Improved model of metalized film capacitors

Metalized film capacitors are commonly used components in power electronics applications and their characteristics are drastically dependent on their operating frequency. Parasitic parameters could appear at low and high frequencies and disturb substantially the behavior of the component. Proper design of metalized film capacitors requires an understanding of all parasitic parameters´ sources and their impacts on the circuit operation. This paper presents a modeling approach based on the complex form of the capacitor impedance to build its equivalent electrical circuit. This approach proved to be more accurate than the traditional modeling technique of identifying the electrical parameters using the modulus of the component impedance. Two different types of capacitors were tested; experimental results allowed to validate our model from 10 kHz to 35 MHz.