A 20-Pulse Autotransformer Rectifier Unit for More Electric Aircrafts

Abstract

In more electric aircraft (MEA), 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 onboard power system may encounter with power quality problems. To limit the harmonics generated by these loads, multipulse rectifiers with the capability of power factor correction and low total harmonic distortion (THD) are required. An increase in the number of pulses in the multipulse 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, an autotransformer rectifier unit (ATRU) is quite popular and widely employed in the industry. In this article, a novel 20-pulse ATRU based on T-connected autotransformer is introduced, discussed, simulated, and implemented with an acceptable power rating for 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: 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 with the other MPATRUs, the kVA rating of the proposed 20-pulse ATRU is 44.48% of the load power.