A Switched-Capacitor Three-Phase AC-AC Converter

The main objective of this paper is to replace autotransformers and transformers in industrial applications by switched capacitor three phase AC-AC converters. The control system is not required in case of open loop operation of AC-AC converters. In this paper, by employing closed loop system, the advantages such as accuracy, reduced error, reliability, fast response and less noise can be ensured. In switched capacitor principle, three different modes of operation are employed. These modes are complete charge, partial charge and no charge. In order to step up or step down the output voltage, partial charge mode is described in this paper. The closed loop control always implies the use of a feedback control. In such a way the accuracy of the output thus depends on the feedback path which in general can be made accurate within the electronic control systems and circuits. Thus the closed loop control is achieved by a PI Controller.