General Injection Transformer Turn Ratio Design Method and Hybrid Harmonic Reduction Methods for Series-Connected Multipulse Rectifiers

To simplify the complex calculation process of the optimal injection transformer turn ratio, a minimum error energy method is proposed in this article. According to the structure of multipulse rectifiers, the injection waveform when the rectifier without harmonics is analyzed, and the relationship between the input voltage and the injection voltage is studied. According to the relationship, the minimum error energy method is researched. To prove the accuracy of the minimum error energy method and improve the harmonic suppression ability of multipulse rectifiers, an improvable hybrid harmonic suppression method is proposed. Based on the structure of the proposed hybrid method, the optimal injection transformer turn ratio is calculated, respectively, by the minimum THD of input voltages and the minimum error energy method. The results show that the proposed minimum error energy method accurately solves the optimal turn ratio of the injection transformer with reduced computation. The proposed harmonic reduction method effectively suppresses the harmonics of the input side, which is suitable for high-power quality requirements.