High power factor modular polyphase AC/DC converters with galvanic isolation based on resistor emulators

Abstract

This paper deals with a modular, isolated-output, polyphase, AC/DC converter based on the use of Resistor Emulators (REs). A RE is a DC/DC converter that behaves as a resistor at its input port. The value of this resistor (input impedance) is controlled by the converter duty cycle. In the proposed topology, all the REs are controlled to have the same input impedance, whose value is determined by the outputvoltage feedback loop. Also the power processed by each RE is the same. As a consequence, the total power is distributed (and also the power losses), thus allowing us to build a modular system. Moreover, the behavior of these DC/DC converters as REs also allows their connection in series and/or in parallel with perfect sharing of voltage (when connected in series) and current (when connected in parallel). This fact makes possible to extend the proposed solution to high power applications.