Series-parallel resonant converter is widely used in pulsed capacitor charger power supplies (PCCPS) due to its soft switching characteristics. In PCCPS, the constant current or constant power control is preferred to increase the charging speed. However, the output voltage of PCCPS varies widely and the charging process under discontinuous current mode (DCM) is highly non-linear, making it difficult to establish the small signal model for constant current or constant power control. Therefore, online model prediction for LCC resonant PCCPS under DCM is firstly proposed in this article, which could be applied to adjust the switching frequency and duty cycle for constant current or constant power control as well as the soft switching in the entire load range. The analytical expressions between the output gain and the initial voltage of the series and parallel capacitor are established based on the quasi-static model. Simulation and experiment verify the effectiveness of the proposed online model prediction for LCC resonant PCCPS under DCM.

Discontinuous current mode; LCC resonant converter; Online model prediction; Pulsed capacitor charger power supply