Main problem with these is the EMI (electro-magnetic interference) filter on the input of the VFD - assuming that there isn't an actual fault, of course! Typical small VFDs tend not to have these fitted as standard, so no problem. The filter unbalances the load on live and neutral and the RCD trips as a result as it works by detecting this kind of imbalance. Fix is to remove the EMI filter and hope the neighbours don't complain!