TRU and ATRU Analysis by Matrix Methods

A new method is proposed for the analysis and design of multipulse three-phase rectifiers such as 12- and 18-pulse rectifiers. The method is based on describing the voltage transformation of the multiphase transformer by a 3×N matrix when N is the number of secondary outputs of the transformer. A key advantage of the method is that the same matrix can be used to describe the current transformation through the transformer as well, avoiding the lengthy and error-prone algebra required in the existing approaches to determine the current responses of multipulse rectifiers. The transformation matrix can be further used to determine harmonic performance of the rectifier, to calculate the rectifier small-signal input impedance, as well as to identify potential triplen harmonic problems. It provides a new, general and effective mathematical tool for the analysis and design of multipulse rectifiers that are widely used in large industrial drives and aerospace systems.