CURRENT-TYPE ACTIVE FILTER FOR POWER DISTRIBUTION

摘要

PURPOSE:To achieve an accurate feedback control when controlling reactor current. CONSTITUTION:High-pass filters (HPF) 27-29 of each phase input currents icuw, icvw and icwu where the fundamental wave component of each phase is eliminated from load current iLi, (i=u, v, w) from a power distribution line. A peak-hold circuit 30 retains only a maximum value icmax out of icuw, icvw, and icwu and inputs it to an operator 31. The peak-hold circuit 30 inputs a reset signal from an oscillation circuit 34 synchronized to the cycle of a load current and updates the maximum value icmax for each cycle. The operator 31 multiplies the maximum value icmax by a coefficient and inputs the result to a hold circuit 33 via a switching circuit 32. The switching circuit 32 performs on/off operations based on a drive signal input for each cycle from the oscillation circuit 34. The hold circuit 33 retains a setting value id*. The reactor current is subjected to feedback control based on the setting value.