| 摘要 |
PROBLEM TO BE SOLVED: To protect a smoothing capacitor which is a component of a power supply apparatus and improve the reliability. SOLUTION: The input current of a smoothing capacitor 2 is limited by a current limiting circuit 3B so as not to exceed a predetermined value and a DC/AC converter 1 is controlled through a driving circuit 5 to protect the smoothing capacitor 2. Further, as the ratio of the terminal voltage to current of the smoothing capacitor 2 is proportional to a loss angle and the loss angle is increased and the capacitance is reduced by the deterioration of the smoothing capacitor 2, it can be decided that the smoothing capacitor 2 is deteriorated if the ratio of the terminal voltage to the current exceeds a predetermined value and is indicated, for instance, on a display and, further, if a required process is not executed, the DC/AC converter 1 is stopped. |
