Do you mean that your actual power source is AC, and you are using an ad-hoc rotary converter consisting of an induction motor driving a brushed DC generator to convert that to the needed DC? If so, the obvious solution to all aspects of this problem would be a properly managed AC-to-DC charger... with no mechanical parts involved. I realize that would be expensive...The particular generator is a twin motor, induction and brushed commutator same shaft setup. In this instance I believe it is "self-rectifying" and it's 20+ phases based on size, but surely there would be a high level of noise compared to other methods. Do you know of any modern and efficient ways to clean this current?