Capacitors

Abstract

Over the last decade, significant increases in capacitor performance, especially in reliability and energy/power densities, have been achieved for energy discharge applications in plasma science and fusion research applications through a combination of advanced manufacturing techniques, new materials, and diagnostic methodologies to provide requisite lifecycle performance for high energy pulse applications. Recent innovations in analysis of aging are introduced for predicting component performance and fault tolerance, especially relevant for very high energy storage applications necessary for next generation simulators, electrically energized fusion research machines, and advanced high power electronics for commercial, industrial, and military applications. Included in this study will be developments in capacitor technologies for electronics filtering and resonant energy transfer applications, as well as multisecond energy reservoir applications for uninterruptible power sources and the like. Next generation power electronics, driven by advances in solid state switching technologies, will require reduced capacitor dissipation factor by 1/3 to 1/10 at the same cost, particularly for AC applications. In addition, higher power electronics will require robust high frequency mica capacitor technology for >300/spl deg/C operation, up to 5 kV. The increasing expansion of the motor drive and industrial switched mode power supply (SMPS) market will be driven in cost by the availability of electrolytic capacitors of 750-850 Vdc ratings, at 450 Vdc cost and size. New formation processes and electrolytes are anticipated to be needed to achieve these extended performance levels. At higher frequencies, advanced power electronics drives the need for lower equivalent series resistance (ESR)/spl Lt/0.1% to 100 MHz, multimicrofarad value solid tantalum capacitors, having fail-safe surface mount configurations. Emerging power electronics applications in the millisecond and longer time are projected to have a broad application need for electrochemical chemical double layer capacitors, especially for compact sizes as this technology has the potential of achieving energy densities of many 20 kJ/kg for discharge times of tens of seconds. The prismatic power conditioning system, designed to be compliant with the available volume and surfaces into which it is to be placed, is described in some detail. It permits flexibility for the design engineer to optimize the design without having to allocate a specific space for the power conditioning system or subcomponents. Such prismatic geometry power and power conditioning systems are becoming commercially feasible In the low power consumer and industrial regime because of dramatic advances in multichip module switching, energy storage, and planarized interconnections. This work builds on assessing the applicability of these technologies to the megawatt-class average power, power electronics regime. Higher power density prismatic power electronics enables abroad range of applications in the commercial arena in areas such as motor drives, inverters, power quality systems, and mobile power systems.