Capacitive energy storage systems are being developed as an alternative to SMES for utility power quality applications and to supplement batteries in electric vehicles. Systems considerations show that the low voltages of "ultra-capacitors" impose a high penalty in terms of increased component count, greater complexity in the power electronics used for charging and discharging, and large ER voltage drops. The consequent dissipation and reductions in efficiency exacerbate thermal management and stresses on the power electronics. Alternative strategies using ceramic hyper-capacitors in the 800-1500 V range will be discussed in terms of system cost and performance. A system analysis indicates that hypercapacitors at 12Whkg have higher effective energy density than ultracapacitors at 20 Whkg when useablehecoverable energy, packing density, and system issues are taken into account. The power quality delivered to the load, the cost, weight, and volume of the power converters used in discharging and recharging are shown to be essential considerations. Cryogenic operation appears to offer numerous attractive performance benefits. 0-7803-3547-3-711 6 $4.00 0 1996 IEEE
Chokes and inductors made from high-temperature ceramic superconducting (HTS) wires offer a new range of design and performance possibilities for high-power converters by making possible near loss-less inductances. Such power supplies can operate efficiently at low frequencies, thereby reducing semiconductor switching losses, decreasing heat sinking requirements, and lowering demands on circuit capacitors. Use of HTS inductors results in power converters up to 50% smaller in size in multi-megawatt installations, while still achieving considerably improved operating efficiencies and greatly simplified heat rejection. The installed cost may be 30-50% less than for conventional designs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.