Sun-tracking And Vibration Control Of Integrated Symmetrical Concentrated Space Solar Power Station

Space solar power station is a kind of space power generation system in geosynchronous orbit which transforms solar energy into electrical energy,and then transmits electrical energy to the power systems of the earth ground through the wireless energy transmission.Space solar power station can work continuously which is independent of the nighttime and climate so that it has high energy utilization.Compared with non-concentrated schemes,the concentrated space power system can significantly reduce the area of the solar photovoltaic panel owing to its function of the concentrated architectures,hence,it is more efficient at generating electricity;furthermore,the long-distance transmission and high-power transformation are avoided for the generated energy.Integrated symmetrical concentrated system is designed with concentrated scheme,which is more high efficient in energy collection efficiency and has more utilization potentiality in that it can keep sun-tracking;nevertheless,the system is faced with the technical challenges such as the difficult tracking adjustment and flexible structural vibration.For this purpose,the thesis studies the attitude planning theories and control methods of flexible vibration on the integrated symmetrical concentrated system to improve the concentrating performance of the system,to speed up the tracking response and to enhance the stability and reliability of the system.Details are listed as follows:To accomplish the sun-pointing to increase the sunlight collecting efficiency of the system,the varying of the tracking parameters with time is analyzed which illustrates the principle of sun-pointing,a novel attitude planning scheme for sun-pointing is presented which analyzed and described the process in which the pointing parameters tracks the sunlight angle,the study results demonstrate that the proposed motion planning method can make the system keep the continuous sun-pointing.To mitigate the regulating difficulty,the position trajectory of the rotating joint is optimized to and a new joint trajectory optimization methods is presented.Simulations show that the proposed optimization method can effectively enhance the smoothness of the system,so that the concentrating performance of the system is improved,the difficulty of regulation is reduced.To perform the tracking motion,the dynamics model with the twin-gyro dynamic device are built,a closed-loop state-feedback PD control scheme is presented with fast response speed.Moreover,to further improve the stability of the system,the cable actuator is utilized to suppress the elastic vibration resulting from the flexible feature,a new linear quadratic controller is developed with anti-windup to suppress the flexible vibration.The simulations demonstrate that the above control scheme can significantly enhance the stability and reliability so that the tracking performance is further improved.Besides,since the cable itself has the characteristics of large flexibility and small damping,the vibration instability of cable is analyze and an active vibration suppression controller is developed based on the optimal control theory to overcome the influence of external disturbance and parameter-excited vibration on performance of inclined stay cable.The study indicates that the proposed active control method can effectively increase the stiffness of taut cable and hence reduce the influence of the unstable vibration on the system,the stability of the system is further improved.