Starting circuitry for series/parallel compensated, current-fed inverter

Claim 1

In a current source inverter comprising first, second, third aNd fourth unidirectional switching elements connected in a bridge configuration having first and second input terminals connected across a source of direct current and first and second output terminals connected across a subcircuit including a compensating capacitor in series with a tank load, said first element being connected between the first input terminal and the first output terminal, said second element being connected between the first output terminal and the second input terminal, said third element being connected between the second output terminal and the second input terminal and said fourth element being connected between the first input terminal and the second output terminal, improved control means for causing said inverter to commence operation by rendering said elements conductive in a predetermined order comprising: a. first means operative in response to an ''''ON'''' command for initially rendering said even numbered elements conductive whereupon direct current flows through said second and fourth elements and commences charging said compensating capacitor; b. second means operative subsequently for rendering said first and second elements concurrently conductive, whereupon said direct current is diverted into a path through said first and second elements and said fourth element ceases conducting; and c. third means operative after operation of said second means for rendering the odd and even numbered elements alternately conductive at a desired frequency starting with said odd numbered elements, whereupon the prior charge on said capacitor is effective for causing said second element to cease conducting when said odd numbered elements are first rendered conductive by said third means and thereafter alternating current flows through the load.