Research On High Frequency And High Voltage Electrostatic Precipitator Power Supply

With the rapid development of the national economy,the nation's demand for fossil energy sources such as petroleum and coal is increasing,and air pollution has become an important issue facing economic development.In order to control the emission of flue gas and dust pollutants,electrostatic precipitator have been widely used.With the continuous improvement of environmental protection requirements,the traditional power frequency high-voltage electrostatic precipitator power supply has been difficult to meet the requirements,while the high-frequency and high-voltage electrostatic precipitator power supply has the advantages of small size,high efficiency,fast response speed,etc.,and has gradually become the development trend of electrostatic precipitator power supply,so it is necessary to study the high-frequency and high-voltage electrostatic precipitator power supply.In this thesis,the high-frequency and high-voltage power supply applied in the field of high-voltage electrostatic precipitator is taken as the research object.The working mode,hardware circuit and control strategy of the power supply are studied.The circuit model is built in the simulation to verify,and the experimental platform is designed.First,this thesis analyzes and compares the power conversion methods of high-frequency and high-voltage electrostatic precipitator power supplies,including PWM hard-switching method,resonant frequency-regulating voltage-regulating method and Buck voltage-regulating + soft-switching inverting method.Finally,three-phase uncontrolled rectification + Buck circuit + LCC series-parallel resonant converter + booster transformer + bidirectional voltage multiplier circuit is selected as the main circuit topology,and the output voltage is adjusted by adjusting the duty ratio of the Buck circuit.Then,this thesis focuses on the theoretical analysis of LCC series-parallel resonant converter and bidirectional voltage multiplier circuit.When the LCC series-parallel resonant converter works in DCM mode,the switching device can achieve zero current turn-on and zero current / zero voltage turn-off,which reduces system switching losses and improves efficiency.This thesis introduces its working mode and analyzes it through time domain.The method establishes the equation of state and solves the mathematical expression of each variable.The bidirectional voltage multiplier circuit can increase the output voltage by several times and reduce the voltage ripple.This thesis focuses on the boosting principle and steady-state charging and discharging process of the bidirectional voltage multiplier circuit,analyzes the effect of the operating frequency and capacitor capacitance on voltage ripple and voltage drop,and verifies it in the simulation.After that,this thesis builds a simulation model in MATLAB? / Simulink? to conduct a simulation study on the whole system,and the simulation verifies the soft switching effect of the LCC series-parallel resonant converter and the boosting effect of the bidirectional voltage multiplier circuit,and also verifies the the power supply has good voltage regulation capability.Finally,this thesis designs an experimental platform,performs parameter calculation and device selection for each module of the main circuit,and focuses on the design of high-frequency high-voltage transformers,including magnetic core selection,turns calculation,wire selection,loss analysis,and insulation treatment In view of the particularity of the dust power supply load,this thesis studies the flashover control strategy and gives the control scheme,including flashover judgment,flashover processing and optimal flashover rate control.