What is Active Front End in variable frequency drive?
Active Front End (AFE) variable frequency drive has some harmonic filtering at the input to the VFD that is "programmable" on the fly. Basically, a microprocessor "brain" in the VFD monitors the harmonics being generated by the power electronics and "actively" supplies a waveform through the filters to dampen the upstream harmonic content. This is important, because not all equipment is capable of handling the amplitudes of voltage and/or current harmonics produced by modern, large-scale power inverters and converters (VFDs).
Each VFD manufacturer is different; however, those who have developed Active Front End offerings are generally capable of powering machines that are rated in the "several megawatt" range. If in doubt, check with the specific variable frequency drives manufacturer for the project in question. Be sure to have the following data on hand so they can evaluate their capabilities: the application, the environment, the output current required, both input and output voltage levels, whether regenerative capability is necessary, and what constitutes acceptable harmonic content on both the upstream and downstream sides of the VFD drive.
Each VFD manufacturer is different; however, those who have developed Active Front End offerings are generally capable of powering machines that are rated in the "several megawatt" range. If in doubt, check with the specific variable frequency drives manufacturer for the project in question. Be sure to have the following data on hand so they can evaluate their capabilities: the application, the environment, the output current required, both input and output voltage levels, whether regenerative capability is necessary, and what constitutes acceptable harmonic content on both the upstream and downstream sides of the VFD drive.
