An algorithm for design considerations on semiconductor rectifier transformers

Semiconductor rectifier transformers, which supply DC load currents, always deal with harmonic problems since the rectifier circuit connected to their secondary windings generates harmonic currents. These harmonic currents play a vital role in accurate designing of such transformers. As it is often impossible to model the transformer and the rectifier together during design process, design engineers do appropriate calculations based on sinusoidal normal operation of the transformer and finally add some correctional factors according to the excising standards to consider the harmonic conditions. This is practically time consuming and there is a high risk of various mistakes. It is the purpose of this paper to make a database including 11 types of rectifier circuits, frequently used for industrial purposes, and to develop a simulating software for design considerations on semiconductor rectifier transformers. In the developed software, the transformer and the chosen rectifier circuit are simulated simultaneously, their harmonic analysis is done, and next, the transformer parameters are designed based on the extracted harmonic spectrum and their effects on transformers. Finally, an example of IEEE Standard No.C57.18.10.1998 is calculated by means of the developed software as a case study. Comparing the results obtained here with those given in the standard, obviously proves the capabilities of this software.