Power
H. Berahmandpour; S. M. Kouhsari; H. Rastegar
Abstract
Background and Objectives: Uncertainty and variability are two main specifications of wind generation and the ability of the power system to overcome these challenges is called flexibility. The flexibility index is a measure to evaluate the flexibility level of the power system mainly to achieve the ...
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Background and Objectives: Uncertainty and variability are two main specifications of wind generation and the ability of the power system to overcome these challenges is called flexibility. The flexibility index is a measure to evaluate the flexibility level of the power system mainly to achieve the best level system flexibility.Methods: Flexibility index should show a good view of the ability of the power system and also be easily converted to an equivalent cost to be combined with the operation cost function. So, in this paper by using economic dispatch simulation for the economic trade-off between the generation cost and the cost of flexibility, the best level of system flexibility in the presence of wind farms considering unit constraints and system loss is achieved. Where the difference between flexibility index in the no wind base case and the flexibility index in each time zone with wind incorporation is defined as the flexibility penalty by the suitable penalty factor. The combination of generation cost and flexibility cost makes the main part of objective function.Results: The results on the test system verify the proposed method where by increasing penalty factor, improvement in flexibility index is achieved but the generation cost will be increased. So, it shows a good economic trade-off between generation cost and flexibility value. Also the desired flexibility level can be obtained by changing the penalty factor in each wind power penetration. So, the result of the sensitivity analysis shows the best level of flexibility regarding operation cost.Conclusion: In this paper a new flexibility index is introduced especially for wind power incorporation and for real time operation purpose. This index can be combined by economic dispatch objective function as the penalty (cost) for economic trade-off analysis and to show the best flexibility level of generation system in each operation point.
Control
M. I. Hosseini; M.R. Jafari Harandi; S. A. Khalilpour Seyedi; H. Taghirad
Abstract
Background and Objectives: Fast-tracking of reference trajectory and performance improvement in the presence of dynamic and kinematic uncertainties is of paramount importance in all robotic applications. This matter is even more important in the case of cable-driven parallel robots due to the flexibility ...
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Background and Objectives: Fast-tracking of reference trajectory and performance improvement in the presence of dynamic and kinematic uncertainties is of paramount importance in all robotic applications. This matter is even more important in the case of cable-driven parallel robots due to the flexibility of the cables. Furthermore, cables are limited in the sense that they can only apply tensile forces, for this reason, feedback control of such robots becomes more challenging than conventional parallel robots.Methods: To address these requirements for a suspended cable-driven parallel robot, in this paper a novel adaptive fast terminal sliding mode controller is proposed and then the stability of the closed-loop system is proven. In the proposed controller, a nonlinear term as a fractional power term is used to guarantee the convergent response at a finite time.Results: At last, to show the effectiveness of the proposed controller in tracking the reference trajectory, simulations and the required experimental implementation is performed on a suspended cable-driven robot. This robot, named ARAS-CAM, has three degrees of transmission freedom.Conclusion: The obtained experimental results confirm the suitable performance of this method for cable robots in the presence of dynamic uncertainties.
