With the fast development of high-temperature metal oxide semiconductor field effect transistors for power electronics in electric vehicles, current state-of-the-art biaxially oriented polypropylene (BOPP) film capacitors need further improvement because they have a temperature rating of only 85 °C without derating the voltage to maintain a long lifetime. If a high-temperature polymer can replace BOPP without sacrificing the overall dielectric performance and cost, it is possible to remove the current water-cooling system for capacitors and significantly reduce the cost of the power electronic unit. In this work, we demonstrated new polycarbonate (PC)/nylon multilayer films (MLFs), which has a potential for even higher temperature rating because of the higher melting temperature for nylons (e.g., nylon-6). Structural and dielectric studies showed that these PC/nylon MLFs had a similar dielectric performance, such as dielectric constant, dielectric loss, and breakdown strength, as the PC/poly­(vinylidene fluoride) PVDF MLFs, which were developed in the past. These PC/nylon MLFs could perform well up to 120 °C, which was limited by the glass transition temperature of PC at 145 °C. More intriguingly, packaged PC/nylon-12 MLF capacitors exhibited a self-healing capability, which had been difficult for packaged high-temperature film capacitors. Because self-healing is such a fundamental requirement for polymer film capacitors, our PC/nylon MLFs offer a potential for next-generation high-temperature and high-energy density film capacitors.

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Voltage overshoot is defined by stray series inductance and turn-off time, which must be managed to avoid failure of IGBT's in inverter applications.The total equivalent series inductance (ESL) is dictated by internal switch branch inductance with a significant contribution in the current path to the DC link capacitor. Using traditional topologies, external ESL dominates and by-pass capacitors ("snubbers") are used to mitigate overshoot. Integrated capacitor/bus designs provide an external ESL comparable to internal values for commercial IGBT's. The minimized ESL regime allows reduced switch turn-off time with slightly increased losses to manage overshoot without the cost, space, weight, dissipation, and reliability associated with by-pass capacitors.

Accurate measurements of beam position and current are critical for the operation of the high-energy electron accelerators used for radiographic applications. Traditional short-pulse (e.g., 70 ns) machines utilize B-dot loops to monitor these parameters with great success. For long-pulse (e.g., 2 micros) accelerators, beam position and current measurements become more challenging and may require new technology. A novel electro-optic voltage probe has been developed for this application and provides the advantages of complete galvanic isolation, excellent low-frequency performance, and no time integration requirement. The design of a prototype sensor is presented along with preliminary accelerator test data.

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