An LC series resonant regulator is connected across the output of the inverter circuit of a static converter apparatus to vary the output voltage level as the inverter operating frequency varies from a preselected frequency at which the regulator circuit is tuned. The load is coupled across the capacitor...http://www.google.fr/patents/US4336584?utm_source=gb-gplus-shareBrevet US4336584 - Autoresonant static converter
