Optimal Coil Design for Maximum Power Transfer Efficiency in Resonantly Coupled Systems

A Design Technique for Optimizing Resonant Coils and the Energy Transfer of Inductive Links

“…In selecting a suitable coil ac ohmic resistance, an FoM parameter (P scf ) has been introduced, in [31] and [32], such that its value indicates how strongly the Tx and Rx coils are linked together. The constant parameter P scf (P scf 1) has been named as strong coupling factor and provides a guideline for designing a geometrically optimized coil.…”

“…However, K based on its definition is affected by both the Tx and Rx [14]. We, in our previous article [31], have modified the approach presented in [6] by considering only one FoM parameter such that its value indicates how strongly both the Tx and Rx sides are linked together. The proposed FoM parameter, named as "strong coupling factor" (P scf ), has been defined as:…”

“…The theoretical method in [31] was practically exemplified by the design of an optimized Tx/Rx solenoid pair geometry for an inductive link with a transmission distance of 9.5 mm (K = 0.215) at f o = 1 MHz [32]: a PTE of 86% was measured thus showing merit in the design approach. However, a proper selection method for identifying a numerical value to represent the FoM parameter (i.e., P scf ) used in [31] and [32] still requires in-depth analysis.…”

“…Building upon the proposed coil optimization technique used in [31] and [32], this article introduces a method to assist selecting the most favorable numerical value for the strong coupling factor which can maximize PTE for the designed optimum coil geometry. The proposed method will be developed through geometrical optimization of a helical coil (i.e., solenoid).…”