铁氧体行波移相-馈电一体化网络的设计与分析

提出了在波导铁氧体移相器传输方向上加载定向耦合开槽以实现移相馈电一体化网络的设计思路.网络以铁氧体移相器实现对信号的相位控制,在铁氧体传输方向上加载多个耦合能力不同的定向耦合开槽以实现对信号的幅度控制.分析了该结构的设计原理,利用HFSS仿真软件对该结构进行仿真分析,并依据计算结果设计制作了样品,样品实测性能与理论计算较为吻合.     

一种新型的六位数字移相器的设计

针对传统的数字移相器插入损耗高和相位精度低等性能的不足,提出了一种新型的加匹配线的开关式移相器设计技术。包括固定长λ/2主线以及在主线边缘长λ/8的平行短路和开路短截线,克服了传统数字移相器设计中端口驻波比高,插入损耗大的缺点,而且在相位精度上也有提高。在设计中,用加匹配线的方法对45°,90°和180°移相器进行设计,并将相位为5.625°,11.25°,22.5°,45°,90°及180°6个二态移相器电路组合起来,构成六位数字式移相器,通过二进制代码控制各个PIN二极管,从而得到64个相移状态,实现了输出频率范围为400～450MHz的低插入损耗,高相移精度的六位数字移相器,通过实际测试得到整个六位数字移相器插入损耗低于5.3dB,相移精度小于3°,驻波比小于1.5的较好实验结果,具有比传统设计方法更优良性能。     

开绕组无刷双馈风力发电机最大功率点跟踪直接转矩模糊控制研究

基于风力发电机最大功率点跟踪原理,结合无刷双馈电机无电刷和集电环的特殊结构及采用双定子磁场调制使得所需变流器容量更小的特点,提出了一种由双两电平变流器拓扑构造三电平馈电的开绕组策略,阐述了无刷双馈风力发电机最大功率点跟踪、开绕组策略及直接转矩控制、模糊控制等各部分工作原理,进而利用Matlab/Simulink仿真软件,搭建了无刷双馈风力发电机控制绕组采用双两电平SVPWM变流器馈电实现最大功率点跟踪的开绕组直接转矩模糊控制模型,并进行了详细的性能仿真,最后,通过无刷双馈电机半实物仿真实验平台,证实了所提开绕组策略的正确性和可行性,为进一步研发半实物仿真实验平台及相关控制策略提供了良好的参考与借鉴。     

新型开绕组双馈电机调速系统研究

针对传统双馈电机控制系统硬件复杂、维护困难等问题,提出一种新型的开绕组双馈电机调速系统。分析开绕组双馈电机的结构特点及功率流向,并研究了磁链变化及磁链保持恒定两种情况下的系统电压、电流和功率的关系。分别设计在不同转速条件下维持定子磁链恒定的开绕组双馈电机定子侧变换器和转子侧变换器的控制策略。建立了开绕组双馈电机的矢量控制系统的仿真模型,并给出了各情况下的双馈电机调速系统的仿真结果。采用基于DSP的数字实验平台,通过实验验证了控制系统的实用性,为开绕组双馈电机应用于实际工程奠定了良好的理论和实验基础。     

阻容移相电路的改善和应用

由阻容移相电路构成的移相器可用作单相电度表校验台的相位调节装置,用来代替需要有三相电源供电的感应式或变压器式移相器。其优点是可由单相稳压电源供电,设备简单经济,运行时无噪音,功率稳定性较好,且易于实现按程序控制变换相位。阻容移相器由电阻R、电容C和具有中心抽头的变压器Bφ组成。接线及移相原理矢量图*如图1所示。图中T_1是电流回路的自耦调     

MEMS 电容型器件边缘效应研究

MEMS 电容型器件在工作过程中,其电容通常情况下为非正对的极板,边缘效应不容忽视。 为解决此问题,基于保角映 射变换和复变函数相关理论,通过继承传统模型并加以修正,得出电容极板在非正对情况下的边缘效应模型。 经过与有限元仿 真、传统 Heerens 模型、Huang 模型的对比,表明当电容极板从正对到完全移开的过程中,本文模型与有限元仿真的误差在 10% ~20%之间,优于传统 Heerens 模型与 Huang 模型。 进一步,根据本文模型,当极板重合度低于 40%时,边缘效应呈快速增 长,此时其电容值可用本文模型进行计算。 以上结论均得到了 MEMS 阵列电容数字式实验验证。 研究对电容型 MEMS 器件的 设计与性能分析具参考作用。     

一种适用于燃料电池的新型高升压DC-DC变换器

高升压DC-DC变换器是燃料电池实现并网的重要环节。针对燃料电池输出电压低、输出特性软的问题，提出一种基于开关电容的电流馈电升压变换器。首先，详细阐述了所提变换器的拓扑结构及其在连续导通和不连续导通模式下的工作原理。然后，具体分析了该变换器的电压增益、各元件的电压和电流应力。在此基础上，将其与SC-Boost、SL-Boost等变换器进行性能对比。最后，搭建一台200 W的实验样机验证了所提变换器的可行性和理论分析的正确性。所提变换器结合电流馈电结构和开关电容网络，具有电压增益高、输入电流连续且纹波低的优势，有利于延长燃料电池使用寿命。同时，通过复用开关电容中的电容-二极管(capacitor-diode, C-D)单元对开关管电压进行钳位，降低了功率元件的电压应力。因此，所提变换器适用于燃料电池并网系统。     

基于电容调压原理的自适应高压直流断路器

能够快速开断大电流的高压直流断路器是影响直流输电的关键因素之一。提出一种自适应电容调压式高压直流断路器设计方案,通过并联调压电容实现电弧电流的反转,形成多个电流过零点,并在一定时间内将电弧电流限制在零点附近,为灭弧创造良好条件。理论推导和仿真结果表明提出的高压直流断路器方案能够适应不同运行工况,避免电力电子器件的通态损耗,有效减小电弧重燃几率,提高断路器的快速分断能力。     

MEMS加速度计敏感元件测试仪的设计与实现

基于敏感元件的特性本文设计出了一种MEMS加速度计敏感元件特性测试仪,即利用电容检测电路和基于虚拟仪器的频谱测试仪对MEMS敏感元件的频谱特性进行测试而得出其重要性能参数。电容检测电路和虚拟仪器频谱测试仪分别在实验室内进行了误差分析,电容检测电路的最大非线性误差为0.127 7%,频率特性测试仪的幅值最大误差为0.352 6 dB,相位最大误差为1.365 6°。     

基于多桥脉冲宽度调制(PWM)交流控制技术的静止移相器

介绍一种基于脉冲宽度调制（ＰＷＭ）交流控制技术的新型静 相器。对单桥ＰＷＭ移相器在１个开关周期中的３种工作模式进行了理论分析,推导了旁路电容及吸收电阻的参数设计公式;采用多桥叠加结构的交流控制器抑制大容量ＰＷＭ移相器的自身谐波发生量、降低装置开关频率及开关损耗;是出了多桥ＰＷＭ交流控制器的电压转移函数以及多桥移相器的线路注入电压表达式;通过计算机仿真分析及物理模型实验,验证了理论推导结果的正确性。     

A low-loss compact six-bit DMTL phase shifter for phased array antenna applications

A phase shifter is one of the main components of radars and phased array systems. In this paper, a novel three-state two-bridge unit cell is presented for a compact low-loss six-bit distributed microelectromechanical systems (MEMS) transmission line (DMTL) phase shifter. The proposed unit cell includes a coplanar waveguide (CPW) transmission line, a MEMS bridge on the signal line, two metal-air-metal (MAM) capacitors on a glass substrate, and two additional electrodes under the MEMS bridge, near the signal line. Using these electrodes, it is possible to generate two different phase states employing the MEMS bridge, and the third state is produced by a metal-air-metal (MAM) bridge. Hence, the designed structure can generate three different phase shifts per unit cell (i.e., 5.625°, 11.25°, and 22.5° phase shifts). The novelty of this design is that the number of unit cells is considerably reduced from 64 in a conventional six-bit phase shifter to only 17 in our design. Therefore, the total length of the six-bit phase shifter and average loss are considerably reduced. The designed structure is calculated and simulated at 32 GHz using MATLAB and ANSOFT HFSS, respectively. According to the calculation and simulation results, the lateral size of the phase shifter is only 8.5 mm, the root mean square (RMS) phase error is 1.38°, and the average loss is 1.1 dB. The feasibility of the proposed design is investigated using the proposed fabrication process. The designed phase shifter can be easily scaled to other frequencies for radar and satellite applications with more bits.     

A new approach for completing the phase shifter angle for load flow control in the network with multiple loops

A phase shifter has been used to control line flow. In the network with multiple loops, it is necessary to modify the angle of the phase shifter to reduce the flow on a certain line if it exceeds the limit. A new method to compute the value of the angle that is set to the phase shifter is proposed. The coefficient is computed by using two relations. No one is between the change of the lined flow on a certain line and modification of power injection and two notes. The other is between the change of the flow on a line in the change of the angle of a phase shifter. Then the phase angle is computed by multiplying the coefficient and the amount of flow on the line. The coefficients can be used for finding the locations where phase shifters will be placed in order to correct any overload that may occur at any line in the loops and can be used for computation of available transmission capacity. The validity of this method was shown by numerical examples using an IEEE 30 bus system. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(3): 9–19, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10297     

相间功率控制器的稳态分析及与移相器的特性比较

借助于移相器的共同性质建立了相间功率控制器（ＩＰＣ）的和电路模型及其数学关系; ＩＰＣ与负荷相连时的特性,并交过些特性与同等条件下的移相器特性进行了对比研究;在常规流网络解算结构不变的条件下实现了系统中不同位置处的多个ＩＰＣ的稳态处理,为分析ＩＰＣ在大型电力系统中的稳态作用提供了应用工具;通过逄例对ＩＰＣ和移相器的稳态特性进行了对比分析,结果表明,ＩＰＣ队了可用于联络线的功率分布外,还可以有效地隔     

Power transmission line operating modes calculation with controllable phase shifters

The article contains the analysis of the influence of the phase shifter (PS) on the energy processes in the power transmission line in terms of the two-unit model of the electric network. The approach to synthesis of the models regulated by the phase shifter providing for both calculation of the steady operation modes of the electric networks with the phase shifters and research of the electromagnetic processes and designing of the device itself is offered.     

可控移相器对系统不对称短路电流的影响研究

以可控移相器在电力系统中得到广泛应用为研究背景,以研究可控移相器接入系统后对不对称短路电流的影响为目标,提出了基于可控移相器的不对称短路电流实用计算方法。首先根据可控移相器的结构与原理建立其正序、负序以及零序模型。然后基于对称分量法建立含可控移相器系统的各序分量网络方程,进而提出含可控移相器系统的各类型不对称短路电流实用计算方法,并分析影响短路电流的因素。最后基于三机九节点系统,运用上述实用计算方法进行不对称短路电流计算,算例仿真结果表明该方法具备有效性。通过对比分析可知移相器的移相角和短路点位置是影响短路电流的因素,而影响情况需通过具体计算得出。     

Power system security enhancement by OPF with phase shifter

This paper presents an integrated optimal power flow (OPF) with phase shifter approach to enhance power system security. The general OPF calculations are hourly based and the control variables of OPF are continuous. However, the calculations of phase shifter are daily based, and the variables related to phase shifter are discrete. Therefore, the general OPF cannot be directly used to solve this problem. The paper develops the rule-based OPF with phase shifter scheme to bridge the problems. In order to effectively alleviate the line overloads, the ranking of phase shifter locations is conducted based on contingency analysis and sensitivity analysis. The best phase shifter sites are identified and selected into a rule-based system accordingly. The handshaking procedure between the adjustment of the selected phase shifters and OPF calculation is proposed using a rule-based method. The hourly-based OPF problem is solved by the extended quadratic interior point method. The IEEE 30-bus system is used to test the proposed scheme     

Phase shifter placement in large-scale systems via mixed integer linear programming

This paper makes use of advances in mixed integer linear programming (MILP) to conduct a preliminary design study on the combinatorial optimal placement of thyristor controlled phase shifter transformers (TCPSTs) in large-scale power systems. The procedure finds the number, network location, and settings of phase shifters that maximize system loadability under the DC load flow model, subject to limits on the installation investment or total number of TCPSTs. It also accounts for active flow and generation limits, and phase shifter constraints. Simulation results are presented for the IEEE 24-, 118-, and 300-bus systems, as well as a 904-bus network. The principal characteristics of our approach are compared with those of other published flexible AC system transmission (FACTS) allocation methods.