磁场系统

In this paper, the mathematic model of a. c. excited generator system based on field-oriented control is established first. The simulated results operating at no-load and steady state are agreed with the test waveforms by means of 2. 8kW ACEG prototype developed by Harbin institute of large electrical machinery and Zhejiang University.

本文建立了磁场定向控制交流励磁发电机系统的数学模型，并采用哈尔滨大电机研究所和浙江大学联合研制的2.8kW ACEG系统实验原理样机，测试。。。

Since the multiple scattering should be considered, the scattering problem of many-cylinders is more complicated than single cylinder. By using scattering matrix method to solve the scattering problem of many-cylinders, first we have to express the incident fieldand scattered field by special function（for example, Bessel function and Hankel function）under cylindrical coordinate, then use the addition theorem of special function to get a linear system of equations to relate the incident field coefficients and scattered field coefficients. The incident and scattered field coefficients for every cylinder can be solved from the linear equations by matching electromagnetic boundary condition pointwisely.

单颗圆柱散射体的散射场解析解很早就被解出，而多个圆柱阵列的散射场问题因为涉及到入射光在圆柱与圆柱间的多重散射，故散射行为较单颗圆柱的散射复杂，因此圆柱阵列的多重散射问题需要利用加法定理来处理；散射矩阵法的主要精神即是先用圆柱座标下的特殊函数对平面波和圆柱散射体的内外域电磁场做无穷级数展开，再藉由特殊函数的加法定理将所有圆柱散射体的展开中心移到同一个展开中心，最后可以得到一组连结整个散射系统的入射电磁场系数及散射电磁场系数的线性方程组，将该组线性方程配合电磁场在散射体边界的连续条件，便可分别求出圆柱阵列中各个圆柱体的内部电磁场与外部散射场，再利用线性叠加原理即可求得整个圆柱系统的全域电磁场分布。

The electron trajectory in the deflection system of electron gun is calculated by using the boundary element method and the Runge-Kutta method.

采用边界元法与等效磁荷法，模拟了偏转聚焦系统的非均匀磁场，再利用龙格－库塔法模拟出电子在该系统中的运动轨迹。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

The system consists of signal acquisition systems, signal processing, show circuit and control circuits, and other components, through the acquisition by Hall sensor voltage signal to the amplifier will signal amplification, and then in the A / D converter after the digital signal into the microcontroller , Through the SCM software programming by the magnetic field signal, the final adoption of LED display to the magnetic field strength.

该系统由信号采集系统、信号处理、显示电路和控制电路等组成，通过霍尔传感器采集得到电压信号，再经放大器将信号放大，然后在A/D转换后将数字信号送入单片机，通过单片机软件编程得到磁场信号，最后通过LED显示出磁场强度。

This device, which is composed of oscillator, switching capacitor, second-order tracking system, digital switching system, power-amplifier circuit and Helmholtz coils , can produce rotating magnetic field whose frequency and strength can be adjusted continuously.

该装置由振荡器、开关电容、二阶跟踪系统、数字开关系统、功放电路及亥姆霍兹线圈组等部分组成，可以产生频率、强度连续可调的旋转磁场。

Magnetoacoustic Tomography Technology with Magnetic Induction, and presents the configuration and principle of the circuit.

摘 要 介绍了感应式磁声成像系统的关键部件脉冲磁场发生系统的设计。

This article introduced the antijamming in the NC system design,from the shield (including electric field shield ,magnetic screen and electromagnetic field shield ) designs mentions,added the absorbing circuit to the perceptual load to suppress the transient state noise to give the specify,might avoid the NC system which disturbed creates softly breakdown.

本文介绍了抗干扰在数控系统中的设计，从屏蔽(包括电场屏蔽、磁场屏蔽和电磁场屏蔽)设计谈起，对感性负载加吸收电路来抑制瞬态噪声做了详细说明，可避免干扰造成的数控系统的"软"故障。

Following that, we implement the algorithms of FOC, space vector pulse-width modulation, and speed control using the digital signal processor. Regarding to the influence of controller parameters on dynamic response of the motor speed, this thesis proposes the speed control of PMSM using self-tuning fuzzy technique. By the self-tuning technique, the on-line fuzzy logic controller output can give better speed response under the load disturbances or variable speed commands.

本文首先使用数位讯号处理器完成磁场导向控制、空间向量脉波宽度调变及速度控制之策略，针对控制器参数对系统动态响应之影响，提出采用自调式模糊控制器於速度控制回路，藉由自调式机制，线上调整模糊控制器之参数，使PMSM在变动负载及速度命令下有较佳之动态响应，达到提升系统响应及强健性之目的。

The technical requirements of the de-excitation system for generators are discussed, including the technical parameters of field circuit breaker, the capacity of de-excitation resistor, the time of de-excitation, the operation conditions for generator de-excitation, etc.

分析讨论了灭磁系统设计的几个主要技术要求，包括磁场断路器的性能参数要求及其选择计算、灭磁电阻容量要求及其选择计算、对灭磁时间的要求、设计应考虑的灭磁工况等，提出了相应的设计计算方法以及在灭磁系统设计中应用ANSI/IEEEC37.18标准时应注意的几个问题。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。