Dry high-voltage medium-power film capacitors for DC filtering applications

AVX has released a new, high-voltage series of dry, medium-power film capacitors specially designed for DC filtering applications, such as the DC filtering of high frequency ripple currents and decoupling DC links in AC/AC and DC/AC motor drive inverters. Rated for 1.5kV to 3kV, the new FFLI Series capacitors are comprised of a novel combination of dry, metallized polypropylene film and a no-free-oil solution sealed in a cylindrical aluminium case filled with self-extinguishing polyurethane resin. This composition equips the FFLI Series with controlled self-healing technology, which prevents potential explosions resulting from avalanche effect, enables a benign failure mode consisting exclusively of capacitance losses, and ensures safe, reliable performance over lifetimes of up to 100,000 hours. Available in a wide range of voltage and capacitance values, FFLI Series capacitors also exhibit low DCL, ESR, and ESL, high current handing capabilities, and excellent high-frequency performance and capacitance retention with frequency, making them ideal for use in AC/DC power converters, renewable energy inverters, rolling stock, and oil drilling applications, says the company. "Thanks to its unique, dry composition and controlled self-healing capabilities, which prevent both avalanche effect and the subsequent potential for explosions typically associated with oil-filled high-voltage power film capacitors, the FFLI Series provides design engineers with a wide variety of exceedingly safe and reliable solutions for a broad range of DC filtering applications, and especially those that prohibit the use of oil-impregnated capacitors, including solar, wind, and hydro inverters," said John Gallipeau, power film technical marketing manager, AVX. Rated for lifetimes of up to 100,000 hours at rated voltage, 70C hot spot temperature, and ?C/C <2%, standard FFLI Series designs are currently available in seven voltage ratings - 1.5kV, 1.75kV, 2kV, 2.25kV, 2.5kV, 2.75kV, and 3kV - and with capacitance values spanning 58µF to 1,110µF ±10% tolerance. Custom sizes, shapes, and performance specifications are also offered. The series' cylindrical aluminium cases span 85mm to 116mm in diameter and 155mm to 340mm in height, and feature a self-extinguishing plastic cover, an M12 x 16 bolt to fix the capacitor in place, and either M6/10 female connections or M8/20 male connections. Designed to withstand operating temperatures ranging from -40C to +85C, the RoHS-compliant series is also qualified to the following standards: IEC 61071, IEC 61881, IEC 60068-2, IEC 61373, and UL 94.