Accuracy Improvement of Modeling Method Assisted by Numerical Calculation for LLC Resonant Converter in High-Frequency Band

A power stage model is very important in the controller design of SMPSs (Switched-Mode Power Supplies). However, LLC Resonant Converter is difficult to model due to its complex operation. So far, our research team had proposed a method to model by using numerical calculation improved on the extended state-space averaging method. However, the model obtained by this method has a problem in that error becomes large in the high-frequency band. In this paper, we considered this error is an approximation error when approximating the difference equation to the differential equation in the modeling method. We also proposed a method to correct this approximation error and applied it to the modeling method. It was confirmed that a more highly accurate model was obtained by this correction method by comparing the corrected model and the experimental result of real circuit.