Control apparatus for power inverter

Claim 1

IN INVERTING APPARATUS, A POWER TRANSFORMER HAVING PRIMARY WINDING MEANS AND SECONDARY WINDING MEANS, A CURRENT TRANSFORMER HAVING A PLURALITY OF WINDING PORTIONS, FIRST AND SECOND SEMICONDUCTOR VALVES, EACH SAID VALVE HAVING A PAIR OF MAIN ELECTRODES AND A CONTROL ELECTRODE, A PAIR OF POWER INPUT TERMINALS, A FIRST POWER PATH CONNECTING SAID INPUT TERMINALS TO A FIRST PORTION OF SAID PRIMARY WINDING MEANS AND INCLUDING SAID MAIN ELECTRODES OF SAID FIRST VALVE AND A FIRST OF SAID WINDING PORTIONS, A SECOND POWER PATH CONNECTING SAID INPUT TERMINALS TO A SECOND PORTION OF SAID PRIMARY WINDING MEANS AND INCLUDING SAID MAIN ELECTRODES OF SAID SECOND VALVE AND A SECOND OF SAID WINDING PORTIONS, SAID PATHS BEING SO ARRANGED THAT WHEN SAID FIRST VALVE CONDUCTS SAID POWER TRANSFORMER IS ENERGIZED IN ONE POLARITY AND WHEN SAID SECOND VALVE CONDUCTS SAID POWER TRANSFORMER IS ENERGIZED IN THE OPPOSITE POLARITY, MEANS CONNECTING A THIRD OF SAID WINDING PORTIONS BETWEEN ONE OF SAID MAIN ELECTRODES AND SAID CONTROL ELECTRODE OF SAID FIRST VALVE, MEANS CONNECTING A FOURTH OF SAID WINDING PORTIONS BETWEEN ONE OF SAID MAIN ELECTRODES AND SAID CONTROL ELECTRODE OF SAID SECOND VALVE, SAID FIRST AND SECOND WINDING PORTIONS BEING PHASED TO ENERGIZE SAID CURRENT TRANSFORMER IN OPPOSITE POLARITY AS A CONSEQUENCE OF THE CONDUCTION OF SAID FIRST AND SECOND VALVES, SAID THIRD AND FOURTH WINDING PORTIONS BEING PHASED SUCH THAT WHEN SAID CURRENT TRANSFORMER IS ENERGIZED AS A CONSEQUENCE OF THE CONDUCTION OF SAID FIRST VALVE SAID THIRD WINDING PORTION RENDERS SAID FIRST VALVE CONDUCTING AND SAID FOURTH WINDING PORTION RENDERS SAID SECOND VALVE NON-CONDUCTING, FIRST AND SECOND UNIDIRECTIONAL CURRENT CONDUCTING DEVICES, MEANS INCLUDING A PORTION OF SAID PRIMARY MEANS CONNECTING SAID FIRST UNIDIRECTIONAL DEVICE IN ANTI-PARALLEL WITH SAID FIRST VALVE AND SAID FIRST WINDING PORTION, MEANS INCLUDING A PORTION OF SAID PRIMARY MEANS CONNECTING SAID SECOND UNILATERAL DEVICE IN ANTI-PARALLEL WITH SAID SECOND VALVE AND SAID SECOND WINDING PORTION, FIRST AND SECOND SWITCH MEANS, AN ASYMMETRIC CURRENT FLOW DEVICE, FIRST CONTROL CIRCUIT MEANS CONNECTING SAID FIRST SWITCH MEANS AND SAID ASYMMETRIC CURRENT FLOW DEVICE ACROSS A FIFTH OF SAID WINDING PORTIONS, SECOND CONTROL CIRCUIT MEANS CONNECTING SAID SECOND SWITCH MEANS AND SAID ASYMMETRIC CURRENT FLOW DEVICE ACROSS A SIXTH OF SAID WINDING PORTIONS, A SOURCE OF UNIDIRECTIONAL VOLTAGE HAVING A DROOPING VOLTAGE MAGNITUDE WITH INCREASE IN CURRENT AND CONNECTED IN SHUNT CIRCUIT WITH SAID ASYMMETRIC CURRENT FLOW DEVICE, AND MEANS CLOSING SAID FIRST AND SECOND SWITCH MEANS IN ALTERNATING SEQUENCE.