A Modified Harmonics Reduction Technique for a Three-Phase Controlled Converter

Three-phase controlled converters have many applications especially in adjustable speed drives and renewable energy. A three-phase controlled converter is a good option in these applications due to its low cost, simplicity, and maintainability with respect to other solutions like a full-bridge insulated gate bipolar transistor converter or a Vienna rectifier. Line current harmonics in this converter is very high; therefore, a harmonics reduction technique is needed to remedy the problem. In this paper, an improved injection current technique is introduced to reduce line current harmonics. The optimal amplitude and phase angle of the injection current for different loads and firing angles have been mathematically determined. Simulation for this technique has been performed by using the PSIM simulation program. An experimental prototype has been built to verify the mathematical and simulation results. The simulation and experimental results show a sensitive variation in the total harmonic distortion of the line current for the amplitude and angle of injection current variations. The simulation and experimental results prove the superiority of this technique in mitigating the requirements for harmonics standards.