Indian researchers have compiled an in-depth review of all existing synchronization techniques for grid-connected PV systems. They divided the methods into open-loop and closed-loop systems and provided what they defined as a basic conceptual framework for developing higher network-related systems.
Researchers from the Maulana Azad National Institute of Technology in India conducted a thorough review of all networks synchronization techniques.
They presented their findings in “Recent Advances in Timing Techniques for Grid-Tied PV Systems: A Reviewwhich was recently published in Energy reports. They described all the synchronization techniques for installations with single-phase or three-phase inverters. They also provided a framework of all grid-related architectures and topologies for PV systems.
“This document helps provide a basic conceptual framework for developing a superior network-bound system,” they said. “Timing is a crucial issue in the operation of grid-tied inverters and control research indicates that frequency, phase and voltage magnitude are the most crucial parameters that need to be measured and controlled for an application. network related.”
They noted open-loop and closed-loop techniques. Open-loop techniques can directly detect parameters of input signals, while closed-loop techniques can reduce phase errors.
“In a closed-loop system, the estimated phase value is updated by adjusting through a feedback loop mechanism. This loop locks the estimated signal value to its true value,” they said. closed loop methods are better than the open loop method.”
In closed-loop systems, the phase-locked loop (PLL) technique is a popular way to create a reference current. A PLL is a system that generates an output signal whose phase is related to its input. It is commonly used to modulate, demodulate, filter or recover a signal from noisy communication channels.
“PLL is a nonlinear feedback control system that freezes its output signal to the input signal maintaining one or more minimum phase errors constant. The block diagram of the PLL consists of a phase detector (PD ), a loop filter (LF), and a voltage-controlled oscillator (VCO),” the scientists said. “There are new techniques reviewed in the literature that have been shown to perform better than conventional PLL, but the PLL is widely accepted for its robustness and simplicity.”
The academics concluded by saying that the right choice between all existing PLLs and synchronization algorithms could be difficult. They said more attention should be paid to converter topologies and technologies.
“Similarly, the use of hybrid artificial intelligence methods with the conventional techniques may gain more popularity and achievements in future research,” they said. “More attention should be paid to robust network interconnection under weak network conditions.”
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