Output Estimation Method for LCC Resonant Converters with High Voltage Capacitor Chargers

This paper discusses the method of estimating the output voltage and output current of the Series-Parallel(LCC) resonant converter applied to high voltage capacitor chargers. Voltage and current sensors located at the output stage are exposed to high withstand voltage in high voltage application. Accordingly, it is difficult to ensure the long term durability and consistent reliability of the sensors. Moreover, directly sensing such high output voltages necessitates high specification sensors. To address this, the output voltage and current were estimated using voltage and current on the low-voltage side of transformer. The operating principles of LCC resonant converter are analyzed. Based on these principles, the estimation algorithm is derived that using information of series resonant current and parallel resonant current. The proposed method is validated through simulations, achieving errors within 1% for output voltage and within 2% for output current.