Are DC link capacitors suitable for use with AC?
The DC voltage rating is the same as the ac peak voltage (not RMS or p-p) and you have to make sure you are using a non-polarized capacitor for ac signals.

Don't use polarized capacitors i.e. electrolytic or tantalum. Read the data sheets. It's a short answer but a suprisingly big subject so if in doubt post a schematic.