Development Of High Frequency Power Supply Control System For Electrostatic Precipitators

Electrostatic precipitator (ESP) plays an important role in the industrial dust pollution control. Traditional electrostatic precipitator has become more and more difficult to meet the increasingly stringent environmental standards. High-frequency electrostatic precipitator power supply can increase the rate of dust removal coefficient, improve power efficiency and reducing power consumption, reduce the size and weight of the power supply as well. The design principles of high-frequency electrostatic precipitator power supply and its control system are described, which is presented as follow:In the first chapter, the working principles of ESP are described. Several commonly used power supplies for ESP are introduced. The advantages and disadvantages are compared that the high-frequency converter is concluded as the future tendency of ESP power supply. The control methods of ESP power supply are introduced.In the second chapter, the working processes of ESP power supply under ideal conditions are analyzed. The two different modes of main circuit are analyzed which take the parasitic parameters of high-frequency transformer into consideration. The voltage and current expressions of all stages are given and the employed one is selected by comparing the advantages and disadvantages of each mode. The specifications of main circuit are given.In the third chapter, the control system of ESP power supply is divided into three parts: protection, closed-loop control and spark control. Each part is designed separately. Protection is realized via hardware circuits and software programs. The incremental PI is chosen as the output voltage closed-loop control algorithm by comparing several digital closed-loop control methods. Spark control includes spark detection, processes after spark, optimal spark rate control and the detection of other fault state such as arc discharge. Spark is detected by the characteristics of output voltage, output current and resonant current. Appropriate actions should be taken after spark occurrence. Optimal spark rate control is to make the spark rate automatic tracking the optimal spark rate. The program flowcharts of each part are given.In the forth chapter, the experimental data and waveforms are presented to verifythe analyzed operating principle and the system design.The last chapter gives corresponding summary and outlook.