Research On The Control Strategy Of The Beam Supply Based On Active Disturbance Rejection Control

High power electric propulsion technology is an important basis for space activities and deep space exploration in China.As the core component of the Power Processing Unit of the electric propulsion system,the Beam Supply is mainly used to provide voltage and power for the establishment of the electric field between the thruster grids and the acceleration of xenon ions,and the resulting thrust is used to perform tasks such as position holding and orbit transfer.Due to the diversity of space missions,and the solar panels are easily affected by light and temperature,the Beam supply should have the characteristics of a wide range of input and output;The Aerospace power supply is a high-end power supply,compared with industrial products,in addition to quite strict stability and reliability requirements,but also need to have the characteristics of short-time power output,and its load characteristics change greatly;At the same time,in space application,the nonlinear dynamics of DC converter is very complex and susceptible to external interference,so the control effect of traditional analog control technology will decline.It limits the development of Beam supply to a certain extent.In this thesis,the control strategy of Beam supply is studied by the combination of digital control technology and Active Disturbance Rejection Control(ADRC)technology.The new dual-bridge topology can meet the requirements of multiple working conditions and a wide range of Beam supply structurally.Digital control technology has greater advantages in multitask smooth switching,power management,and performance control.ADRC technology can improve the anti-interference capability and robustness of Beam supply.The main research work of this thesis is as follows:(1)Based on the analysis of the research background and significance of Beam supply,the topology structure and performance indicators of Beam supply,as well as the application scope,parameter setting,and algorithm improvement of ADRC at home and abroad are summarized.(2)To meet the requirements of multi-working conditions and a wide range of Beam supply,a new dual-bridge converter is selected as the topology of Beam supply,and its working principle and working mode are analyzed and studied,and the small-signal equivalent model under two modes is established considering the parasitic effect and effective duty cycle.(3)Aiming at the problem that the output voltage of the Beam supply is unstable when the external disturbance or internal parameter transformation occurs in the practical application and meets the demand of the output voltage in a wide range,this thesis proposes a control strategy of the Beam supply based on Linear Active Disturbance Rejection Control(LADRC)to meet the performance demand of the Beam supply.The proposed control strategy adopts a double closed-loop control structure with LADRC as the outer voltage loop and PI control as the inner current loop,which not only improves the anti-interference ability of the system but also improves the dynamic response speed.Based on Matlab/Simulink simulation platform,the LADRC strategy and the traditional double closed-loop PI control strategy are compared and analyzed in steady-state performance,dynamic performance,and anti-interference performance,and the results show that the proposed control strategy has better control quality.(4)To further improve the control accuracy and control effect of Beam supply,this thesis combines the advantages of Sliding Mode Control(SMC)and ADRC to introduce Sliding Mode Active Disturbance Rejection Control(SM-ADRC)into the Beam supply control system.The SM-ADRC takes ADRC as the main body and arranges the transition process for the input signal to solve the contradiction between rapidity and overshoot and improve the robustness of the controller.At the same time,the sliding mode surface and the sliding mode control law based on the exponential approach law are introduced into the error feedback control law to improve the dynamic quality and reduce the impact of chattering.Based on Matlab/Simulink simulation platform,SM-ADRC,LADRC,and traditional double closed-loop PI control are compared and analyzed in steady-state performance,dynamic performance,and antiinterference performance.The results show that SM-ADRC has better dynamic response speed,stronger anti-interference ability,and better control quality.(5)To verify the controller performance in practical application,based on TMS320F28335 processor built experimental platform and 2 k W prototype,by full load wide adjustable range,load mutation experiments,and dual-mode switching experiments to verify the effect of SMADRC,the results show that the SM-ADRC with excellent quality,can complete the input and output a wide range of multi-point work and multi-task smooth switch,at the same time with faster dynamic response speed and stronger anti-interference ability.