A 20-pulse Autotransformer Rectifier Unit for More Electric Aircrafts

Abstract- In more electric aircraft, the power rating and the number of electric loads have considerably been increased. Most of these new loads are power electronics interfacing loads and motor drive systems. As a result, the on-board power system may encounter with power quality problems. To limit the harmonics generated by these loads, multi-pulse rectifiers with the capability of power factor correction and low THD are required. An increase in the number of pulses in the multi-pulse autotransformer rectifier unit (MPATRU) will lead to an increase in the kVA rating, cost, and complexity of the rectifier. Due to the weightlessness and simplicity of the MPATRU, a multi-pulse autotransformer rectifier unit (ATRU) are quite popular and widely employed in the industry. In this study, a novel 20-pulse ATRU based on T-connected autotransformer is introduced, discussed, simulated and implemented with an acceptable power rating for more electric aircraft (MEA) applications. The T-connected autotransformer makes use of only two main windings resulting in saving of space, size, volume, weight, and cost. Its simulation results confirm that the proposed novel rectifier has several advantages such as it can operate at near-unity power factor and the THD of the input current is less than 8% within IEEE-519 Standard limits for SCR>20. Compared to the other MPATRUs, the kVA rating of the proposed 20-pulse ATRU is 44.48% of the load power.

INDEX TERMS: multi-pulse autotransformer rectifier unit (MPATRU), 20-pulse ATRU, T autotransformer, total harmonic distortion (THD)