Development of a regenerative braking energy storage system using supercapacitors for metro and light rail vehicles

In this thesis study, development, laboratory setup and realization of a energy storage system based on supercapacitor which aims to recover braking energy in metro and light rail vehicles is presented. In this context, storage and reuse of the energy that would be wasted while braking, has a significant meaning. Supercapacitors are devices with high power density and relatively low energy density where they are suitable for efficiently storing the energy in urban rail transportation systems that halts and speeds up again and again. Braking in rail transportation systems is mostly in the form of converting mechanical energy into electrical energy and converting this energy into heat energy in braking resistors. In this thesis, a supercapacitor energy storage system has been developed by designing a new generation silicon carbide (SiC) metal oxide semiconductor field effect power transistor (power MOSFET) based a low volume bidirectional power converter which has high efficiency, long life and less audible noise. This system has been integrated and verified with the catenary and railway traction simulators developed and set up in the same laboratory. In the development process of these three systems, the innovations, potential problems and effects of SiC power MOSFETs have been emphasized and thus studies have been carried out. In addition, research and development has been carried out on algorithms and working methods aimed at using supercapacitors more effectively for the braking energy recovery. By applying the standard methods, the energy saving, which was about 31% on the straight road, was 38% with the developed algorithm, and the energy saving, which was about 33% on the slightly negative slope, was increased to 43% with this algorithm. When this algorithm is applied to a whole rail track, the energy savings increased from 31% to 39%. These methods have been verified by running the whole system installed in the laboratory environment.