A Design Method for High Power Density Coupling Mechanism with Zero Air Gap

Tightly coupled wireless power transfer systems achieve efficient energy transfer through the use by close-packed transmitter and receiver coils, and this transformer-like design can result in a significant increase in system efficiency and power density over loosely coupled systems. However, the improvement of power density also brings many problems, including thermal management, electromagnetic compatibility issues, and overall system stability. Hence, this paper introduces a novel design approach for a magnetic coupling mechanism where the secondary coil is integrated within the primary coil in the same plane. By enhancing the coupling coefficients compared to existing tightly-coupled systems, this method achieves greater self-inductance and mutual-inductance values within a smaller volume. These improvements lead to increased system efficiency and power density, while reducing the whole wireless power transfer system losses.The parameters of the coupling mechanism in this design approach are obtained from the simulation model, which indicates that this method can enhance the power density of the system as demonstrated by the simulation results.