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This article introduces a new configuration of the doubly-fed induction generator (DFIG) based wind energy conversion system (WECS) employing only a reduced-size rotor side converter (RSC) in tandem with a supercapacitor. In the proposed structure, the grid side converter (GSC) utilized in conventional DFIG-based WECSs is successfully eliminated. This is accomplished by employing the hydraulic transmission system (HTS) as a continuously variable and shaft decoupling transmission unit. This transforms the conventional constant-ratio drives by providing an opportunity to control the power flow through the generator's rotor circuit regardless of the wind turbine's shaft speed. This feature of HTS can be utilized to control the RSC power and ultimately regulate the supercapacitor voltage without a need for GSC. The proposed system is investigated and simulated in MATLAB Simulink at various wind speeds to validate the results and demonstrate the dynamic performance of the system.

Industrial Internet of Things (IIoT) is an architecture that facilitates the feasibility of the distributed control of the modernized industrial systems mainly through the Internet of Things and cloud computing. This article proposes an optimal scheduling framework for the real-time operation of smart microgrids in the IIoT environment using an average consensus-based algorithm. The introduced framework suggests a fog layer as a complementary layer of IIoT to reduce latency and provide local computation and data storage for the proposed industry. Security of the system against probable attacks is the other concern that should be observed. To this end, this article sets out to evaluate the impact of a particular type of attack called the denial of service on the performance of the proposed method. Accuracy, feasibility, and fast response of the scheme are demonstrated through simulation results on a microgrid test system in the presence of dispatchable and nondispatchable generation units with heterogeneous devices.

Employment of a specific technology in the conversion of wind energy to electrical power highly influences the cost and reliability of power generation. To help the selection of the best drivetrain technology, this article presents a thorough review of three major wind turbine drivetrains, namely gearbox, direct drive, and hydrostatic. Although the gearbox drivetrain has offered a mature and applicable technology, some inherent difficulties and manufacturing of specific generators and advancements in fluid power machinery resulted in new technologies that are true competitors of the gearbox. The cost, performance, and functionality of these drivetrains are now comparable with the gearbox peers. This article presents a comprehensive review of three different types of the drivetrain and their generators. This article particularly helps researchers and the engineers in the field with new insight into all technologies.

This paper presents the dynamics and control of a new wind power plant configuration where multiple turbines are connected to a shared drivetrain. A hydrostatic transmission system is utilized to collect and transfer the harvested mechanical energy of individual turbines to the generator. The interconnected wind turbines are controlled individually to achieve maximum power point tracking (MPPT) while regulating the generator speed. In the first control loop, the pump displacement is adjusted accordingly to satisfy the MPPT. In the second control loop, the electrical load on the generator is controlled to balance the torque and reach a stable frequency operation. Simulation results show the performance of the control system operation. It also demonstrates an increase and improved smoothness of a power generation profile.

Hydraulic wind power transfer systems deliver the wind energy from multiple wind turbines to a centralized generator through a hydraulic medium, which effectively reduces the equipment and maintenance costs. In this system, the main generator should be remained at a constant rotational velocity regardless of the rotor speed to provide a fixed electrical voltage to the grid. To achieve this, a proportional valve is used to control the amount of flow between the main and auxiliary generators. In this paper, a controller is designed, simulated, and implemented to regulate the flow in the proportional valve. The control system is tested in MATLAB/Simulink and experimentally validated using dSPACE 1104.

Hydraulic circuits can transfer remarkable amounts of energy in the desired direction without taking large space. To implement this technology for harvesting the energy of wind appropriately, models of the system are required. Hydraulic wind power technology has the benefits of eliminating expensive and bulky variable ratio gearbox and its costly maintenance, while enabling the integration of multiple wind turbines in a single generation unit. In this paper, the dynamics of different hydraulic elements are studied, nonlinearities are taken into account, pressure dynamics in different parts of the system are studied, and the motor load effects are considered. Based on these considerations, a novel nonlinear state-space representation of the system is introduced. Results of the mathematical model and the experimental data are compared to verify the proposed model. The comparison demonstrated that the mathematical model captures all major characteristics of the hydraulic circuit and can model the system behavior under different operating conditions.