A Modified 72-Pulse Rectifier for Harmonic Suppression in More Electric Aircraft Applications

A parallel-connected 72-pulse rectifier (72PR) based on a 36PR with a passive harmonic mitigation method (PHMM) is proposed for harmonic mitigation in more electric aircraft applications. The PHMM is connected to the 36PR dc-side and consists of two harmonic reduction circuits (HRCs) and contains a four-tapped interphase reactor (FTIR) and four auxiliary diodes. Since the proposed design only requires a low-capacity PHMM (about 0.23% of the load power) and does not need any switching and control circuits, therefore; the proposed 72PR is a modified and low-cost solution. On the other hand, by using the proposed circuit, the input current is almost sinusoidal and its input current total harmonic distortion (THD) is less than 1%, which meets the IEEE-519 standard. In addition, the input current harmonic components at 400-800 Hz are less than the requirements mentioned in the DO-160G standard without using any input and output filters. Also, in all types of diode open-circuit faults, the proposed improved 72PR shows more fault-tolerant behavior and better performance in THD reduction. In this article, the effectiveness of the proposed 72PR in reducing harmonic distortion is confirmed, using simulation and experimental results.