Comparison of DSOGI-Based PLL for Phase Estimation in Three-Phase Weak Grids

Pinto, Jorge; Carvalho, Adriano; Rocha, Agostinho; Araújo, Ana Cristina Tomáz

doi:10.3390/electricity2030015

Cited by 12 publications

(20 citation statements)

References 27 publications

(40 reference statements)

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“…In the literature, there are different sequence extraction schemes available [21][22][23][24][25]. Most of these sequence extraction techniques use the fundamental equation in the stationary reference frame that is given in (2).…”

Section: Sequence Extractormentioning

confidence: 99%

Development of a Novel Control Scheme to Achieve the Minimum Unbalance Factor and Real Power Fluctuations under Asymmetrical Faults

Abubakar,

Renner,

Schürhuber

2023

Energies

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The increasing share of converter-based renewable energy sources in the power system has forced the system operators to demand voltage support from the converters in case of faults. In the case of symmetric faults, all the phases have equal voltage support, but in the case of asymmetric faults, selective voltage support is required. The grid codes define the voltage support required in the case of symmetric/asymmetric faults, which is the reactive current injection in the respective sequence proportional to its voltage dip, but studies confirm that it does not result in a minimum unbalance factor in the case of asymmetric faults. The unbalance factor is an indication of the level of imbalance voltage among the phases. Moreover, it also results in fluctuated active power injection in the case of asymmetric faults, which causes dc link voltage fluctuations, and the power reversal may also occur due to such fluctuations, which leads to higher protection costs for the dc link. In order to (1) enhance the uniformity of voltage among different phases in the case of asymmetric faults and (2) minimize the real power fluctuations in such conditions, a novel control scheme is presented in this paper. It optimally distributes the negative sequence current phasor into its active and reactive components to achieve the minimum voltage unbalance factor. It also confirms the minimum real power fluctuations by adjusting the positive and negative sequence current phasors. The proposed scheme also ensures the current limit of the converter. The proposed scheme is developed in Matlab/Simulink and tested under different faulty conditions. The results confirm the better performance of the proposed scheme against the grid code recommendation under different faulty conditions.

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Section: Sequence Extractormentioning

confidence: 99%

Development of a Novel Control Scheme to Achieve the Minimum Unbalance Factor and Real Power Fluctuations under Asymmetrical Faults

Abubakar,

Renner,

Schürhuber

2023

Energies

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“…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].…”

Section: ) Dsogi Based Positive Sequence Calculationmentioning

confidence: 99%

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

Atmaca

Karabacak

2023

IEEE Access

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In recent years, integrating renewable energy sources (RESs) has achieved significant attention due to the growing demand for sustainable energy solutions. Inverter-interfaced Islanded Microgrids (IGs) have appeared as an advantageous approach to integrating RESs into the power grid. Grid-forming inverters (GFIs) are a critical component of IGs, and their synchronization is essential for stable and reliable operation. The literature has widely proposed soft transition, pre-synchronization, and re-synchronization to synchronize IGs to the main grid. However, methods for synchronizing GFIs in the islanded microgrid are restricted. Parallel operation of GFIs is required to guarantee the high-power demand of IG and improve voltage-frequency stability. For parallel operation, GFIs must be synchronized with each other. In the conventional synchronization control systems that are highly nonlinear, the linear proportional-integral (PI) controllers are commonly used in synchronization loops without considering the nonlinearity resulting from the initial condition dependency and cross-coupling. Thus, conventional synchronization methods can be exposed to concerns of stable operation, narrow operation area, and performance degradation. This study proposes a new linearized synchronization control system for GFIs in IGs. In this way, it is possible to analytically design robust linear controllers and ensure a stable operation, high performance, and wide (full) operation area. In addition, a new soft-commissioning method is proposed to deactivate synchronization loops and soft-start the synced GFI. The proposed system has been tested in real-time and CHIL hardware setups for two 550 kW GFIs operating in parallel, and the results in the perfect agreement are presented in this study.INDEX TERMS Commissioning, control hardware-in-the-loop (CHIL), grid-forming inverter, islanded microgrid, load sharing, microgrid, synchronization.

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“…θ PLL u αβ In order to meet the requirements for reactive current injection in a negative sequence [23], the double second-order generalized integrator (DSOGI)-based PLL [24,25] is used during the fault. Thus, when a fault is detected, the current loop control uses the reference current generated by (2) with the assistance of the DSOGI-PLL directly, while disconnecting the reference currents from the P-f and Q-E loops and the voltage loop control.…”

Section: Control Strategiesmentioning

confidence: 99%

“…Optimized grid-forming strategies have been proposed for fault ride through capability [16][17][18][19][20][21][22]. However, more experience has been gained with phase-locked loop (PLL)-based techniques to fulfill the control requirements of negative sequence currents in grid codes [23], particularly for reactive current injection in positive and negative sequences [24,25]. Therefore, mostly, grid-forming converters currently activate a backup PLL during the Low-Voltage Ride Through (LVRT), thus temporarily turning into a grid following-like converter [8,26] so as to meet the requirement for the reactive current injection in negative sequences.…”

Section: Introductionmentioning

confidence: 99%

Transient Stability Analysis and Post-Fault Restart Strategy for Current-Limited Grid-Forming Converter

et al. 2022

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Grid-forming converters are attracting attention for their significant advantages in terms of stability in a weak grid and simulated inertia. However, while they offer great flexibility due to the use of power semiconductors, they are also affected by their low current-carrying capacity. This means that during a fault, instead of the usual voltage control, a current limiting control is active, which changes the dynamic performance of the converter and influences transient stability. This manuscript focuses on the dynamic performance of grid-forming converters during the restart phase at the post-fault period, and proposes an initial phase threshold to prevent the converter from going into current saturation. Based on this, the manuscript proposes several restart strategies during the post-fault period, by using some fast resynchronization methods in order to meet the requirements of the converter’s stable operation and fast active power restoration. Finally, the above findings and the proposed strategies are validated by a joint control hardware-in-the-loop system.

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Comparison of DSOGI-Based PLL for Phase Estimation in Three-Phase Weak Grids

Cited by 12 publications

References 27 publications

Development of a Novel Control Scheme to Achieve the Minimum Unbalance Factor and Real Power Fluctuations under Asymmetrical Faults

Development of a Novel Control Scheme to Achieve the Minimum Unbalance Factor and Real Power Fluctuations under Asymmetrical Faults

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

Transient Stability Analysis and Post-Fault Restart Strategy for Current-Limited Grid-Forming Converter

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