| Space Solar Power Station(SSPS)is a system that collects and converts Solar energy into electricity in Space,then transmits it back to the ground through wireless energy transmission device,and then converts it into ground electricity through ground device.When demonstrating the feasibility of space solar power plants and other indicators,it is necessary to establish a SSPS demonstration system on the ground.The SSPS ground demonstration system consists of three subsystems: power generation system,energy transmission system,and energy reception system.In the whole demonstration system,the energy emission system is a very important part.This thesis will research and design the beam pointing control of the microwave transmitting antenna for the energy transmitting system in the SSPS ground demonstration system.The main work is as follows:1.Design the beam pointing machine control system of the transmitting antenna.In the SSPS ground demonstration system,the concentrator needs to move with the sun in space according to the functional design,and the movement of the concentrator will structurally drive the movement of the transmitting antenna installed on the concentrator,thereby changing the attitude of the transmitting antenna.Therefore,in order to keep the transmitting antenna horizontal in space,it is necessary to make mechanical adjustment to the hardware platform of the transmitting antenna,so that its attitude in space is not affected by the external environment,which provides the basis for the subsequent electrical control.In order to achieve this requirement,this thesis designs a PID control system based on ARM,which controls the servo motors of the X-axis and Y-axis of the transmitting antenna to adjust the pitch angle and roll angle of the transmitting antenna,so as to realize the fast,stable and accurate adjustment of the space attitude of the transmitting antenna.2.Design the beam pointing electrical control system of the transmitting antenna.First,through the analysis of the composition principle of the transmitting antenna in the SSPS ground demonstration system,it is determined that the implementation method of the beam control system in this system is a distributed beam control architecture: 1 wave control mother-board + 177 wave control sub-board.Then,according to the function of the wave control mother-board in the electro-modulation system,a beam control mother-board composed of ARM+FPGA is designed,in which the ARM is responsible for calculating various information in the beam pointing through algorithms,including the transmit antenna coordinates,Phase difference in the antenna array,etc.,while FPGA is responsible for communication control.Finally,according to the working characteristics of Transmitter Assembly in the antenna unit channel,a beam control sub-board based on STC15 is designed to realize switching control and phase shift control of a single antenna unit.Through this electro-modulation control system,the beam synthesized by the 177 antenna units can be aimed at the ground receiving antenna,so as to realize the maximum efficiency of microwave energy transmission between the transmitting and receiving antennas.3.Design the communication system of the beam pointing control system.Considering the transmission distance and transmission reliability between the transmitting antenna and the ground control platform in the SSPS ground demonstration system,the communication system between the ground PC master computer,beam control mother-board and 177 beam control sub-boards is designed.The bidirectional communication between beam control board and ground control platform is realized by 2.4G module.The bidirectional communication between the beam control motherboard and 177 beam control sub-boards is realized by 485 communication.Finally,a test platform is built to complete the transmitting antenna beam pointing test and test results analysis.The results show that the control system meets the functional requirements and technical indexes of transmitting antenna beam pointing. |
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