| 摘要 |
An inverter circuit (100) having a DC capacitor (105) is connected to an AC power supply (1) in series. At the next stage of the inverter circuit (100), a smoothing capacitor (3) is connected through a converter circuit (300). The converter circuit (300) is controlled by providing, within one cycle, a short-circuit period (T) for short-circuiting between the AC terminals of the converter circuit (300), and the inverter circuit (100) is PWM-controlled so as to improve an AC power supply power factor. When it is impossible for the inverter circuit (100) to control current, the PWM-control is switched to the converter circuit (300) to control the current. |
