We are developing compact converters for rapid charging of Energy Storage Capacitors for Compact Marx Generators. Compact Marx Generators have numerous applications in Pulsed Power Systems where Pulses with amplitudes of several 100kV with ns or sub-ns rise-times are needed. One example is the generation of High Power Microwaves. Initially all energy storage capacitors in a Marx generator are charged in parallel. During the so-called erection cycle, the capacitors are connected in series. The charging voltage in the parallel configuration is around 40-50kV. Rapid charging of the capacitors in the parallel configuration will enable a high pulse repetition-rate of the compact Marx generator.