Deterioration diagnosis of ultracapacitor for power electronics applications

As a new energy storage device, ultracapacitors are able to attain greater energy densities while still maintaining the characteristic high power density of conventional capacitors. As a result, ultracapacitor based power electronics system will become an attractive power solution to an increasing number of applications. But in this situation, the ultracapacitor usually has the shortest span, and then determines the system lifetime. Therefore, a deterioration diagnosis of the ultracapacitor is needed for preventive maintenance of the circuit. In this paper the deterioration characteristics of ultracapacitor is presented and an online deterioration diagnosis method is proposed. Experimenal results are given to verify the analysis.