Magnetic and Electric Coupling Analysis for Angular Misalignment of Spiral Resonators in WPT Systems

Abstract

Angular misalignment is an issue for many potential applications of wireless power transfer (WPT). It is necessary to keep coupling coefficient, especially the magnetic coupling to be insensitive to angular misalignment. This paper analyzes the coupling between the spiral resonators when one resonator rotates with respect to the other. The quantitative data of magnetic and electric coupling components as well as the total coupling coefficient in angular misalignments are presented. Furthermore, a 3D spiral resonator which is less sensitive to angular misalignment is proposed. The coupling when the 3D spiral rotates is studied and the results of analysis and experiment both show that the proposed 3D spiral resonator can keep coupling coefficient at a certain level under angular misalignment.

An Omnidirectional Resonator for Wireless Power Transfer

“…This study is an extension of our previous work reported in [17]. The study proposes an omnidirectional resonator which can keep coupling at a certain level when it rotates around all x, y, and z axes.…”

“…It is necessary to understand the magnetic and electric coupling components for these two basic resonators. In our previous study, we analyzed the dependence of coupling on alignment angle for spiral resonator and showed that the magnetic coupling component was 0 when two spiral resonators were in perpendicular positions [17]. In this study, we give an example of the coupling analysis on helical resonators to indicate the coupling dependence on the alignment angle.…”

“…Figure 1 shows the calculated coupling coefficients k, and magnetic and electrical components k m and k e as the functions of the rotating angle. Here, k, k m , and k e are calculated by the overlap integral method shown in the following equation [17][18][19][20]…”

“…Our previous study proposed a 3D spiral resonator which was less influenced by angular misalignment [17]. The proposed 3D resonator was constructed with 3 spirals arranged in a regular triangular prism.…”

“…The simulated and measured results indicated that the resonator could keep the coupling at a certain level when it rotated around two axes, for example, x and y axes. However, it was unable to maintain the coupling when it rotated around the third z axis [17].…”