Research On AC/DC Converter And Power Supply System Of More-electric Aero-engines

Modern aircraft and aero-engines are gradually developing towards more-electrification and fullelectrification,which is called more-electric aircraft and more-electric aero-engine.The large-scale use of more-electric load has posed greater challenges to the generation,transmission and distribution of power.The traditional power supply system and power electronic converters have been unable to meet the needs of more-electric aero-engines.In order to provide efficient and reliable power supply system and further improve the efficiency of power conversion,this thesis studied the power supply system and power electronic converter of more-electric aero-engines based on the power standard made by U.S.military.This thesis designed a set of power supply system and power electronic converter solutions for more-electric aero-engines.The working principle and control system design of AC/DC converter are studied in this thesis.In order to improve the robustness and steady-state characteristics of DC bus,a variety of non-linear control algorithms are designed to improve the transmission efficiency of power.Aiming at the actual demand,this thesis also designs an AC/DC hybrid power supply system,and studies its feasibility and steady-state characteristics.The research work of each part of the thesis is as follows:(1)The research of auto-transformer rectifier unit based on active power filter is carried out.Based on the analysis of the working principle of the auto-transformer rectifier,the topological structure of the new auto-transformer rectifier is designed,and its working principle is introduced in detail.The fractional PI controller and hysteresis current control scheme are used to design the control system,and the multi-objective optimization algorithm based on grey wolf optimization algorithm is used to optimize the control system.(2)The voltage stability of HVDC bus based on VIENNA rectifier is studied.Firstly,the topology and working principle of VIENNA rectifier are introduced.On this basis,the advantages of VIENNA rectifier compared with auto-transformer rectifier are analyzed,and the state space model of VIENNA rectifier is established.On the basis of the above model and taking improving the robustness of DC bus voltage as the design criterion,the control algorithms based on fuzzy terminal sliding mode and disturbance observer are designed respectively.The nonlinear control scheme based on fuzzy terminal sliding mode controller solves the shortcomings of slow response and weak robustness of PI controller,and the nonlinear control scheme based on disturbance observer further improves the robustness of HVDC bus with full consideration of external disturbances.The simulation results show the advantages of the VIENNA rectifier and the effectiveness of the designed control algorithm.(3)The AC/DC hybrid power supply system is designed.Based on the analysis of the insufficiency of bus voltage control in traditional power supply system,corresponding control schemes are proposed for each bus.For HVDC bus,besides the auto-transformer rectifier and VIENNA rectifier mentioned above,a voltage stabilization scheme of DC bus based on storage battery and bidirectional DC/DC converter is designed,which can compensate the DC bus power in real time through storage battery and provide inertia for AC load.Aiming at AC bus,a virtual synchronous generator is used to design DC/AC converter.By designing appropriate active and reactive power,the steady state control of AC bus is realized.The simulation results show that the AC/DC hybrid power supply system designed in this thesis is effective.