Dynamic wireless charging is imagined to uninterruptedly charge moving electric vehicles(EVs)through the powered roadway as a potential solution to the battery bottleneck. In order to reduce the power coils loss and leakage magnetic field

the primary coils layout usually adopts sectional track type. However

the number of primary coils increases rapidly and a power supply management of primary coils chain should be required. Thus

a relay control method for dynamic wireless charging system based on the secondary active excitation and distributed control diagrams is proposed

ensuring accurate positioning and local excitation mode. As the primary and secondary power coils are fully reused

no additional sensing devices and centralized signal lines are needed. The secondary active excitation is based on the S-S type compensation network with the excitation frequency set at the splitting point to enhance the strength of detection signal and solve the overcurrent problem of secondary excitation. With the design of rational relay control flow

the detection power is reduced and the conflict of excitation between the primary and secondary sides is avoided. Finally

a 5∶1 physical scale-down dynamic wireless charging demonstration platform based on sectional track is built. The relay power management of eight primary transmitter coils is realized to verify the feasibility of the proposed relay control method. This work is supported by the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(No. 51361130150).