A wireless power transfer system for roadway powered
electric vehicles (EVs) is presented. The system concept is
using inductive coupling of primary coils arranged in a linear
array in the roadway to secondary coils in each EV. The system
is geared to minimize loss of the stored energy in the primary
coils and compensation capacitors by passing the energy on
to the subsequent coil and capacitor of the linear array. The
inductive power transfer (IPT) system is operated as a switched
resonant inverter controlled by the primary and secondary coil
currents. By this way power transfer in both directions can
be accomplished. We describe an extension of the moving field
inductive power transfer (MFIPT) system by introducing a
synchronous switched DC-DC converter. A rectangular AC power
supply voltage is provided by a switched inverter from the underroad
DC power supply. An automatic switching adapts to load
changes and switches in optimum phase. Also the analysis of a
basic IPT cell is discussed and efficiency considerations are given.
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