Digital signal processor implementation of isolated reduced-rating voltage source converter using a zig-zag transformer for three-phase four-wire distribution static compensator

Abstract

The proposed distribution static compensator is used to compensate the reactive power for power factor correction or voltage regulation along with load balancing, neutral current compensation, and harmonics current elimination. A zig-zag/star transformer is used to isolate the voltage source converter, and it is operated as a three-phase four-wire distribution static compensator for power quality improvement in a three-phase four-wire system. In order to reduce the current rating of the voltage source converter, the zig-zag configuration is used in the primary windings of the transformer. The voltage source converter is connected to the secondary windings of the zig-zag/star transformer, and this allows the optimum selection of voltage rating of the voltage source converter. Moreover, this transformer connection provides isolation for the voltage source converter system. The distribution static compensator is implemented using the dSPACE DS1104 R and D controller (dSPACE Inc., Wixom, Michigan, USA) and a slave digital signal processor subsystem based on the TMS320F240 digital signal processor (dSPACE Inc., Wixom, Michigan, USA) to validate the design and the developed control algorithm.