Small-signal modeling of multipulse rectifiers for more-electric aircraft applications

This paper presents small-signal input impedance models for multipulse rectifiers that are widely used on next-generation more-electric aircraft (MEA). The basic modeling method is a generalization of the impedance mapping method that has been previously applied to single- phase and three-phase six-pulse rectifiers. Mapping functions are first defined for general TV-phase rectifiers and used to calculate their input impedances by assuming symmetrical TV-phase input voltages and ideal operation. The resulting impedance models are then transformed to the primary of the phase-shifting transformer which is modeled by a transformation matrix. Magnetizing inductance and phase commutation due to transformer leakage inductance are also considered. Details of the modeling method are presented, and its application is demonstrated based on an 18-pulse rectifier. The developed models are validated by experimental measurements from an 18-pulse ATRU.