50 kW Reflexive Tuning Networks With Low Uncoupled Transmitter Currents for Dynamic Inductive Power Transfer Systems

Abstract

This paper proposes a novel reflexive tuning dynamic inductive power transfer (DIPT) system with a single inverter connected to multiple transmitter coils, which makes DIPT systems simpler and more cost-effective. Traditional DIPT systems have an individual inverter per transmitter coil, leading to considerable costs when transmitter coils span long distances on roads. The proposed reflexive tuning DIPT system leverages a reflected reactance from a receiver coil to allow a single inverter to drive multiple transmitter coils. Using reflexive tuning, the approach naturally achieves high currents solely on the transmitter coil coupled with a receiver coil when a vehicle moves along a DIPT roadway. Simultaneously, the other uncoupled transmitter coils connected to the shared inverter operate at notably reduced currents. Theoretical analysis, design, simulation, and experimental results are provided for the proposed reflexive tuning circuits. Simulation results indicate that the proposed reflexive tuning circuit can reduce the uncoupled transmitter current by 37% compared to the conventional double-sided LCC tuning circuit while maintaining the output power at the same level. Experimental results with a 50 kW prototype demonstrate operation on both automated rail and vehicle systems. The results demonstrate dc-dc efficiency of 90% per a single transmitter coil configuration with 223 mm air gap and capability of power delivery at least up to 60 km/h speed.