Robust Tracker of Hybrid Microgrids by the Invariant-Ellipsoid Set

Awad, Hilmy; Bayoumi, Ehab H.E.; Soliman, Hisham M.; Santis, Michele De

doi:10.3390/electronics10151794

Cited by 14 publications

(6 citation statements)

References 28 publications

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“…The authors of [25] stipulate an ellipsoidal outline of decentralized state feedback with integral control for DC-MGs [26]. Notably, unlike the invariant-set design in [25,34], the present method is entirely different, and is based on a dissipative control approach.…”

Section: Simulation Validationmentioning

confidence: 99%

Attractive Ellipsoid Technique for a Decentralized Passivity-Based Voltage Tracker for Islanded DC Microgrids

Poznyak,

Soliman,

Alazki

et al. 2024

Energies

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A new passivity-based voltage tracker for islanded Direct Current (DC) microgrids is presented in this paper. The proposed design develops a new sufficient condition for passivity-based state feedback with proportional and integral control using the attracting ellipsoid method. In this paper, we consider the time behavior of the extended vector, which completely describes the principle properties of the closed-loop system such as the boundedness of the trajectories within some ellipsoid and the dependence of its “size” on the feedback gains. The next step, which we are realizing in this paper, is the minimization of the attractive ellipsoid by selecting the “best” admissible feedback parameters. Here, it is important to note that the applied feedback is of PD-type (proportional differential) on the system state and I-type (integral) on the output. This is a new construction of the suggested feedback which gives several advantages for a designer. The suggested control is decentralized and uses only the local states; it is cost-effective and avoids the time delays in the communication networks which are needed if centralized control is used. The suggested control is carried out in the bilinear matrix inequality (BMI) framework. Extensive simulation is performed on a test system composed of renewable energy sources, under plug and play (PnP) operations, and uncertainties in distribution lines and loads. The performance of the proposed decentralized voltage controller is compared with that of a voltage tracker present in the literature. The comparison shows the improvements introduced by the proposed control ensure the stability of the dc bus voltage and a quick response under different scenarios of operating conditions.

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Section: Simulation Validationmentioning

confidence: 99%

Attractive Ellipsoid Technique for a Decentralized Passivity-Based Voltage Tracker for Islanded DC Microgrids

Poznyak,

Soliman,

Alazki

et al. 2024

Energies

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“…Other advantages include improved power management and stable performance [22]. The MG solves source and load compatibility difficulties and integrates energy sources and consumer loads with minimal conversion stages [23]. However, the problem of low power factor has been reported for many MG systems such as maritime MGs [24], MGs employing three-phase three-wire grid-connected inverters [25], MGs utilizing thyristor-based compensation (series or shunt) [26,27], and AC MGs integrating wind-energy systems [28].…”

Section: Problem Formulationmentioning

confidence: 99%

Unity Power Factor Operation in Microgrid Applications Using Fuzzy Type 2 Nested Controllers

et al. 2023

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The issue of low-power factor operation microgrids was reported for several layouts. Although numerous power factor improvement strategies have been applied and tested, various concerns remain to be addressed such as transient performance, simplicity of implementation, and satisfying the power-quality standards. The presented research aimed to design and implement controllers that can improve the transient response of microgrids due to changes in the load demand and achieve a near-unity power factor at the AC grid side, to which the DC microgrid is connected. Due to the nonlinear nature of microgrids, as they rely on power electronics converters, a Fuzzy type 2 controller was designed, implemented, and tested. The focus was given to improving the power factor of the DC microgrids. The validation of the proposed technique was verified by comparing its performance with Fuzzy type 1 and autotuned conventional PI controllers. To achieve the set aims, two nested control loops were designed with an inner current loop and an outer voltage loop. Besides MATLAB/Simulink simulations, a 10 kHz-sampling dSPACE platform was used to implement the suggested system. Two operational scenarios were tested: (1) a step change in the DC link voltage and (2) a change in the AC load (increase and decrease) at the output of the power inverter, connected to the DC grid. The simulation and experimental results confirmed that the proposed Fuzzy type 2 controller performed better than the other two techniques regarding the dynamic response, steady-state error, and compliance with power quality standards. Conventional approaches develop controllers using a linearized model, which limits the model accuracy and ignores higher-order variability. The method employs the nonlinear model. Fuzzy type 2 can better approximate high-precision problems than Fuzzy type 1.

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“…The invariant-set approach [ 30 , 31 ], and its reference applications [ 32 , 33 , 34 ], is an approach used for designing systems controllers that are disrupted by external disturbances (perturbed systems). An invariant-set is one in which if an initial state vector x ( 0 ) begins within it, the trajectory x ( k ) will not leave it for the future time k > 0.…”

Section: Decentralized Passive Sensor Fault-tolerant Controlmentioning

confidence: 99%

Decentralized Sensor Fault-Tolerant Control of DC Microgrids Using the Attracting Ellipsoid Method

Soliman

Bayoumi

El-Sheikhi³

et al. 2023

Sensors

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System stability deterioration in microgrids commonly occurs due to unpredictable faults and equipment malfunctions. Recently, robust control techniques have been used in microgrid systems to address these difficulties. In this paper, for DC-islanded microgrids that have sensors faults, a new passive fault-tolerant control strategy is developed. The suggested approach can be used to maintain system stability in the presence of flaws, such as faulty actuators and sensors, as well as component failures. The suggested control is effective when the fault is never recognized (or when the fault is not being precisely known, and some ambiguity in the fault may be interpreted as uncertainty in the system’s dynamics following the fault). The design is built around a derived sufficient condition in the context of linear matrix inequalities (LMIs) and the attractive ellipsoid technique. The ellipsoidal stabilization idea is to bring the state trajectories into a small region including the origin (an ellipsoid with minimum volume) and the trajectories will not leave the ellipsoid for the future time. Finally, computational studies on a DC microgrid system are carried out to assess the effectiveness of the proposed fault-tolerant control approach. When compared with previous studies, the simulation results demonstrate that the proposed control technique can significantly enhance the reliability and efficiency of DC microgrid systems.

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Robust Tracker of Hybrid Microgrids by the Invariant-Ellipsoid Set

Cited by 14 publications

References 28 publications

Attractive Ellipsoid Technique for a Decentralized Passivity-Based Voltage Tracker for Islanded DC Microgrids

Attractive Ellipsoid Technique for a Decentralized Passivity-Based Voltage Tracker for Islanded DC Microgrids

Unity Power Factor Operation in Microgrid Applications Using Fuzzy Type 2 Nested Controllers

Decentralized Sensor Fault-Tolerant Control of DC Microgrids Using the Attracting Ellipsoid Method

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