Novel semi‐analytical method for mutual inductance calculation of the thin spiral disk coils

Abstract

Accurate and fast calculation of the self and mutual inductance of coils is an important factor in system design and optimization for many applications. The methods of calculation mutual inductance between two spiral disk coils include elliptic integral solutions and coefficients in literature. In this study, a new semi-analytical method is proposed to calculate the mutual inductance between two thin disk coils without any coefficient and complex integral solutions. For this purpose, the circular winding is treated as polygonal winding with multiple edges. Unlike Grover's average diameter approach, the gaps between the turns of the coils and the diameter of the wire are included in the calculation. To observe the reliability of the method developed here, the mutual inductance between identical disk coils with an inner diameter of 10 and 20 cm were calculated using both methods. To confirm the accuracy of the proposed method, the experimental results are compared with two methods using the same coils. It is observed that the new method gives acceptable results (maximum error of 2.83%) especially at the distances equals to the inner radius. Consequently; this method is useful for the design of loosely coupled systems, such as wireless power transfer and pressure sensors.