A novel harmonic reduction technique for controlled converter by third harmonic current injection

Three-phase controlled converter has many applications in interfacing renewable energy sources and adjustable speed drives as a rectifier or inverter. The utility line currents of this converter have high harmonic distortion more than the harmonic standards. This research introduces a new technique of circulating third harmonic currents from dc-link to the line currents to reduce its harmonic contents. The new proposed system uses single-phase controlled converter to control the angle of injection current for each firing angle of the three-phase converter. A detailed analysis is introduced to achieve a relation between the firing angles of three and single-phase controlled converters. Also a detailed design for other injection path components is introduced. A simulation and experimental work is introduced to prove the mathematical derivations. Analysis, simulation and experimental results prove the superiority of the proposed technique.

► High harmonic distortion of three-phase controlled converter.
► New technique of circulating third harmonic currents from dc-link to the line currents.
► Using of single-phase controlled converter to control the angle of injection current.
► Achieve a relation between the firing angles of three and single-phase controlled converters.