Abstract: | Electric double‐layer capacitors showing a remarkably high energy density (compared with conventional electrolytic capacitors) are now under development. Capacitors of this type have significant advantages, namely, high durability against repeated charge and discharge and no need for maintenance. Therefore, we have studied feasible basic circuit configurations and control methods required to apply electric double‐layer capacitors as an energy storage element in output‐power leveling systems for solar cells or windmill power generators, and in uninterruptible power supply systems. This paper discussed operating methods for a capacitor bank to improve the efficiency. High efficiency has been demonstrated by the simulations and the experiments. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(3): 33–42, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10155 |