Patent ID: 7652900

Claim:
An inverter type AC generator for converting DC output from a DC power source generating unit into AC output of a predetermined frequency and capable of supplying the AC output to a load via an output line, comprising: a zero-crossing detection circuit configured to detect at least one zero-crossing of an AC output waveform on the output line between an AC generating unit and an external load, the AC generating unit comprising an inverter and electrically connected to an AC generator driven at least in part by a power supply unit; a controller configured to generate a drive signal in synchronization with a timing of the at least one zero-crossing detected by the zero-crossing detection circuit when the at least one detected zero-crossing meets a predetermined condition, the controller configured to drive the inverter via the drive signal to perform a synchronized operation process between the inverter type AC generator and a second inverter type AC generator electrically connectable to the inverter type AC generator; and a storage unit configured to store a plurality of preset frequencies and a plurality of control programs, the control programs configured to generate drive signals for the plurality of preset frequencies, wherein the controller calculates a frequency of the AC output based on the timing of the at least one zero-crossing detected by the zero-crossing detection circuit, the controller executing one of the plurality of control programs for one of the plurality of preset frequencies stored in the storage unit that corresponds to the calculated frequency to generate the drive signal.