Selective Reduction of Harmonics in AC Controller

Abstract

A method, involving three pulses per half cycle is presented to reduce any one unwanted harmonic from the line current of an ac controller with resistive load operating in a single-phase system. The principle adopted in the proposed pulse-width control is that the pulse positions are fixed and they are located symmetrically to supply voltage wave. Control is affected by varying the pulse width symmetrically around the pulse position. The present method and the method presented in ref.1 are compared for their performance.