【作者】 张彬；

【导师】 何霁； 张希；

【作者基本信息】 上海交通大学 ， 车辆工程（专业学位）， 2022， 硕士

【摘要】 无线充电系统能提高车辆充电的便捷性,将是汽车电动化、智能化进程中最优的充电解决方案之一。金属异物检测是保障电动汽车无线充电系统安全运行的基础。当前金属异物检测的主要技术挑战包括检测灵敏度要求高、受充电功率磁场干扰严重、存在检测盲区等。据此,本文提出了针对性的解决方法,主要研究内容如下:研究金属异物对螺旋线圈物理参数变化的影响,提出了金属异物检测系统结构,将金属异物介入导致检测线圈的参数变化通过检测电路转换成电信号后放大输出,并消除无线充电功率磁场噪声干扰。基于通用矩形检测线圈,提出了灵敏度优化方法。给出了一种基于等效环路近似的金属异物集总参数建模方法,建立了金属异物介入矩形检测线圈的等效电磁模型,研究了线圈的物理参数变化机理,得到不同尺寸金属异物介入引起的检测线圈参数变化解析公式。分析了多个线圈构型参数对检测线圈灵敏度的影响,并结合无线充电实际工况得到最优检测线圈构型。该方法解决了矩形检测线圈参数众多、设计困难、难以优化的问题。通过电磁场仿真和实验验证,证明了理论模型准确性和普适性以及优化后线圈构型的可行性和优越性。为提高金属异物检测抗干扰能力,提出了一种基于最优矩形线圈的双极性解耦线圈结构,其由四个单极性矩形线圈中心对称组合得到。在基于等效环路近似的金属异物集总参数建模方法的基础上,提出了分块金属异物等效方法,给出了金属异物介入时线圈等效自感和灵敏度的表达式。通过仿真和实验说明了双极性解耦线圈与无线充电功率磁场解耦,可以消除低频噪声干扰,同时保证了金属异物检测灵敏度较高。线圈采用非重叠式印刷螺旋结构,简单易行,成本低廉。分析对比多种电路拓扑,结合检测线圈物理参数,设计了可调参的检测电路,提出串联谐振采样放大网络,调谐优化得到非谐振最优工作频率,进一步提高检测灵敏度。为保证无线充电系统充电区域无检测盲区,提出了多路金属异物检测系统结构以及相应的自适应控制算法,降低系统复杂度,提高鲁棒性。最终,在3k W无线充电系统中进行金属异物检测系统实验,验证了以最优矩形线圈为基础搭建的金属异物检测系统,可以准确检测到25mm及以上尺寸的金属异物,符合无线充电国标要求与实际工况;验证了以双极性解耦线圈为基础搭建的MOD系统具有较强的抗干扰能力,同时满足无线充电系统金属异物检测要求;验证了最优工作频率处系统检测灵敏度相较于其他频率更高。更多还原

【Abstract】 The wireless charging system can improve the convenience of vehicle charging and is one of the best charging solutions in the process of vehicle electrification and intelligence.Metal object detection(MOD)is the basis for ensuring the safety of electric vehicle wireless charging systems.The main technical challenges of current MOD include high detection sensitivity requirements,serious interference by the magnetic field of wireless charging power,and detection blind spots.Accordingly,this thesis proposes targeted solutions,the main research contents are as follows:The influence of metal objects on the physical parameters of the helical coil is analyzed.The structure of the MOD system is proposed.The parameter change of the detection coil caused by the proximity of metal objects is converted into an electrical signal and amplified by the detection circuit.Meanwhile,the magnetic field noise interference of the wireless charging systems is eliminated.Based on the general rectangular detection coil,a sensitivity optimization method of the detection coil is proposed.A lumped parameter modeling method for metal objects based on the equivalent loop approximation is given.The equivalent electromagnetic model of the rectangular coil with metal objects approaching is established.The change mechanism of the physical parameters of the coil is studied.The analytical formula of the parameter change of the coil caused by metal objects of different sizes is obtained.The influence of multiple coil configuration parameters on the sensitivity of the detection coil is analyzed.The optimal detection coil is obtained by combining theory with the actual working conditions of the wireless charging system.Through simulation and experiments,the accuracy of the theoretical model and the feasibility and superiority of the optimal coil configuration are proved.To improve the anti-interference ability of metal object detection,a bipolar decoupling detection coil(BDDC)structure based on the optimal rectangular coil is proposed.It is obtained by the center-symmetric combination of four unipolar rectangular coils.On the basis of the lumped parameter modeling method of metal object based on equivalent loop approximation,the equivalent method of subregional metal obejcts is proposed.The expressions of equivalent self-inductance and sensitivity of the BDDC when metal object is apporaching are given.The simulation and experiments show that the BDDC is decoupled from the magnetic field of the WPT system,which can eliminate low-frequency noise interference and ensure high detection sensitivity.The coil adopts a nonoverlapping printed spiral structure,which is simple and has a low cost.Based on the analysis and comparison of various circuit topologies,a detection circuit with adjustable parameters is designed in consideration of the physical parameters of the detection coil.A series resonance sampling amplifier network is proposed.The non-resonant optimal operating frequency is given to further improve the sensitivity.Finally,the MOD system experiment was carried out in a 3 k W wireless charging system.It was verified that the MOD system built based on the optimal rectangular detection coil can accurately detect metal objects of 25 mm and above,which meets the requirements of the national standard for wireless charging and the needs of actual working conditions.It is verified that the MOD system built based on the BDDC has a strong anti-interference ability,and still has high sensitivity.It is verified that the system detection sensitivity is higher at the optimal operating frequency compared with other operating frequencies.更多还原