Patent ID: 8624533

Claim:
An inverter power generator having a prime mover, a synchronous motor coupled with the prime mover, a converter connected to the synchronous motor, an inverter connected to the converter, and a capacitor arranged between the converter and the inverter, the prime mover rotating the synchronous motor to generate AC power, the converter converting the AC power into DC power, and the inverter inverting the DC power into AC power of a required frequency, the inverter comprising: a voltage command generator generating a voltage command value according to an externally specified voltage value and outputting the voltage command value; a frequency command generator generating a frequency command value according to an externally specified frequency value and outputting the frequency command value; a PWM signal generator generating a PWM signal according to the voltage command value and frequency command value; a switching unit configured to turn on/off a plurality of semiconductor elements according to the PWM signal and generate the AC power of the required frequency; and a current detector detecting an output current of the switching unit, wherein the voltage command generator includes a voltage command changer configured to: (i) generate and output a voltage value corresponding to the externally specified voltage value in a normal state where the output current detected by the current detector is equal to or lower than a preset upper current threshold, and (ii) output a voltage value corresponding to a minimum output voltage that is preset to be lower than the externally specified voltage value in a case where the output current is higher than the upper current threshold.