Static inverter system

Claim 1

IN AN INVERTER CIRCUIT WHICH INCLUDES AN INPUT CIRCUIT HAVING A PAIR OF INPUT CONDUCTOR FOR RECEIVING D-C ENERGY THEREOVER, A FIRST PAIR OF SEMICONDUCTOR SWITCHES RESPECTIVELY COUPLED TO SAID INPUT CONDUCTORS, A COMMUTATING CHOKE ASSEMBLY INCLUDING A CORE AND A PAIR OF WINDINGS MAGNETICALLY COUPLED TO SAID CORE AND ELECTRICALLY COUPLED BETWEEN SAID SEMICONDUCTOR SWITCHES FOR ASSISTING IN SHUT-OFF OF ONE OF SAID SWITCHES AFTER THE OTHER IS GATED ON, MEANS FOR APPLYING A FIRST SET OF GATING SIGNALS TO SAID SEMICONDUCTOR SWITCHES, MEANS FOR PASSING COMMUTATING ENERGY INTO ONE OF SAID COMMUNITATING CHOKE WINDINGS AS SAID OTHER SEMICONDUCTOR SWITCH IS TURNED ON TO ASSIST IN SHUT-OFF OF SAID ONE SWITCH WHICH COMMUTATING ENERGY IS TRAPPED IN THE CHOKE ASSEMBLY AND TENDS TO BE RETURNED BY RECIRCULATION THROUGH SAID OTHER SEMICONDUCTOR SWITCH, AND AN ENERGY RETURN CIRCUIT INCLUDING AN ENERGY RETURN TRANSFORMER HAVING A PRIMARY PORTION COUPLED TO SAID CHOKE WINDINGS AND A SECONDARY PORTION COUPLED TO SAID INPUT CIRCUIT, THE IMPROVEMENT WHICH COMPRISES A SECOND PAIR OF SEMICONDUCTOR SWITCHES RESPECTIVELY COUPLED TO OPPOSITE ENDS OF SAID PRIMARY PORTION, A THIRD CHOKE WINDING MAGNETICALLY COUPLED WITH SAID CORE OF THE COMMUTATING CHOKE ASSEMBLY, MEANS FOR COUPLING ONE END OF SAID THIRD CHOKE WINDING TO AN INTERMEDIATE POINT ON THE PRIMARY PORTION OF THE ENERGY RETURN TRANSFORMER AND UNIDIRECTIONAL CURRENT CONDUCTION MEDANS FOR COUPLING THE OTHER END OF SAID THIRD CHOKE WINDING TO SAID SECOND PAIR OF SEMICONDUCTOR SWITCHES, AND MEANS FOR APPLYING A SECOND SET OF GATING SIGNALS TO SAID SECOND PAIR OF SEMICONDUCTOR SWITCHES SUBSTANTIALLY IN TIME COINCIDENCE WITH THE APPLICATION OF THE FIRST SET OF GATING SIGNALS TO SAID FIRST PAIR OF SEMICONDUCTOR SWITCHES, WHEREBY THE ENERGY TRAPPED IN THE COMMUTATING CHOKE ASSEMBLY IS RETURNED OVER THE CONDUCTING ONE OF THE SECOND PAIR OF SEMICONDUCTOR SWITCHES AND SAID ENERGY RETURN TRANSFORMER TO THE INPUT CIRCUIT TO OBVIATE HEATING OF THE FIRST PAIR OF SEMICONDUCTOR SWITCHES WHICH WOULD OTHERWISE BE CAUSED BY RETURN OF THE TRAPPED COMMUTATING ENERGY.