Are there any guidelines for sizing an Active Harmonic Filter for a DC Drive Load?
Yes. First, determine the corrective current requirement for an AC VFD load by using the HPS TruWave Active Harmonic Filter Excel Sizing Estimator. Then multiply by 1.33 to account for the increased harmonic distortion at reduced speed. Higher harmonic levels occur at lower operating speeds occur due to phasing back to the rectifier which chops up the waveform.