Mutual Inductance Behavioral Modeling for Wireless Power Transfer System Coils

Abstract

This paper derives low-complexity behavioral analytical models of the mutual inductance between the coupling coils of Wireless Power Transfer Systems (WPTSs), as functions of their reciprocal position. These models are extremely useful in the characterization and design optimization of WPTSs. Multi-Objective Genetic Programming (MOGP) algorithm is adopted to generate models ensuring an optimal trade-off between accuracy and complexity. The training and validation data sets needed for the generation of the models are here obtained by performing numerical full-3D electromagnetic simulations. The resulting behavioral models allow accurate and fast evaluation of the WPTS coils mutual inductance, over a wide range of misalignment conditions, enabling easier system analysis and optimization.

Self and Mutual Inductance Behavioral Modeling of Square-Shaped IPT Coils With Air Gap and Ferrite Core Plates

“…However, the proposed modeling approach is fully general and can be also implemented to search analytical expressions of the inductance values as a function of misalignment parameters. For instance, this approach is adopted in [14], where the mutual inductance value of a coil pair for an automotive IPT system is derived as a function of the axial and lateral misalignments of the coils and parametrized with respect to their reciprocal rotation angle. Therefore, in this paper we will only focus on analytical expressions that relate the selfinductance L and the mutual inductance M to geometrical design variables under perfect alignment conditions for fast prototyping of IPT systems by obtaining geometries that match the desired inductance and coupling factor.…”

“…The behavioral modeling approach has been recently demonstrated to be extremely helpful in both static and dynamic IPT system-level simulations. In [14], a behavioral analytical modeling of the mutual inductance of a coupled coil pair used in a static WPT system has been proposed. The paper also shows that it is possible to use the same behavioral model for modeling different coil pairs with the same shape (e.g., rectangular coils) but different dimensions and form factors.…”

Analysis of Dynamic Wireless Power Transfer Systems Based on Behavioral Modeling of Mutual Inductance

“…As the efficiency is function of M according to (9), the proposed behavioral model allows calculating the derivative of the efficiency with respect to ∆z. By using the first-order linear approximation (14), it is possible to obtain the function ∆z max (∆y) given in (15):…”

“…In this paper, we follow the second approach, by deriving, validating and using an analytical behavioral model of M. This modeling approach has been previously used to assess the losses and performances in power devices and power modules, like IGBTs [12], inductors [13], and inverter modules [14], and to study static WPTSs [15]. Compared to the static condition analyzed in [15], the dynamic problem analyzed herein introduces new challenges and features, related to the geometry and to the time-domain behavior. Indeed, the paper focuses on the misalignments of the EV trajectory [16], and on their impact on the operation of the entire WPTS [17].…”

Comparison of Coupling Coils for Static Inductive Power-Transfer Systems Taking into Account Sources of Uncertainty

“…In [13], circular coils were designed and investigated for planar and angular misalignment through the FEM model. Reference [14] proposed the use of an analytical behavioral model, able to relate mutual inductance to a wide range of misalignment conditions for IPT coil system (axial, lateral, and rotational). However, in such previous publications, the number of possible misalignments conditions was limited, and no accurate comparison among different coupling coils was given.…”