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Sliding Mode Control of Hybrid Renewable Energy System Operating in Grid Connected and Stand-Alone Mode

Benadli Ridha, Bjaoui Marwen, Khiari Brahim, Sellami Anis

Power Electronics and Drives

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2021

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Vol. 6 (41)

144--166

EN

This paper studies innovative application of sliding mode control (SMC) for a Hybrid Renewable Energy System (HRES) in grid-connected and autonomous modes of operation. The considered HRES includes a photovoltaic (PV), wind turbine (WT) based on a Permanent Magnet Synchronous Generator (PMSG). The PV generator is coupled to the common DC bus via a DC/DC converter. The latter is controlled by an MPPT algorithm based on the Adaptive Perturbation and Observation Algorithm Method (APOAM) to search the optimum working of this source. A SMC is utilized to manage the PV voltage to achieve the Maximum Power Point (MPP) by altering the obligation duty cycle. The battery interfaced by a bidirectional buck-boost DC/DC converter can be charged or discharged depending on the production situation. On the one hand, the wind turbine conversion chain is equipped with a PMSG and a rectifier controlled to regulate the operating point of the wind turbine to its optimum value. During a Stand-Alone Mode (SAM) operation, the Voltage Source Converter (VSC) was used for controlling the output voltage in terms of amplitude and frequency delivered to the AC load. However, in Grid-Connected Mode (GCM) operation, the VSC was adapted to control the electrical parameters of the grid. To better appreciate the advantages of the proposed SMC approach, we have proposed a series of comparative tests with the conventional PI control in the operating modes GC and SA and under different scenarios. The proposed control strategy has undeniable advantages in terms of control performance and very low total harmonic distortion THD value compared with the conventional PI control. Finally, It is concluded that the proposed approach improves the quality and provides a stable operation of the HRES.

2

Communication assisted fuzzy based adaptive protective relaying scheme for microgrid

Chaitanya B. K., Soni A. K., Yadav A.

Journal of Power Technologies

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2018

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Vol. 98, nr 1

57--69

EN

This study proposes a communication assisted fuzzy based adaptive protective relaying scheme for fault detection, fault classification and faulty phase identification of microgrid along with a solution to isolate the microgrid from the utility grid by disconnecting the static-switch. Any fault in the utility grid causes the microgrid to be isolated from the utility grid whereas if there is a fault in the microgrid it continues to operate with the utility grid. An adaptive fuzzy inference system has been developed using a separate fuzzy rule base for the two modes of operation of microgrid, i.e. islanded mode or grid connected mode. The Central Grid Status Communication System (CGSCU) is considered which monitors the status of PCC and sends a command signal to the relays so that the relay settings are updated with new rules for any transition in the mode of the microgrid. The fundamental phasor amplitude and zero sequence component of current signals are used as input features, fault detection, fault classification and faulty phase identification. A standard microgrid model IEC 61850-7-420 was simulated using MATLAB/SIMULINK. The proposed method is tested for all types of faults by varying fault parameters and also for dynamic situations such as connection/disconnection of DGs and loads. The test results substantiate the effectiveness of the method.

3

Monitoring and Control Algorithms Applied to Small Wind Turbine with Grid-Connected/Stand-Alone Mode of Operation

Milczarek A., Malinowski M.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 12a

18-22

EN

This paper presents control of a three-phase DC/AC converter with grid monitoring algorithm applied to Small Wind Turbine (SWT). Monitoring through voltage amplitude and frequency measurement detect electrical grid faults and automatically change the grid-connected/standalone mode of operation. Inverse transition stand-alone/grid-connected is preceded by synchronization of DC/AC converter to electrical grid with the help of special Phase Locked Loop (PLL) block.

PL

Poniższy artykuł opisuje sterowanie trójfazowym przekształtnikiem DC/AC z algorytmem monitorowania sieci elektroenergetycznej do zastosowania w Małej Elektrowni Wiatrowej (MEW). Algorytm monitorujący amplitudę oraz częstotliwość napięcia sieci wykrywa awarię sieci elektroenergetycznej i automatycznie przełącza tryb pracy elektrowni z pracy z siecią elektroenergetyczną do pracy autonomicznej. Natomiast przełączenie z pracy autonomicznej do pracy elektrowni z siecią elektroenergetyczną następuje po uprzedniej synchronizacji przekształtnika DC/AC z siecią elektroenergetyczną za pomocą pętli synchronizacji fazowej (PLL).