Recursive Domain Decomposition Approach in 2-D Time-Harmonic Wireless Power Transfer Simulations Considering Litz Wires

Antero Marjamaki,Paavo Rasilo

doi:10.1109/tmag.2020.3024158

Abstract

A recursive domain decomposition approach based on a 2-D time-harmonic finite element (FE) model with AVI formulation is used to model a wireless power transfer (WPT) unit with litz wires. Similar techniques exist in the literature, but they have not yet been applied to WPT units. The approach produces a model that is significantly faster to update and resolve than a traditional FE model, and hence, it is suitable for performing parametric sweeps where the positioning of the coils is varied. Using the technique, it is possible to study losses emerging in individual strands even with an extremely high number of strands. The loss distribution between the litz wire strands is studied, varying the number of strands from 7 to 925. The results and speed are compared with a traditional FE AVI model. The method yields the results up to a 1% relative error compared with the traditional model with significantly faster simulation time.

Highlights

W IRELESS power transfer (WPT) systems can be used to transfer power without the need for physical contacts [1]
Parking squares and sections near traffic lights could be equipped with dynamic wireless charging coils that would boost the ranges of electric vehicles without the need for larger batteries [2]
For further details of the spatial decomposition technique, we refer to our earlier work [31] where we demonstrate the use of the Fourier basis for the Lagrange multiplier space in static magnetic field computations

Summary

Introduction

W IRELESS power transfer (WPT) systems can be used to transfer power without the need for physical contacts [1]. Parking squares and sections near traffic lights could be equipped with dynamic wireless charging coils that would boost the ranges of electric vehicles without the need for larger batteries [2]. In these kinds of applications, the WPT coils are perfectly aligned only for a short period of time, so it is crucial to analyze and optimize the operation of the windings when the coils are badly aligned. The load affects the operation of the WPT device On top of these considerations, there are several parameters that have a negative impact on the performance of the WPT unit. These parameters include offsets from the optimal position, variance in the distance between the windings, and misalignment of the magnetic axes of the windings

Methods

Results

Conclusion