Design of Coal Quality Disturbance Free System for Coordinated Control System Based on Gain Scheduling
The economic and stable operation was affected seriously by coal quality disturbance for power plants. Based on model analysis, influence of the disturbance can be considered as gain change of control system. Power capability coefficient of coal was constructed to inhibit it. Accuracy of the coefficient was verified by operating data. Then coal quality disturbance free system based on gain scheduling was designed for coordinated control system. Simulation showed that, the strategy improved control quality obviously, and inhibited the coal quality disturbance. Keywords—coordinate control system, coal quality disturbance, energy coefficient of coal quality, gain scheduling
Research of coordinated control system based on robust control
It is proposed robust control algorithm for inaccurateness of coordinated control system model. In order to improve performance of robust controller, the dynamic compensation is used for balancing the difference of dynamic between boiler side and turbine side. A loop-shaping H∞ controller is designed for a boiler-turbine unit nonlinear model with adding dynamic compensation. In order to implement the complex H∞ controller, a multivariable controller with PID form can be got by reducing robust controller. Simulation show that the effect of robust controller can be approached by multivariable PID controller, and the controller has better robustness and dynamic is improved after dynamic compensation.
A new method of near field analysis
The problem of the accurate determination of the total electromagnetic field produced by a current distribution on a circular disc type aperture is examined. For comparison of the near and Fresnel region solutions, an exact Maxwellian integral is used as the starting point. Aperture and space coordinates are separated by the use of Bessel function addition theorems, allowing the field to be expressed as a sum of terms containing radial and angular integrals. The radial integrals involve only the disc (aperture) distribution and coordinates while the angular integrals involve only the elevation angle. The distance from origin appears implicitly in the series coefficients. These integrals are suitable for high speed computations and have been evaluated for a number of cases. The results are compared with the small angle and general Fresnel formula values for various observation angles, distances from the aperture, and aperture distributions.