Ultracapacitors Utilization for Automotive Applications

摘要

This paper describes the basic properties of ultracapacitors and a converter for ultracapacitors with application zero-voltage switching (ZVS). Because of the very high efficiency of the ultracapacitor, the efficiency of the converter for ultracapacitors also has to be high; otherwise, the converter reduces efficiency of the whole drive unit. Further, the paper describes the drive unit concept for the City El electric vehicle, with the use of ultracapacitors in cooperation with a fuel cell. This co-operation with ultracapacitors is useful for the supply unit as a fuel cell, which cannot deliver peak power in dynamic conditions while maintaining its nominal efficiency. However, this poses no problems for ultracapacitors.rnThere is also a description of the basic principles of soft switching using zero-voltage and zero-current switching together with a comparison of the power losses between hard and soft switching.