An experimental technique for estimating the aluminum electrolytic capacitor equivalent circuit, at high frequencies

This paper presents an experimental technique that allows the determination of the equivalent circuit of an aluminium electrolytic capacitor. The impedance of these electrolytic capacitors changes with frequency, becoming approximately equal to a resistance near their resonance frequency. This resistance, the equivalent series resistance (ESR), becomes one of the most critical problems of static converters, which operate near the resonant frequency of the capacitor. The ESR leads to a significant increase in the alternating (AC) component of the output voltage, requiring a constant action of the control system. To validate this technique some experimental and simulated results are presented