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PLL Synchronization Method Based on Second-Order Generalized Integrator for Single Phase Grid Connected Inverters Systems during Grid Abnormalities

The phase, amplitude and frequency of the grid voltage are key information for the operation of inverter systems connected to the grid. In grid-connected inverters, the correct and accurate detection of the phase angle, amplitude and frequency of the grid voltage is essential to ensure the correct generation of reference signals and to meet future standards, which can be estimated using a phase-locked loop (PLL). This paper presents the improvement of a new method of phase-locked loop. The novelty is to generate an orthogonal tension system using a structure based on second order generalized integration (SOGI). The proposed method is a good alternative for creating an orthogonal system in single-phase systems compared to the known process. The performance of the proposed method was performed under normal operating conditions and tested in three abnormal scenarios: amplitude variations, amplitude and frequency, frequency and jump phase. In addition, simulation results with PSIM software are developed to confirm the validity of the strategy of the proposed method. Finally, an experimental test aims to extract the result and discuss the validity of the proposed new algorithm using the STM32F407 microcontroller card with phase angle and frequency estimation that are visualized using a digital oscilloscope.