Modeling And Control Of High-Power Arc Heater Power Supply System

The main function of the arc wind tunnel is to simulate the high-temperature and high-pressure aerodynamic environment of the aircrafts when they enter the atmosphere,and it has important guiding significance for the design of thermal insulation materials and power layout of aerospace vehicles.As the core part of the arc wind tunnel,the arc heater system directly affects the test capability of the arc wind tunnel.At present,the research of arc heating power supply is relatively mature,but there are few researches about plasma arc heater.Therefore,the modeling and control of arc heater are studied in this thesis.First,the electrical characteristics of the arc heater are analyzed and studied,and a plasma arc neural network model based on current,voltage and gas flow is established.The model mainly considers the effect of arc current and gas flow on arc voltage.The MATLAB software is used to establish the m file of the plasma arc model,and the joint simulation with the high-power thyristor rectifier power circuit in Simulink.The comparison between the simulated data and the experimental data verifies the validity of the arc model.Then,the stability of the arc heater power supply system is analyzed,and it is decided to adopt the current closed-loop control method with "sag" characteristics.The power system adopts the main circuit topology of six sets of phase-shifting transformers with a phase difference of 10° connected to the thyristor rectifier bridge,and realizes the output of different power levels through the series and parallel connection of the thyristor rectifier units.The control requirements of the power supply system are analyzed,the parameters of the fuzzy PID controller are designed through theoretical analysis and experience summary,and the simulation circuit is built using MATLAB software to verify the control effect of the fuzzy PID control algorithm.Finally,a 2k W experimental prototype with input 220 V AC,output 6A,is built.The dual-core DSP+FPGA high-performance digital controller was used to verify the fuzzy PID controller.The experimental results show that the power system has good dynamic performance and steady-state output characteristics in different working modes,which verifies the correctness of the control strategy.