摘要 |
A control section generates a quasi-sine wave with a plurality of gradation voltages including power supply voltages from DC power supplies with different voltages and one or more potential differences between two of the power supply voltages. Specifically, the control section generates the quasi-sine wave by, in a time range where a sine wave voltage is at two gradation voltages, generating a PWM signal with one gradation voltage set at a low level and the other gradation voltage set at a high level. The timing for switching the PWM signal is determined using an intersection between a sine wave and a triangular wave in the time range where the sine wave voltage is at two gradation voltages, where the triangular wave is generated with one gradation voltage set at a low level and the other gradation voltage set at a high level.
|