UPQC implemented with Cascade Asymmetric Multilevel Converters

Abstract

The power quality (PQ) in distribution systems is affected by the pollution introduced by the customers. The Unified Power Quality Controller (UPQC) custom power device is the most integral actuator to improve the quality of the systems. Today, several manufacturers offer solutions using multilevel inverters in medium voltage applications with different control methods. In particular, the Cascaded Asymmetric Multilevel Converter (CAMC) is a novel alternative among the 5-level converters for back-to-back application. In this paper an UPQC with two CAMC in back-to-back connection is proposed. The hybrid modulation technique used in the CAMC made easier the implementation of the control objectives. Those are, regulating the voltage on sensitive load and control of its reactive power and harmonics current. They are carried out managing the active and reactive power into the UPQC. The model and the control strategy are discussed in d-q coordinates and the performance of the proposed UPQC is evaluated with SPICE simulations.