Higher-harmonic distortion canceller using a switching amplifier with minimum output power

A new feedforward-controlled higher-harmonic distortion canceller is presented in this paper. The input currents of electronic apparatus or industrial machines are pulsatile and contain many higher harmonic components, because capacitor-input smoothing circuits, phase-controlled rectifiers and so on are utilized. These higher-harmonic currents distort the line voltage waveform, and influence the equipment connected with the same line. The proposed circuit was composed by making use of our original noise superimposer, and decreased the total harmonic distortion from 5.07% to 0.34%.