Analysis of Single-Phase Second Order Generalized Integrator Based Phase-Locked Loop And Derivative Element Based Phase-Locked Loop Under Weak Grid Condition

Abstract

The modern power system where the numbers of Distributed Energy Resources (DERs) are connected to the grid, forces to proliferation in power electronics devices, in this scenario proper and fast synchronization become very important. To achieve this many synchronization techniques have been discussed in literatures. For this purposes PLL is widely used because of its simple implementation and robust structure. The Generalized Integrator (GI) based Phase-Locked Loop (PLL) has become favorite among researchers specially Second-Order-GI-PLL. It is widely used in grid connected single-phase system because of its advantages over conventional and others PLL. However, in weak grid conditions the performance of the SOGI-PLL greatly affected, it is sensitive to DC-offset and sub-harmonics. It is having frequency feedback loop that degrade the performance of the PLL during rapid changes in the frequency. To overcome these issues a Derivative Element (DE) based PLL is used. DE-PLL having no frequency feedback loop that allows it to achieve high performance even during sudden frequency variation. In this literature both the SOGI-PLL and DE-PLL have discussed in detailed and their performance is analyzed under weak grid condition by using MATLAB/SIMULINK.