[Canberrauav] DC-DC switching regulators

Samuel Dudley dudley.samuel at gmail.com
Tue Feb 9 00:42:06 AEDT 2016


Hi Carlos,
I'm not involved with the CUAV activities, but im sure one of the people
over there will give you a contact.

Here's a video of the twitching that occurred when the second converter was
installed for anyone that’s interested... no rc input, just armed.
https://drive.google.com/file/d/0B5sEoCRsxmzkbThDcmM1b1lGM28/view?usp=sharing

Cheers,
Sam

On Mon, Feb 8, 2016 at 8:38 PM, Carlos Peco <carlos.peco at gmail.com> wrote:

> Hi Samuel (et al.),
>
> My name is Carlos, just moved to Canberra from Sydney. I'm interested in
> UAV technology and have been looking at CUAV activities since I saw the OBC
> documentary on BBC.
>
> Because of my work, I have access to some radio monitoring equipment and
> antennas (the demo stock we use for demonstrations and loans). They are not
> spectrum analyzers, that's another part of the company I have little to do
> with.
> I'm more than happy to take some gear to the airfield one of these
> weekends to make noise fieldstrength measurements at the frecuency ranges
> of interest (remote control, GPS and the like) for different DC-DC
> converter configurations, if considered useful.
>
> cheers,
> Carlos
>
>
> Le lundi 8 février 2016, Samuel Dudley <dudley.samuel at gmail.com> a écrit :
>
>> Hi CUAV,
>>
>> I noticed you were looking at GE critical power for a DC-DC switching
>> regulators. I can only comment on the particular model which I have used
>> and for my use case but the results were not great… No issues with the
>> power rail but the RF noise that come off the module was considerable. On
>> the regulated end I had around 2cm of cable exposed before entering a
>> shielded cable run (shield was connected at only one end to a common -ve
>> post off the main lipo). To be fair I was using the module as a plug and
>> play brick and this particular module (similar to the later power brick)
>> require external circuitry to meet the RF emissions specified in the
>> datasheet.
>>
>>
>> http://au.element14.com/ge-critical-power/ehhd006a0b41-hz/dc-dc-12v-6a-1-8-brick-heat-plate/dp/2076849
>>
>> When the module was powering the load (highly transient ~6A max) the
>> digital radio in the room would stop working. It wasn't until I added a
>> second identical DC-DC converter that problem really manifested. I didn't
>> nail down exactly where the noise was entering the system but the frame
>> loss on the 4 satellite spectrum receiver combined with possible induced
>> noise on the lined to the 3DR PPM sum encoder was enough to corrupt the PPM
>> signal to cause random full scale defections in the RC system even while
>> idle.
>>
>> Upon reflection the issue was present, but much less noticeable /
>> diagnosable with a single regulator in place.
>>
>> I switched over to the following part and now the digital radio works in
>> the workshop :)
>>
>>
>> http://au.mouser.com/ProductDetail/Murata-Power-Solutions/UQQ-12-8-Q12PB-C/?qs=b13bmSh8y6zbImiRVI7nEQ%3D%3D
>>
>> Cheers,
>> Sam
>>
>
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