| 摘要 |
A smoothing unit includes a first and a second smoothing capacitors, a first and a second discharge resistors connected in parallel to both ends of the first and the second smoothing capacitors, respectively. During a normal operation, both the first and the second smoothing capacitors are connected electrically to a live line. On the other hand, during a degradation diagnosis, the first and the second smoothing capacitors are alternately connected electrically to the live line at a predetermined timing, and a smoothing capacitor not electrically connected to the live line is subjected to the degradation diagnosis. |
