Smart Opportunity Charging Strategy for Electric Buses

In decarbonizing the road transport sector, electric buses play a vital role due to their higher decarbonization capability. Anxiety of charger unavailability and limited driving range are among the major reasons for low electric bus adoption, and therefore various charging approaches are developed viz., depot charging, opportunity charging, wireless charging, and battery swapping. Opportunity charging includes charging at different potential locations and time, for example bus stops, terminals, and depots for limited duration (few minutes). The technical analysis of opportunity charging profile from demonstration and commercial projects have shown that in 24% of the opportunity charging instances the arrival SoC of the e-buses are greater than 80%, thereby leading to under-utilization of chargers. Opportunity charging at every possible instance can result in life cycle reduction of charger (in case of opportunity charging: pantograph) and increased number of battery charging cycle. This paper proposes a smart opportunity charging strategy using charger utilization factor and battery SoC to mitigate the issue of under-utilization of charger. The proposed strategy implements smart opportunity charging that includes travel schedule of a bus, traffic scenarios, and battery charging modes. The paper presents modelling of electric bus route considering the practical aspects i.e., traffic, bus stops, and schedule of a bus. The results show that the proposed strategy improves charger utilization, reduces the battery charging cycles, and maintains sufficient battery SoC to deal with range anxiety.