Increasing the Life of Electrolytic Capacitor Banks Using Integrated High Performance Film Capacitors

摘要

Inverters for wind and solar applications require DC link capacitors to provide a local reservoir of charge during switching, and store energy for ride-through of grid events. Electrolytic capacitors are desirable for this application with regard to capacitance density, but must be de-rated for acceptable service life. A hybrid bank combining the best features of film and electrolytic capacitors has been developed to address this problem. Advanced film capacitors supply the high frequency components of the system ripple current to reduce electrolytic temperature rise and increase life. Simulation and laboratory test results are presented for practical DC link capacitor banks.