A Modular and Distributed Grid Interface for Transformer-less Power Supply to Road-side Coil Sections of Dynamic Inductive Charging Systems

This paper presents a distributed converter interface for the road-side infrastructure of dynamic inductive power transfer (IPT) systems for roadway-powered electric vehicles (RPEV). The proposed system configuration is based on a modular multilevel topology, with each individual module supplying power at a floating potential to a road-side coil section. Transformer-less integration with the high voltage distribution grid is enabled due to the series connection of modules as seen from the ac-side. When supplying a high number of road-side coil sections, the proposed system can significantly reduce the cabling requirements compared to a conventional low voltage dc distribution system. A control strategy for the presented system configuration is introduced, and simulation results demonstrate the operation under various loading conditions. It is shown how balanced three-phase currents at the interface with the grid can be ensured independently of the load distribution and the movement of the vehicles along the road. The presented control strategy also ensures that the individual capacitor voltages of each module are balanced and bounded within the design range.