Improved single phase instantaneous p-q theory for DVR compensating nonlinear load

The main objective of this paper is to compensate voltage sag in single phase system connected with nonlinear load. For achieving this improved instantaneous reactive power (IRP) theory based efficient controller for Dynamic Voltage Restorer (DVR) has implemented. In nonlinear load connected single phase system different theories fail to compensate harmonics in addition with voltage sag. Hence, compensation of voltage sag present with certain harmonics is the most severe issue in industries. Therefore, the study concentrates on complete removal of harmonics with effective compensation of voltage sag. Hence this paper proposes modification in originally existing IRP theory where generation of fundamental component is obtained through synchronous reference frame (SRF) theory. This is achieved with the application of moving average (MA) filter. Systematic theoretical and mathematical study of the modified single phase IRP theory based DVR controller has been presented. Simulation results of compensated nonlinear load system with presence of voltage sag indicates the effectiveness of improved IRP theory used in control circuit of DVR.