Phase-locked loops for grid-tied inverters: comparison and testing

Abstract

The increasing number of power electronic inverters connected to the utility grid means their synchronization to the utility grid plays an increasingly key role. Typically a phase-locked loop (PLL) is used, however limited information is still only available on PLLs in the public domain comparing them for power system applications. This paper presents quantified analyses and comparisons of the main PLL techniques based on different structures for both single phase and 3-phase systems. A more comprehensive comparison than previous work is made by introducing the robustness to geomagnetically induced current effects and islanding.

Deployment of a full‐size converter utilised hydropower plant to enhance inter‐area oscillation damping

“…WSCC 9-bus three-machine model [54] Generator fourth order [42] Excitation ST1A [43] Hydro turbine [46] Hydro governor [15] Converter model [33,44] Phase-locked loop [51]…”

“…To reach the desired $$V_{\text{dc}}$$ and $$Q_{\text{g}}$$, the outer control loop provides the corresponding current demand values to the inner control loop, to output the appropriate converter voltage $$V_{\text{c}}$$ to the grid. In order to obtain a converter model with high accuracy, the converter dynamics and also the phase‐locked loop (PLL) with the park transformation is modelled, which utilises the synchronization with the grid [50] and estimates the grid frequency $$\omega _{pll}$$ [51]. Because of current decoupling in the GSC, the dq‐grid currents can be changed without influencing each other [52].…”

“…To synchronize the converter with the grid, the dq‐frame of the FSC is aligned with PCC voltage through a PLL from Figure 6. This is achieved by the regulation of the q‐axis of the grid voltage $$V_{g,q}$$ to zero and as a result, the gird voltage is aligned with d‐axis [51]. The PLL estimates the frequency $$\omega _{pll}$$ and the voltage phase angle $$\theta _{pll}$$ at PCC.…”

A Study on the High Reliability Audio Target Frequency Generator for Electronics Industry

“…This RF is usually generated by oscillation using the vibration of the device itself or by using the LC circuit, but the concept of a FS (frequency synthesizer) has been introduced to generate a specific frequency quickly and efficiently. There is a traditional analog method called PLL (phase-locked loop), a digital method, and a hybrid method that combines the two [2][3][4][5][6][7][8]. In this way, various technologies have been developed, from low-frequency to microwave, depending on the frequency range of frequency synthesis that produces the specific frequency desired.…”

A new SOGI-PLL method based on fuzzy logic for grid connected PV inverter

“…Its purpose is to support the power system in case of a possibledefault, and take account various disturbances that can occur on the electrical network (change of amplitude, phase jump, harmonics, imbalance).It is generally, based on rapid and accurate detection of the phase angle of the grid voltage of electrical network, which can be estimated with the aid of a phaselocked loop (PLL) [3][4]. Most popular synchronization approaches for grid connected inverter with the grid voltage are based on the phase-locked loops (PLL) algorithms as shown in Figure 1 [4][5][6]. Figure 1.…”