A capacitance control method for two-terminal active capacitor

The two-terminal active capacitor concept based on power electronic circuits is proposed recently to exceed the physical limit of the passive capacitor. It retains the convenience of use as a passive capacitor and has the potential to either increased power density or lifetime depending on the applications. However, the equivalent capacitance of the existing active capacitor is infinite ideally and can not be controlled to a specified value, which is inapplicable to replace the passive capacitors in the applications with accurate value needed, and could result in higher current stress as well as power loss at the light load condition and slower charging/discharging speed as well as dynamic response during the load change. This paper proposes a novel capacitance control method, which is able to configure the active capacitor with a specified capacitance value. It has the following advantages: 1) specific functions with capacitance value can be achieve; 2) power loss is reduced significantly with the light load; and 3) the dynamic response is improved during the load change. The functionality and accuracy of the proposed control method have been verified and the performance is benchmarked with the passive capacitor and the active capacitor with conventional control method.