A modified DSTATCOM topology for power quality enhancement

Abstract

In this paper, the topology of distribution static compensator (DSTATCOM) with a three-phase four-wire system is modified. The modification concerns with the interfacing filter and DC-link capacitor with a goal of improving the system power factor, stabilizing the system voltages and eliminating the harmonic distortion resulting from nonlinear loads. The modified DSTATCOM has a three-leg inverter with a DC-link having a single DC capacitor in addition to a small capacitor connected between the system neutral wire and the negative terminal of the DC-link. To interface the inverter, series inductor with shunt filter capacitor is applied to ensure correct injection of the compensation current. Instantaneous symmetrical component theory (ISCT) is used to generate the compensator reference current which satisfies the power quality improvement through power factor correction, harmonic elimination and load balancing. Matlab Simulink programs are used to validate the advantages of the proposed modification and control of DSTATCOM. The simulation results show that the modification and associated control algorithm emphasize the system current balance, extremely low value of total harmonic distortion (THD) and desired power factor.