Modified Method for Minimizing Current Distortion of A Single Phase Bridge Rectifier Based on Current Injection

Single phase bridge controlled rectifier, nonlinear load,, produces harmonics that effects on power quality of the AC power system. These distortions cause different problems that need to be solved. Therefore, reducing harmonics is very important issue. In this paper, line injection technique is used to reduce harmonics on the ac side of the single-phase bridge controlled and uncontrolled rectifier. This method depending on injecting harmonic components of the dc converter current with an opposite phase to its ac side lines at a particular frequency to get sinusoidal wave as possible and improving the power factor. Two injection circuits are used. The simulation results of the modified suggested circuits have been compared in order to show the advantages and disadvantages of each type. Parameters of the injection circuits are chosen depending on derived mathematical equations. The system is modeled implemented by  Matlab/Simulink. Simulation results show that THD of the AC current reduced about 81% with power factor around unity.