Current Issue : October-December Volume : 2025 Issue Number : 4 Articles : 5 Articles
Speed, position, and load torque information are crucial for the stable control of wind turbines, and existing control methods heavily rely on position and torque sensors to obtain these parameters. However, under the extreme scenario of sensor faults, the performance of these control methods deteriorates significantly, often leading to instability. In this paper, an acceleration-observer-based position and load torque estimation method is proposed for wind turbines, which effectively mitigates the impact of sensor faults. The position, speed, and acceleration estimators are developed based on current and voltage sensors information instead of position and load torque sensors. Then, the load torque can be calculated directly through the current and acceleration information. Thereby, the proposed method reduces reliance on position and load torque sensors for stable control and enables effective load torque estimation even under sensor faults. Rigorous theoretical analysis is provided to show that the proposed estimation method is stable and can effectively estimate position, speed, acceleration, and load torque information. Our numerical simulation results demonstrate that the proposed method exhibits excellent dynamics, accuracy, and robustness under various operating conditions....
Traditional sand casting is limited by mold fabrication, cost control, and data collection, which restrict its further advancement. However, 3D sand printing technology represents a sophisticated rapid prototyping approach that directly utilizes three-dimensional models to fabricate complex sand molds and cores, thereby bypassing the traditional mold-making steps. This technology significantly enhances production efficiency and design flexibility, thereby advancing the modernization of casting processes. In the context of wind tunnel testing, the application of 3D-printed sand shell additive manufacturing has successfully produced sand molds and cores for the non-axisymmetric intake duct structures. This demonstrates the feasibility of this technology for complex casting applications and its capability to meet experimental requirements....
Understanding aeolian sediment transport and wind erosion enhances our knowledge of desert dune formation and sand migration. The Makran region of southern Sistan and Baluchistan is prone to wind-driven erosion alongside frequent sand and dust storms (SDSs). Hourly wind data from two meteorological stations spanning 1994–2020 were analyzed to study erosive winds and sand transport. Wind energy analysis using drift potential (DP) indicated low energy (DP < 200 in vector unit) and minimal spatial variation across the Makran dune elds. The eective winds transporting sand particles were towards the east from November to May, and in the northwestern direction from June to October. The DP showed a gradual decline in the study area from 1990 to 2022, with no signicant temporal trends. The sand dune morphology analysis indicates that bimodal wind regimes primarily form linear dunes and sand sheets, while crescentic, transverse, and topographic dunes are also present....
There have been numerous reported accidents of lightning strikes damaging wind turbine blades, which poses a serious problem. In certain accidents, the blades that were struck by lightning continued to rotate, resulting in breakage due to centrifugal force. Considering this background, wind turbines situated in Japan have been mandated to be equipped with emergency stop devices. Consequently, upon detection of a lightning strike by the device installed on the wind turbine, the turbine is promptly stopped. In order to restart the wind turbine, it is necessary to verify its soundness by conducting a visual inspection. However, conducting prompt inspections can be difficult due to various factors, including inclement weather. Therefore, this process prolongs the downtime of wind turbines and reduces their availability. In this study, an approach was proposed: a SCADA data analysis method using an autoencoder to assess the soundness of wind turbines without visual inspection. The present method selected wind speed and rotational speed as effective features, employing a sliding window for pre-processing, based on previous studies. Besides, the assessment of a trained autoencoder was conducted through the utilization of the confusion matrix and the receiver operating characteristic curve. It was suggested that the availability of wind turbines could be improved by employing this proposed method to remotely and automatically verify the soundness after lightning detection....
In previous studies, the possibilities of Ku-band radar measurements at low incidence angles were investigated for the task of sea ice detection. In this paper, the sensitivity of normalized radar cross-section to sea ice concentration is investigated at various wind conditions. The data of Ku-band radar onboard GPM satellite are used, and the sea ice concentration product from Bremen University website is implemented as reference data and the information on wind speed from reanalysis was applied. Simple analytical parameterization was obtained for the normalized radar cross-section depending on sea ice concentration and wind speed for various incidence angles using the regression method. The threshold behavior of the normalized radar cross-section with increase in wind speed was revealed and preferable wind conditions for sea ice concentration detection were identified....
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