Modified Second Order Generalized Integrator-frequency Locked Loop Grid Synchronization for Single Phase Grid tied System Tuning and Experimentation Assessment

Abstract

T he phase-locked loop (PLL) is applied in grid-tied systems to synchronise converter operation with grid voltage, affecting converter stability and performance. Synchronous reference frame PLL (SRF-PLL) is a popular grid synchronisation method due to its simplicity and reliability. Normal SRF-PLL cannot suppress DC offset, causing basic frequency and phase oscillations.When a grid is irregular, its bandwidth should be reduced to ensure acceptable disturbance rejection without sacrificing detection speed. T o enhance the phase-angle estimation speed and accuracy, the researchers modified structure by adding the pre/in-loop filter in advanced PLLs.The capacity to deliver improved dynamic response and reduced settling time without compromising system stability or the ability to eliminate disturbances is a major issue for PLLs. Among different control methods, SOGI-FLL (second-order generalised integrator-based frequency locked loop) had the best performance. It tracks grid voltage frequency precisely even when there is harmonics,voltage variations, frequency fluctuations, etc. In the event of a dc offset, the calculated frequency incorporates low frequency oscillations. A modified second-order generalised integrator frequency-locked loop (MSOGI-FLL) is presented in this work to address grid voltage anomalies of all types, including dc offset. Using the Waijung Block-set of MAT LAB/Simulink, a Modified SOGI-FLL is realized and evaluated by applying abnormal grid voltage situations using a low-cost DSP-based ST M32F407VGT microcontroller. T he results demonstrate MSOGI-better FLL's performance in harsh circumstances.

A Behavioural Model for Accurate Investigation of Noisy Lorenz Chaotic Synchronization Systems

“…1) The noise voltage spectrum is calculated using the ADS program. The noise of multipliers is neglected and the noise of other components is modelled by series voltage sources and a parallel current source according to the manufacturer's data-sheet on the online published user-manuals 1 .…”

“…Chaotic signals can be generated by electrical circuits and nonlinear deterministic equations. It is shown that chaotic oscillators can be synchronized by linking them together with chaotic signals [1,2]. Most of the researches on chaotic oscillators and chaotic synchronization systems are using an electrical circuit in a simulated environment [3].…”