Power electronics in broader aspect actually controls the flow of power to make it suitable to be used by diverse type of instruments and appliances. The ability to control the flow of power is derived from using solid state switches along with their controllers. In most of the cases the power input are in the form of a 50-Hz sine-wave ac voltage provided by the electric utility, which is first converted to a dc voltage. This conversion can be done by using uncontrolled (diode rectifiers) rectifiers or controlled (Thyristor, MOSFET, IGBT rectifiers) rectifiers. Different types of rectifiers have different advantage and disadvantages. Main disadvantage is distorted input line current due to harmonic contents in line current. It creates different serious problems and pollute the utility supply. So it’s necessary to minimize the harmonic contain in line current.