Design,Implementation And Optimization Of EPS For Cubesat Satellites

With the advantages of small volume,low mass,short R&D cycle,high functional density and low cost,CubeSat recently has become a research hotspot in pico-satellite field,possessing high scientific and economic value.As the key system of the CubeSat satellite,power system directly affects the performance and lifespan of the satellite.Because the traditional design of CubeSat power system can not meet the design requirements of miniaturization,integration and intelligence,a new design of EPS with high integration,high efficiency,high reliability and intelligent control is presented in this thesis based on the research experience of EPS of the ZDPS-1 and ZDPS-2 satellite.The design adopts the tri-junction GaAs solar cells as the energy source of CubeSat and the lithium-ion batteries as the storage energy of EPS,which were validated by the ZDPS-1 and ZDPS-2 satellite.The power distribution module is realized through the centralized architecture and standard output interface.Meanwhile,the main optimization of the design contains two aspects:MPPT module and FPGA controller.1)Since the traditional MPPT configuration cannot meet the requirements of CubeSat,an optimized MPPT configuration is proposed,which can minimize the space waste and increase energy density through centralized control and fixed shunt.Both theoretic analysis and simulation results verify that compared to the traditional MPPT configuration,the optimized MPPT configuration can improve the power system efficiency and the power density in the conditions of different sunlight,different solar cells areas,solar cell parameters mismatch and the simulated orbit environment.2)Due to the weak intelligence processing capability of the domestic power system,the management center of EPS is designed based on FPGA,including communication bus design,energy management module design and power self-detection module design.Based on the above design,the principle prototype for EPS has been produced.The following conclusion is obtained after the related function experiment.The optimal MPPT configuration of EPS has accurate tracking efficiency which is more than 98%and high tracking speed which is less than Is.Moreover,the optimal MPPT configuration has higher MPPT circuit efficiency and over 2%-4%improvement in enengy conversion efficiency than the traditional MPPT configuration.The ripple of the power distribution module is below 50mV and the conversion efficiency is over 90%.When a short circuit occurs,the fast detection for outputs can be realized in the power distribution module to increase the reliability.In the management center of EPS,the functions of communication,energy management and self-detection have already been verified.Therefore,EPS meeting the design requirements of standardization,high integration and intelligent control,satisfies the application for CubeSat.