Danfoss AHF005 Design Manual page 11

Introduction to Harmonics a... AHF005/010 Design Guide
The simplest solution is to add inductors/reactors of typically 3
% to 5 % in front of the frequency converter. This added
inductance reduces the amount of harmonic currents
produced by the drive. More advanced passive solutions
combine capacitors and inductors in trap arrangement
specially tuned to eliminate harmonics starting from e.g. the
3 3
th
5 harmonic.
The active solutions determine the exact current that would
cancel the harmonics present in the circuit and synthesizes
and injects that current into the system. Thus the active
solution can mitigate the real-time harmonic disturbances,
which makes these solutions very effective at any load profile.
To read more about the Danfoss active solutions Low Harmon-
ic Drive (LHD) or Active Filters (AAF) please see MG.34.Ox.yy
and MG.90.Vx.yy.
®
MG.80.C3.02 - VLT is a registered Danfoss trademark 11