An inverter control device is disclosed. The device is configured: for determining a fundamental-wave magnitude of a phase-voltage corresponding to a modified voltage; for performing a proportional-integral (PI) operation of an error between the fundamental-wave magnitude of the phase-voltage and a magnitude of a reference voltage, and for outputting a compensation voltage; configured for adding the compensation voltage to the magnitude of the reference voltage to obtain an output; and for over-modulating the output and for outputting the over-modulated output as the modified voltage.