Evaluation of various methods for energy storage calculation in nonlinear capacitors

In the practical application of capacitors, especially in pulsed application, recoverable energy is a key parameter, which represents the ability to store energy. However, many existing evaluation methods for energy storage calculation have not been systematically implemented and comprehensively understood. In this work, four methods were applied to calculate the energy storage in linear, ferroelectric, and antiferroelectric capacitors. All methods were valid when the linear capacitor was examined. In terms of the ferroelectric capacitor, the method of equivalent parameter using DC-bias capacitance was infeasible under the high voltage owing to a massive decrease in field-dependent capacitance. As for the antiferroelectric capacitor with noticeable hysteresis, the maximum of energy storage was obtained by the method of integration of hysteresis loop, while the lower one was obtained in the fast discharge condition by the method of integration of UI (product of voltage and current). In summary, for different materials, both test conditions and calculation methods should be considered to get accurate energy storage, which best fits the working conditions.