Small-Signal Input Impedance Modeling of Multipulse Rectifiers 2008-01-2869

This paper presents small-signal input impedance models for multipulse rectifiers that are widely used on more-electric aircraft (MEA) for powering variable-speed motor drives and other loads requiring dc inputs. The models are intended for MEA ac power system stability and power quality analysis using impedance-based method. Both Transformer Rectifier Units (TRU) and Autotransformer Rectifier Units (ATRU) are considered. The modeling method is based on the concept of impedance mapping which is applicable to various TRU and ATRU topologies. The basic modeling method will be reviewed, followed by application of the method to TRU and ATRU with and without inter-phase transformers. Closed-form small-signal input impedance models are then presented along with an overview of their derivation procedure. Experimental measurements from a 12-pulse TRU are also reported to validate the developed models and to illustrate TRU and ATRU input impedance characteristics.