In the data-sheet of polypropylene DC-Link capacitor (Vishay MKP1848 or Epcos B32778), I can read: "The peak-to-peak ripple voltage (Upp) shall not be greater than 0.2xUndc". Undc is max DC voltage.
Up to now I have assume that AC voltage could be 350Vrms for a 500V MKP capacitor if we assume a very clear and very safe sine voltage. In the reality, it is not the case, and a margin is necessary, like 900VDC for household line use (other email list: with 240VAC in switzerland we have Upp=71%*Undc).
However the data-sheet of DC-Link MKP capacitor, they are more restrictive: the capacitor is design for DC voltage, and Upp (peak-2-peak) should be < 20%*Undc (VDC-max). So for 500V, we should not apply more than 35Vrms and always with the same voltage sign?
Polypropylene is non-polarized capacitor, so why such restriction for DC-Link? Is there a risk to not strictly follow the data-sheet? Where is the problem?