The invention relates to the technical field of
power electronics, in particular to a
ripple analysis-based
electrolytic capacitor life calculation method. The method comprises the steps of solving current ripples of an
electrolytic capacitor under different frequencies by utilizing double Fourier series, and solving
electrolytic capacitor life in combination with impedance characteristics of the electrolytic
capacitor and an inner temperature rise-based electrolytic
capacitor model. Specifically, the method comprises the steps of A, calculating an effective value of each
harmonic current in a buck circuit; B, giving out the electrolytic
capacitor model and performing calculation through the effective value of the
harmonic current and
equivalent series resistance (ESR) of the electrolytic capacitor at a
harmonic frequency by utilizing an iterative
algorithm to obtain an inner temperature rise of the electrolytic capacitor; and C, substituting the inner temperature rise of the electrolytic capacitor into an electrolytic capacitor life formula and performing calculation to obtain the electrolytic capacitor life. According to the method, the electrolytic capacitor life model is combined with
system parameters, so that the influence of
inductance in a main circuit on the electrolytic capacitor life is analyzed; and the life calculation of the electrolytic capacitor is closely combined with the
impedance properties of the electrolytic capacitor, so that the electrolytic capacitor life can be accurately solved.