A Novel Single Stage_ Single Switch_ Soft Switched_ Power Factor Corrected AC_DC Converter

Abstract

newline Innovations and inventions in Electronics have made deep inroads into human life. newlineVirtually, every task in daily life is being assisted with an electronic gadget. This, in newlineturn, has created a massive demand for electronic gadgets and billions of electronic newlineappliances are operating off the AC electric grid. All these units require a stable low newlinevoltage DC for their operation and hence require AC-DC converters as front end. newlineMost of the converters connected to the grid are nonlinear electrical loads consuming newlinenon-sinusoidal currents, containing significant harmonics and thereby give rise to newlineheavy losses in the transmission and distribution networks. newlineTo overcome these problems, international standards agencies have laid down strict newlineinterface specifications for all electronic appliances connected to the grid. These newlinespecifications are intended to facilitate a balanced operation of all the electronic newlineappliances on the grid and to optimize the grid utilization. newlinePower Factor correction and specifying the limits for harmonic currents form a key newlinepart of such specifications that mandate the current drawn by an appliance to be near newlinesinusoidal and in phase with the applied voltage. Electrical circuits, consisting of newlinelinear circuit elements such as inductors and capacitors, consume sinusoidal currents newlinefrom the AC electric grid but the current may not be in phase with applied voltage. In newlinesuch conditions, the power factor can be corrected by passive techniques with the help newlineof adding reactive elements in the local vicinity of the appliance. This technique of newlinecorrecting the phase of the current with respect to the applied voltage is termed as passive power factor correction. newlineHowever, in the case of a nonlinear load, passive power factor correction will not newlinesuffice. Special techniques are needed for correcting the shape and phase of the line newlinecurrent to match the line voltage.