The Role of Power Electronics Overload Capability in Minimizing Battery Size for In-Motion Charging Trolleybus Power Networks

Abstract

The high cost and weight of traction batteries remain significant barriers to the widespread adoption of electric buses. This paper proposes the In-Motion Supplemented Opportunity (IMSO) charging method, a hybrid solution that combines InMotion Charging (IMC) with high-power stationary “flash” charging at route terminals. Statistical analysis of real-world energy demand shows that peak power requirements, primarily driven by auxiliary systems in extreme weather, occur with low frequency. Leveraging this, the study investigates the impact of the OBC’s short-term overload capability on the system’s overall efficiency. Simulation results for a 14 km route with 25% catenary coverage demonstrate that utilizing the converter’s thermal inertia for a 600-second overload during flash charging can reduce the maximum battery depth of discharge by up to 40% during winter peaks. The findings suggest that the IMSO approach, coupled with optimized power electronics, allows for a significant reduction in battery capacity (to the range of 50–100 kWh) and infrastructure costs while maintaining full operational reliability in diverse climatic conditions.