Many researchers have sought to use different methods to reduce harmonics
in the input current wave of the rectifier, In this study the method of passive filter
connections are used, which is the most commonly used method. The filters that have
been used in this study are connected in parallel (shunt) with the rectifier. Where the
idea of these filters to provide a path with a very low impedance to the harmonics of the
current. These filters must be capable of withstanding rated voltage of the system. In
this study two types of passive filters are explained and used (Single tuned filter and
Second order high-pass filters). Also mathematical analysis of these types of filters and
waves are given. Filters were designed at several values of the firing angles of the