输入电流

Meanwhile, this detected voltage difference is amplified and filtered, and finally the processed signal is transmitted to the analog input of the DAQ card for further software operation, display, and storage.

其工作原理是利用DAQ卡类比输出通道，送出不同频率且幅值恒定的正弦电压信号，透过修正型Howland定电流驱动电路将电压信号转成电流信号加入体内，由量测电极取出电压信号经放大滤波后，把讯号送入类比输入DAQ卡，并在LabVIEW人机介面上做运算处理、分析、显示与储存。

The bridge loses balance and sensitive parts have a output signal,which will transform to related current signal after differential magnifying and conversion between current and voltage. Linear 4~20mADC standard signal is formed by compensation of magnifying and non-linear rectified ring circuit ,and second temperature compensation.

输出的电信号，经过差分放大，电压电流转换，变换成相应的电流信号，通过放大和非线性矫正环路的补偿，以及精密的二次温度补偿，产生与输入压力输成线性关系的4~20mADC 二次制标准信号。

In the power supply circuit, series power supply and the adjustment of the series load, the load current flows through all of the adjustments, and transistors Guozainaili worse, once output overload or short circuit, the input voltage increases in the full set of adjustment an emitter, the current surge to adjust the fierce heat, if not over-current protection measures at this time, the adjustment will be burned, power Zhengliuguan also will be greatly threatened or damaged.

中文摘要：在稳压电源电路中，串联型稳压电源的调整管与负载串联，负载电流全部流经调整管，而晶体管的过载能力较差，一旦输出端过载或短路，输入电压全部加在调整管集---射极间，其电流剧增，使调整管猛烈发热，如果此时没有过流保护措施，调整管就要被烧坏，电源整流管也将受到巨大威胁或损坏。

The feedback resistance, R1, is dependent on cell sensitivity and should be chosen for either maximum dynamic range or for a desired scale factor. R2 is elective: in the case of photovoltaic cells or of photodiodes, it is not required in the case of photoconductive cells, it should be chosen to minimize bias current error over the operating range.

反馈电阻R1的取值由电池的灵敏度和要求的最大动态范围，或者需要的电流——电压转换比例决定。R2分情况选取：在光电池和光电二极管时不需要这个电阻，在光电导的时候，电阻的阻值应该能使在工作范围内，由OP输入偏置电流所带来的误差最小。

A control circuit is connected to the field effect transistor and provides a current through a control current path to produce the field effect transistor input voltage.

控制电路连接到场效应晶体管并提供通过控制电流路径的电流以产生场效应晶体管输入电压。

Switching Power Supply with the traditional distinction between :(1) not only the output voltage feedback, feedback from the average input current;(2) Current benchmarks signal voltage error signal and full-wave rectifier voltage signal sampling the product.

与传统开关电源的区别是：不仅反馈输出电压，还反馈输入平均电流；(2)电流环基准信号为电压环误差信号与全波整流电压取样信号之乘积。

As shown in Figure 2-15, the input offset current adds to the measured current so that the meter measures the sum of the two currents

如图2-15所示，因输入失调电流叠加到测量电流，故此表测量的是两个电流的和

S1 is then changed to position 1. The voltage stored on C1 is inserted between the output and inverting input of the amplifier and the output of the amplifier changes by VIN to maintain the amplifier input at the input offset voltage. The output then changes from (VOS + IbiasR2) to (VIN + IbiasR2) as S1 is changed from position 2 to position 1. Amplifier bias current is supplied through R2 from the output of the amplifier or from C2 when S1 is in position 2 and position 1 respectively. R3 serves to reduce the offset at the amplifier output if the amplifier must have maximum linear range or if it is desired to DC couple the amplifier.

接着 S1 拨到位置 1，使 C1 的电压加在放大器的输出端和反相输入端之间，(由于电容端电压不能突变，所以)输出端的电压将产生大小等于 VIN 的变化，使放大器输入端维持输入失调电压，即当开关 S1 从位置 2 拨到位置 1 时，输出端电压将从(VOS + IbiasR2)变为(VIN + IbiasR2)。S1 处于位置 2 时，放大器的偏置电流是由输出端经电阻 R2 提供的，当 S1 转向位置 1 时则由 C2 提供。R3 的作用是降低输出失调电压，如果要求放大器具有最大的线性范围，或者采用直流耦合，就应该使用该电容。

The technique made full use of the characteristic of PR controller which can realize zero steady-state error in AC input signal in stationary frame. In the method, the active and reactive current component in the vector control strategy were transformed in the stationary frame to achieve the objective of keeping the DC-link voltage constant, adjusting the power factor and decoupling the active and reactive power. Compared with conventional double close-loop proportional integral controller, the PR technique is better in harmonic compensation without the complex rotating frame transformation and the couple or feedback voltage which is easily influenced by temperature and circuit parameters. The control algorithm is easy to be realized while the robustness and power quality is improved.

该方法充分利用了PR控制器能够在静止坐标系下对交流输入信号无静差控制的优势，将矢量控制策略下的有功电流和无功电流分量转换到静止坐标系下进行调节，实现网侧变换器维持直流电压稳定和调节功率因数的控制任务和双馈电机有功、无功功率的解耦控制，与传统的双闭环PI控制相比，该策略无需繁琐的坐标旋转变换，不存在受温度及电路参数影响的耦合项和前馈补偿项，且易于实现对系统低次谐波电流的补偿，减小了控制算法实现难度，提高了控制系统的鲁棒性和电网电能质量。

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Do not gum up the work by telling mother what we are going to do .

别告诉母亲我们要干的事，那会把事情搞糟的。

In recent years, application of the partial prestressed concrete beam s is developed.

近年来，随着部分预应力砼梁应用的推广，发现我国规范所采用的名义拉应力法的计算结果不稳定。