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Author Topic: Reliable and Flexible Switching System  (Read 53193 times)

Farmhand

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Re: Reliable and Flexible Switching System
« Reply #60 on: May 18, 2014, 06:28:05 AM »
Seems to work ok, I did put 10 Ohm resistors between the driver outputs and the gates, at lower frequencies like under 400 Hz the hi gate drive drops a fraction I think. It seems to switch transformers quite well, I tested a ferrite core transformer up to 200 kHz and also a steel core at 400 Hz. The 10 Ohm resistors seemed to take out a lot of the noise I could find at 200 kHz

I've noticed before that the gate driver chips I used for low side switches (TC4420, 6 amp parts) can get quite warm to hot when I try to use them at over about 900 kHz, and previously I have used two low side mosfets out of phase to switch the same coil so as to share the load and better handle the higher frequency I wanted.

So I'm thinking that it could maybe be beneficial to make a four phase signal to switch two half H bridges one after the other to share the load of switching the same coil, all the previous components in the signal train seem to be able to handle higher frequencies no problem. Effectively either double the reliable switching frequency or halve the work on the switches and driver chips.

Keeping dead time minimal while avoiding shoot through current seems to be the challenge, I'm sure that can be better adjusted with a different signal arrangement though. If I power the signal components from 15 volts rather than 5 volts they should work quicker. Only the micro is limited to 5 volts. Unless I'm reading the data sheet wrong it looks like a CD4049 chip which I have, if it is powered by 15v can translate a 5 v signal into a 15v signal, I think the data sheet is telling me it will do the opposite so I'll have to try it and see.  :)

..

EMJunkie

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Re: Reliable and Flexible Switching System
« Reply #61 on: May 18, 2014, 08:37:40 AM »
Hi All,

What Microcontroller do you think is best for this project? Price wise and Feature wise?

BeagleBone (Black Series)   -     3 (75%)
FEZ Hydra                          -     0 (0%)
Arduino Mega                     -     1 (25%)

All the Best

  Chris

EMJunkie

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Re: Reliable and Flexible Switching System
« Reply #62 on: May 20, 2014, 07:35:36 AM »
@All - I have been in conversation with my friend Albert. We have been talking about pricing on the setup he has.

Can anyone make any recommendations on a cheap Chinese Manufacturer that can also place the components?

All the Best

  Chris

Farmhand

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Re: Reliable and Flexible Switching System
« Reply #63 on: May 20, 2014, 10:03:13 AM »
Hi EM, is that a setup you posted previously in the thread ? I was thinking about the poll and maybe the low votes was because in essence all the micro's do basically the same stuff so it's difficult to say. I'll buy and use whatever I can get code for or write code for.  :)

..

EMJunkie

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Re: Reliable and Flexible Switching System
« Reply #64 on: May 20, 2014, 11:21:05 AM »
Hi EM, is that a setup you posted previously in the thread ? I was thinking about the poll and maybe the low votes was because in essence all the micro's do basically the same stuff so it's difficult to say. I'll buy and use whatever I can get code for or write code for.  :)

Hi Farmhand,

Yes but the V5 Version. I may have posted V1 or something.

Not sure I understand you fully, if I do understand, then I would have to disagree.

Microcontrollers are awesome. Micro's are the heart of any system, or better, the brain. At all costs we need to protect our Microcontrollers. The whole point of this thread is to achieve a result and that result is to use a Microcontroller that can control a Highly Flexible Highly Reliable Switching Unit.

A unit that can do most anything we want it to do, this can be controlled by the Microcontroller...

So a Micro controls a top of the line Switching system, this switching system can switch all sorts of Frequencies, it can do all sorts of Duty Cycles, It can be an Isolated H-Bridge, Isolated Half H-Bridge, Single Isolated Switch and so on. Multiple Frequencies on each Isolated Single Switch...

So This Switching System is only a part of the equation, not the full System and that's why I wanted to know what people thought of the Microcontrollers, remembering some are much better for this sort of thing than others. For example Raspberry Pi is not one I would use, Arduino Duemilanove/Arduino Uno is last on my list, many Micros are not really satisfactory for a project like this. Of course this is my opinion.

There is no way a Microcontroller can switch any sort of Load, maybe at most 1/2 a watt, with most Microcontrollers. The Tantratron is rated to 1600VA.

The Micro might shut down the entire system in the event of an overheat for example...

All the Best

  Chris

dancombine

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Re: Reliable and Flexible Switching System
« Reply #65 on: May 28, 2014, 05:54:13 PM »

Hi Chris,


I'm the designer of the circuits you mentioned in the start of this thread.
The design is well proven so far in many hard switching cases, up to 500kHz. Soft switching could go to few MHz.
Of course to every design there are improvements possible, but the point is that the design has proven to provide good results, and is flexible and modular.


Attached is a picture of the latest board we use.
I'm using several such boards (self-made), which are called now "IPC" (Isolated Power Channel) and comes in 4 or 8 drivers, so IPC-quadra and IPC-octa.
Many people are suffering by trying to build themselves H-bridges, but have either no galvanic isolation, is not modular, or does not work reliable.
The intend I had, together with my friend and partner Selfonlypath, is to create the above for our private research.
However we understand the community could benefit from this as well.


I wonder if there would be an interest if I would start manufacturing and selling these boards to anyone who is interested in this stuff?


Note that the board has an Arduino Mega landing. I know the Mega is not the fastest and coolest on teh market, but it is sort of a standard, which is also important for modulatory.
The good thing about the ATmega is that the pulses are predictable with clock-precision, which is a must. This is not the case where boards are used with an O/S (like Rasperry Pi).


In fact we are checking if our future platform could be FPGA based. In this sense, I'm closely following the development of a new board by Jack from Gagdetfactory - see http://forum.gadgetfactory.net/index.php?/topic/1876-the-next-generation-papilio-help-me-shape-it/


In anycase some additional analog circuitry is required as front-end for the measured feedback signal conditioning, and threshold control.


I think there could be value if we share and/or sell these.


What do you think?


-Dan


MarkE

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Re: Reliable and Flexible Switching System
« Reply #66 on: May 28, 2014, 11:42:03 PM »
I think that there is value in a well documented and well behaved driver for experimenters.  Finding the right combination of price and performance might be a little tricky because I think that most experimenters do not realize all the things that can go wrong with power drivers and therefore why it is worth some money to buy a well engineered one.

EMJunkie

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Re: Reliable and Flexible Switching System
« Reply #67 on: May 29, 2014, 12:06:17 AM »
Hi Chris,


I'm the designer of the circuits you mentioned in the start of this thread.
The design is well proven so far in many hard switching cases, up to 500kHz. Soft switching could go to few MHz.
Of course to every design there are improvements possible, but the point is that the design has proven to provide good results, and is flexible and modular.


Attached is a picture of the latest board we use.
I'm using several such boards (self-made), which are called now "IPC" (Isolated Power Channel) and comes in 4 or 8 drivers, so IPC-quadra and IPC-octa.
Many people are suffering by trying to build themselves H-bridges, but have either no galvanic isolation, is not modular, or does not work reliable.
The intend I had, together with my friend and partner Selfonlypath, is to create the above for our private research.
However we understand the community could benefit from this as well.


I wonder if there would be an interest if I would start manufacturing and selling these boards to anyone who is interested in this stuff?


Note that the board has an Arduino Mega landing. I know the Mega is not the fastest and coolest on teh market, but it is sort of a standard, which is also important for modulatory.
The good thing about the ATmega is that the pulses are predictable with clock-precision, which is a must. This is not the case where boards are used with an O/S (like Rasperry Pi).


In fact we are checking if our future platform could be FPGA based. In this sense, I'm closely following the development of a new board by Jack from Gagdetfactory - see http://forum.gadgetfactory.net/index.php?/topic/1876-the-next-generation-papilio-help-me-shape-it/


In anycase some additional analog circuitry is required as front-end for the measured feedback signal conditioning, and threshold control.


I think there could be value if we share and/or sell these.


What do you think?


-Dan

Welcome Dan!

I think this thread has proved about the value of a Reliable and Flexible Switching System! People that have an idea about the area of research we all are investigating already see value here.

Isn't it funny how thing go around in circles and come back to the start sometimes! Three or so years ago I said to Albert how beneficial a Board like yours could be to people.

Please feel free to post your product range when you're ready. I am sure people will buy.

All the Best

  Chris

EMJunkie

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Re: Reliable and Flexible Switching System
« Reply #68 on: May 29, 2014, 12:16:47 AM »
I think that there is value in a well documented and well behaved driver for experimenters.  Finding the right combination of price and performance might be a little tricky because I think that most experimenters do not realize all the things that can go wrong with power drivers and therefore why it is worth some money to buy a well engineered one.

Hi MarkE,

I fully agree. Its critical to have something that will suit most all purposes.

Have we come to any hard decisions in the thread other than "Reliable and Flexible Switching System", not really. We don't have an improved design, we don't have any Circuits Designed, really we are no further than the first thread that I posted a few months back.

I wonder why some groups of people can get things done and other groups of people can not?

Procrastination or fear of being ridiculed, I don't know. Isn't it a shame how so many people can join for the good cause but not really do anything...

Apologies for my attitude today, I have seen some rather disheartening things occur in the last few weeks and it saddens me. Rant now over...

All the Best

  Chris

MarkE

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Re: Reliable and Flexible Switching System
« Reply #69 on: May 29, 2014, 01:30:14 AM »
Chris I think that the big issue is setting out constraints.  I would think that something capable of 100W peak hard switching is probably reasonable:

Say 32VDC input max, 4A current, half bridge or full bridge.

Half bridge solves the question of what to do about flyback protection.

Then the next issue is over current fault protection.  Some sort of cycle by cycle and burp burp for severe faults is really critical as part of the driver.

Then the next issue is what measurements if any feed back to the controller.

I think that once specified the design work is not demanding.  The best performance can be had from surface mount parts, but that depends on whether you want to supply finished assemblies or kits or instructions only.

dancombine

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Re: Reliable and Flexible Switching System
« Reply #70 on: May 29, 2014, 10:15:10 AM »
Chris, MarkE,


The design I have was improved over the years and is very stable. I made several prototypes and versions, and works now very well.
here's a picture of v5 of the board: http://users.skynet.be/fc372083/public/boards/2014-05-29%2009.32.37.jpg

Since then I made some minor adjustments and the board is now called IPC-quadra v6.
The changes are mostly some small layout changes (not related to the core of the isolated power switching), and make it universally usuable to interface with any control board (Arduino, Beaglebone, etc.)
The specs are:
- 1kV galvanically isolated for control signals
- 1kV galvanically isolated between all 4 power channels (as such user is flexible on how to connect those together, either H-bridge, push-pull, etc...)
- control signals 3 - 5V compatible
- power section: max 600V & 4A (10A with re-enforced copper traces by soldering) (so 6kVA reachable, and tested in vitro as such)
- operating frequency: DC to 1MHz (depending on choosen power transistor)




I'm willing to make a batch of 25 such boards, if there would be enough people interested.


Regards,
-Dan

MarkE

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Re: Reliable and Flexible Switching System
« Reply #71 on: May 29, 2014, 11:24:15 AM »
Dan, maybe the thing for you to do is publish specifications and then do an IndieGoGo or Kickstarter campaign to cover your internal cost for 25 - 100 boards and something for your time.  If the campaign fully funds then you can offer to sell the boards for what you think is a reasonable price. 

dancombine

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Re: Reliable and Flexible Switching System
« Reply #72 on: May 29, 2014, 12:31:41 PM »
Hi MarkE,


yes I've been thinking about a Kickstarter project.
The practical drawback for you guys is that this will take time before boards can be available.


If there is a small community of 25 interested, I can start a small batch quickly, and later move to a larger Kickstarted based volume.


-Dan


MarkE

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Re: Reliable and Flexible Switching System
« Reply #73 on: May 29, 2014, 01:12:59 PM »
Dan, you are being generous by taking such a risk on people's say so.  In your shoes I would collect enough deposits first to at least cover the fixed costs.  Essentially you could set-up KickStarter to do that.

EMJunkie

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Reliable and Flexible Switching System
« Reply #74 on: June 04, 2014, 12:40:42 PM »
Ok Guys,

Please let us know who is interested! See attached File. No PLL, No Microcontroller, this is bare board with Components Soldered and ready for you to plug in your gear.

Price coming tomorrow when confirmed.

All the Best

  Chris

P.S: Poll Results:

How Much would you be happy to pay for a high quality Switching Unit with advanced PLL?

$2000                 -  0
$1000                 -  0
$500                  -  2
$300                  -  0