Flexible Power Electronic Converters for Producing AC Superimposed DC (ACsDC) Voltages

Several applications such as power supplies for electric precipitators, ozone generation, partial discharge, etc., require ac superimposed dc (ACsDC) voltage supply. Most of such applications use intransigent systems for producing ACsDC voltages. In this paper, three different kinds of flexible power electronic converters are proposed for producing ACsDC voltages. These converters have two power conversion stages: input and output. In the input stage, two isolated dc voltages are obtained by using an isolated three-port dc-dc converter or two isolated two-port dc-dc converters. In the output stage, one of the input-stage dc voltages is used to generate an ac voltage and the obtained ac voltage is added to the remaining input-stage dc voltage to obtain an ACsDC voltage. Based on the converters used in the input stage, the proposed ACsDC converters are named as a dual active bridge (DAB) converter-based ACsDC converter (DAB-ACsDC), triple port active bridge (TAB) converter-based ACsDC converter (TAB-ACsDC), and dual transformer-based asymmetrical triple port active bridge (DT-ATAB) converter-based ACsDC converter (DTATAB-ACsDC). A detailed analysis of these ACsDC converters and their verifications using simulations and experimental studies are presented, which depict that the proposed converters can be used effectively for producing ACsDC voltages.