电压

In this paper, according to the equation of voltage vector of single-phase motor operating at symmetrical condition, author presents a new voltage-vector PWM method of variable frequency control for single-phase motor. In system, the voltage vector is used as a control parameter.

本文根据单相电动机对称运行时的合成电压矢量方程，提出了以合成电压矢量为控制量的单相电动机电压矢量式PWM变频调速控制方法，并进行了计算机仿真及制作了单相变频器。

Accordingly, using graph theory and operating experience abroad for reference, It firstly brings forward a new method of voltage rectification which based on pilot bus with voltage control area In view of the weak coupling among every VCA,using decomposing method of multi critical value, it realizes the eliminating vinculum of every VCA.

因此利用图论的基本理论，借鉴国外电力系统电压三级控制模型的运行经验，首次提出了一种基于电压控制区的主导节点电压校正方法。

First of all, the circuit output waveform in the case of losing it by measuring the input voltage and output voltage in order to detect amplification of analog circuits, and then by adjusting the frequency of AC voltage source to reduce the output gain make 3db analog circuits in order to measure the maximum cut-off frequency, pass band can be obtained.

本电路首先在输出波形不失真的情况下通过测量输入电压和输出电压从而测出模拟电路的放大倍数，然后通过调节交流电压源的频率使得输出增益减少3db从而测量出模拟电路的上限截止频率，即可求出通频带。

It has a base internal circuit, resulting in a period of 20ms, the base width of 1.5ms signal, will be the DC bias voltage and the voltage comparator potentiometer to obtain the output voltage difference.

它内部有一个基准电路，产生周期为20ms，宽度为1.5ms的基准信号，将获得的直流偏置电压与电位器的电压比较，获得电压差输出。

The feedback signal and a reference voltage are compared by the comparator, and when the value of the feedback signal is equal to that of the reference voltage, the comparator produces a switch control signal to regulate the duty ratio of the switch circuit so as to stabilize the output voltage.

通过一个比较器比较这个反馈信号和参考电压，当反馈信号与参考电压的值相等时，此比较器产生一个开关控制信号调节开关电路的占空比以稳定输出电压。

Although designed as fixed-voltage regulators, the output voltage can be increased through the use of a simple voltage divider.

尽管作为修理电压管理者设计了，输出电压能通过一简单的电压分配的使用被增加。

With this important concept which the reads of wattmeter was equal to the product of the effective value of the voltage across the potential coil, the effective value of the current flowing in the current coil, and the cosine of the phase-angle between the current and the voltage. It was speciled with some examples to determine the phase-angle measured between line voltage, line current in different connection.

围绕有功功率表的读数等于该功率表电压线圈所接电压的有效值、电流线圈所通过的电流的有效值以及电压与电流相位差余弦的乘积这一重要的概念，用实例说明在不同的接线情况下如何利用各电量的相量关系来确定所测的线电压、线电流之间的相位差角。

But how a more accurate measurement of voltmeter resistance, the experimental use of Wheatstone bridge resistance values measured in the arm, etc.

但如何更精确的测量电压表内阻，本实验利用了惠斯通电桥测中值电阻等臂测量的方法测量并分析了电压表的内阻，依据此实验的结果分析给出了精确测量电压表内阻的建议。

It points out that under the hard-switching PWM pattern, the movement speed of flux linkage is adjusted by zero space voltage vector, but when soft-switching PWM pattern is used, effect time of space voltage vector vary greatly, sometimes even no zero space voltage vector exist.

指出在硬开关PWM模式下，磁链的运动速度靠零空间电压矢量调节；而在软开关PWM模式下，空间电压矢量的作用时间发生了很大变化，有时甚至没有零空间电压矢量。

The difference is discussed in the paper and a novel PMSM DTC system based on the fuzzy distribution of zero voltage vector strategy is proposed at last. Simulation results show that the new method decreases the torque ripple after using zero voltage vectors properly.

论文分析了零电压矢量在永磁同步电机直接转矩控制系统中的作用，并提出了一种基于模糊零电压矢量分配策略的永磁同步电机直接转矩控制方法，仿真结果表明该方法有效地利用零电压矢量达到了减小转矩脉动的目的。

Shop assistant: Please check at the door.

店员：请您到门口柜台交费。

In the end, transportation of PAHs in the environmental matrix was preliminarily investigated and discussed according to PAHs data of soils and sediments from a certain region in Shanghai. The result indicated that there are two or more pathways on PAHs transportation in the environmental matrix.

最后，对上海特定地区内PAHs在环境介质中的迁移径途进行了分析讨论，结果表明上海市土壤和沉积物等环境介质中PAHs的迁移存在多种途径。