| 摘要 |
A transformer (2) steps down and feeds an inputted AC power to a converter (3). A primary voltage of the transformer (2) detected by a voltage detector (8) is sent to a converter control unit (4) and a frequency detection unit (6) via a BPF (5). The converter control unit (4) controls a converter (3) on the basis of the primary voltage so that the power factor becomes a predetermined value or greater, and the converter (3) converts the AC power to DC power. The frequency detector (6) detects the frequency of the primary voltage on the basis of an interval between time points when the primary voltage which has passed through the BPF (5) exceeds a threshold value. A filter regulation unit (7) calculates filter characteristics using the detected frequency as the center frequency of the BPF (5), and regulates the BPF (5) on the basis of the filter characteristics. |
