Modified Droop Control for Microgrid Power-Sharing Stability Improvement

Rashwan, Ahmed; Mikhaylov, Alexey; Senjyu, Tomonobu; Eslami, Mahdiyeh; Hemeida, Ashraf Mohamed; Osheba, Dina S. M.

doi:10.3390/su151411220

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…Microgrid which is an interface to various non-linear elements, the effect of switching events in the presence of such loads is of utmost relevance, especially in islanded autonomous mode. The behaviour of such microgrids with nonlinear elements under transient events using established droop and resonant controller has been investigated in (Rashwan et al 2023;Valedsaravi et al 2023), but the performance of VOCbased control during the switching of such loads is barely investigated. During load-switching events, voltage transients penetrate the electrical system and their unpredictable nature and extremely short-duration of incidences makes them hard to be captured by conventional analysis methods (Pannila et al 2020).…”

Section: Research Articlementioning

confidence: 99%

Virtual oscillator with delayed feedback for transient mitigation in inverter-based islanded microgrids

Salim,

Babu,

Krishna

2024

Int. J. Renew. Energy Dev.

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In recent years, the conventional control schemes for renewable energy-based inverter-dominated microgrids have been expeditiously replaced by Virtual Oscillator-based Control (VOC). The method of VOC ensures fast synchronisation and efficient load-sharing capabilities in inverter-based renewable energy systems. This work evaluates the effectiveness of VOC-based inverters in mitigating the transient dynamics of power system parameters like voltage, frequency and current under different types of switching events involving active and reactive load combinations. Further, to enhance the control efficiency of VOC under such load-switching scenarios a modified form of VOC is proposed utilizing the ability of the feedback mechanism to strengthen the state space trajectory of dynamical systems. In the proposed method, the control oscillator of conventional VOC driven by the inverter current is modified by providing a feedback signal in the form of an integral function of the error between the drive oscillator and the trajectory of the inverter output. The efficiencies of different forms of feedback are quantified in terms of percentage deviation in power system parameters as well as THD. The proposed feedback strategy can improve the control performance by bringing down the voltage deviation from 57 % in conventional VOC to around 4%. Likewise, the frequency deviation is brought down to 0.14% from 19.26 %. These advantages are achieved without any significant adverse impact on the THD. The proposed approach can be utilized in multi-inverter-based systems serving sensitive loads in microgrids.

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Section: Research Articlementioning

confidence: 99%

Virtual oscillator with delayed feedback for transient mitigation in inverter-based islanded microgrids

Salim,

Babu,

Krishna

2024

Int. J. Renew. Energy Dev.

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“…Droop‐based approach is widely used in the inverter‐based MGs for proper power sharing among the converters [5–13]. The droop control of parallel‐operated VSCs has been mainly studied for the cases in which the power transmission line is dominantly inductive [14]. Also, some applications of droop control in low‐voltage MGs with mainly resistive transmission lines exist in the literature [15, 16].…”

Section: Introductionmentioning

confidence: 99%

VSG‐controlled parallel‐connected voltage‐source converters in low‐voltage microgrid with dominant resistive impedance

Rahimi

2024

The Journal of Engineering

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This paper deals with the control and performance improvement of parallel‐operated voltage‐source inverters (VSIs) controlled as virtual synchronous generators (VSGs). In publications regarding the parallel‐operated VSGs, transmission lines are considered to be mainly inductive. However, less analytical works have been done regarding the control of paralleled VSGs in low‐voltage grids with dominant resistive impedances. Once VSIs are controlled as VSGs in a microgrid with more resistive transmission lines, swing equation and system representation for the power‐angle synchronization will change leading to a new control structure. Therefore, this paper deals with the control of parallel‐operated converter‐based VSGs in low‐voltage grids with dominant resistive line impedances. In this way, the VSG representation, comprising the swing equation and V‐P droop characteristic, for applications in highly resistive microgrids is presented, in which the swing equation and VSG frequency are related to reactive power. Then, the V‐P droop characteristic is modified and an enhanced P‐V droop characteristic for proper sharing of active power between the VSGs in highly resistive microgrids is proposed. Next, the VSG control is modified so that the R/X ratio at the VSG output increases and thus the decoupled control of active/reactive powers in relatively inductive cases is realized as well.

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“…A basic and advanced approach for isolated microgrid was suggested to enhance the reactive power distribution of PCI [3]. The CDC technique utilized in inverter-based islanded microgrid systems faces difficulties in delivering satisfactory performance [4]. A novel power management strategy (PMS) is introduced to facilitate power distribution among renewable sources like photovoltaic and wind systems and battery and super capacitor energy storage [5].…”

mentioning

confidence: 99%

Improved Power Sharing Strategy for Parallel Connected Inverters in Standalone Micro-grid

Gaddameedhi,

Susheela

2024

IJEER

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The primary goal of integrating alternative energy systems such as solar and wind turbines into the power grid using power electronic devices is to meet the growing energy demands. Connecting inverters in parallel effectively enhance power capacity, reliability, and overall system efficiency. However, an uneven power distribution among the inverters is a significant limitation in these parallel connected inverters (PCI). This study focuses on a distributed generation (DG) unit comprising a solar photovoltaic system (SPV) and a battery energy storage system (BESS) connected to voltage source inverters (VSI) 1 and 2. The proposed approach aims to achieve uniform load/power distribution among the inverters with power management, maintaining a constant DC link voltage despite variations in solar irradiation and temperature. Additionally, the strategy targets the reduction of total harmonic distortion (THD) in the load current. The conventional droop control method is restricted in its ability to achieve accurate and uniform power distribution during load changes. An enhanced P-f and Q-E-based droop control technique (EDCT) and a fuzzy logic controller (FLC) have been proposed to address these challenges. Performance analysis using MATLAB/Simulink was conducted with two test cases, and a comparative assessment was carried out with a conventional controller, such as a Proportional Integral Controller (PIC) and Sliding Mode Controller (SMC), to showcase the effectiveness of the developed control technique. The proposed control method ensures equal sharing of active power of 2.5 and 4kW, 2.5 and 7.5kW and reactive powers of 2.5 and 4Vars, 2.5 and 7.5Vars among the inverters for the two cases even during the load change at t=0.5seconds. The settling time for DC link voltage and THD is effectively diminished to 0.03 and 0.25 seconds and 1.18% and 2.87% for the two test case studies of the proposed method, which are much lower than those of existing methods available in the literature.

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Modified Droop Control for Microgrid Power-Sharing Stability Improvement

Cited by 5 publications

References 34 publications

Virtual oscillator with delayed feedback for transient mitigation in inverter-based islanded microgrids

Virtual oscillator with delayed feedback for transient mitigation in inverter-based islanded microgrids

VSG‐controlled parallel‐connected voltage‐source converters in low‐voltage microgrid with dominant resistive impedance

Improved Power Sharing Strategy for Parallel Connected Inverters in Standalone Micro-grid

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