ACTIVE FILTER FOR REDUCING NON-FUNDAMENTAL CURRENTS AND VOLTAGES

摘要

An AC power line is monitored for currents and voltages at non-fundamental frequencies (including harmonics). A controlled active filter (16) injects compensating current into the AC power line (12). The injected compensating current is responsive to both the sensed non-fundamental frequency current and to the sensed non-fundamental frequency voltage residing on the power line. In one embodiment, the controlled active filter (16) comprises a transconductance amplifier which obtains its operating power from a controlled flow of power from the AC power line being monitored.