| 摘要 |
The present invention is a single-phase/three-phase direct conversion device having an improved input amplitude modulation factor. During a first period (T1) during which, when the AC waveform outputted by a single-phase AC power supply is expressed as the sine of the phase angle (ωt) thereof, the cosine of twice said phase angle (cos (2ωt)) is positive, a discharge duty cycle (dc), namely the percentage of time that a first switch is conducting, is set higher than a first value obtained by dividing the product of the amplitude of the AC voltage from the single-phase AC power supply and the aforementioned cosine by the product of the voltage across the terminals of a capacitor and the square root of two. Alternatively or additionally, during a second period (T2) during which the abovementioned cosine is negative, a rectifier duty cycle (drec), namely the percentage of time that a diode rectifier is conducting, is set higher than a second value consisting of the reciprocal of the product of the absolute value of the abovementioned sine and the square root of two. |
