Testability modeling and analysis play an increasingly important role in improving the level of testability design of products. Based on the correlation matrix, the testability analysis is carried out with a gas purif...
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When the substation grounding grid and part of the underground metal pipe grid are close to each other, the two produce resistive coupling, and the current of the transmission line will flow through the grounding body...
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As the converter-based renewable power generation has been extensively integrated into grid, the transient synchronizing stability accidents of gird induced by voltage source convert (VSC) are emerging more and more f...
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ISBN:
(数字)9798350368345
ISBN:
(纸本)9798350368352
As the converter-based renewable power generation has been extensively integrated into grid, the transient synchronizing stability accidents of gird induced by voltage source convert (VSC) are emerging more and more frequently and severely. In this paper, the transient synchronizing dynamics of the VSC are depicted by a reduced-order model. Then, its transient synchronizing stability is examined and analyzed by the large-signal basin of attraction (BOA) of the VSC. The system shows two kinds of boundaries of the BOA under different parameters, including the closed-loop area and the fish-like area. The boundary of the closed-loop area is depicted by the equipotential plane estimation based on the energy function. The boundary of the fish-like area is estimated through the method of hyperplane in the first quadrant. Meanwhile, the transient synchronizing stability criteria can be established based on the estimated boundaries and the numerically integral fault trajectories. Furthermore, the critical clearing angle (CCA) is analytical calculated through the analytically derived fault trajectory under the worst fault conditions. Meanwhile, the critical clearing times (CCT) can also be analytical calculated. Both the analytical CCA and CCT can provide enough margin for the transient control and protection. Finally, several simulations have verified the effectiveness and accuracy of the proposed method in MATLAB.
Integrated navigation technology is widely used in aviation, aerospace, sailing and other ground-based navigation equipment, the inertial navigation system (INS) is the most common tool. In practice, the key to naviga...
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Modal frequencies are often used in structural model updating, based on the finite element model, while the metamodel approach is often used in the respective optimization process. In this work, the Kriging model is a...
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This paper investigates the long-time deorbiting problem of an electrodynamic tether system. The dynamics modeling is conducted by adopting an assumption of a dumbbell model. Besides,the effects of Lorentz force,atmos...
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ISBN:
(数字)9789887581581
ISBN:
(纸本)9798350366907
This paper investigates the long-time deorbiting problem of an electrodynamic tether system. The dynamics modeling is conducted by adopting an assumption of a dumbbell model. Besides,the effects of Lorentz force,atmospheric drag,and J2perturbation on the orbital dynamics are involved in to improve the accuracy of the system model. Three current control strategies,including the constant current input,directionally variable current input,and the optimal current control,are proposed for deorbiting of the electrodynamic tether system. To maintain the stability of the attitude motion of the system and maximize the utilization of Lorentz force,a current switching control strategy is adopted to facilitate the control strategies. Finally,comparative numerical simulations are presented to exhibit the deorbiting efficiency and to validate the effectiveness of the control strategies.
This paper introduces in detail the origin of the development of automatic control methods, applications and current research hotspots. It also introduces some control methods commonly used in industrial and agricultu...
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ISBN:
(数字)9798350363173
ISBN:
(纸本)9798350363180
This paper introduces in detail the origin of the development of automatic control methods, applications and current research hotspots. It also introduces some control methods commonly used in industrial and agricultural production, and expounds the current application hotspots and new advanced control methods that are developing rapidly. The background, current situation and classification of the inverted pendulum platform are introduced in detail. In the first chapter, the LQR method in modern control theory is introduced in detail. The influence of parameters is analyzed through simulink space modeling and simulation control experiment. At the same time, the real-time experiment is also done in combination with the hardware platform. In the second chapter, the fuzzy control theory in intelligent control is introduced in detail. By combining fuzzy control with LQR method, suitable LQR parameters are calculated by pole assignment. After proper adjustment, reasonable fuzzy rules are adopted and adaptive fuzzy control principle is applied to adjust the control situation in real time. Using simulink space modeling, a good simulation control effect is obtained. Finally, the summary is made.
The inverse heat transfer method is an effective inversion algorithm for solving the heat transfer at non-measurable places of the study object. However, the current inverse heat transfer inversion method has the prob...
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ISBN:
(数字)9789887581581
ISBN:
(纸本)9798350366907
The inverse heat transfer method is an effective inversion algorithm for solving the heat transfer at non-measurable places of the study object. However, the current inverse heat transfer inversion method has the problems of low accuracy and difficult selection of temperature measurement point locations. To solve this problem, this paper proposes an optimization algorithm for measurement point locations based on improved fuzzy c-means clustering(IFCM). The method first generates the initial clustering center through a specific density function and introduces the Mahalanobis distance to solve the problem that the traditional fuzzy c-means clustering results depend on the initial clustering center and the results are unstable. Then, an optimized deployment algorithm based on IFCM temperature measurement points is proposed and compared with other mean value clustering algorithms. Finally, the optimal temperature measurement position on the crystal surface is selected by the IFCM temperature measurement point optimization deployment algorithm on the CZ(Czochraski)silicon single crystal growth equipment, and the inversion results of the randomly selected temperature measurement point scheme and the optimized temperature measurement point scheme are compared by the real-time inversion algorithm based on the dynamic matrix control multi-boundary heat flux, and the results of the optimized temperature measurement point scheme are obtained to be better than that of the randomly selected temperature measurement point scheme.
Both the phase-locked loop (PLL) and the common coupling point (PCC) voltage feedforward may have impacts on the inverter system stability in weak grid. Therefore, a hybrid impedance reshaping control strategy is prop...
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In this paper, the design and optimization of multi-aircraft cooperative guidance law with multi-constraint is studied for high-speed and large maneuvering targets. Firstly, the motion of the aircraft and the target a...
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