Are Cockroft-Walton multpliers used exclusively at low output currents?

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SiCEngineer

Joined May 22, 2019
299
I will often see Cockroft-walton and their bipolar variants used in high voltage, low output current applications such as x-ray generators.

Is there anything about their possible power delivery that limits them to this usage case? I have designed an LCC converter which operates at a maximum output voltage of -3kV, but the output current is a bit higher at -200mA. (Power = 600W).

I had originally planned to use a typical voltage doubler, or a simple full bridge rectifier on the output, something like 2-3 of them in a series-connected combination.

But I am looking at the viability of using a planar transformer to isolate the primary and secondary voltages, and believe this will be made much, much easier if I can use one single secondary winding. For this reason, I am thinking of generating about 500V on the secondary, and having a string of Bi-polar cockroft Walton multipliers connected in series to generate the final output.

The load regulation is not stringent, at +200/-200V or so, and the ripple requirements are also quite relaxed, about 20V-50V. As a results I think this could be a good candidate.

I have a separate 6kV output @ 10mA, which I plan to generate with a flyback converter, without the use of a planar transformer as I believe this will pose too many issues. The transformer for the 6kV should be fairly small anyway, considering the low power delivery required.

Any insight is appreciated!
 
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