Suitable for use as a DC link capacitor in EV and HEV applications, TDK has announced a power capacitor with an innovative ring configuration, the RingCap. The device can be integrated into a clutch bell housing or wheel hub motors and its dimensions can be adapted according to the specific requirements of the customer: the outer diameter may be up to 315mm, while its width is no more than 50mm.
The RingCap is designed for rated voltages between 100 and 900VDC and offers capacitance values of 100-2000µF. 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 from -40 to +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 values ranging from less than 10 up to 30nH, 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.