电动汽车无线充电金属异物检测线圈电磁特性

Electromagnetic characteristics of metal foreign object detection coil in wireless charging system of electric vehicle

在电动汽车无线充电系统中,为实现较大范围内对小型金属异物的有效检测,提出一种金属异物检测线圈电磁特性的分析方法.基于谐振电路在受到金属异物干扰后会产生失谐现象,论述金属异物检测的基本原理;分析检测线圈电磁特性的主要影响因素,给出将若干个PCB(Printed Circuit Board)型小线圈通过串并联构成线圈组的线圈设计方案;用Maxwell软件仿真分析金属异物进入检测线圈上方对线圈磁场的影响,得到不同的线圈结构参数和线圈连接方式对检测线圈电磁特性的影响规律;在无线充电环境下,用检测线圈组的感应特性仿真实例验证所提出的检测线圈组设计方案的可行性.结果表明:本文提出的设计方案能够有效抑制电动汽车无线充电过程中环境磁场引起检测线圈的感应电压噪声,金属异物检测线圈电磁特性的分析方法能够为电动汽车无线充电系统中金属异物检测线圈的设计提供指导.

Aiming at improving the effectiveness for detecting the small pieces of metal foreign object detection(MFOD)scattered in large area of wireless charging system(WCS)of Electric Vehicle(EV),a method for analyzing the electromagnetic characteristics of MFOD coil is presented.The principle of MFOD based on the mistuned appearance of resonant circuits disturbed by metal foreign object(MFO)is introduced.The main factors of affecting the electromagnetic characteristics of MFOD coil are analyzed,and the general design scheme for MFOD coil is proposed as combination of several printed circuit board(PCB)type small coils by series-parallel connection.By the Maxwell simulation,the influences of MFO entering above the MFOD coil on the magnetic field of MFOD coil are analyzed,and the influences of parameters and structural type of MFOD coil on electromagnetic characteristics of MFOD coil are obtained.The simulation result verifies that the presented design scheme for MFOD coil can restrain the induced electric noise under the condition of WCS of EV.The method can be used to guide the design of MFOD coil in WCS of EV.