Constant current (CC) and constant voltage (CV) charging are two charging stages for li-ion batteries in an electric vehicle wireless charging system. Based on the three-coil structure, this letter proposes a novel reconfigurable topology to achieve CC and CV charging. The transmitting coil is split into two windings with one winding having a turn number much smaller than the other. The two windings are fully compensated and connected to the corresponding inverter phase. The system can be reconfigured to perform as the two-coil structure with a CC output or as the three-coil structure with CV output. Unlike existing methods, the working frequency is fixed and only one relay is utilized to achieve the shift of CC and CV charging, which has the advantages of simpleness and low cost. An experimental prototype with 94.4% maximum efficiency is implemented to validate the proposal.

Wirelesscharging for electric vehicles (EVs) enjoys many benefits, such as convenience, safety, and automation. One of the major issues concerning EV wireless charging is misalignment tolerance along the door-to-door direction of the EV. This letter proposes a misalignment-tolerant dual-transmitter EV wireless charging system with a reconfigurable topology. At central positions, the system can be reconfigured to the S-S (series-series) topology where the two transmitting coils are connected in series to feed the load. At boundary positions, the two transmitting coils form the LCCC-S (inductor-capacitor-capacitor-capacitor-series) topology to enhance power transfer capability and tolerate weak couplings. In this way, not only the output power can be smoothed with door-to-door misalignment, but also wireless charging is guaranteed at weak couplings. Experimental results reveal that within the cover area of the transmitting coils, high-efficiency stable output can be achieved.

For electric vehicles (EVs) equipped with an onboard charger (OBC) and a wireless power transfer (WPT) system, there will be two charging systems in the EVs, which increases the cost, weight, and complexity. Based on the proposed design of magnetic couplers, this letter proposes a novel integration method for OBC and WPT systems of EV charging. The isolation transformer of the OBC system can be regarded as two strongly coupled coils. The secondary-side coil, namely the receiving coil, can also be loosely coupled with the transmitting coil of the WPT system. Thus, the receiving coil, the compensation, and the rectifier of both the OBC and WPT systems can be shared. In this way, the EV charging system can be capable of conductive charging and wireless charging while still having the advantages of cost effectiveness and high power density. An experimental prototype is implemented to validate the proposal.

A typical charging profile for the Li-ion batteries in electric vehicles (EVs) includes a constant current (CC) charging stage and a constant voltage (CV) charging. This letter proposes a simple and reconfigurable topology for CC and CV outputs in an EV wireless charging system. The proposed system can be switched to series–series topology for CC output and inductor–capacitor–capacitor-series topology for CV output. Only one relay is introduced, unlike existing solutions where many passive components and relays are utilized for reconfiguration. Also, there is no need for frequency variation to achieve the shift of CC and CV. An experimental prototype is implemented to validate the proposal.

Wireless power transfer (WPT) has the advantages of safety, convenience, and freedom from the impact of the environment. Misalignment tolerance is a major issue for the electric vehicle wireless charging system. In this letter, a WPT system with antioffset characteristic is proposed based on dual coupled transmitting coils with antiparallel windings, forming the inductor-capacitor-capacitor-series ( LCC -S) topology. The T-shaped equivalent circuit is developed to obtain the decoupling circuit. Based on the misalignment tolerant characteristic of the antiparallel windings, the two transmitting coils are designed to have the same coil structure with antiparallel windings, leading to the same variation trend of the coupling between the two transmitting coils and the receiving coil and the opposite influence on the output. Therefore, the output voltage can be stable within a certain misalignment range. An experimental prototype is built to verify the effectiveness of the proposal. The experimental results show that the output voltage can remain stable within the range of −150 to 150 mm in the horizontal direction and 80–160 mm in the vertical direction.

The unipolar, bipolar, and quadrupolar coils used in an electric vehicle wireless charging system are not interoperable with each other. Thus, there would be interoperability issues when the transmitting and receiving coils are not the same. To solve this issue, in this letter, we propose an asymmetrical quadrupolar coil that can be interoperable with the four conventional coils at the same position for efficient wireless power transfer, namely the unipolar coil, the bipolar coil along two perpendicular directions, and the quadrupolar coil. Large coupling coefficients can be achieved for the proposed coil with the four conventional coils when perfectly aligned. The misalignment performance with the four conventional coils is also investigated. An experimental prototype is developed to compare the conventional symmetrical quadrupolar coil with the proposed asymmetrical quadrupolar coil for validation of interoperability. The proposed asymmetrical quadrupolar coil achieves a maximum coupling coefficient of over 0.10 and a maximum dc–dc efficiency of over 85% with the four conventional coils.