Large-signal modeling of LCC resonant converter operating in discontinuous current mode applied to electrostatic precipitators

Two large-signal models namely an ideal and a practical model of the LCC series-parallel resonant converter operating in a discontinuous current mode (DCM) are derived. The models accurately predict steady state and startup performance of the electrostatic precipitator (ESP), particularly because of frequent startup of the ESP after a flashover. Peak component stresses can be obtained from the models, which helps to design the converter. In this paper, the operational principles of the LCC resonant topology operating in DCM are introduced and simple and accurate expressions describing the resonant topology are derived. Then the ideal large-signal model, neglecting converter power loss is deduced, which results in simpler expressions. An optimized practical model is introduced to obtain more accurate results when the power losses are not ignored, but some practical approximations are used to simplify the calculations. Simulation and experimental results verify the analysis, with good agreement.