Grid voltage detection method based on a novel adaptive notch filter for control of transformerless dynamic voltage restorer

Abstract

In the near future, the power system network may experience severe voltage distortions due to evolving concepts of microgrid, and the large penetration of power electronic based loads into a conventional grid. To protect sensitive loads from voltage disturbances under such severe grid conditions, the commonly used dynamic voltage restorer (DVR) requires control algorithms. Therefore, in this paper, widely used PI control strategy for transformerless single phase dynamic voltage restorer (DVR), based on a T-type multilevel inverter(MLI) is presented. In addition, the novel adaptive notch filter (NANF) is used for accurate extraction of DVR reference voltage for highly distorted grid conditions. Unlike conventional filters, NANF does not require phase-lock loop (PLL) or frequency-lock loop (FLL) for grid phase angle or frequency extraction. The performance of the system with the control algorithm is studied in MATLAB/Simulink to evaluate various power quality problems such as voltage sag, voltage swell, and harmonics. © 2020 IEEE.