VRM(voltage regulator module) beat frequency issue: sine wave phase current

[bhl777]

Hi All, I am reading an online file regarding beat frequency issue. (**broken link removed**)

From there it shows phase current look like a sine wave when load frequency is close to switching frequency.


The author proposed a quadrature mixer model to explain this in the slides

Could anybody help in explaining about this? Thank you very much!

 

[FvM]

I think the quadrature mixer isn't but a very general (and vague) model of the intermodulation effects that can happen, if the load current of a switched mode supply or inverter has strong, stationary frequency components at or near the switching frequency.

But you need to analyze the circuit behaviour in details, e.g. the effect of existing filter elements. The paper just claims: There can be a problem, and if so, spread spectrum respectively pseudo-random techniques might be a solution. I guess, nobody will disagree.