直流的

First, the dissertation summarizes the properties, developing state and application fields of BLDCM, then its fundmental structure; operation principle and control strategy is also presented. On the base of roundly analyzing all kinds of the drive motor in electromotion type railway switch, BLDCM is proposed to replace the formerly traditional DC motor in railway switch. Second, the whole design scheme and key technology of control system is put forward based on analyse of the technical parameters and requirements.

首先，论文介绍了无刷直流电动机的特点、发展和应用概况，分析了稀土永磁无刷直流电机系统的基本构成、工作原理和控制方法；在对目前各种电动转辙机驱动电机分析的基础上，提出将稀土永磁无刷直流电机用于铁路转辙机，以替换原有的串励有刷直流电动机。

In the proposed device to remedy the defect that overhigh withstand voltage of thyristors used in converter are needed due to the overhigh DC link voltage, a method to control DC link voltage is put forward, that is, a special control logic for full-controllable switching elements is designed to make them equivalent to half-controllable switching elements which are naturally turned on and turned off by triggering, then connecting such a half-controllable switching element in series with DC link the defect of overhigh DC link voltage is effectively solved.

为了克服该装置直流母线电压过高，因而对逆变器开关管耐压要求过高的缺点，提出一种对直流母线电压进行控制的方法。对全控型开关器件设计一种特殊的控制逻辑，使其等效为一个自然导通、触发关断的半控型开关器件，将该半控型开关串联在直流母线上，有效解决了直流母线电压过高的问题。

In this thesis, a charge pump voltage converter with push-pull type structure is proposed.

本论文的主题为直流转交流型与直流转直流型电荷泵。

The DC generator produces multiphase alternating currents in its armature windings, and a commutator on the armature shaft converts these alternating currents into a direct current output; or a homopolar generator produces a direct current without the need for a commutator.

直流发电机出示其骨架绕组多相交流电流和电枢轴上的一个换向器将这些交流电流转换成直流电流输出；或 homopolar 发电机一直流电流，而无需一换向器。

Considering the switch of the DC control mode, a new load margin solution is presental that is to solve the maximum load incremental under each DC control mode separately and add them together. The method is characterized by its convenience of considering varialle constraints of DC system and adjustment of DC operation mode.

交直流系统直流控制方式会发生调整，提出分段求解负荷裕度的方法，即分别用内点法求解系统不同直流控制方式的最大负荷增量再求和，该方法能方便考虑直流变量约束及运行方式的调整。

To meet with the DC feeder cable without ground wiring, different DC current method was proposed to solve the problem of DC leakage curren on-line detection of the cable. The paper still studied in primary the feasibility of low frequency superposition method to detect the DC feeder cable. It not only explained the working theory of the system, but also presented some problems to be solved.

针对直流馈出电缆无接地线，提出采用差量直流电流法解决了电缆直流泄漏电流的在线检测问题，并初步研究了低频叠加法监测直流馈出电缆的可行性，给出了工作原理及还需解决的问题。

The results of laboratory experiment and filed operation indicated that the system operated stably and could credibly evaluate the insulation state of DC feeder cable.

实验室试验及现场运行结果表明综合监测直流泄漏电流和直流放电信号能够较好及时地诊断出电缆故障，研制的系统稳定、可靠，能够评估直流电缆绝缘状况。

This text introduces the main structure and characteristics of the 1000MW super criticality once-through boiler and it's start system in HDPI Zouxian Power Plant firstly, then aiming HDPI Zouxian Power Plant 1000MW super criticality once-through boiler's dry state and wet state conversion in starting and shuting down ,the author makes research and analysis.finally, the author thinks that we could ensure that the dry state and wet state conversion is all right and smooth , then ensure opening and shuting down to be all right,if choosing control strategy properly and opportune moment.

本文首先介绍了邹县电厂1000MW超超临界直流锅炉及其启动系统主要结构特点，然后针对邹县电厂1000MW超超临界直流锅炉启动及停机过程中的干、湿态转换控制策略做了研究和分析。文章最后认为，只要干、湿态转换控制策略得当，时机把握合适，就会保证超临界直流锅炉干、湿态转换顺利完成，进而保证开停机顺利进行。

In this paper the basic principle of dynamic simulation with PSS/E is presented; the effectiveness and adaptability of flexible HVDC power transmission model are analyzed, and on the basis of actual power system the quasi steady-state VSC-HVDC dynamic model VSCDCT is simulated. Simulation results show that it is available to apply PSS/E in transient stability analysis of practical large-scale AD/DC power system.

介绍了PSS/E动态仿真的基本原理；分析了柔性直流输电模型VSCDCT的有效性和适用性，并基于实际系统对准稳态直流动态模型VSCDCT进行了仿真研究，仿真结果表明 PSS/E直流模型能够满足大规模交/直流系统仿真的要求。

Introduced the analysis and processing of a transformer with three-phase winding of DC resistance imbalanced defect,through further analysis of the after processed DC resistance,believed the transformer still existing the polarity selector"-" side contact deficiency,further on finding out the method of comparing corresponding DC resistance difference rate at each tap has the advantage to detect the polarity selector defect more accurately more sensitively and more directly.

对一台变压器出现三相绕组直流电阻不平衡缺陷的分析和处理情况做了介绍；通过对处理后直流电阻的进一步分析认为，该变压器还存在极性选择开关&－&向侧仍有接触不良方面的缺陷，遂进一步提出，如采用比较各对应分接位置下直流电阻差率的方法能够有更准确、灵敏、直接地发现极性选择器方面缺陷的优点；还提出了测试变压器绕组直流电阻时的几点注意事项。

I'm gonna go pack my regular, long bathing suit.

我要去打包我那不起眼的超长泳裤

Random number generators are used in many areas, with the improvement of the computational ability of the computer.

随着计算机计算能力的不断提高，随机数发生器在许多领域有了更加广泛的应用。