Numerical analysis of series-resonant charging converter

In pulse power systems, series-resonant topology under high working frequency has realized fast energy conversion from initial energy-storage devices to pulsed energy-storage devices and has also improved the stability of output pulse. Usually linear increase of the voltage across load-capacitor is a typical characteristic of this kind of converter. On the other hand, continual increase of charging-power in each separate charging-period is a major shortcoming. However, these two characteristics seem dominant in the first stage of charging but disappear in the second stage of charging. Numerical analysis is carried out in this paper to explain these inherent laws based on detailed derivations for transient operation under ideal condition that on-state voltages of switches and diodes, as well as the presence of non-ideal transformer are not taken into account. Moreover, approximate generalized-expressions of voltages across resonant capacitor and load-capacitor, maximum resonant current as well as numbers of charging periods in both stages have been derived. Also, some relations based on these expressions have been depicted.