A Smooth Synchronization Methodology for the Reconnection of Autonomous Microgrids

Alves, André G. P.; Dias, Robson F. S.; Rolim, L.G.B.

doi:10.1007/s40313-020-00576-x

Cited by 8 publications

(6 citation statements)

References 19 publications

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“…If it can be neglected for low frequencies (

ω ≪ 1 / T_{d}

), the closed‐loop system could be written as

\begin{matrix} right left right left right left right left right left right left0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em3pt \\ \frac{i_{d q} (s)}{i_{d q}^{*} (s)} = \frac{(K_{p}) / (s L_{est})}{1 + (K_{p}) / (s L_{est})}, \end{matrix}

\frac{i_{d q} false(s false)}{i_{d q}^{*} false(s false)} = \frac{1}{\frac{L_{est}}{K_{normalp}} s + 1},

where the time constant

L_{est} / K_{p}

can be selected to provide a settling time

t_{s}

approximately equal to a grid's fundamental period. Considering the grid's frequency to be

f_{g} = 60 Hz

, the 2% steady‐state criterion that relates the settling time with the respective time constant [27, 28], and using (7), the calculations give

\begin{matrix} right left right left right left right left right left right left0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em3pt \\ t_{normals} = 4 \frac{L_{est}}{K_{p}} = \frac{1}{f_{g}}, \end{matrix}

K_{p} =...

…”

Section: Proposed Methodologymentioning

confidence: 99%

VSC plug‐and‐play operation using online grid parameter estimation for PI self‐tuning

Alves

Rolim

Dias

et al. 2020

IET power electron.

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This work presents a plug‐and‐play solution for voltage source converters controlled by proportional–integral controllers to automatically operate connected to a previously unknown grid. The methodology consists of an initial operation using hysteresis band current control in order to synthesise harmonic currents, which are used for online grid parameter estimation, allowing the proper analytical tuning of the controllers using the grid's equivalent model. The method is firstly simulated and then validated through experimental results using Texas Instruments TMS320F28377S Digital Signal Processor and BOOSTXLDRV8305‐EVM static converter.

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“…If it can be neglected for low frequencies (

ω ≪ 1 / T_{d}

), the closed‐loop system could be written as

\begin{matrix} right left right left right left right left right left right left0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em3pt \\ \frac{i_{d q} (s)}{i_{d q}^{*} (s)} = \frac{(K_{p}) / (s L_{est})}{1 + (K_{p}) / (s L_{est})}, \end{matrix}

\frac{i_{d q} false(s false)}{i_{d q}^{*} false(s false)} = \frac{1}{\frac{L_{est}}{K_{normalp}} s + 1},

where the time constant

L_{est} / K_{p}

can be selected to provide a settling time

t_{s}

approximately equal to a grid's fundamental period. Considering the grid's frequency to be

f_{g} = 60 Hz

, the 2% steady‐state criterion that relates the settling time with the respective time constant [27, 28], and using (7), the calculations give

\begin{matrix} right left right left right left right left right left right left0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em 2em 0.278em3pt \\ t_{normals} = 4 \frac{L_{est}}{K_{p}} = \frac{1}{f_{g}}, \end{matrix}

K_{p} =...

…”

Section: Proposed Methodologymentioning

confidence: 99%

VSC plug‐and‐play operation using online grid parameter estimation for PI self‐tuning

Alves

Rolim

Dias

et al. 2020

IET power electron.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The first one,

i_{d 1}

, is used for the operation mode 1 (grid‐feeding converter) and it refers to the active power during permanent state [33, 34]. For example, in PV systems,

i_{d 1}

refers to reference current given by a maximum power point tracker (MPPT) algorithm [36, 37].…”

Section: Control Strategymentioning

confidence: 99%

“…In this paper, one suggests a modified FCMI with internal supercapacitors storage system (SCSS). This converter will allow two operation modes: ensuring power transfer from the DC to AC side (grid‐feeding converter [33, 34]) and compensating grid‐power fluctuations using the SCSS.…”

Section: Introductionmentioning

confidence: 99%

Hybrid four‐level FC inverter using an internal supercapacitor storage system for a microgrid connected application

Mansouri

Tnani

Bachelier

2020

IET power electron.

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In this study, a new topology of grid‐connected four‐level inverter is introduced. The proposed structure, based on intermediate supercapacitors energy storage, is introduced to ensure two operation modes: to provide power to a microgrid from renewable energy sources and to regulate its voltage during short‐term power disturbances. The main idea is to replace ordinary capacitors of a four‐level flying capacitor (FC) inverter by supercapacitors and operate them under variable voltage conditions. The control strategy applies linear matrix inequalities approach as well as space vector modulation technique to generate the appropriate switching states. The latter part of this study is dedicated to the redundant state selection method for supercapacitors voltages balancing. Through experimental implementation, presented results highlight the efficiency of the proposed hybrid inverter in ensuring microgrid stability.

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“…These control systems are studied as synchronization of microgrids from islanded to grid-connected mode. In addition, these synchronization control systems are known as synchronizing, reconnection, smooth transition, pre-synchronization, and re-synchronization [26], [27], [28], [29], [30], [31], [32]. There are many studies in the literature on these topics.…”

Section: Introductionmentioning

confidence: 99%

“…In this respect, the conventional synchronization control systems come from Phase Synchronization Loop (PSL) and Voltage Synchronization Loop (VSL) [10], [67], [86]. PSL depends on initial conditions [31], [58], [77]. This initial condition is the continuous change of phase difference between the output voltages of the two GFIs at the start of synchronization.…”

Section: Introductionmentioning

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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A Smooth Synchronization Methodology for the Reconnection of Autonomous Microgrids

Cited by 8 publications

References 19 publications

VSC plug‐and‐play operation using online grid parameter estimation for PI self‐tuning

VSC plug‐and‐play operation using online grid parameter estimation for PI self‐tuning

Hybrid four‐level FC inverter using an internal supercapacitor storage system for a microgrid connected application

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

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