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Hongjun Shi, Lei Xiong, Xuchen Nie and Qixin Zhu
This paper aims to mainly discuss how to suppress the disturbances accurately and effectively in the wind energy conversion system (WECS) of the direct drive surface mount…
This paper aims to mainly discuss how to suppress the disturbances accurately and effectively in the wind energy conversion system (WECS) of the direct drive surface mount permanent magnet synchronous generator (SPMSG).
The disturbances in wind energy conversion system have seriously negative influence on the maximum power tracking performance. Therefore, a model predictive control (MPC) method of model compensation active disturbance rejection control (ADRC) strategy in parallel connection is designed, which optimizes the speed tracking performance compared with the existing control strategy of MPC and ADRC in series connection. Based on the traditional ADRC, a multi parameter model compensation ADRC strategy is added to better estimate the disturbances. At the same time, a torque feedback strategy is added to compensate the disturbances caused by load torque and further optimize the speed loop tracking performance.
The simulation results show that the designed control method has advantages than the traditional control method in compensating the disturbances and tracking the maximum power more effectively.
The simulation results show that the designed control method is superior to the traditional proportional control method, which can better compensate the internal and external disturbances and track the maximum power more effectively.
Hang Yin, Jishan Hou, Chengju Gong and Chen Xu
The behavior of the entities in a small and medium-sized enterprise (SME) cooperation network is influenced by the core enterprise. Addressing the problem of how the…
The behavior of the entities in a small and medium-sized enterprise (SME) cooperation network is influenced by the core enterprise. Addressing the problem of how the network vulnerability changes when the core enterprise is attacked is a challenging topic. The purpose of this paper is to reveal the failure process of SME cooperation networks caused by the failure of the core SME from the perspective of cascading failure.
According to the Torch High Technology Industry Development Center, Ministry of Science & Technology in China, 296 SMEs in Jiangsu province were used to construct an SME cooperation network of technology-based SMEs and an under-loading cascading failure model. The weight-based attack strategy was selected to mimic a deliberate node attack and was used to analyze the vulnerability of the SME cooperation network.
Some important conclusions are obtained from the simulation analysis: (1) The minimum boundary of node enterprises has a negative relationship with networks' invulnerability, while the breakdown probability has an inverted-U relationship with networks' invulnerability. (2) The combined effect of minimum boundary and breakdown probability indicates that the vulnerability of networks is mainly determined by the breakdown probability; while, minimum boundary helps prevent cascading failure occur. Furthermore, according to the case study, adapting capital needs and resilience in the cooperation network is the core problem in improving the robustness of SME cooperation networks.
This research proposed an under-loading cascading failure model to investigate the under-loading failure process caused by the shortage of resources when the core enterprise fails or withdraws from the SME cooperation network. Two key parameters in the proposed model—minimum capacity and breakdown probability—could serve as a guide for research on the vulnerability of SME cooperation networks. Additionally, practical meanings for each parameter in the proposed model are given, to suggest novel insights regarding network protection to facilitate the robustness and vulnerability in real SME cooperation networks.