What is the maximum number of VFDs that an Active Harmonic Filter can support?

There is no maximum number of VFDs an Active Harmonic Filter (AHF) can support.  AHF's are sized by current.  As long as the total three phase active harmonic current doesn't exceed the AHF's capacity, the AHF will operate properly.  Up to ten TruWave AHFs can be wired in Parallel for loads with large harmonic currents.