Accurate Distance and Battery Capacity Estimation for Battery-Powered Electric Locomotives

This thesis focuses on investigating the impact that on-board energy storage devices have on battery powered electric railways as an alternative to conventional railway electrification. For battery locomotives to achieve maximum distances in catenary-free routes, the majority of current research is around the design of the rail vehicle and sizing of batteries. There is a lack of study of the effect of design parameters on the battery locomotive performance for design engineers to consider. Currently, the maximum distance known for the battery to provide before the need for re-charging is known for straight tracks. Most of the time, railway corridors do not face ideal conditions and designers must deal with the challenges of varying rail routes such as those containing curved and elevated tracks, tunnels and bridges which limit speeds and multiple stations. Knowing the estimated distance the battery can provide for any railway infrastructure condition will allow designers and operators to optimise their design and allocate conventional routes in geographical areas only where required. Further where the given distance is not enough, knowing the battery capacity required to achieve the distance for a given railway route with any varying external rail condition through this mode will be helpful. In this research, an energy balance approach has been proposed to determine the battery sizing and maximum distance travelled by battery driven electric vehicles (commonly lithium-ion battery driven) during catenary-free operation for any railway environment. Using the developed energy balance approach, an algorithm has been developed to determine the maximum distance the battery can deliver, and battery sizing required to travel a desired distance as a function of several variables. This research further presents a mathematical model and dynamic simulation of an electric train from a railway electrification designer's perspective, with real-life issues and design constraints considered and input into the model. MATLAB based simulation model consists of the battery train’s longitudinal dynamics, electric system, and on-board energy storage for any given railway route as a function of time. This allows the study of the internal operations and characteristics of the battery locomotive and the effect of the on-board energy storages on the rail vehicle’s performance. The results have been compared and validated with real life railway routes and data following Australian railway standards to ensure accuracy and validity.