Research On Control Strategy Of Beam Supply Based On Adaptive Internal Model Control

With the rapid development of China’s aviation industry,China’s aerospace technology requirements become more stringent.As an important part of space technology,propulsion system still needs to be upgraded.Compared with the chemical propulsion system,the ionic electric propulsion system reduces the problems caused by the type and quantity of propellant,and the electric propulsion system has the advantage of high specific impulse,which can fully meet the implementation of various exploration projects in the future.Beam Supply is the key module of power processing unit(PPU)in ion electric propulsion system,which is mainly used to generate and output high voltage and high power electric energy.Output stability is the key to achieve high efficiency and high power density of PPU,so in order to meet the requirements of high efficiency and high power density of beam supply,this thesis adopts the third generation Wide Band Gap semiconductor technology to design high power density digital power supply.The third generation of Wide Band Gap semiconductor technology can greatly improve the operating frequency of the system,reduce the size of the device magnetic device,improve the power density of the device,greatly promote the development of power electronics in the field of high frequency,high efficiency,high temperature,and become more and more competitive with the price drop of new materials.(1)Aiming at the design requirements of the beam supply,this thesis analyzes the working mode of the dual full bridge converter in a working cycle by taking the dual full bridge topology as the research object,and establishes the mathematical model of the duty cycle mode and phase shift mode dual full bridge converter,which provides the theoretical basis for the research of the beam supply adaptive internal model control strategy in the following.(2)According to the topological circuit of dual full bridge converter and the technical specifications of beam supply,a voltage and current dual closed-loop adaptive internal model control strategy is designed by digital control.The dual full bridge converter adopts PID control of current inner loop and fuzzy adaptive internal model control of voltage outer loop to ensure the system has good anti-interference ability.The current inner loop PID controller of the dual closed-loop controller is designed firstly,and the current inner loop transfer function is treated as a part of the voltage outer loop internal mode control.However,the parameter value of internal model control will affect the response speed and robustness of beam supply,and it is difficult to take into account the technical requirements of all aspects.Therefore,in order to solve the above problems,fuzzy control is introduced to build a fuzzy adaptive internal mode controller of voltage outer loop.The controller can adjust parameter values in real time according to the real-time status of the system to ensure that the system works in the best state.Through simulation analysis,fuzzy adaptive internal model control has better performance in mutation working state,input given mutation,dual mode switching and so on compared with the commonly used double closed-loop PID control.(3)According to the principle and technical requirements of beam supply prototype design.The prototype design mainly includes hardware circuit(main circuit,drive circuit)parameter selection design and software design based on TMS320F28335 controller.The selection of drive circuit and circuit design process are designed in detail,and the rationality of the design circuit is finally verified.(4)Finally,a 2k W beam supply prototype was built in the laboratory.The experimental results are similar to the simulation results of the fuzzy adaptive internal model controller,which also proves the superiority of the fuzzy adaptive internal model control strategy proposed in this thesis.The beam supply based on fuzzy adaptive internal model control has good robustness and excellent dynamic characteristics,and can complete the output of wide voltage range and dual mode switching,with high efficiency and high power density.