646 research outputs found
Short-Circuit Impedance of Power Transformers: the Fractional Order Calculus Approach
First IFAC Workshop on Fractional Differentiation and Its Application - 19-21 July 2004, Enseirb, Bordeaux, France - FDA'04This paper reports investigation on the modeling of the short circuit
impedance of power transformers, using fractional order calculus, analyzing the
influence of the diffusion phenomena in the windings. This aims to better
characterize the medium frequency range behavior of leakage inductances of power
transformer models, which include terms to represent the magnetic field diffusion in
the windings. Calculated and measured values are shown and compared
Adaptive Fractional-Order Sliding Mode Controller with Neural Network Compensator for an Ultrasonic Motor
Ultrasonic motors (USMs) are commonly used in aerospace, robotics, and
medical devices, where fast and precise motion is needed. Remarkably, sliding
mode controller (SMC) is an effective controller to achieve precision motion
control of the USMs. To improve the tracking accuracy and lower the chattering
in the SMC, the fractional-order calculus is introduced in the design of an
adaptive SMC in this paper, namely, adaptive fractional-order SMC (AFOSMC), in
which the bound of the uncertainty existing in the USMs is estimated by a
designed adaptive law. Additionally, a short memory principle is employed to
overcome the difficulty of implementing the fractional-order calculus on a
practical system in real-time. Here, the short memory principle may increase
the tracking errors because some information is lost during its operation.
Thus, a compensator according to the framework of Bellman's optimal control
theory is proposed so that the residual errors caused by the short memory
principle can be attenuated. Lastly, experiments on a USM are conducted, which
comparative results verify the performance of the designed controller.Comment: 9 pages, 9 figure
Fractional order calculus on the estimation of short-circuit impedance of power transformers
This paper reports investigation on the use of fractional order calculus to analytically estimate the inlfuence of skin and proximity effects in the short circuit impedance of power transformers. The aim is to better characterize the medium frequency range behavior of leakage inductances of power transformer models, which include terms to represent the magnetic field diffusion process in the windigns. Comparisons between calculated and measured values are shown and discussed.N/
On the Estimation of the Short-Circuit Impedance of Power Transformers Using Fractional Order Calculus
This paper reports investigation on the estimation of the short circuit
impedance of power transformers, using fractional order calculus to analytically
study the influence of the diffusion phenomena in the windings. The aim is to better
characterize the medium frequency range behavior of leakage inductances of power
transformer models, which include terms to represent the magnetic field diffusion
process in the windings. Comparisons between calculated and measured values are
shown and discussed
The potential of fractional order distributed MPC applied to steam/water loop in large scale ships
The steam/water loop is a crucial part of a steam power plant. However, satisfying control performance is difficult to obtain due to the frequent disturbance and load fluctuation. A fractional order model predictive control was studied in this paper to improve the control performance of the steam/water loop. Firstly, the dynamic of the steam/water loop was introduced in large-scale ships. Then, the model predictive control with an extended prediction self adaptive controller framework was designed for the steam/water loop with a distributed scheme. Instead of an integer cost function, a fractional order cost function was applied in the model predictive control optimization step. The superiority of the fractional order model predictive control was validated with reference tracking and load fluctuation experiments
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