Reliability Study on Front-end Capacitors in Boost PFC Architectures

Single-phase line rectifiers usually implement a PFC front-end to reduce the input current distortion; Power factor correction is often implemented using a boost converter. This topology demands bulky electrolytic capacitors necessary to achieve unity power factor and low output voltage ripple while maintaining restrained volumes, thereby reducing system lifetime since electrolytic capacitor is one of the main causes of failure in power electronics. An alternative control of the PFC boost converter allows reducing the required capacitance and enables the electrolytic capacitor substitution with a long-life low-ESR film one, reaching high power factor and low output voltage ripple. In this study, a thermo-electric model of the two different PFC methods allowed us to analyze the system behavior. Employing two commercial capacitors, an electrolytic and a film type, a full lifetime model has been derived, from which emerges that film capacitor lifetime is almost two times longer compared to electrolytic one.