换流器

A modified backward Euler method is developed which enables to increase considerably the accuracy of jump voltage computation as a result of freeing its computing from the influence of the faint asymmetrical initial current in such an inductive circuit as converter and completely eliminate numerical oscillation in converter simulation as often seen in the case of implicit trapezoidal integration method.

本文提出一种变形的后退欧拉法，用该法对换流器这样的纯电感电路进行跃变电压计算，可完全避免初始电流中微弱的不平衡对跃变电压计算的影响，大大提高了跃变电压的计算精度，并彻底消除了隐式梯形积公法用于换流器仿真时所存在的非原型数值振荡。

Thus, the output will always be driven by a single transistor, either P- channel or N-channel. Since they are as closely matched as possible, the output resistance of the gate will always be the same, and signal behavior is therefore more predictable. Fig. 3.4 CMOS NAND gate One of the main problems with CMOS gates is their speed. They cannot operate very quickly, because of their inherent input capacitance. B-series devices help to overcome these 24 Lesson 3 CMOS Logic Circuit 25 limitations to some extent, by providing uniform output current, and by switching output states more rapidly, even if the input signals are changing more slowly. Note that we haven't gone into all of the details of CMOS gate construction here. For example, to avoid damage caused by static electricity, different manufacturers developed a number of input protection circuits to prevent input voltages from becoming too high. [3] However, these protection circuits don't affect the logical behavior of the gates, so we won't go into the details here. New Words and Phrases 1. CMOS abbr.

略语互补金属氧化物半导体(complementary metallic oxide semiconductor)逻辑，逻辑学，逻辑性，推理方法补充的，补足的，互补的电池供电的门电路，逻辑门，闸门，控制栅，大门，通道，门口，入口伏特，环骑，闪避基础的，基本的，主要的基本原则，基本原理增强型金属氧化物半导体场效应晶体管(metallic oxide semiconductor field effect transistor)反相器，反用换流器，变极器来源，水源，消息来源，原始资料，发起者源，源极排水沟，消耗，排水漏极排出，喝干，耗尽排水，流干，耗尽相同的，相配的，匹配的匹配有效地，有力地，事实上，实际上无限的东西无穷大无穷的，无限的，无数的，极大的接地的正向偏置的，正偏的或非 25 2。

The use of thyris to r valves has increased the reliability of HVDC converters to impressive levels.

晶闸管换流阀的采用已将高压直流换流器的可靠性提高到相当惊人的水平。

The results of theoretical analysis and simulation indicate that commutation converter based on New-Type converter transformer-Filter Commutated Converter have superiority on harmonic characteristics.

理论分析和数字仿真结果均说明了基于新型换流变压器的换相换流器—滤波换相换流器在谐波特性方面的优越性。

The capacitor commutated converter, that is CCC, can overcome the inherent drawbacks of conventional converters.

电容换相换流器能够很好地克服传统HVDC换流器存在的固有缺陷。

The relationship between currents of Filter Commutated Converter and the harmonic characteristics of multifrequency AC/DC interconnected systems based on New-Type converter transformer have been studied with ideal models by means of theoretical analysis and matlab simulation.

采用理想化的研究方法，通过理论分析和MATLAB仿真对滤波换相换流器的电流变换关系以及基于新型换流变压器的多基频交直流互联系统的谐波特性进行了系统的研究。理论分析和数字仿真结果均说明了基于新型换流变压器的换相换流器—滤波换相换流器在谐波特性方面的优越性

Taking the development platform of HVDC power transmission for example, the calculation result of impedance-frequency characteristic of traditional line commutated converter and that of FCC are compared. Simulation results show that the impact of impedance-frequency characteristic of converter on the resonance frequency of AC system is not negligible, and FCC can enhance the strength of AC system in a certain extent, improve system stability and effectively reduce AC equivalent impedance under resonance frequency, thus the harmonic instability of HVDC power transmission system can be avoided.

以直流输电开发平台为例，对传统电网换相换流器(line commutated converter，LCC)与FCC的阻抗频率特性计算结果进行对比，仿真结果表明换流器的阻抗频率特性对交流系统的谐振频率有着不可忽略的作用，FCC在一定程度上提高了交流系统强度，改善了系统稳定性，有效降低了系统谐振频率下的交流等值阻抗，从而更好避免直流输电系统谐波不稳定现象的发生。

The windings in the valve side adopt prolonged delta connection providing the circuit for three-multiple harmonic currents, and implementing 12-pulse converter through fit ratio; this connection between the common winding and prolonged winding can decrease the current impact when phase conversion takes place.

该换流变压器阀侧绕组采用延边三角形接线，为3倍次谐波电流提供通路；通过匝比配合，实现12脉波换流；其延边绕组与公共绕组构成自耦变压器接线，可减少换流器换向时的电流冲击；在公共绕组上连接滤波支路，并调至谐振点，配之以变压器巧妙的零阻抗设计，可以在阀侧实现无功补偿，可实现网侧绕组中无5、7、11、13次特征谐波，即谐波屏蔽。

The use of thyristor valves has increased the reliability of HVDC converter s to impressive levels.

晶闸管换流阀的采用已将高压直流换流器的可靠性提高到相当惊人的水平。

DC power transmission simulationmodel is set up in this paper with the Matlab software, and various faults such as single-phasegrounding short circuit, phase to phase short circuit, three-phase circuit grounding shortcircuit and inverter bridge short circuit are simulated in this model.

用MATLAB软件建立了电力系统直流输电仿真模型，模拟了单相接地短路故障、相间短路故障、换流器桥臂以及单桥故障，经过近百次仿真运行，得出了各种故障下的特性曲线，准确描述了直流输电系统在发生大扰动后的暂态过程，并从理论上进行了科学分析，得出了各种故障对换相失败的影响。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了