A study for electric double layer capacitor (EDLC) application to railway traction energy saving including change over between series and parallel modes

In this paper, possibilities for application of the electric double layer capacitors (EDLCs) to railway vehicles are described. Expected advantages are not only energy saving or high efficiency operation, but also keeping regenerative braking even when the power source line is missing. Based on the practical EDLC design, storing energy is calculated by the typical running of assumed commuter cars. Additionally, by applying the change over method between series and parallel modes of the EDLC blocks, the equivalent capacitance is much increased without using a continuously working power converter for keeping output voltage.