A low-rating 40-pulse AC-DC rectifier based on a new passive harmonic mitigation circuit

A novel 40-pulse autotransformer rectifier is proposed to reduce total harmonic distortion (THD) of the input current in aircraft electrical power systems. The 40-pulse rectifier (40PR) includes a passive harmonic reduction circuit (PHMC) with a low kVA rating (about 0.95% of the load power) to enhance the performance of the conventional 40PR. This PHMC is based on 2 harmonic suppression circuits and contains four tapped reactor and 4 auxiliary diodes. 50 Hz simulations of the improved 40PR indicate that THD of the input current and voltage is less than 2%, which meets the IEEE-519 standard. In addition, without using any input and output filters, input current harmonic components at 400-800 Hz are less than the requirements mentioned in the DO-160G and MIL-STD-704F standards. The suggested PHMC can easily be implemented. A prototype is developed to verify the proposed design. A good agreement can be seen in simulation and experimental results.