电压型CPT系统输出品质与频率稳定性分析

针对CPT系统能量传输能力与输出品质会随频率漂移产生较大波动的特点,在对电压型CPT系统工作原理的分析基础上,根据系统原副边的耦合关系建立系统的阻抗模型,分别总结在谐振条件下系统的输出特性和在失谐条件下系统的拾取端阻抗随频率变化的规律,提出较小的拾取端线圈电感值有益于电压型CPT系统的频率稳定;发现并证明了SP型CPT系统的拾取端至少存在两个谐振频率点和一个负载突变频率点,并给出了拾取端电感的取值范围,对系统的参数设计具有指导意义.最后以SP型CPT系统为实验平台验证了理论分析的正确性.     

错位条件下基于“感应盲点”分析的非接触变压器建模及优化

感应式无线电能传输系统中,非接触变压器存在错位等多种工况,引起耦合系数等参数大范围变化,影响系统特性。为了建立错位条件下非接触变压器的耦合系数模型,文中基于场路结合的分析方法,分析磁通耦合特性,给出了非接触变压器的"感应盲点"求解方法;并结合其耦合系数的变化规律,建立非接触变压器错位条件下耦合系数的计算模型。基于磁场分布的特点,进一步提出副边多绕组的新型非接触变压器结构。采用优化后的变压器结构,设计制作了60 W输出的非接触变换器,耦合系数的计算结果和实际测试结果一致,证明了所提"感应盲点"分析方法与耦合系数计算模型的正确性,验证了优化后的新型非接触变压器具有良好的错位自适应能力。     

交流包络调制无线电能传输系统的负载稳压输出研究

为了实现交流包络调制无线电能传输系统的输出电压稳定,基于冲量定理与能量守恒原理,在初级侧采用能量注入与自由振荡模态组合的形式,调整注入初级回路的能量规模以适应负载的功率变化,从而实现动态负载条件下输出端的稳压。仿真与实验结果验证了在系统负载切换时,系统输出交流电压保持恒定。     

Power Flow Control of a Power Conversion Circuit for Contactless Power Transformer Systems with Coil Misalignment

The coupling coefficient between the coils of a noncontact power supply system is reduced by coil misalignment. This reduces the output voltage and the active power in the coils. To cope with these problems, an instantaneous current control method is applied to a single‐phase contactless power transformer system in order to apply the equivalent impedance of the PWM rectifier at the load side of the transformer. We propose a control method to supply power constantly to the load even when there is a misalignment in the receiving coils. The limit of the transferred power associated with the proposed control method is investigated. The proposed system, including the control method, is verified by experimental tests over a power range of several tens of watts.     

一种抗宽范围耦合系数波动的三元件补偿型感应式能量传输系统

常规LCL型感应式能量传输系统具有电压增益独立于负载的特性,在耦合系数波动小而负载范围较宽的无线能量传输场合应用较广。然而其输出特性受耦合系数影响很大,不适用于动态能量传输场合。在LCL型补偿拓扑的基础上,通过改造其输出特性,提出一种适用于动态感应式能量传输场合的改进型拓扑,以适应大范围耦合系数的变化。从平滑输出电压增益的角度出发,定量分析电压增益和输出阻抗角与耦合系数和无源元件参数的关系。通过对LCL型谐振腔增加一阶自由度,构造了三元件补偿的LCC型拓扑,实现了耦合系数大范围波动情况下输出功率近似恒定。与常规拓扑相比,该补偿拓扑对耦合系数的敏感性大大降低。最后,设计一台原理样机,传输功率在耦合系数大范围波动下保持平稳,相比常规拓扑,使得输出特性关于耦合系数的敏感性大大降低。验证了设计方法的有效性。     

基于E类放大器的感应电能传输系统研究

主要研究了一种基于E类功率放大器的非接触感应电能传输拓扑,分析了其运行的基本原理,并主要在感应充电等实际应用场合中充电负载会出现大范围变动的情况,从负载的角度出发,对原、副边补偿阻抗网络的选择和系统各参数的设计,给出了基于最优负载下的具体设计方法.理论和实验结果表明,在负载大范围变动时,无须外加复杂的控制电路,依靠系统...     

无接触电能传输系统的补偿及性能分析

运用松耦合变压器互感电路模型,推导出无接触电能传输系统原、副边分离的等效电路.选取合适的副边补偿电容,以增强系统的功率传输能力;选取合适的原边补偿电容,以降低对系统电源容量的需求.研究表明:当原边电流恒定时,在副边串联补偿,则负载所获取功率与负载大小成反比;在副边并联补偿,则负载获取功率与负载大小成正比.当原边电压恒定时,在原边并联补偿方式下,等效负载所获取的功率随负载的增加先升高后降低,针对不同的副边补偿方式,等效负载分别在相应的负载点取得最大传输功率.Pspice仿真结果验证了上述结论的正确性.     

Improvement of equivalent magnetic coupling coefficient of wireless power transfer system with multiwinding transmission coil

This article proposes a novel method of improving the overall coupling coefficient of a wireless power transfer system by using a four‐winding transformer of which two pairs of windings each are connected in parallel in the primary side and secondary side. By weakening the coupling coefficients k_c between the parallel windings, the overall magnetic coupling between the primary side and secondary side of the transformer is improved. In order to confirm the validity of the proposed method, a conventional high‐k_c four‐winding transmission coil and the proposed low‐k_c four‐winding transmission coil are experimentally assessed. Then, the coils are introduced into a nonresonant inductive power transfer system utilizing a dual active bridge converter in order to confirm the correction of the input power factor. As a result, the overall magnetic coupling of the proposed four‐winding coils was found to be improved by 17% compared with the overall magnetic coupling of the conventional coil. Moreover, the input power factor for the entire load is corrected with the proposed four‐winding coil. Therefore, a low k_c is effective in improving the overall magnetic coupling.     

松耦合感应电源性能的影响因素分析

本文针对串并补偿结构的松耦合感应电源系统,建立了互感模型,分析了输出功率和传输效率达到最大值的条件,得出了系统在谐振频率工作时输出功率和传输效率只与映射阻抗的实部和线圈内阻有关的结论.最后根据实验参数,分析了工作频率、线圈内阻和负载变化对系统性能的影响.     

输入串联输出等效并联多逆变器驱动的高压大功率无线电能传输系统研究

提升逆变器输入侧直流电压源的电压等级,是实现更大功率无线电能传输的可行方案之一。但单个开关器件的额定电压有限,满足不了更高输入电压的需求。为此,文章设计了一种输入串联输出等效并联多逆变器驱动的高压大功率无线电能传输系统。该系统采用多个逆变器串联以承担较高的输入直流电压,同时每个逆变器驱动一个独立的发送线圈向同一个接收线圈发送功率。文章在考虑多个发送线圈之间互感的情况下对该系统的谐振电路参数进行了设计,分析在零相差(Zero Phase Angle,ZPA)及非零相差两个条件下系统的电流和功率输出能力,发现了运行角频率及互感的乘积对系统输出能力具有重要影响。开发出由三个逆变器串联驱动的无线电能传输样机,在750 V直流输入条件下获得最大38. 4 kW的无线电能传输功率,效率达88. 7%。     

新型恒定一次侧电流无接触电能传输系统的建模与优化

提出一种新型无接触式感应耦合电能传输系统(inductively coupled power transfer,ICPT),系统一次侧线圈与电感/电容/电容所组成的谐振槽谐振、二次侧线圈与补偿电容并联谐振。利用互感理论,分别建立相互分离的原边等效电路模型和负载等效电路模型,采用正弦交流分析法对其等效电路模型进行分析,获得谐振槽电容及电感元件的参数计算公式,导出系统向负载传输功率及输出电压的计算表达式,并对谐振槽元件参数进行优化设计, 以便减小装置体积, 降低成本。额定频率下系统一次侧线圈电流保持恒定而与负载大小无关,保证电能由电源向负载的稳定传输。同时谐振槽输入电流随负载的减小而减小,提高系统的部分负载能效值。PSpice仿真实验验证该系统的上述优点。     

基于PZT的超声波无接触能量传输系统的研究

给出一种基于PZT的超声波无接触能量传输系统。通过机电等效和类比的方法建立了系统的数学模型。结合声波能量传输理论和电路理论对系统模型进行了分析,推导出控制系数的表达式及输出电压与输入电压之间的关系和负载功率表达式,通过实验研究了负载阻抗与负载功率及传输距离与负载功率之间的关系。当换能器间发生共振时,系统能量的传输达到最大值;当系统参数和传输距离一定时,负载功率的大小随负载的变化而变化,并存在一个最大值;负载功率和系统效率随传输距离的变大而减小。理论分析和实验证明,将超声波作为媒介可以摆脱隔板电能传输的局限性,在一定有效距离范围内进行无接触电能传输。     

基于线圈定位与电容阵列的感应式无线电能传输系统调谐控制

在实际应用中,感应式无线电能传输系统通常存在耦合线圈错位的复杂工况,影响系统的传输功率和效率。基于线圈定位与电容阵列提出一种适于S/SP补偿网络的调谐控制策略,在错位失谐工况下,主动利用原、副边线圈的位置信息,优化系统特性。为了量化系统的输出电压波动,建立了S/SP补偿网络在全工况下电压增益曲线的计算模型。进而为确保错位工况下系统的恒压输出特性,在给定的耦合系数变化范围和输出电压波动指标内,给出了电容阵列切换级数和容值调节步长的最优设计,并与传统定电容补偿进行对比。最后,通过一台800 W输出的原理样机对所提策略的有效性进行验证。验证结果表明,采用所提调谐控制策略,可以显著提高系统的输出功率与效率,并大幅降低其输出电压波动。     

Performance analysis and calculation of critical inductance and output voltage ripple of a simple non‐isolated multi‐input bidirectional DC‐DC converter

In this paper, a simple non‐isolated multiple input (MI) bidirectional DC‐DC topology is proposed which can operate in buck, boost, or buck‐boost modes. The proposed topology utilizes a battery pack to realize the bidirectional power flow operation especially when the input sources are non‐storable ones. The excess energy of input sources can be stored in the battery and be injected to the load, when required. Simultaneous or independent power transfer of input sources is also provided. For better evaluation, the proposed topology has been compared with several recently presented novel topologies, from view point of number of inductors, capacitors, switches, and diodes. Comparison results show that the proposed topology utilizes less number of components (switches, inductors, capacitors, and current sensors) which can reduce the size, cost, and complexity of converter. Different operational modes of the proposed topology (unidirectional buck, boost, buck‐boost modes, and bidirectional mode) have been presented. Also, boost mode of the proposed topology has been investigated in detail, from design point of view, and generalized relationships have been proposed for calculation of critical inductance (CI) and output voltage ripple (OVR) of proposed n‐input boost topology. To validate proposed theoretical concepts, the proposed topology has been modeled and simulated in PSCAD/EMTDC software, and the 3‐input boost version has been experimentally implemented. Simulation and experimental results confirm appropriate performance of the proposed topology.     

基于恒流-恒压复合拓扑的感应式充电系统

感应式电能传输技术IPT(inductive power transfer)应用到电动汽车中具有许多独特的优点。由于IPT变换器输出特性复杂,与变压器参数、补偿参数、工作频率和负载均有关,而电池在整个充电过程中负载变化范围宽,故IPT变换器难以直接提供负载电池所需的充电电流或电压。针对此问题,根据4种基本的IPT补偿结构的输入和输出特性,找到可同时实现输入纯阻性和输出恒流或恒压的拓扑结构及工作条件,从而解耦负载对输出的影响,消除无功功率。但单个拓扑无法满足电池先恒流后恒压的充电特性,因此进一步提出了一类复合拓扑结构,采用最少的器件实现恒流拓扑和恒压拓扑的切换,电路简单可靠,传输效率高。     

Development of a novel spindle-shaped coil-based wireless power transfer system for frequency splitting elimination

To eliminate frequency splitting in wireless power transfer, a novel spindle-shaped coil-based wireless power transfer system is introduced and designed. Based on the equivalent circuit model, the transmission coefficient and the input impedance are calculated. A comparative analysis is performed between the traditional and the proposed systems. It is found that the frequency splitting is suppressed by utilizing spindle-shaped transmitting and receiving coils in the proposed system because of the larger mutual inductance between the source coil (load coil) and transmitting coil (receiving coil) and the smaller mutual inductance between the transmitting and the receiving coils in comparison with the traditional system. In the overcoupled region, the transmission coefficient of the proposed system almost remains unchanged and keeps at a high value. The input impedance is characterized with high amplitude and small argument, which is beneficial for efficient power transfer. Experimental setup is established to validate the performance of the proposed wireless power transfer system. The results indicate that the proposed system is superior to the traditional one in eliminating the frequency splitting, which is well consistent with the simulation analysis.     

港口RTG无线供电技术研究

针对港口RTG(rubber tyre gantry)已有滑触线式供电系统,设计改造为无线电能传输系统.考虑负载所需输入特性,采用LCC-S&S谐振拓扑实现恒压输出.根据RTG工作特性,将动态供电问题简化为准静态供电问题.由于RTG存在停靠偏移的情况,选取DDQ(double-D-quadrature)线圈结构作为耦合...     

电动汽车无线充电系统磁耦合线圈耦合系数的研究

针对电动汽车无线充电系统磁耦合线圈之间耦合系数小、存在偏移的问题,对磁耦合线圈的耦合系数进行了研究分析。首先根据无线充电系统串-串补偿模型,分析了耦合系数与传输功率和传输效率之间的关系。其次,比较了不同形状的线圈在相同围绕面积的条件下,耦合系数随线圈间气隙距离和偏移的变化。以圆形-圆形线圈为例分析了线圈内部参数变化对耦合系数的影响。最后,对比分析了圆形线圈增加磁芯时对耦合系数的影响。研究结果证明了所提方法的有效性。     

基于松耦合变压器的小功率CPT系统

设计并实现了一种基于松耦合变压器小功率CPT(Contactless Power Transfer)系统。采用互感模型对松耦合变压器进行了分析,对其原边和副边进行了补偿。采用有芯PCB螺旋电感线圈来制作松耦合变压器的原边和副边绕组,给出了有芯电感的几何参数和物理参数。原边、副边之间通过高频方波传递能量。最后给出了整个系统的电路图。测试结果表明,当原边和副边距离在5mm以内时,电能传输效率较高,可为手机等小功率用电设备充电。     

一种动态无线电能传输系统的线圈切换方法

阵列式动态无线电能传输系统因其运行损耗和漏磁更小、灵活性更好而被提出,其工作性能通常取决于发射阵列和接收线圈的结构。提出了一种基于LCC-S补偿拓扑的线圈切换方法,使切换时刻的互感下降和互感突变最小化以提高系统的偏移容忍度;同时,比较了应用该切换方法后,单层和双层发射阵列系统的工作性能。仿真结果显示,虽然双层发射阵列系统的切换控制更复杂,但在接收线圈与发射线圈间发生偏移时其输出功率下降更小,偏移容忍度更高。实验结果证明,该线圈切换方法在实际中有效可行。