Improvement of DSOGI PLL Synchronization Algorithm with Filter on Three-Phase Grid-connected Photovoltaic System

Abstract

Synchronous Reference Frame Phase Locked Loop (SRF PLL) has been widely used for synchronization three-phase gridconnected photovoltaic (PV) system. On the grid fault, SRF PLL distorted by negative sequence component and grid harmonic that caused an error in estimating parameter because of ripple and oscillation. This work combined SRF PLL with Dual Second Order Generalized Integrator (DSOGI) and filter to minimize ripple and minimize oscillation in the phase estimation and frequency estimation. DSOGI was used for filtering and obtaining the 90 o shifted versions from the v αβ signals. These signals (v αβ ) were generated from three phase grid voltage signal using Clarke transform. The v αβ signal was the inputs to the positivesequence calculator (PSC). The positive-sequence v αβ was transformed to the dq synchronous reference frame and became an input to SRF-PLL to create the estimation frequency. This estimation frequency from SRF PLL was filtered by the low-pass filter to decrease grid harmonic. Moreover, the output of low-pass filter was a frequency adaptive. The performance of DSOGI PLL with filter is compared with DSOGI PLL, SRF PLL, and IEEE standard 1547(TM)-2003. The improvement of DSOGI PLL with filter gave better performances than DSOGI PLL and SRF PLLbecause it minimized ripples and oscillations in the phase and frequency estimations.

Frequency, Phase, and Magnitude Difference Locked-Loop Based Linear Synchronization Scheme for Islanded Inverters and Microgrids

“…6, Proportional Resonant (PR) controllers are used in the inner (current) and outer (voltage) control loops, and their design can be done using the referenced methods [106], [107], [108], [109], [110]. DSOGI based Positive Sequence Calculation (DSOGI-PSC) method can obtain positive sequence components from three-phase voltages and currents, and instantaneous powers can be calculated using the sequence components [111], [112]. P/f and Q/V droop controllers provide GFIs, namely Distributed Generators (DGs), with sharing active and reactive powers [113], [114], [115], [116].…”

“…DSOGI is often used in three-phase PLL loops [122], [123] and frequency-locked loops (FLL) [124], [125], [126] due to its superior performance in the phase and frequency estimation [127], [128], [129]. Additionally, from source currents and/or voltages, it precisely extracts positive-negative sequence harmonic components [111], [112].…”

Adaptive active and reactive power control strategy for virtual synchronous generator

“…DSOGI PLL resolves the above issues with a low-pass filter that will remove the negative sequence component as mentioned in the literature. 21,22 An transient damping method is proposed in 23 to stabilizes the system against disturbances. Other methods like self-adaptive control for rotational inertia has been proposed in, 24 an adaptive algorithm is not considered for regulator coefficient of reactive power and a small-signal analysis can provide a better perspective on the parameters design principle as proposed in this paper.…”

“…Along with this in a three‐phase system grid harmonic distortion, frequency, and phase estimation of SRF‐PLL are distorted by negative sequence component. DSOGI PLL resolves the above issues with a low‐pass filter that will remove the negative sequence component as mentioned in the literature 21,22 . An transient damping method is proposed in 23 to stabilizes the system against disturbances.…”