Reliable and Flexible Switching System

[EMJunkie]

Hi Everyone,

I have been around for a long time in different FE Community's. Mostly collecting information.

The biggest problem with Building and Testing Devices that I have seen, is a Reliable and Flexible Switching System. We should all work together and bring the best of us in to go from Step one to actually selling the kits to those that want them.


I propose a collaboration of users to work on a better more Reliable and Flexible Switching System!

Some initial requirements:
1: Microcontroller Controlled with a Client so as can be controlled from ones Laptop/PC.
2: Capable of fine adjustments for fine tuning of frequency's.
3: Capable of reasonable Voltages and Currents.
4: Capable of a large range of Frequencies.
5: Wide range of Switching Capabilities, Single H-Bridge, Dual H-Bridge, Single Switching mode...
6: Plenty of Circuit Protection/Isolation for the Microcontroller and also the User, fused etc...
7: Clean Slim and cost efficient for all.

I have a friend 'Selfonlypath' that is no longer online that did something similar. To give him and Dan, his friend, credit, they did a very good job but not all is still available. See attached Picture below. A few problems I had found with this circuit, supply current was not high enough from the RK-0515s at high frequency and the Fetts would not switch properly.

Some Recommendations for Microcontrollers:

1: FEZ Hydra Mainboard (Medium Speed reasonable price)
2: FEZ Raptor Mainboard (Fast 400MHz but expensive)
3: Arduino Mega 2560 (Slow 16MHz)

Personally I like the GHI Boards.

I can do the programming of the board and the Windows Client. Can someone do the Circuit Design and source cheap Chinese Manufacture? I already have a similar unit to SelfOnlyPath running and it is worth its weight in Gold. I will admit, if it can be improved on it would be great and if the entire Community can benefit and have the same access to it then it would help immensely!

I have attached some pictures of my unit so others can see the clunker I use.

All the Best

  Chris

[lost_bro]

Good day EMJunkie

I've been thinking along the same lines for a while also:

Found this about a year ago and saved it:

http://www.source-for-innovations.com/pgen.htm

Seems like it will do PLL also and can program from LCD or laptop.

take care, peace.
lost_bro

[MarkE]

There are several considerations and they are unlikely to be met by a single solution.  For the control side considerations include:

1. Frequency capability.
2. Synchronization capability.
3. Power topologies supported.
4. Fault handling.  This is really important because it means the difference between constantly frying the power section, or just gracefully losing function.

On the power side:

5. Single ended, or half bridge.
6. Number of sections:  1, 2, 3, 4, or 6 being the most common. 1, 2, 3 for half bridges, and 1, 2, 4, and 6 for single ended.
7. Type of conduction:  continuous, discontinuous, critical conduction.
8. Trapezoidal, Quasi-resonant, or fully resonant.
9. DC or AC output
10. Voltage capability
11. Current capability


For any combinations there are a number of solutions that would work.  My recommendation is that rather than try and find a one size fits all, start with at least one class of machine, and then work on meeting your goals of low cost and flexibility within that framework.  For high power switches, Avageo has some really great isolated IGBT drivers that include lots of housekeeping functions that make it a lot easier to drive the devices reliably and survive faults.

[EMJunkie]

Good day EMJunkie

I've been thinking along the same lines for a while also:

Found this about a year ago and saved it:

http://www.source-for-innovations.com/pgen.htm

Seems like it will do PLL also and can program from LCD or laptop.

take care, peace.
lost_bro

Hey Lost_Bro,

I like it! Problem is its only good to 100KHz.

All the Best

  Chris

[EMJunkie]

There are several considerations and they are unlikely to be met by a single solution.  /...

Hi MarkE,

Agreed! Its going to be hard to do a single unit that will do it all!

My unit is good from about 0.04 to 7MHz for switched DC in either H-Bridge Mode or Single Switched Mode.

I think if we think broadly and then expandable after that then we can move forward with units like the Arduino Shield concept! I think there is sufficient technology out there now that this is a very achievable task and at low cost.

All the Best

  Chris

P.S: Anyone willing to do some Circuit Re-Design and throw it out there? Even if its based on the Above design!