DETERIORATION PREDICTION METHOD OF ELECTROLYTIC CAPACITOR

PROBLEM TO BE SOLVED: To predict deterioration of a smoothing electrolytic capacitor of an output voltage of a power circuit in a simple and practical procedure. SOLUTION: A survival rate νn=Vn/Voof an electrolytic solution of the electrolytic capacitor 17 after the elapse of N years from a reference point of time is calculated from the relation formula ESRn/ESRo=(Vo/Vn)2between values ESRn, ESRoof an equivalent series resistance 17b of the electrolytic capacitor 17 measured at the reference point of time and after the elapse of N years from the reference point of time and electrolytic solution amounts Vo, Vnof the electrolytic capacitor 17 at the reference point of time and after the elapse of N years from the reference point of time. Then, a decreasing rate δ=(1-νn)/N of the electrolytic solution per year is calculated, and a mean value R between ESRnand ESRois determined. An acceleration factor K=ESRn/R of decrease of the electrolytic solution is defined, and the survival rate νn+1=νn-δK of the electrolytic solution after the elapse of (N+1) years from the reference point of time is predicted, and a value ESRn+1of the equivalent series resistance 17b corresponding to the predicted νn+1is predicted. COPYRIGHT: (C)2006,JPO&NCIPI