Smart public transit system using an energy storage system and its coordination with a distribution grid

In this paper, a transportation network based on a supercapacitor-powered electric city bus (Capabus) has been shown to work in harmony with the electric grid. The load profile of the transportation network and the grid are interfaced using a battery-based energy storage system (ESS), which is used at each bus stop to continuously charge the supercapacitors for bus operation and provide grid support. The power flow from the ESS to the grid and vice versa is regulated using a fuzzy logic controller (FLC). The FLC takes as input the energy of ESS, node voltage [in per unit (p.u.)], and the frequency of the buses plying on a practical ring-road circuit of a typical city. The ESSs stabilize the grid at the corresponding node through peak shaving and valley filling during peak and off-peak hours, respectively. The objective of this paper is to achieve the required frequency of buses and maintain the grid voltage close to 1 p.u. Increasing penetration of the electric-bus-based transit system will substantially improve grid operation efficiency and reduce oil consumption by the transport sector.