Fast functional modelling for 18-pulse autotransformer rectifier units in more-electric aircraft

This paper studies the development of a functional model for an 18-pulse autotransformer rectifier unit (ATRU) in a more-electric aircraft (MEA). The developed model is a non- switching model and is in the DQ0 frame. The three-to-nine phase autotransformer is simplified to a three-to-three phase transformer and then reduced to a functional model in the DQ0 frame. The rectifier is modelled as a DC transformer with commutation losses represented by an equivalent resistor. The developed functional model is simulated and compared with an ABC benchmark model, which is built from the Dymola standard library. The DQ0 model shows significant improvement in performance under both balanced and unbalanced conditions. Particularly the DQ0 model is more than 1000 times faster than the ABC benchmark model under balanced conditions.