Pushing dielectrics to the limit — Self-healing metalized film capacitors for high energy density

Capacitors for pulse power applications have been custom-designed to maximize specific energy while operating with specific circuit requirements such as charge voltage, peak current, voltage reversal, series inductance and resistance, charge time, hold time at peak voltage, and pulse repetition rate. In addition, these capacitor designs had to meet application-specific constraints such as operating temperature and pressure ranges, lifetime, and reliability. To simultaneously minimize size and/or weight, not only was the packing factor addressed, but the electric field in the dielectric system was maximized within the performance constraints. Applications with moderate high voltages (<; 50 kV) and peak currents (<; 5.0 × 10
⁷
A-V/μF) have been addressed using self-healing metallized electrodes to both increase packing factor and electric field. In laboratory environments where pulse power capacitors are operated in single-shot mode, very high electric fields, approaching the intrinsic strength of the dielectric, have been employed. In industrial environments with continuous, high pulse repetition rate operations, electric fields had to be significantly reduced, but were still much higher than those that could be used in non-self-healing capacitors in the same applications. This paper will describe examples of self-healing capacitors custom-designed for a wide range of pulse power and related applications, employing a variety of materials to achieve optimum solutions.