High energy density DC link capacitors offer performance benefits for larger inverter systems

April 17, 2012 // By Paul Buckley
Cornell Dubilier has released high energy density DC link capacitors for larger inverter systems which are suitable for supporting DC link applications where high bus voltage, high capacitance, and high ripple current are required for smoothing and filtering.

Compared with major competitive types, the Type 947D DC link capacitor offers up to 20% more capacitance in the same size case with lower ESR and higher ripple current ratings. Since a fused, segmented metallization pattern is used, the 947D capacitors offer greater open circuit protection and superior control of capacitance loss than competitive types. The pattern is deposited on a low-loss, high-grade polypropylene dielectric.  Built-in fuse links limit capacitance loss to a small segment within the capacitor in lieu of the larger areas of uncontrolled capacitance loss observed with non-segmented types.

Available in 130 to 3600 µF and rms current ratings in excess of 100 A. The 947D DC link capacitors are packaged in cylindrical aluminum cases with diameters of 85, 90, 100 and 116 mm. Voltage ratings range from 800 to 1300 Vdc. The heavy duty M8x20 threaded studs or optional M6 threaded inserts are used to connect the high current terminals to the inverter’s bus. An optional M12 mounting stud at the bottom of the case provides a robust mechanical connection where needed. Where increased strike distance between live parts is important for applications, the UL94V-0 plastic top offers greater terminal-to-case and terminal-to-terminal insulation.

With a 200,000 hour life expectancy at nameplate ratings of current, voltage and temperature, the 947D DC Link capacitor will excel at providing reliable filtering and smoothing for today’s demanding applications in inverters for wind and solar energy, electric vehicles, motor drives, UPS systems, and more.

Visit Cornell Dubilier’s Power Film Division at www.cde.com