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Global environmental changes, nuclear power risks, losses in the electricity grid, and rising energy costs are increasing the desire to rely on more renewable energy for electricity generation. Recently, most people prefer to live and work in smart places like smart cities and smart universities which integrating smart grid systems. The large part of these smart grid systems is based on hybrid energy sources which make the energy management a challenging task. Thus, the design of an intelligent energy management controller is required. The present paper proposes an intelligent energy management controller based on combined fuzzy logic and fractional-order proportional-integral-derivative (FO-PID) controller methods for a smart DC-microgrid. The hybrid energy sources integrated into the DC-microgrid are constituted by a battery bank, wind energy, and photovoltaic (PV) energy source. The source-side converters (SSCs) are controller by the new intelligent fractional order PID strategy to extract the maximum power from the renewable energy sources (wind and PV) and improve the power quality supplied to the DC-microgrid. To make the microgrid as cost-effective, the (wind and PV) energy sources are prioritized. The proposed controller ensures smooth output power and service continuity. Simulation results of the proposed control schema under Matlab/Simulink are presented and compared with the super twisting fractional-order controller.

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Variable speed wind turbine generators installation has been significantly increased worldwide in the last few years. Faults at the grid side may call for the disconnection of the wind turbine from the grid as under such events, wind turbine generator (WTG) may not comply with the recent developed grid codes for wind energy conversion systems (WECS). In this paper, a unified power flow controller (UPFC) is applied to improve the fault ride through (FRT) capability of doubly fed induction generator (DFIG)-based WECS during voltage swell and voltage sag at the grid side. Simulation is carried out using MATLAB/Simulink software. Results show that UPFC can effectively improve the FRT capability of DFIG-based WECS and hence maintaining wind turbine connection to the grid during certain levels of voltage fluctuation at the grid side.

A little attention has been paid to the faults within the converter switches of a wind energy conversion system (WECS). Solutions suggested in the literature to improve the performance of a WECS rely on compensating the reactive power at the point of common coupling (PCC) to maintain the PCC voltage within the limits specified by the grid codes. Recently, transmission line operators have expanded WECS codes to include active power support to the grid during fault conditions. Therefore, to maintain the connection of a wind turbine during various disturbance events, it is essential to fulfil grid codes. This paper introduces a new application for a static synchronous compensator (STATCOM) equipped with a high-temperature superconducting coil (HTS) to compensate both active and reactive powers at the PCC during short-circuit events within the insulated-gate bipolar transistor (IGBT) switches of the grid side converter (GSC) of a doubly-fed induction generator (DFIG)-based WECS. Compliance of the voltage profiles of the DFIG with the fault ridethrough (FRT) specified in the recent grid codes of the USA, andSpain, with and without the proposed controller, is examined. Simulation results show that the proposed controller can bring the active and reactive power at the PCC to their nominal steady-state levels during studied fault.

This paper designs an intelligent energy management control for a stand alone smart DCmicro-grid using super twisting fractional order method. Based on mathematical model of the micro-grid, controllers are derived for the source side converters such as photovoltaic (PV),wind, AC grid and battery management system, and load side converters. Based on the available measured input and consumed output power, an intelligent energy management algorithm decides the appropriate mode of operation for the source and load side converters controller.All DC loads connected to the micro-grid are treated as essential loads and no load shedding can be allowed by the energy management unit. The energy management unit prioritizes the renewable energy sources (PV and wind) in order to make the micro-grid as cost effective. The performance of the proposed control scheme is compared with the integer order controller and the system is simulated in MATLAB/SIMULINK environment for different test cases.

The use of voltage source multilevel inverters (VS-MLIs) has grown enormously over the last decade, and it is expected that these inverters will be deployed in future power grids (smart grids), especially for medium voltage-high power applications. This paper investigates the application of passive power filters (PPFs) for harmonic mitigation at the output of VS-MLIs for more efficient grid integration of renewable energy sources. It proposes a generic model, using a heuristic approach, for the optimum design of an LCL power filter at the output of VS-MLIs. The proposed model transforms the LCL filter design problem into an optimization problem and applies a genetic algorithm (GA) to solve it. The objective function to be optimized is a multi-objective function based on inverters' total harmonic distortion and energy losses. The optimization problem is subject to applied design constraints. As a main optimization objective, a precise evaluation methodology for the inverter power losses is presented, which was built according to a practical switching device datasheet. The method is applicable to any VS-MLI topology and any number of levels (N). As a case study, the proposed design optimization approach was implemented to optimally design the LCL filter at the output of a grid connected 11 KV, 5 MVA 7-level cascaded H-bridge multilevel invert (CHB-MLI). The IGBT module Device IGBT of type FZ400R65KE3 by Infineon was used for simulation. MATLAB-SIMULINK is used for the modelling and simulation. We found that the proposed design approach is more generic, efficient, and simple to apply than conventional design approaches which requires more system detail, relies more on the designer's experience, and normally does not results in optimum design. The proposed approach is generic and can be applied for different VS-MLIs topologies and for any number of levels (N).

This book presents information about the application of various flexible AC transmission system devices to wind energy conversion systems. Devices such as unified power flow controllers, superconducting magnetic energy storage and static synchronous compensators are covered in this book. Chapters detail features of the topology and basic control systems of each device. Additionally, case studies are presented where necessary to demonstrate practical applications. This book is a reference for students and technicians studying wind power and AC transmission systems in advanced engineering courses.