IMPROVED POWER INVERTER

摘要

An improvement is provided in a power inverter for converting a D.C. current into alternating current having a frequency controlled by the rate at which a series of gating signals are created, which inverter includes first and second branches controlled by separate switching means to create the alternating current through the load. The improvement is the provision of a starting inverter having a D.C. input and an A.C. output with a frequency controlled by a series of repeating gating commands, means for selectively applying the A.C. output of the starting inverter across the load until a preselected load condition exist and an arrangement for controlling the frequency of the gating command in the starting inverter to produce a generally unity power factor across the load during the starting cycle. The improved inverter includes a circuit responsive to the voltage wave across the load for controlling the firing position of the gating signals. …Also, a method of operating a power inverter including provision of a separate starting inverter having an alternating current output with a frequency controlled by repetitive gating commands, connecting the output of the starting inverter across the load, energizing the starting inverter, adjusting the frequency of the gating command to produce a substantially unity power factor across the load, maintaining the power factor for a starting cycle and then energizing the power inverter for normal operation.