Integrated Dual-Decoupled Transmitter With Battery Voltage Interoperability for Wireless Charging of EVs

With the development of electric vehicles (EVs), lithium-ion batteries have two rated voltages: 400 and 800 V, and are suitable for different output power scenarios. Considering the interoperability of public wireless power transfer (WPT) facilities, the WPT system for EVs not only needs to be compatible with the battery voltage class (BVC) under the premise of meeting the corresponding output power level, but also needs to take into account different coupling structures, namely unipolar (Q) and bipolar (DD) coils. Under the background of the interoperability of the above-mentioned BVC and coupling structures, an integrated dual-decoupled transmitter is proposed. First, finite element analysis and optimization were carried out for the proposed coupling structure. While obtaining the optimal coil parameters, the interoperability performance with Q and DD coils was also achieved. Then, by combining circuit topology, four different output modes can be achieved, which are used to adapt to the BVCs under different power levels and different coupling structures. A downscaled experimental prototype with the power of 5.0-kW was established. Under the premise of 200 V input voltage, the efficient transmission of 200 and 400 V output of Q and DD coil was achieved. The dc-dc efficiency is greater than 91%. Finally, on the premise of meeting the interoperability of Q and DD coils, the proposed structure also has a certain degree of antimisalignment characteristics.