TDK launches new DC-link film capacitors for high-frequency SiC power converters

TDK has unveiled its B25696H series of MKP DC-link film capacitors, specifically designed to meet the demands of high-frequency silicon carbide (SiC) power converters. These capacitors are tailored to handle the rapid voltage transitions and elevated switching frequencies characteristic of SiC technology, which surpass the capabilities of traditional silicon IGBTs. The series offers a broad range of capacitance values from 47 µF to 1280 µF and supports DC voltages between 900 V and 2,000 V, making them suitable for applications such as energy storage systems, traction drives, solid-state transformers, and renewable energy inverters. A key innovation in the B25696H series is its internal busbar configuration, which ensures uniform current distribution across the capacitor windings and results in an exceptionally low equivalent series inductance (ESL) of just 30 nH. This low ESL is critical in mitigating voltage overshoot during the fast switching events typical of SiC devices. Additionally, the capacitors feature a low equivalent series resistance (ESR) of 0.8 mΩ at 10 kHz, maintaining stability up to 100 kHz, which is vital for accurate loss calculations at high switching frequencies. The units also boast a ripple current capability of up to 91 A at 60° C ambient temperature and 10 kHz. Constructed with metallized polypropylene dielectric and housed in cylindrical aluminium cases, the capacitors incorporate self-healing properties to enhance reliability. They are available in two diameters, 85 mm and 100 mm, and are equipped with M6 screw terminals and an M12 mounting bolt. The operating temperature range spans from −40° C to +85° C at the hotspot, with a baseline lifetime rated at 100,000 hours under 75° C and nominal voltage conditions. This lifespan can be extended to 200,000 hours through appropriate voltage and temperature derating, providing flexibility for various operational demands. To support engineers in optimising capacitor performance within specific applications, TDK offers a free online CapThermal simulation tool. This resource allows users to model thermal behaviour and estimate lifetime under customised conditions, aiding in the design and reliability assessment of SiC power converter systems. The introduction of the B25696H series represents a significant advancement in capacitor technology, addressing the unique challenges posed by the rapid switching speeds and high voltages of next-generation SiC power electronics.