| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device having a simple lifetime predictive diagnosis function which eliminates the need for a temperature sensor or the like and can prevent any unnecessary predictive diagnosis, without being affected by load fluctuations, since a general method or apparatus for predicting a lifetime of the power supply device, which needs to install the temperature sensor or the like, performs the predictive diagnosis using a temperature and a voltage of an electrolytic capacitor, wherein the predictive diagnosis of the lifetime is affected by fluctuations in a load connected to the power supply device. SOLUTION: The power supply device includes: a diode bridge 2 used as a rectifying means for rectifying an AC power supply 1; a capacitor 3 for smoothing a rectified voltage; and a lifetime determining means 4 for determining the lifetime of the capacitor 3 based on a difference between the DC voltage obtained by rectifying the AC power supply 1 and an absolute value of an instantaneous voltage at each phase of the AC power supply 1. Therefore, the lifetime of the capacitor 3 can be detected by using a sensor with which an AC-DC converter should be equipped, without the need for the temperature sensor or the like in order to determine the lifetime of the capacitor 3. COPYRIGHT: (C)2009,JPO&INPIT
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