In a power inverter system, an inverter unit includes first to third single-phase inverters. In the power inverter system, a reference-frequency calculating unit calculates a reference frequency of each of the first to third single-phase inverters. A reference-voltage-calculating unit calculates a reference voltage of each of the single-phase inverters. In the power inverter system, a voltage-correcting unit adds a correction voltage to the reference voltage calculated by the reference voltage-calculating unit. The correction voltage has a frequency three times as high as the reference frequency.