Research On High Voltage Pulse Generator For Electrostatic Precipitator

Electrostatic dust removal is a technical method to effectively remove solid dust particles from industrial waste gas.In view of the increasingly severe atmospheric pollution situation in China,dust removal equipment used in domestic coal-fired power plants,cement plants,and metallurgical plants is mainly based on electrostatic precipitators.As a basic component of the electrostatic precipitator,high-voltage power supply and control system are particularly important in achieving ultra-low emissions.The theory and practice show that the use of pulse power supply in the electrostatic precipitator can break the limitation of the DC flashover voltage and increase the peak electric field intensity.It can better suppress the back corona and spark phenomenon under adverse conditions.As a result,dust collection efficiency is greatly improved.In addition,the pulsed power supply system has a flexible composition and control method which facilitates the transformation of the traditional power supply,and it is the ideal power supply for the final electric field of the electrostatic precipitator.Based on this background,this paper studies the pulse generating circuit with pulse transformer,and a 15 kV DC superimposed 23 kV pulse generator prototype was designed for experimental demonstration.Firstly,this paper introduces the main circuit topology of mid-frequency DC superimposed hundred microsecond high-voltage pulse,and its working principle and mathematical model is analyzed in detail.With the theoretical deduction and simulation analysis of the circuit process during flashover,Transient overcurrent problem is studied to complete the selection of main circuit component parameters.Then,by analyzing the influence of pulse transformer parasitic parameters on the pulse output waveform,the design method of unipolar pulse transformer's winding structure and bias magnetic circuit is expounded,and the correctness of the design is verified in the pulse power supply prototype test.Based on the operation of pulse power supply,a control scheme based on DSP and CPLD coordinative controller is proposed.The DSP minimum system and peripheral expansion circuits,as well as IGBT over-current detection circuit,pulse peak sampling circuit,zero-crossing detection circuit are comprehensively designed.Finally,the DSP program framework and the upper computer test system based on Labview are designed to complete the experiment of the power supply prototype.