High-frequency silicon-controlled-rectifier sinusoidal inverter

In inverter circuits employing switching elements such as silicon controlled rectifiers (s.c.r.) the recovery time of the device normally limits the maximum operating frequency of the circuit. The recovery time allowed by the circuit is invariably limited to some fraction (usually about one-fifth) of one half-cycle. Circuits employing s.c.r.s with 20 ¿s recovery time cannot therefore be used in inverters intended to run above 5kc/s unless this proportion can be increased by some means. The inverter described in the paper generates a sinusoidal waveform and uses the principle of time sharing to enable the circuit quenching time to be extended over several half-cycles.1 It is thus possible to use large s.c.r.s with long recovery times to generate directly very high powers at frequencies up to at least 100 kc/s, and the small diffused type of s.c.r. should be capable of operation at much higher frequencies. A simple inverter delivering 100 W at 50kc/s is described as an illustration of the general principle.