Unbalanced Voltage Mitigation using D2VC with Proportional Resonant Controller in αβ-Frame

Abstract

This paper proposes a control algorithm for unbalanced voltage compensation using the Dynamic Direct Voltage Controller (D2VC). An advantage of this device is the possibility of a online direct voltage control in distribution systems, rather than on-load tap changers or other indirect control schemes. The proposed algorithm is based on the instantaneous positive and negative sequence components in αβ-frame, dismissing the use of a Unified Three-Phase Processor (UTSP), consequently avoiding its complexity and excessive computational efforts, and the compensation reference signals are obtained using proportional plus resonant (PR) controllers. There is no need of using any synchronism algorithm, e.g. PLL, which means that the D2VC’s performance is independent of the dynamics of this type of synchronization circuit. Simulation results carried out in time domain using PSCAD/EMTDC are presented to show the effectiveness of the proposed solution.