Power capacitor addresses e-mobility

February 26, 2015 // By Christoph Hammerschmidt
Battery and hybrid electric vehicles use large power capacitors as a DC link cap, an energy buffer typically located near the motor. The RingCap from TDK company Epcos addresses this use case with a ring-shaped capacitor - it fits into a clutch bell housing or wheel hub motors.

The Epcos RingCap is designed for rated voltages of between 100 V DC and 900 V DC and offers capacitance values of between 100 µF and 2000 µF. Apart from the main winding, Y-capacitors with separate terminals can additionally be integrated in the winding. A special heat-treatment under vacuum increases long-term stability of the capacitor. In the standard version with dielectric made of polypropylene (PP) or polyethylene terephthalate (PET), the capacitor is suitable for a temperature range between -40 °C and +105 °C. With a dielectric made of polyethylene naphthalate (PEN), it can even handle temperatures of up to +150 °C.

Due to the low equivalent series inductance (ESL) values ranging from less than 10 nH up to 30 nH, no unwanted overvoltages occur in the DC link circuit during high-speed switching operations. For better protection against environmental effects, the capacitor is also available with a resin-filled housing.

The dimensions of the capacitor can be adapted according to the specific requirements of the customer: The outer diameter may be up to 315 mm, while its width is no more than 50 mm.

More information: www.epcos.com/inquiry