查询词典 direct current

The principle of the novel single-phase hybrid active power filter is described in detail. Based on the above analysis, Kalman filtering approach for estimation of harmonics is presented to improve the speed and precision of harmonic detection, and it also can avoid the influence made by voltage distortion on harmonic detection. A new current control strategy based on energy balance is presented to regulate the active part absorbing or releasing active power and control the inverter to produce current opposite to the harmonic current reflowing in injection branch, the above method combined with harmonic current tracking control that keeps the stabilization of dc-side voltage and improve the reliability of the system.

并详细分析了系统的滤波原理，提出了基于卡尔曼增益自调整的改进型动态谐波含量估计方法，能够快速准确的跟踪检测电网谐波电流，并且克服了电力机车等冲击性负荷引起的电网电压畸变对谐波检测精度的影响；提出了基于逆变器两侧能量平衡的电流控制方法使有源部分吸收或释放一定有功或无功功率及产生与注入支路回灌谐波电流相反的抑制电流，然后联合电网谐波电流跟踪控制以获得系统参考信号，保证了直流侧电压的稳定，提高了装置可靠性，增强了系统滤波性能。

At first the current sampling values pass through virtual digital CVTs. And then the voltage and current sampling values are processed by a low pass filter. According to the instantaneous value of transmission line voltage, the current instantaneous values of shunt reactors and P equivalent circuit capacitance can be calculated. After removing these two kinds of current, sampling value differential protection based on all components and fault component can be applied.

由线路电压瞬时值分别实时计算出流入并联电抗器和流入线路Π型等值电路两侧电容的电流瞬时值，再从线路每侧电流除去这两部分电流，用得到的新电流瞬时值作常规采样值差动和故障分量采样值差动保护计算。

Just as I had set my Mast and Sail, and the Boat began to stretch away, I saw even by the Clearness of the Water, some Alteration of the Current was near; for where the Current was so strong, the Water was foul; but perceiving the Water clear, I found the Current abate, and presently I found to the East, at about half a Mile, a Breach of the Sea upon some Rocks; these Rocks I found caus'd the Current to part again, and as the main Stress of it ran away more Southerly, leaving the Rocks to the North-East; so the other return'd by the Repulse of the Rocks, and made a strong Eddy, which run back again to the North-West, with a very sharp Stream.

我刚竖起桅杆张好帜，船就开始向前行驶了。我发现四周水色较清，知道那股急流在附近改变了方向。因为，水急水则浊，水缓水则清，我知道那股急流在这儿已成了强弩之末了。不久我果然发现，在半海里以外，海水打在一些礁石上，浪花四溅。那些礁石把这股急流分成两股，主要的一股继续流向南方，另一股被礁石挡回，形成一股强烈的回流，向西北流回来，水流湍急。

To solve the above problems, a novel resonance injection type hybrid active power filter is presented, it allows the energy exchange between the DC-side capacitor and grid, DC-side voltage will be stabilized after the proposed control method base on the regulation of reactive current is adapted. On the other hand, a new current control method is proposed which is based on the control of error between injection current and harmonic current compensated by passive power filter using recursive PI.

在此基础上结合提出的基于基波无功电流闭环调节的直流侧电压控制方法，保证了直流侧电压的稳定；提出了采用递推积分将无源滤波器作用后电网谐波电流与注入支路补偿电流进行闭环比较控制以获得参考电流的方法，减小了误差，提高了系统的控制精度。

Direct shot can shoot most of times, movement shot and fill shot cannot shoot at that much. The most shooting happened at normal position. The gap between normal position and non-normal position is closer and closer. The percentage of non-direct confrontment shot far more than direct confrontment shot, and also this percentage is close to each other year by year.

直接射门的进球数量最多，运球突破射门和补射进球数量较少；绝大多数的进球是在正常状态下打入的，正常状态和非正常状态进球占全部进球的比例差距越来越小；非直接对抗射门进球数所占的比例远远大于直接对抗射门进球的比例，但直接对抗和非直接对抗的比例成逐年接近趋势。

The result verifies that the discrete model with power series direct discretization method requires 100 memory length to obtain the better approximation, while one with continued fraction direct discretization method requires only 10 order. Thus the continued fraction direct discretization method is preferable to digital realization of fractional order control algorithms in engineering applications.

研究结果表明，幂级数直接离散法得到近似离散模型需要记忆长度为100方可获得较好的近似，而连分式直接离散法近似离散模型为10阶时就可以获得较好的近似，因此连分式直接离散法比较适合于分数阶控制算法的实际工程应用。

On the base of the single-diameter laser-scanned measuring technology, a double direction laser-scanned measuring system is presented. Which combinate the laser-scanned measuring technology with special optical system. In the system, the collimation semiconductor laser-scanned beam scanning two perpendiculars direct of one plane of the measured workpiece at the same time is made. The beams with the dimension information of two perpendiculars direct are processed by the scanning receive system, the high-speed photoelectric transition and electronic data process. Two measured results of the diametric directs and ellipse tolerance,etc, parameter, of the turning workpiece on the same plane are obtained by non-contact automatic measurement. The problem of non-contact measurement of two perpendiculars direct of one plane of turning workpiece is settled. It processes many peculiarities, such as high speed, high accuracy and non-contact automatic measurement, etc.

在单向激光扫描检测技术的基础之上，提出了一种双向激光扫描检测系统，其采用激光扫描检测技术与特殊光学系统相结合，用准直半导体激光扫描光束对被测工件径向某一截面的两个相互垂直方向同时扫描，经扫描接收光学系统、高速光电变换、电子学系统和微机数据处理系统，对将携带有垂直方向被测量信息的光束进行处理，实现了回转体工件同一截面两个垂直方向的径向尺寸和椭圆度等参数的非接触自动测量，解决了同时非接触测量回转体零件同一截面两个径向尺寸的难题，它具有高速，高精度和非接触自动测量等特点。

The present paper uses the direct sequence spread spectrum technology, key to short-wave communication and direct sequence spread spectrum correspondence characteristic as well as union advantage, wide frequency code production, the direct sequence spread spectrum communications system technology and the principle, the wide frequency synchronization technology, the RAKE receive technology has conducted the research and the analysis.

本论文采用直接序列扩频技术，重点对短波通信与直接序列扩频通信的特点以及结合的优点，扩频码的产生，直接序列扩频通信系统的技术与原理，扩频同步技术，RAKE接收技术进行了研究与分析。

The direct cost of production of industrial enterprises include direct materials, direct labour and production overheads.

工业企业的生产成本项目，包括直接材料、直接工资和制造费用。

We find that providing Internet direct channel does not necessarily lead to lower expected payoff for Internet retailer, it depends on the effect of drop-shipping channel free ride on Internet direct channel. When the effect is good, the retailer can achieve higher payoff. Of course, the supplier always achieves higher payoff by providing Internet direct channel.

5在渠道之间存在免费搭乘现象的情况下，建立了drop-shipping渠道和网络直销渠道之间的竞争模型，指出供应商提供网络直销渠道后，并不一定就导致零售商利润的下降，这依赖于drop-shipping渠道免费搭乘网络直销渠道的效果，当效果高于一定水平时，零售商的利润增加。

It inculcates justification before God on the ground of human merits.

它说明在上帝灌输在地上人类优点。

TH Leaguer has excellent Quality Control and Management System.

本公司具有完善的品管部门。