Potential starter/generator technologies for future aerospaceapplications

This paper presents a search and comparative review of the literature available on variable speed constant frequency (VSCF) technologies. In particular, most of the progress made in the past ten years, using power electronics and electric machines for VSCF systems, is reported. Two VSCF systems, based on induction and switched reluctance machine technologies are presented. The research on the singly- and doubly-fed induction machines has focused on VSCF for wind power generation, whereas that on switched reluctance machines has been directly studied as a VSCF technology in aircraft systems. Results obtained so far favor the switched reluctance machine over the induction machine. Based on the foregoing comparative review, it is recommended that the induction machine be fully investigated as a VSCF drive for aircraft systems. The findings should then be compared with the counterpart SRM system. Issues of comparison may include fault tolerance and redundancy, power density, torque requirements, overload ratings, temperature range and cooling, efficiency and stability over expected operating speed range     

Potential starter/generator technology for future aerospaceapplication

This paper presents a search and comparative review of the literature available on variable speed constant frequency (VSCF) technologies. In particular, most of the progress made in the past ten years, using power electronics and electric machines for VSCF systems is reported. Two VSCF systems, based on induction and switched reluctance machine technologies, are presented. The research on the singly- and doubly-fed induction machines has focused on VSCF for wind power generation; whereas, that on switched reluctance machines has been directly studied as a VSCF technology in aircraft system. Results obtained so far favor the switched reluctance machine over the induction machine. Based on the foregoing comparative review, it is recommended that the induction machine be fully investigated as a VSCF drive in aircraft system. The findings should then be compared with the counterpart SRM system. Issues of comparison may include fault tolerance and redundancy, power density, torque requirements, overload ratings, temperature range and cooling, efficiency and stability over expected operating speed range     

B777飞机供电系统的性能分析

B777飞机集中了当代飞机最先进的供电技术,因而它的电源系统具有最佳的性能。本文分析这些性能,并重点阐述支持双发延程越洋飞行能力的大容量多余度电源和变速恒频备用交流电源系统的特点。     

B737飞机变速恒频电源分析

分析Ｂ７３７飞机变速恒频电源的基本组成、工作原理，介绍按谐波抑制原理的正弦脉宽调制技术，给出试用结果和存在的主要问题，指出ＶＳＣＦ飞机电源的应用前景。     

航空变速恒频电源系统中优化的SPWM调压研究

 在航空变速恒频系统（VSCF）中，航空发电机发出的变频交流电经整流变换为直流电，再经逆变器变换成恒频交流电。逆变器通常采用固定开关点的优化的ＳＰＷＭ技术，通过调节发电机激磁调节输出电压。由于系统是高阶系统，为了降阶，提出改变开关点的位置来调节输出电压，并提出优化ＳＰＷＭ的定义，分析了调节范围和谐波含量的变化，并给出了实现电路。     

盘式对转永磁风力发电机设计与分析

针对现有风力发电系统普遍存在的工作风速范围较窄、风能利用率较低等问题,设计了一种盘式双转子对转永磁风力发电机,双转子对转运行。在介绍该电机的结构与运行原理的基础上,推导了电机功率尺寸方程,给出了该电机的初步设计方法。利用有限元软件对电机进行了三维建模和动态仿真分析,得到其磁路特点和电磁性能,验证了所提设计方法的有效性。     

分段式笼型转子无刷双馈电机的设计与分析

无刷双馈电机(BDFM)在风力发电系统中具有广阔的应用前景。其转子的磁场调制能力优劣直接影响着该类电机的功率密度和效率。基于笼型转子结构提出一种分段式笼型转子结构。介绍了BDFM的拓扑结构和变速恒频发电的基本原理,将几种笼型转子结构的BDFM进行有限元对比分析,深入研究转子导条间隔角度和导条层数对新型转子耦合能力的影响,确定了使得分段式笼型转子具有较强磁场调制能力的结构参数。结果表明:该新型转子结构在保证一定耦合能力的情况下,端部空间利用率更高,电机功率密度更大,且转子结构简单可靠、易于制造。     

Output Power Controller for a Wind-Driven Induction Generator

A constant stator power output controller for a wind-driven grid-connected induction generator is described. The load torque of the generator is controlled by varying the rotor resistance electronically. A dynamic model for the wind energy conversion system is proposed for both controlled and uncontrolled operation.The model is then used to predict the changes in shaft speed,turbine torque, and stator power output in response to change in wind speed. Data pertaining to a 60 kW commercial wind turbine generator is used in this investigation. Results based on analog computer simulation demonstrate the feasibility of the controller for scheduling a desired power output from the induction generator.Results of the tests on a laboratory induction generator driven by amicrocomputer-controlled dc motor drive simulating the characteristics of the wind turbine are included.     

Unified Voltage and Pitch Angle Controller for Wind-Driven Induction Generator System

A unified voltage and pitch angle controller (UVPC) for a wind-driven induction generator system is presented to reach effective voltage control and to stabilize generator speed and system frequency. The proposed UVPC comprises a linear optimal controller (LOC), a supplementary voltage regulator (SVR), and a supplementary pitch angle controller (SPC). An ac voltage regulator and a dc voltage regulator are designed in the SVR to generate the desired voltage magnitude and phase angle for the voltage-sourced inverter (VSI). On the other hand, the SPC is designed based on fuzzy logic inference rules in order to generate the desired pitch angle command for the variable blade pitch such that the mechanical power can be controlled in a very efficient manner. When the system is operated in the islanding condition, an approach based on the concept of relative rotating speed has been developed for the measurement of system frequency deviation. Simulation and experimental results reveal that both bus voltage and mechanical power can be effectively controlled by the proposed UVPC for the wind energy conversion system (WECS) either connected with or disconnected from the power grid when there is sufficient wind energy.     

永磁直驱风电系统中最大功率点跟踪控制优化的仿真研究

分析了风力机特性、永磁直驱电机模型、变换器控制策略及各种功率跟踪控制算法优缺点,并提出一种基于爬山搜索法的最大功率点跟踪(MPPT)控制方法的优化。在MATLAB/Simulink环境下搭建了永磁直驱风力发电系统模型,仿真分析了控制方法对最大功率点的跟踪效果,结果表明当风机起动及风速变化时MPPT控制方法能够使系统快速稳定在新的工作点,捕获得最大功率。由此验证了改进优化后的控制方法及所搭建模型的准确性与有效性。     

Z-源稀疏矩阵变换器励磁的双馈风力发电系统

针对矩阵变换器电压传输比低和其励磁的双馈风力发电系统(DFIG)易受非正常输入波动影响的不足,提出了一种适用于DFIG励磁的Z-源稀疏矩阵变换器系统。利用Z-源的升压特性来提高电压传输比,检测电容电压实现对直通因子的自动调节,从而实现对网侧波动的自动抑制。建立了系统数学模型,推导了DFIG系统定子磁场定向矢量控制策略表达式,搭建试验样机对所提方案进行试验验证,在亚同步、同步、超同步三种发电状态下的波形和并网试验结果验证了方案的可行和有效性。     

无刷双馈电机静止坐标系数学模型的研究

由于没有电刷和滑环,提高了运行的可靠性,降低了维护成本,因此无刷双馈电机(BDFM)在变速恒频发电领域有着广阔的应用前景。由于特殊的结构和工作原理,BDFM数学模型十分复杂。从BDFM多回路空间矢量数学模型出发,推导出了两个静止坐标系之间的坐标变换关系以及功率绕组静止坐标系数学模型和控制绕组静止坐标系数学模型,推导过程简洁明了。所得结果为BDFM理论分析和不同控制策略的研究提供了理论基础。MATLAB/Simulink环境下的仿真结果验证了数学模型及坐标变换关系的正确性。     

系留悬浮式风力发电技术的研究进展与展望

风力发电作为清洁能源利用的重要方式,具有无污染、可再生、方便采集等特点,近年来得到快速发展。相对于传统低空风力发电,系留悬浮式风力发电具有容量系数高、发电成本低等优点,拥有更大的开发价值和发展潜力,已有多个国家开展研究并取得一定成果。本文通过对系留悬浮式风力发电技术发展的调研,归纳四种系留悬浮式风力发电技术类型,分析各技术类型的工作原理与特点,总结未来系留悬浮式风力发电需要重点突破的轻质高强系留缆绳设计与制造、高性能囊体复合材料、稳定与智能控制、高效风力发电飞行平台总体设计、便利展开部署五种关键技术,为后续研究提供参考。     

吊舱发电系统涵道式冲压空气涡轮叶片性能的研究

涵道式冲压空气涡轮是提供飞机吊舱自主发电系统能量的关键部件,其性能直接影响系统的效率。在对比了不同翼型的气动性能之后,优选出具有NACA6321、NACA23015和NACA4412三种翼型的叶片NACAZ1、NACAZ2和NACAZ3作为吊舱发电系统实验用涡轮叶片。采用优化Glauert方法,对上述3种叶片的推力系数、扭矩系数、功率系数与叶尖速比之间的关系进行了计算。计算结果表明:同样风速条件下,NACAZ2的推力系数和扭矩系数最大,NACAZ1的最小;在叶尖速比为2时,NACAZ2叶片的功率系数比NACAZ1的大16%。实验表明:NACAZ2的功率系数最大,NACAZ3的功率系数与NACAZ2的相近,叶尖速比为2时,NACAZ2的功率系数比NACAZ1的大37%。具有NACAZ2叶片的实验涡轮启动性能好,输出功率较大,综合性能较优。     

一种含风电-电池储能的多场景输电网规划方法

以可再生新能源(如风电、光伏)及化学电池为载体的电源系统已为航天器及电动机等用电客户提供了一种有效供电方式。针对风电的不确定性以及电池储能系统功率双向流动特性,尤其是风电的波动性与间歇性对输电网规划的影响,采用多场景概率法以风电场的风速数据作为划分依据,以风机的切入风速、切出风速以及额定风速的组合区间作为划分区间,利用Monte Carlo方法来计算场景概率,以输电网规划建设成本与过负荷费用最低为目标函数,设计了一种含风电-电池储能的输电网扩展规划模型,并采用遗传算法对规划模型进行求解。最后,以Garver-6节点系统为仿真算例,验证所设计规划方法的有效性。仿真结果表明,接入储能系统后,其输电网规划适应度很小(约为900),可提高系统经济效益。     

The Solar Wind in the Outer Heliosphere

The solar wind evolves as it moves outward due to interactions with both itself and with the circum-heliospheric interstellar medium. The speed is, on average, constant out to 30 AU, then starts a slow decrease due to the pickup of interstellar neutrals. These neutrals reduce the solar wind speed by about 20% before the termination shock (TS). The pickup ions heat the thermal plasma so that the solar wind temperature increases outside 20–30 AU. Solar cycle effects are important; the solar wind pressure changes by a factor of 2 over a solar cycle and the structure of the solar wind is modified by interplanetary coronal mass ejections (ICMEs) near solar maximum. The first direct evidences of the TS were the observations of streaming energetic particles by both Voyagers 1 and 2 beginning about 2 years before their respective TS crossings. The second evidence was a slowdown in solar wind speed commencing 80 days before Voyager 2 crossed the TS. The TS was a weak, quasi-perpendicular shock which transferred the solar wind flow energy mainly to the pickup ions. The heliosheath has large fluctuations in the plasma and magnetic field on time scales of minutes to days.     

飓风古斯塔夫(2008)过境过程风特性研究

对飓风Gustavo(2008)登陆美国路易斯安那州的全过程进行了风雨特性实测,共获得高度分别为2.5m、4m、5m、7m、10m处约48h的风速、风向、气压、温度、湿度、雨量数据,将采样数据划分为飓风过境前期、中期、后期三个典型区间;从时域角度分析了10min子样本的阵风因子、紊流强度、紊流积分尺度、相关性、分布特性,从频域角度对各子样本水平相脉动风谱进行了拟合平均;从时频域角度对三个典型区间的Hilbert时频谱进行计算和观测。研究发现:阵风因子和紊流强度在飓风过境之前大于飓风过境之后,紊流积分尺度反之,阵风因子均值为1.67,阵风因子随紊流度的增大呈指数率增长;风速概率密度函数服从高斯分布,水平向脉动风谱的拟合平均值呈现低频偏高和高频偏低于规范风谱的现象;三个典型区间内的脉动风时频谱曲线显示,飓风过境前后的脉动风均为非线性和非平稳过程。     

起动发电机在中国大型客机上的应用

变频交流（AC）发电机在三级式恒频交流同步发电机的基础上发展而来，其宽的变速工作范围给发电机系统带来了新的特点，而变频交流起动发电机又是在变频交流发电机基础上进一步发展的，其运行条件及工作特性更为复杂。首先介绍变频交流发电机的结构特点，并给出其设计关键点以及变频工作对发电系统的影响；进一步针对变频交流起动发电机新增的起动功能，重点分析起动工作时励磁机的两种工作方式，并给出建议的工作方式。通过分析现有变频交流起动发电机及其起动发电系统，指出进一步提高其功率密度和效率是完全可能且必要的，从而为其在中国未来大型客机上的应用和发展提供参考与建议。     

Variable Speed Wind Energy Conversion Using Synchronous Machine

A power generation scheme using a synchronous generator with an excitation control system driven by a variable-speed wind turbine is described. The proposed scheme has been analyzed over a wide speed range and under wind gusting conditions. Performance characteristics show that it is feasible to use variable-speed fixed-pitch wind turbines to generate electric power.     

润扬大桥悬索桥桥址风环境的长期监测与分析

基于结构健康监测系统记录的2006年桥址日常持续风环境数据,开展了润扬大桥悬索桥桥址平均风特性及湍流脉动特性的分析研究,给出了湍流度、阵风因子、湍流积分尺度及脉动风功率谱密度函数的推荐值或公式,进一步研究了平均风速与上述湍流特征参数的相关性以及湍流特征参数之间的相互关系.分析结果表明:①湍流度、阵风因子和湍流积分尺度的实测统计值均高于规范推荐值;②纵向风谱拟合模型与Simiu谱较为接近,但横向风谱拟合模型则与之相差较多,并且都存在拟合模型中湍流动能往高频偏移的现象;③湍流度、阵风因子和湍流积分尺度之间存在较为明显的相关性,并且与平均风速也存在一定的相关性.