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With the development of wind energy conversion system (WECS), sub-synchronous oscillations (SSO) phenomena have occurred in direct-drive permanent magnetic synchronous generators (D-PMSGs)-based wind farms. There are several studies on the analysis of the SSO worldwide. However few researchers are concern about the interaction among D-PMSGs. Considering the interaction among D-PMSGs, especially in the weak grid condition, some researches are conducted in this study. The model of D-PMSG is shown firstly. Then the simulations are carried out to research the characteristics of interaction among D-PMSGs. Control parameters of grid side converter and wind turbine (WT) operating conditions are taken into consideration. At last, a proper mitigation method is introduced. Meanwhile, the impact of interaction among WTs on the effect of mitigation method is studied. The simulation result shows that there are distinct interactions among D-PMSGs. The interactions among D-PMSGs need to be considered when coordinating the SSO mitigation control among D-PMSGs. [ABSTRACT FROM AUTHOR]

This study presents a non‐linear adaptive control (NAC) for the energy storage system (ESS) embedded dynamic voltage restorer (DVR) in enhancing the low‐voltage ride through (LVRT) capability of wind farms. The proposed NAC features a perturbation observer to estimate and then compensate the real perturbation of the whole system, including parameter uncertainties, measurement noise, and external disturbances such as different grid faults and intermittent wind power. It can achieve an adaptive and robust control without requiring accurate system model and full‐state measurements. This control is then applied to the ESS embedded DVR (ESS‐DVR) system, in which the ESS can store the blocked wind power for potential power fluctuation suppression. Simulation studies have verified that the proposed control for ESS‐DVR can effectively enhance the LVRT capability of wind farms installed with different types of WTGs under different operating conditions. Moreover, its superiority has also been demonstrated by comparing with fixed gains‐based conventional vector control and accurate system model‐based feedback linearising control. [ABSTRACT FROM AUTHOR]

Following a converter outage in a Multiterminal dc (MTDC) for offshore wind farm integration, the conventional droop control shares the power mismatch to minimize the impact on the wind power generation with a fixed droop coefficient; however, it may easily lead to the converter overloading and large dc voltage deviation. The paper proposes a fuzzy logic based adaptive droop controller, which utilizes the available power capacity of the converters to update the droop coefficient. It can make a compromise between the dc voltage deviation and the power sharing. Furthermore, the impact of the droop coefficient change on the stability of the MTDC grid is analyzed, and the effect of the dc-bus capacitor on the system dynamic is identified. The stability region is determined through the eigenvalue analysis. Time-domain simulations are conducted to compare the control strategy proposed with the conventional one. It has been proved that the adaptive control scheme can constantly track dynamic behaviors of the converters, and exhibit desirable response under different outage scenarios. [ABSTRACT FROM PUBLISHER]

The paper "Complete Provision of MPC-Based LFC By Electric Vehicles With Inertial and Droop Support from DFIG-Based Wind Farm," [1] contains two errors which are detailed as follows: [ABSTRACT FROM AUTHOR]

Since wind generation is one of the most mature renewable energy technologies, it will have the greatest share of future renewable energy portfolio. Due to the special characteristics of the wind generation, it requires extensive research to explore the best choice for wind power integration. In light of the practical project experience, this paper explores the feasibility of using HVdc transmission technology, particularly multiterminal HVdc (MTDC), as one of the preferable solutions to solve the grid interconnection issue of wind generation. This paper mainly focuses on the application of the hybrid MTDC to integrate wind farms into the electric power grid. A five-terminal hybrid MTDC model system including a large capacity wind farm is set up in PSCAD/EMTDC, in which the corresponding control strategy is designed. The operation characteristic of the hybrid system is studied, and the proposed control strategy is verified through simulation under various conditions, including wind speed variation and faults on ac side and dc side. [ABSTRACT FROM PUBLISHER]