磁场系统

The present magnetic resonance electrical impedance tomography method can only be used in MRI systems in which the main magnetic fields are parallel to the horizontal plane. In this paper, a new MREIT method with currents injected from an oblique plane is proposed. It can be used on MRI scanners with either permanent magnet or superconductive magnet.

现有的磁共振电阻抗成像方法只适用于主磁场平行水平面的磁共振系统，本文中提出了一种新的MREIT方法即斜位电流注入磁共振电阻抗成像，同时适用于主磁场垂直于水平面的磁共振系统。

The propulsion control system is one of the four subsystems of theMaglev vehicle. The propulsion control theory with field-oriented control is the key technology of the propulsion control system. In this paper,the characteristics of Maglev vehicle propulsion control system with FOC aredeeply studied and analyzed.

牵引控制系统是高速磁悬浮列车四大子系统之一，基于磁场定向控制理论的牵引力控制又是牵引控制系统的核心技术，本文深入研究和分析了在不同磁场定向控制方式下高速磁悬浮列车的牵引特性。

ABSTRACT Aiming at problems of trans-vector controller in a vehicle-carried induction motor such as variable rotor and stator resistance following motor temperature, and their inductance varying with flux saturation degrees. Firstly, CSI and VSI are introduced, for CSI, it can hold the advantages both FOC and DTC using stator flux directional, PI parameter and simulation are also introduced. Secondly, equations of IM in the synchronous rotary frame and its static counterpart, as figuring in the saturation condition of magnetic field, are dealt in this paper and the simulation results are presented. Thereafter, the parameter designing of PI trans-vector controller is processed, which features the non-linear model. In practical realization, as neglecting the dynamical change of motor inductance, this paper employs online modification of inductance parameters, according to the flux saturation, then transforms the non-linear equations into linear ones, and so compacts the structure of controller. Thirdly, in view of the maximum torque output is extraordinary requisite when Electrical Vehicle start up, accelerate, and overtake, this paper issues the maximum torque when both inverter and battery capacity is corporeally definite. Fourthly, on-line differentiating and analyzing both rotor's time constants and its flux by using the expanding order reduction and discrete Kalman filter equation are fathomed, in order to realize high-performance trans-vector algorithm, and also the simulation results are presented. Fifthly, the close-loop regenerative brake system, when the EV's torque is set constant, is deduced; at the same time, unification of electric drive model and brake model is executed. Combined with maximum charge current demands, the mathematical model for online yielding torque as a demand.

本论文针对车载异步电机在矢量控制器所遇到的问题：定转子电阻随温度变化及随电机饱和程度变化的转子电感及定子电感而影响电机调速性能提出一套完整的解决方案：分析了电流型逆变器和电压型逆变器在实现矢量控制时控制器参数的计算，分析出对于电流型逆变器在采用定子磁场定向时，其性能同时具有矢量控制和直接转矩控制两者的优势，并对电压型逆变器在转子磁场定向下的模型进行了仿真研究；建立异步电机非线性模型，推导出考虑磁饱和时异步电机在同步旋转坐标系及静止坐标系下的方程，并做出了仿真结果，建立异步电机在非线性模型下的矢量控制调节器的PI参数设计，在实际应用中，若忽略电机电感的动态变化，可以根据当前的磁路饱和状态而在线修正电感参数，从而将非线性方程线性化，降低控制器的复杂度；考虑到电动汽车在起动和加速超车时需要电机有最大转矩输出，本文讨论在逆变器容量一定和电池供电能力有限的情况下电机最大转矩输出问题；推导了异步电机扩展降阶、离散卡尔曼滤波方程在线辨识转子时间常数和转子磁通，用于实现高性能的矢量控制算法，并给出了仿真结果；推导出了电动汽车恒转矩给定的闭环回馈制动系统，实现了电动控制模型和制动模型的统一，而且结合铅酸电池最大充电电流的要求，为制动转矩在线给定建立了数学模型；设计了基于双DSP系统的高性能矢量控制器软硬件框图，并以大量实验数据说明矢量控制在电动汽车应用的实际应用状况。

As a result that this design, on the one hand, protected microwave system better, on the other hand, it made the microwave transmit efficiently; Using triangle copper plane to couple rectangle wave-guide can make the microwave transmission efficiency reach as high as 92%; Adjusting the magnetic electric current can realize the changes of the magnetic profiles.

这种设计，一方面能很好地保护微波系统，另一方面又能使微波高效地馈入，效率高；同时采用三角形均铜片的耦合矩形波导的设计，使微波转换功率达92%；磁场分布的设计上，通过改变磁场线圈电流来实现，当磁场线圈电流减小时，ECR 区位置朝微波窗口方向移动，将更有利于提高微波的吸收。

The instantaneous power theory was employed to analyze the instantaneous power of the control winding and the control scheme for the DWIG system with diode bridge load was obtained. The component of the currents on the control-winding flux determines the instantaneous reactive power, and the component on the perpendicular direction of the flux decides the reactive power. The former one influences the DC voltage of the diode bridge on power winding and the latter one influences the DC voltage of the static excitation controller of control windings.

基于瞬时功率理论，推导出按控制绕组磁场定向时控制绕组的瞬时功率，在此基础上分析了带整流桥负载的定子双绕组感应电机发电系统在宽转速运行时的电压调节机理，即：控制绕组电流在控制绕组磁场及其法线上的分量，分别决定着发电系统功率绕组整流桥直流侧电压和控制绕组静止励磁控制器(static excitation controller，SEC)直流侧电压，据此提出宽转速运行时DWIG发电系统电压控制策略。

For one-dimensional mesoscopic metal rings system in external magnetic field, supposing the system has a symmetry under translation in charge space, the quantum current relation in mesoscopic metal rings is given by solving the eigenvalue equation of the current, the property of quantum current have been investigated and analysed.

针对处于外磁场中的一维介观环系统，假设在电荷空间中具有变换的对称性，通过求解电流算符的本征值方程，给出系统中的量子电流关系，分析和研究一维介观金属环中量子电流的性质。结果表明，量子电流不仅与外磁场、介观金属环参数有关，而且还明显地依赖于电荷的量子化性质

Seeing that the basic researches of the method of metal magnetic memory insufficiently, this text has done the following work mainly:(1)Studied the basic theory of the method of metal magnetic memory;(2)Studied the signal of metal magnetic memory of samples both anneals and not anneals in natural magnetic field and drive magnetic field under the drawn loads;(3) Studied the signal of metal magnetic memory of anneals samples in three magnetic fields under the drawn loads.

鉴于其基础研究工作不足，本文主要做了如下工作：(1)系统地研究了金属磁记忆检测技术的基本理论：(2)研究了退火试件和未退火试件在自然磁场和激励磁场环境中进行拉伸的磁记忆信号；(3)研究了退火试件在三种磁场环境中进行拉伸试验的磁记忆信号。

Firstly, this thesis makes an introduces on the developement of PMSM servo system based on DSP. According to the control theory of AC PMSM servo system, this paper analyzes the coordinate transformation, the rotor magnetic field orientation and the current control strategy of AC servo system. The control strategy is i_d=0. The system is orientates towards rotor magnetic field. Then the mathmatic models of PMSM in d-q coordinate are set up.

本文首先对基于DSP的永磁同步电机伺服系统的发展概况进行了介绍；根据永磁同步交流伺服系统的基本控制理论，分析了交流伺服系统坐标变换原理、常用的磁场定向方式及电流控制策略，并给出i_d=0电流控制策略及永磁同步电机按转子磁场定向的控制方式，从而建立永磁同步电机d-q坐标系下的数学模型。

The study results had shown that the GPR and magnetic field of grounding system will produce detrimental effects on the breaker control system. Especially, for those poor insulation control lines, large GPR and longitudinal induction voltage during ground fault may lead to flash-over at control line terminals and thus inducing breaker mis-trip out. For the practical case in this thesis, to do well maintenance and to renew those old breakers and control lines with poor insulation situations are very important strategy for preventing breaker mis-tripping. Other protection measures from GPR and magnetic field induction interferences are important too. This study may provide useful information for planning the protection measures.

本研究结果显示变电所接地系统之GPR及其产生的磁场对断路器控制回路确有不利的影响，尤其当控制系统线路及端子若有绝缘不良，在接地故障发生的GPR及磁场纵向感应电压有可能造成闪络而引发断路器跳脱，对於本研究所探讨的案例而言，经由良好的维护或更新那些绝缘情况不良的老旧断路器及其控制线路，对於本研究所探讨的案例相当重要，而做好GPR及磁场感应干扰的防护措施亦相当重要，本研究分析结果可供规则防护措施之参考。

Firstly, the relationship between the magnetic pole state of active magnetic pole and the running state of passive magnetic pole was analyzed. The electromagnet's four magnetic pole state and switch sequence, which can drive permanent magnet rotate, were ascertained. Secondly, taking one of magnetic pole state NS (N denotes electromagnet's left magnetic pole and S right magnetic pole) as an example, the distribution of space magnetic field was studied. In addition, the mathematical model of space magnetic field was set up based on the magnetic circuit fundamental and using the method of magnetic analysis and modeling. Lastly, the four states' mathematical model of space magnetic field was solved by using the MATLAB.

首先，分析系统主动磁极磁极状态和从动磁极转动状态之间的关系，确定驱动永磁体转动的电磁体4个磁极状态及切换顺序；其次，基于磁路基本原理，通过磁场分析和建模，以电磁体4个磁极状态之一的NS（N表示其左极、S为右极）为例，对电磁体的空间磁场分布进行研究并建立空间磁场数学模型；最后，以MATLAB为平台对4个磁极状态的空间磁场数学模型进行求解，将求解结果与实验数据进行对比。

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。