Abstract
Three-phase controlled/uncontrolled converters have been used in renewable energy applications such as photovoltaic and wind energy as rectifiers and inverters. The main drawback of these converters is the high THD (Total Harmonic Distortion) in their line currents. Many techniques have been used to remedy this problem. Third harmonic current injection is one of the best solutions for the harmonic reduction in line currents of these converters. Injecting third harmonic current from the dc-bus to the line currents reduces its harmonic contents. Minimum THD for any firing angle of the controlled converter is a function of the phase-angle and amplitude of harmonic injection current that can be controlled by a single-phase controlled converter and a boost converter, respectively. This scheme is used with a zigzag transformer to circulate the harmonic injection current to the line currents. A novel mathematical analysis for the proposed scheme and state of the art scheme is introduced. The mathematical analysis introduces the optimum values for components on the harmonic injection path at minimum THD and the corresponding efficiency. The scheme under study has been simulated using the PSIM program. A lab prototype for this scheme has been implemented. Mathematical, simulation, and experimental results for this scheme have been introduced, compared, and discussed. The results show the superiority of the proposed scheme. Published by AIP Publishing.