A Complementary Asymmetrical Triangular Coil Set for Wireless Power Transfer Applications

This paper presents the design and analysis of a new bipolar right-angled Double-D (DD) coil as the transmitter and a concentric rectangular spiral coil as the receiver. Additionally, a bipolar-bipolar configuration with DD coils for both Tx and Rx, as well as a proposed unipolar-unipolar coil consisting of a concentric rectangular Rx and two asymmetrically placed rightangled triangular Tx coils, are investigated. A comprehensive comparison of these coil configurations is conducted to evaluate misalignment tolerance and coupling efficiency. The proposed coil design, with the vector synthesis strategy, improves magnetic flux density and power transfer efficiency while generating a highly concentrated magnetic field. It also ensures effective flux circulation and improved misalignment tolerance along both the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$x$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$y$</tex> axes. The two asymmetrical coils form a unified unipolar structure, and directly provide misalignment data to the circuitry, facilitating real-time adjustments. Finite element analysis (FEA) is utilized in Ansys Maxwell to validate the design, demonstrating complementary power delivery and enhanced wireless power transfer performance.