New traction capacitors

Electric trains, buses, and heavy vehicles need capacitors that act like shock absorbers for voltage spikes, and KYOCERA AVX said on April 20 it has launched a new FFLK series for that job. (kyocera-avx.com) In traction electronics, a DC-link or DC-filter capacitor sits between the power source and the inverter, smoothing the fast on-off current swings that drive electric motors. Vishay’s traction-capacitor application note says the capacitor carries the difference between the line’s slower average current and the inverter’s pulsed current. (vishay.com) KYOCERA AVX’s new parts are cylindrical film capacitors with axial terminals and a mounting bolt, built for DC filtering applications such as DC link. The company lists voltage ratings from 900 volts to 3,800 volts and capacitance values from 25 microfarads to 3,020 microfarads on the product page. (kyocera-avx.com) The company said the series uses dry metallized polypropylene film and “controlled self-healing” construction, a design that lets tiny internal faults burn away isolated spots instead of disabling the whole part. KYOCERA AVX said that approach is meant to improve safe operation and long service life in traction equipment. (kyocera-avx.com) KYOCERA AVX is pitching the FFLK line against both competing film capacitors and aluminum electrolytic capacitors in rail and industrial traction systems. Its broader DC-filtering catalog says film capacitors can handle higher surge voltage, lower equivalent series resistance, and higher root-mean-square current than aluminum electrolytics, which are the traits designers chase in hard-switched power converters. (kyocera-avx.com; kyocera-avx.com) The timing lines up with a larger build-out in electric drivetrains. The International Energy Agency said global electric car sales exceeded 17 million in 2024, up more than 25% from 2023, and more than 20% of new cars sold worldwide were electric. (iea.org; iea.org) Capacitor vendors have also been shifting from one-off custom traction parts toward more standardized product families. TDK said in October 2024 that its xEVCap platform was designed to shorten development time for traction inverters by offering a modular DC-link capacitor architecture. (tdk-electronics.tdk.com) KYOCERA AVX already sells FHC1 and FHC2 film capacitors for hybrid and electric vehicle DC-link filtering up to 115 degrees Celsius, and the FFLK launch adds another narrowly specified option at higher voltages for traction-duty power electronics. The near-term question is not whether traction systems need DC filtering, but which capacitor package and rating designers standardize on as electrified platforms multiply. (kyocera-avx.com; kyocera-avx.com)