Research On PWM Modulation Strategy Of Three-Phase Input Aviation Power Supply Based On PFC

At present,the development direction of aircraft has changed from the comprehensive utilization of multiple secondary energies such as electric energy,hydraulic energy and mechanical energy to the replacement of other secondary energies with clean and convenient electric energy.Multi-electric/all-electric aircraft driven by electric energy,which greater use of electrical energy as secondary energy can make the overall structural design of the aircraft simpler and more efficient in energy utilization.Therefore,there is an urgent need for an aviation power supply system with higher electrical capacity as the overall power supply system of the aircraft.The 270 V high-voltage DC power supply system came into being at the historic moment.The main research content of this thesis is to design a converter device for this system.Its goal is to stably output 270 V DC power on the DC-link,achieve unit power factor operation and reduce the pollution of input current harmonics at the grid side to the power grid through power factor correction(PFC)control and modulation strategies.This thesis conducts in-depth research on the above objectives.First of all,this thesis introduces the topology and working principle of the three-phase aviation current-source PWM rectifier,and establishes a mathematical model in the time domain according to the Kirchhoff’s law circuit principles.Secondly,the SPWM modulation strategy is introduced.Its main working principle is to use the principle of area equivalence to convert the reference standard sine modulation wave into a series of rectangles with equal height but unequal width.The rectangles are approximately equivalent to sine waves.After the power amplification of the rectifier bridge,the fully controlled semiconductor devices are controlled.After that,the SVPWM modulation strategy is introduced,which is mainly obtained by using the vector synthesis rule,judging the sector of the input current vector at the AC side,selecting the relevant vector required for synthesis,calculating the vector action time using the vector synthesis rule,and reasonably allocating the vector action time according to the sevensegment formula.Finally,a PFC control strategy is introduced,which consists of a voltage and current double closed-loop consisting of an outer voltage loop and an inner current loop.Last but not the least,the simulation platform is built on Simulink/Matlab software,and the correctness of the previous theory is verified through simulation experiments.On the basis of the theoretical analysis and simulation results obtained in the previous thesis,the hardware and software of the low-power experimental platform are designed,and the low-power experimental platform based on FPGA as the core controller is built.The experimental program is written in Verilog HDL language,and the experiment is completed,the experimental results are collected collate and analyzed to verify the correctness and feasibility of theoretical analysis.