• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology


Indian Journal of Science and Technology

Year: 2021, Volume: 14, Issue: 5, Pages: 445-456

Original Article

Experimental assessment of Single Phase Grid assisted system using Second Order Generalized Integrator–Frequency Locked Loop

Received Date:01 September 2020, Accepted Date:26 January 2021, Published Date:16 February 2021


Objectives: To design and develop a simple, robust, and novel SOGI based frequency lock loop approach with DC-offset elimination capability for extracting precise phase angle of the grid voltage. As the additional objective of the work is to utilize the unused capacity of the PV system for providing reactive power support to the grid. Method: The second-order generalized integrator (SOGI)-Frequency Look loop (FLL) is implemented to achieve precise phaseangle for the control system, filtering capability for the adaptive frequency tuning as well as an orthogonal signal generation. The DC blocker is designed to eliminate the dc-offset generated during analog to digital conversion without compromising the dynamics of the system. To achieve the second objective, the virtual two-axis current control is simulated and experimented on in a single-phase grid-assisted system. Synchronous-frame current controllers are designed to inject active power to the grid and also ensure the unity power factor by providing reactive power support to the grid. The developed system is simulated using MATLAB /Simulink and implemented on the experimental stepup. Findings: The precise phase-angle is extracted from the grid voltage during the abnormal grid conditions like frequency shift, distorted by harmonics, and dc-offset. The DC-offset can be eliminated without adopting high-order FLLs by choosing the appropriate control parameter and DC cancellation block (DBC). Novelty: This study presents simple, efficient, novel SOGI based control that provides assurance of power quality as well as injection of active power injection into the grid using the virtual two-axis reference frame power control. The experimental and simulation results confirm that the presented control approach provides fast and accurate phase angle extraction in the grid synchronization with DC-offset cancellation.

Keywords: Grid synchronization; STM32F407VG microcontroller; WAIJUNG Blockset; phase detection; Phase Locked Loop (PLL); virtual two axis reference frame power control


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© 2021 Brambhatt & Chandwani.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Published By Indian Society for Education and Environment (iSee)


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