This paper presents the design of a robust fixed-order H<sub>∞</sub> controller to damp out the inter-area oscillations and to enhance the stability of the power system. The proposed H<sub>...This paper presents the design of a robust fixed-order H<sub>∞</sub> controller to damp out the inter-area oscillations and to enhance the stability of the power system. The proposed H<sub>∞</sub> approach is based on shaping the open-loop transfer function in the Nyquist diagram through minimizing the quadratic error between the actual and the desired open loop transfer functions in the frequency domain under linear constraints that guarantee robustness and stability. The proposed approach is robust with respect to multi-model uncertainty closed-loop sensitivity functions in the Nyquist diagram through the constraints on their infinity norm. The H<sub>∞</sub> constraints are linearized with the help of a desired open-loop transfer function. The controller is designed using the convex optimization techniques in which the difference between the open-loop transfer function and the desired one is minimized. The two-area four-machine test system is selected to evaluate the performance of the designed controller under different load conditions as well as different levels of wind penetrations.展开更多
Excess minority carrier’s diffusion equation in the base of monofaciale silicon solar cell under frequency modulation of monochromatic illumination is resolved. Using conditions at the base limits involving recombina...Excess minority carrier’s diffusion equation in the base of monofaciale silicon solar cell under frequency modulation of monochromatic illumination is resolved. Using conditions at the base limits involving recombination velocities <i>Sf</i> and <i>Sb</i>, respectively at the junction (n<sup>+</sup>/p) and back surface (p<sup>+</sup>/p), the AC expression of the excess minority carriers’ density <i>δ</i> (<i>T</i>, <i>ω</i>) is determined. The AC density of photocurrent <i>J<sub>ph</sub></i> (<i>T</i>, <i>ω</i>) is represented versus recombination velocity at the junction for different values of the temperature. The expression of the AC back surface recombination velocity <i>Sb</i> of minority carriers is deduced depending on the frequency of modulation, temperature, the electronic parameters (<i>D</i> (<i>ω</i>)) and the thickness of the base. Bode and Nyquist diagrams are used to analyze it.展开更多
文摘This paper presents the design of a robust fixed-order H<sub>∞</sub> controller to damp out the inter-area oscillations and to enhance the stability of the power system. The proposed H<sub>∞</sub> approach is based on shaping the open-loop transfer function in the Nyquist diagram through minimizing the quadratic error between the actual and the desired open loop transfer functions in the frequency domain under linear constraints that guarantee robustness and stability. The proposed approach is robust with respect to multi-model uncertainty closed-loop sensitivity functions in the Nyquist diagram through the constraints on their infinity norm. The H<sub>∞</sub> constraints are linearized with the help of a desired open-loop transfer function. The controller is designed using the convex optimization techniques in which the difference between the open-loop transfer function and the desired one is minimized. The two-area four-machine test system is selected to evaluate the performance of the designed controller under different load conditions as well as different levels of wind penetrations.
文摘Excess minority carrier’s diffusion equation in the base of monofaciale silicon solar cell under frequency modulation of monochromatic illumination is resolved. Using conditions at the base limits involving recombination velocities <i>Sf</i> and <i>Sb</i>, respectively at the junction (n<sup>+</sup>/p) and back surface (p<sup>+</sup>/p), the AC expression of the excess minority carriers’ density <i>δ</i> (<i>T</i>, <i>ω</i>) is determined. The AC density of photocurrent <i>J<sub>ph</sub></i> (<i>T</i>, <i>ω</i>) is represented versus recombination velocity at the junction for different values of the temperature. The expression of the AC back surface recombination velocity <i>Sb</i> of minority carriers is deduced depending on the frequency of modulation, temperature, the electronic parameters (<i>D</i> (<i>ω</i>)) and the thickness of the base. Bode and Nyquist diagrams are used to analyze it.
