Research On 4-arms Phase-shift Series Resonant Power Supply For Electrostatic Precipitator

Electrostatic precipitator (ESP) is important equipment for the prevention of air pollution, and is widely used in industrial emission control. As a main part of ESP, the ESP power supply affects the dust collection efficiency severely. The traditional power supply based on thyristor and operation on power frequency is unable to meet the requirement of increasing strict of air pollution emission standards, and it replaced by modern high frequency high voltage power supply with higher efficiency is an inevitable trend.Phase-shift full-bridge series resonant converter with capacitive filter is well suited for high voltage output applications with the main problem of limited range of ZVS. Auxiliary network could be used to expand the range of ZVS.4-leg resonant converter is based on a SRC which is modified by adding low power auxiliary circuitry. The auxiliary circuitry could provide a controlled current to ensure the ZVS over the entire operation range, which contributes to lower switch loss and higher reliability.Analysis for the converter operation above resonance is performed. By fundamental approximation, analytical expression for the converter input/output voltage gain as a function of phase-shift and frequency is derived. Different converter operation modes are demonstrated with simulation results. Analytical expression for mode boundaries is derived. Analysis and simulation for the auxiliary circuit is performed. These analyses establish the foundation for resonant elements design.Design of main power circuit and control circuit is carried out. The control circuit contains sampling circuit, protection circuit, etc. A new method to produce 4 arm phase shift driver signal by software is proposed.Finally, experimental results obtained from a prototype build as designed verify the analysis and simulation.