Emerging Technologies in Alternate Drive Train Management: Power Capacitor Chip in Hybrid- and Fuel Cell Powered Drives

The development work on the HEV power train has put its emphasize on the most efficient electric drive, which in turn demands a compact, low loss and cost effective DC Link Capacitor with bus voltages ranging from up to 1000 VDC and capacitance values ranging from up to 3000µF. The System development shows in the graph: P_output vs. V_rated a ramping up tendency and has now reached V_r ≈ 650VDC based on C_r -range of 500…1000µF. Consequently for modern HEV converter design engineers trying to find alternative options for the once popular Electrolytic Caps which had the advantage of high CV values, for U_r below 450 V the choice now rests with Film- and Metallized PP Capacitors in particular [1]. However, the relatively low temperature rating of standard round wound MKP Capacitors in the range of 85 deg C and the large dimensions had made it difficult for the designers to make the total change over till now.

A new development in the DC Link Capacitor technology overcomes these short falls and offers a capacitor with voltage ratings up to 1000 VDC, maximum fill ratio and temperatures up to 125 deg C and short excursions even to 135 deg C. This paper deals with various designs of PCC that were developed and successfully tried out in HEV-inverters for automotive applications, test results and its mechanical adaptability for use in the new generation of inverters, which demand compact sizes, high temperature conditions and tough mounting options, in addition to the uncompromising electrical requirements.