 4r7 used in bigger Power board (picture attached)
is this correct?
Please would you confirm if you use 2onz PCB instead of 1onz in this design.

Thanks in advance
SM
I didn't know it couldn't be done, so I did it

Offline oztules

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Re: testing the egs002 inverter board
« Reply #478 on: November 06, 2017, 07:14:39 pm »
Yes 2oz board, and whatever I pick up first  in the resistor box.... think the last one was 4r7, but the difference in minimal.

Have fun.

Note there are some small changes on the control board as well.

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

Offline Sandramar

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Re: testing the egs002 inverter board
« Reply #479 on: November 06, 2017, 08:21:15 pm »
Perfect.

Thanks for the reply

SM
I didn't know it couldn't be done, so I did it