Simulation of in-vehicle Power Flows for Electric City Buses with Inductive Power Transfer Technology

This article describes the study of power flows inside an electric commuter bus with a propulsion system that is powered wirelessly while the vehicle drives along its realistic daily trajectory in the context of public transport. The necessary energy is transferred along the trajectory through inductive coupling, from coils integrated in the road to an on-board power pick-up element in the vehicle. This transfer of power can happen dynamically, while driving, or when the vehicle is at standstill, something that occurs regularly along the trajectory of a bus for public transport. The insight in the distribution and intended use of these power pick-up pads is one of the objectives and obtained results of this simulation study. Moreover, these different geographically spread external power inputs are considered together with the possibility of use of on-board rechargeable energy storage systems, with the purpose of being able to formulate optimized strategies for the design of an inductively powered electric public transport system.
For given trajectories with features like bus stops, simulations of the flow of power from the incoming pick-up element to the combination of multiple consumers and storage systems is performed, and these results are used to further improve the overall working efficiency, cost-effectiveness and power sharing strategy of the vehicle.
The simulation method is primarily based on a 'backwards-looking' modeling approach, where the desired performance at the wheel is considered as the model input and the power required from the components upstream the power flow are calculated up to the vehicle energy input point. A 'forwards-looking' calculation component is also integrated in the tool to check for consistency.