41 research outputs found

    Control Strategy for Uninterrupted Microgrid Mode Transfer during Unintentional Islanding Scenarios

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    This paper presents a microgrid control strategy to unify the control topology for energy storage systems (ESS) and renewable energy sources (RES) inverters in an AC microgrid and to protect the microgrid reliability from unintentional islanding instability using control loops which use the DC link voltage as a feedback. This bounds the DC link voltage and provides reliable operation in the microgrid. Simulation validates the proposed control strategy, and experiment results extol the concept

    A Novel Power Sharing Control Method for Distributed Generators in DC Networks

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    The power sharing control method is a desirable solution to integrate multiple renewable energy generators into the grid and to keep them working synchronously. Power sharing control between different distributed generators is an important consideration for the stabilized operation of the power grid network. In this thesis work, a novel method is used with the concept of droop control technique and is designed to control power from each individual generator in DC network particularly. The proposed power sharing control method can be widely applied to grid connected network and to islanded power grid network for obtaining high efficiency of power distribution and also provides higher stability. An efficient power control method to share the load demand power is designed based on the concept of droop control. This method does not follow sequential or predefined topology of power sharing but uses the availability of power from each generator as a factor of control. The proposed controller can be applied to an individual distributed generator to regulate its output power quickly and accurately. The power sharing control method was formulated, modeled and verified by simulation studies of steady state and transient stability tests. The optimal coupling resistance for power sharing was also identified. The interaction of the controller and the communication delay was also studied. The interference of communication delay is negligible for the power sharing controller. The system is simulated in MATLAB/SIMULINK environment

    Virtual Oscillator Control of Multiple Solar PV Inverters for Microgrid Applications

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    This paper proposes the inverter control strategy for multiple solar PV generation sources based on the two-stage converters with a combination of the modified virtual oscillator control (VOC) and the cascaded sliding mode control (SMC). With this proposed control strategy, the load power-sharing in proportion to the inverter rating is guaranteed when the solar PV output satisfies the power-sharing requirement. On the other hand, the control algorithm autonomously forces the solar PV to operate at the maximum power point if the solar PV output is lower than the power-sharing requirement. Various operating scenarios have been simulated to appreciate the effectiveness of the proposed control scheme for ensuring the load-power sharing and maintaining the voltage and frequency stability of the islanded microgrid containing a 100% solar PV generation

    A Comprehensive Inertial Control Strategy for Hybrid AC/DC Microgrid with Distributed Generations

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    A New Robust Control Strategy for Parallel Operated Inverters in Green Energy Applications

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    This research work puts forward a hybrid AC/DC microgrid with renewable energy sources pertaining to consumer’s residential area for meeting the demand. Currently, the power generation and consumption have experienced key transformations. One such tendency would be integration of microgrids into the distribution network that is characterized by high penetration of renewable energy resources as well as operations in parallel. Traditional droop control can be employed in order to get an accurate steady state averaged active power sharing amongst parallel inverters pertaining to hybrid AC/DC microgrid. It is presumed that there would be similar transient average power responses, and there would be no circulating current flowing between the units for identical inverters possessing the same droop gain. However, the instantaneous power could be affected by different line impedances considerably and thus resulting in variation in circulating power that flows amongst inverters, especially during unexpected disturbances like load changes. This power, if absorbed by the inverter, could result in sudden DC-link voltage rise and trip the inverter, which in turn causes performance degradation of the entire hybrid microgrid. When the hybrid generators act as unidirectional power source, the issue worsens further. In this research work, we have put forward a new distributed coordinated control pertaining to hybrid microgrid, which can be applied for both grid connected and islanded modes that include variable loads and hybrid energy resources. Also, in order to choose the most effective controller scheme, a participation factor analysis has been designed for binding the DC-link voltage as well as reducing the circulating power. Moreover, to both photovoltaic stations and wind turbines, maximum power point tracking (MPPT) techniques have been used in order to extract the maximum power from hybrid power system when there is discrepancy in environmental circumstances. Lastly, the feasibility and effectiveness pertaining to the introduced strategy for hybrid microgrid in various modes are confirmed via simulation results

    Priority-driven self-optimizing power control scheme for interlinking converters of hybrid AC/DC microgrid clusters in decentralized manner

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    Hybrid AC/DC microgrid clusters are key building blocks of smart grid to support sustainable and resilient urban power systems. In microgrid clusters, the subgrid load-priorities and power quality requirements for different areas vary significantly. To realize optimal power exchanges among microgrid clusters, this paper proposes a decentralized self-optimizing power control scheme for interlinking converters (ILC) of hybrid microgrid clusters. A priority-driven optimal power exchange model of ILCs is built considering the priorities and capacities in subgrids. The optimization objective is to minimize the total DC-voltage/AC-frequency state deviations of subgrids. To realize the decentralized power flow control, an optimal-oriented quasi-droop control strategy of ILCs is introduced to not only achieve a flexible self-optimizing power flow management, but also provide an ancillary function of voltage support. Consequently, as each of ILCs only monitors the local AC-side frequency and DC-side voltage signals, the whole optimal power control of the wide-area microgrid clusters is achieved in a decentralized manner without any communication link. Thus, the proposed control algorithm has the features of decreased cost, increased scalability, reduced geographic restrictions and high resilience in terms of communication faults. Finally, the proposed method is validated by case studies with four interconnected microgrids through hardware-in-loop tests

    Electric Power Conversion and Micro-Grids

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    This edited volume is a collection of reviewed and relevant research chapters offering a comprehensive overview of recent achievements in the field of micro-grids and electric power conversion. The book comprises single chapters authored by various researchers and is edited by a group of experts in such research areas. All chapters are complete in themselves but united under a common research study topic. This publication aims at providing a thorough overview of the latest research efforts by international authors on electric power conversion, micro-grids, and their up-to-the-minute technological advances and opens new possible research paths for further novel developments

    Microgrid energy management and monitoring systems: A comprehensive review

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    Microgrid (MG) technologies offer users attractive characteristics such as enhanced power quality, stability, sustainability, and environmentally friendly energy through a control and Energy Management System (EMS). Microgrids are enabled by integrating such distributed energy sources into the utility grid. The microgrid concept is proposed to create a self-contained system composed of distributed energy resources capable of operating in an isolated mode during grid disruptions. With the Internet of Things (IoT) daily technological advancements and updates, intelligent microgrids, the critical components of the future smart grid, are integrating an increasing number of IoT architectures and technologies for applications aimed at developing, controlling, monitoring, and protecting microgrids. Microgrids are composed of various distributed generators (DG), which may include renewable and non-renewable energy sources. As a result, a proper control strategy and monitoring system must guarantee that MG power is transferred efficiently to sensitive loads and the primary grid. This paper evaluates MG control strategies in detail and classifies them according to their level of protection, energy conversion, integration, benefits, and drawbacks. This paper also shows the role of the IoT and monitoring systems for energy management and data analysis in the microgrid. Additionally, this analysis highlights numerous elements, obstacles, and issues regarding the long-term development of MG control technologies in next-generation intelligent grid applications. This paper can be used as a reference for all new microgrid energy management and monitoring research

    Design and Control of Power Converters 2019

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    In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc
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