谐振式能量传输系统频率分裂特性研究

基于磁耦合谐振式的无线供电系统可在中等传输距离内实现高效能量传输,因而成为当前科学与工程技术领域研究的热点.主要研究了磁耦合谐振式无线供电系统在传输过程中有可能存在的频率分裂现象.通过在FEKO中对磁耦合谐振式无线供电系统进行建模分析,验证了现象的存在,并指出前人解决频率分裂方法的局限性.提出一种可行的方法去消除频率分裂现象对系统传输的影响,为后续磁耦合谐振式无线能量传输系统的设计提供参考.     

耦合谐振无线电能传输中负载线圈的影响分析

从两个相同谐振频率线圈耦合模型出发,介绍了系统的工作原理。分析了负载线圈对系统效率和距离的影响,并利用Matlab对其进行实验仿真。通过与硬件测试结果对比分析验证了理论的有效性,为提高无线电能传输距离和线圈的优化设计提供参考。     

磁耦合谐振式无线电能传输系统频率跟踪的自适应模糊控制

谐振频率是无线电能传输(Wireless Power Transfer, WPT)系统中提高传输效率的关键因素,考虑到WPT系统是一种松散耦合系统,可能因负载、传输距离等因素的变化,使WPT系统的谐振工作频率出现分裂或失谐等问题,导致系统传输效率大幅降低。为确保磁耦合谐振式无线电能传输系统保持较高的能量传输效率,结合谐振状态对系统传输效率影响的电路分析,提出模糊控制的方法来实现谐振频率的自适应跟踪,并设计出频率跟踪的模糊自适应控制器,实时非线性调节逆变驱动电路的频率,以确保对WPT系统谐振频率的精确跟踪。仿真与实验结果表明,该控制算法增强了WPT系统的工作谐振频率的自适应跟踪能力,对系统传输效率有较大提高。     

基于磁谐振式无线输能系统频率调谐的效率优化

磁耦合谐振式无线输能系统理论设计上可在临界耦合的一段区间内达到高效率能量传输,但还存在远距离弱耦合区效率急剧衰减,近距离强耦合区出现谐振频率分裂现象的问题。为此,仿真并设计制作附有铁氧体磁芯的平面螺旋耦合线圈,在传输系统中做频率跟踪调谐,使传输距离在强耦合区变化时,依旧保持系统高效率传输。测试表明,整个系统可实现传输距离在5~20 cm变化时,都能保证无线输能效率高于80%。     

基于谐振耦合原理无线电能传输装置系统的研究

无线电能传输技术是一种新型的电能传输技术,它可以克服有限电能传输方式的诸多弊端。本文分析并设计了一种基于近距离无线电能传输原理的传输系统,阐述了磁耦合谐振式无线传输系统工作原理,叙述了对系统的发射模块、接收模块的设计,分析计算线圈的电感量及传输效率及系统各部分参数对传输效率、功率的影响。     

磁耦合谐振无线携能通信系统建模与分析

摆脱有形介质的束缚,让信息与能量传输能够更加灵活方便一直是用户对于设备的潜在需求。文中基于磁耦合谐振方式提出一种无线能量与信息同步传输并形成信息回路反馈的方式,通过建立实验装置模型,验证系统方案的可行性,并对系统能量传输效率部分建立等效模型分析,通过仿真给出传输效率与距离的关系曲线,并通过对比仿真数据与实验数据,验证了等效模型分析的正确性。     

磁耦合谐振串串式无线电能传输研究

磁耦合谐振式无线电能传输技术作为一种新兴无线能量传输技术,具有传输距离远、传输功率大、传输效率高、无辐射性和穿透性等优点。基于等效电路模型建立了磁耦合谐振式无线输电串串式拓扑模型,给出了输出功率、传输效率的计算方法,搭建了磁耦合谐振式无线电能传输试验平台,通过仿真与实验,分析了线圈距离、工作频率、负载电阻以及系统谐振对输出功率、传输效率的作用规律,为磁耦合谐振式无线电能传输系统的设计及参数优化提供了理论依据。     

对非相干光纤激光组束耦合效率的仿真研究

为了提高非相干光纤激光组束系统的耦合效率,需要分析影响耦合效率的各参数.理论分析及仿真研究结果表明,较小的高斯模场纵向偏移、离焦度和透镜焦距,较大的光栅周期对提高耦合效率是有利的,并且还存在最佳的光斑半径.在优化的系统参数基础上,系统的平均耦合效率可以达到58.1%.     

基于超介质的无线充电研究

磁耦合谐振式无线充电是最具发展前景的无线充电技术,在磁耦合谐振式无线充电系统中加入超介质,可以提高系统传输效率。文章首先构建该系统的集总电路模型,分析影响传输效率的因素;其次阐述将超介质应用于磁耦合谐振无线充电系统的原理;最后设计出工作在9.6MHz的磁耦合谐振无线充电系统,提出一款在9.599MHz等效磁导率m=-1的超介质结构,经过仿真分析得出结论:超介质应用于磁耦合谐振式无线充电系统能提高系统传输效率。     

非铁磁性介质中的磁谐振无线传能系统仿真

理论上磁谐振无线能量传输可以做到很高的效率,然而在实际情况下由于各种各样介质的影响,实测效率与理论值难以保持良好的一致性。为了解决实测效率与理论效率偏差较大的问题,提出了基于等效电路模型的非铁磁性介质中的磁谐振无线能量传输系统。从计算与仿真角度分析了不同介质的对线圈阻抗与谐振频率的影响,且计算与仿真结果吻合良好。提出了介质中高效率系统的设计步骤,优化后仿真结果表明可以提高30%以上的效率。     

谐振式电能无线传输系统中串串式模型研究

谐振耦合式电能无线传输系统利用磁场通过近场传输,具有辐射小、效率高、传输距离远且方向性强等特点。文中采用等效简化电路方法分析了谐振式电能无线传输系统串串模型的间距、工作频率、负载等参数对传输效率和功率的影响及内在关系,进一步推导出其计算模型。在间距和负载一定的条件下,通过Matlab仿真得到效率最优与功率最大时的工作频率相一致,输出功率对工作频率的变化敏感度更高这一规律。此外,设计了一套串串式结构的谐振式电能无线传输装置,通过实验验证了理论分析的正确性,为研究电能无线传输提供了参考。     

用于无线能量传输系统的微带天线设计

本文提出一种用于组成无线能量传输(Wireless Power Transmission,WPT)系统的微带天线结构,并采用基于有限元法的电磁仿真软件(HFSS)对微带天线进行3D建模.在二端口网络分析法的基础上,建立磁耦合共振无线能量传输等效电路模型,求解出系统发生频率分叉现象产生的条件以及最大效率时的频率表达式.基于以上方法,研究本文设计的微带天线传输特性,包括:系统的最优传输效率与耦合距离的关系,工作频率与耦合距离的关系,得出在能量传输距离在50cm左右时,天线的谐振频率为12.5MHz,效率可达63%.微带天线具有很大的结构优势,如与集成电路兼容,成本低,体积相对较小,且工艺相当成熟,易大规模批量生产等优势.因此该设计的平面微带天线可用于无线能量传输系统.     

Design of auto-tuning capacitive power transfer system for wireless power transfer

This paper presents the design of capacitive wireless power transfer systems based on a Class-E inverter approach. The main reason for adopting the Class-E inverter approach is because of its high efficiency, theoretically 100%. However, the operation of a Class-E inverter is highly sensitive to its circuit’s parameters. In a typical capacitive wireless power transfer application, the capacitive coupling distance between plates is subject to changes, and hence its power transfer efficiency is greatly affected if the Class-E inverter is properly tuned. This drawback motivates us to develop an auto frequency tuning algorithm for a Class-E inverter which maintains its power transfer efficiency in spite of the variations of capacitive coupling distances between plates and circuit’s parameters. Finally, simulation and experiment are carried out to verify the effectiveness of the auto frequency tuning algorithm.     

Selection of maximum power transfer region for resonant inductively coupled wireless charging system

In order to uphold the maximum power transfer in a resonant inductively coupled wireless power transfer system, an operating region has been proposed based on the coupling coefficient, frequency and electric load. The effectiveness of the proposed condition has been examined both theoretically and experimentally. The obtained results are in well agreement with each other. It has been seen that the operating frequency region is different for different electric loads corresponding to the coupling coefficient between the transmitter and receiver coils of the resonant inductive link. The operating frequency region shifts to lower frequency side for lower value of electric load at larger value of coupling coefficient even maintaining the optimum power transfer. The obtained knowledge reveals the design modus operandi through which an effective wireless charging system can be intended not only for low power device applications but also for high power EV charging.     

High-efficiency resonant coupled wireless power transfer via tunable impedance matching

For magnetic resonant coupled wireless power transfer (WPT), the axial movement of near-field coupled coils adversely degrades the power transfer efficiency (PTE) of the system and often creates sub-resonance. This paper presents a tunable impedance matching technique based on optimum coupling tuning to enhance the efficiency of resonant coupled WPT system. The optimum power transfer model is analysed from equivalent circuit model via reflected load principle, and the adequate matching are achieved through the optimum tuning of coupling coefficients at both the transmitting and receiving end of the system. Both simulations and experiments are performed to evaluate the theoretical model of the proposed matching technique, and results in a PTE over 80% at close coil proximity without shifting the original resonant frequency. Compared to the fixed coupled WPT, the extracted efficiency shows 15.1% and 19.9% improvements at the centre-to-centre misalignment of 10 and 70 cm, respectively. Applying this technique, the extracted S₂₁ parameter shows more than 10 dB improvements at both strong and weak couplings. Through the developed model, the optimum coupling tuning also significantly improves the performance over matching techniques using frequency tracking and tunable matching circuits.     

磁耦合谐振式无线电能传输系统建模与分析

磁耦合谐振式无线电能传输技术具有传输距离中等、传输效率高、能穿过非磁导性障碍物传输电能等优点,使其有望取代电池为物联网中的传感器节点无线供电。本文通过研究磁耦合谐振式无线电能传输机理,构建了传输系统的集总参数电路模型,对各模型参数进行了理论计算,并根据模型对不同传输距离下系统的传输效率与负载功率进行了分析,得出了不同耦合状态下系统获得最大负载功率的条件。     

Single frequency wireless power transfer and full-duplex communication system for intracranial epilepsy monitoring

Current clinical neural recording methods which employ wired connections to the external world can be improved by eliminating the wires thanks to integrated circuit and microsystems technology. This study presents design and implementation of such a system which performs wireless power transfer and data transmission for intracranial epilepsy monitoring. Proposed system provides power to the implant by inductive coupling. Full-duplex communication is also performed at the same frequency as the power transfer. Consequently, a system which can transfer power from 10 mm distance with 30% efficiency has been realized. The system supports 400 kbps uplink communication while downlink communication is performed with 1 kbps at the same time. Design challenges for uplink communication in terms of energy-per-bit and interaction between uplink and downlink communication have been discussed in detail to give an insight about the design trade-offs for a full-duplex communication system superposed on a wireless power transfer link.     

Design of a novel receiving structure for wireless power transfer with the enhancement of magnetic coupling

In a wireless power transfer (WPT) system, the transfer performance is related to the mutual inductance between coils. However, the mutual inductance decreases with the increase of transfer distance. In this work, the relationship between the output voltage and the mutual inductance for WPT systems with air core and with ferrite core are analyzed. In order to improve the mutual inductance, a novel configuration of receiving resonator with a strong magnetic coupling is proposed. The mutual inductance and magnetic field distribution for coils with a cylindrical core and with the novel configuration are compared. Experiments are carried out for validation. The results indicate that the proposed WPT system is superior to the system with the cylindrical ferrite core in increasing the output voltage and power transfer efficiency.     

基于磁耦合谐振的无线电能传输装置

在基于耦合谐振技术上,设计一种无线电能传输装置,采用软件对所设计的耦合谐振电路进行了建模与仿真,在此基础上实际制作了无线电能传输装置,实测效果良好.该设计方法简洁实用,但从效率角度考虑,有进一步改进的空间.