查询词典 variable resistance

The current sensitivity probability density function of energetic materials was deduced based on Frank-Kamenetskii parameter and resistance supposing as stochastic variable of normal distribution, by the application of the probability density formula of function in two random variables.

将Frank-Kamenetskii参数和电阻假设为正态分布的随机变量，应用二维随机变量函数的概率密度公式，推导出了含能材料电流点火感度的概率密度函数。

Resistor are usually divided into three series: fixed resistors, variable resistor and special resistance.

电阻器通常分为三大类：固定电阻，可变电阻，特种电阻。

ABSTRACT Aiming at problems of trans-vector controller in a vehicle-carried induction motor such as variable rotor and stator resistance following motor temperature, and their inductance varying with flux saturation degrees. Firstly, CSI and VSI are introduced, for CSI, it can hold the advantages both FOC and DTC using stator flux directional, PI parameter and simulation are also introduced. Secondly, equations of IM in the synchronous rotary frame and its static counterpart, as figuring in the saturation condition of magnetic field, are dealt in this paper and the simulation results are presented. Thereafter, the parameter designing of PI trans-vector controller is processed, which features the non-linear model. In practical realization, as neglecting the dynamical change of motor inductance, this paper employs online modification of inductance parameters, according to the flux saturation, then transforms the non-linear equations into linear ones, and so compacts the structure of controller. Thirdly, in view of the maximum torque output is extraordinary requisite when Electrical Vehicle start up, accelerate, and overtake, this paper issues the maximum torque when both inverter and battery capacity is corporeally definite. Fourthly, on-line differentiating and analyzing both rotor's time constants and its flux by using the expanding order reduction and discrete Kalman filter equation are fathomed, in order to realize high-performance trans-vector algorithm, and also the simulation results are presented. Fifthly, the close-loop regenerative brake system, when the EV's torque is set constant, is deduced; at the same time, unification of electric drive model and brake model is executed. Combined with maximum charge current demands, the mathematical model for online yielding torque as a demand.

本论文针对车载异步电机在矢量控制器所遇到的问题：定转子电阻随温度变化及随电机饱和程度变化的转子电感及定子电感而影响电机调速性能提出一套完整的解决方案：分析了电流型逆变器和电压型逆变器在实现矢量控制时控制器参数的计算，分析出对于电流型逆变器在采用定子磁场定向时，其性能同时具有矢量控制和直接转矩控制两者的优势，并对电压型逆变器在转子磁场定向下的模型进行了仿真研究；建立异步电机非线性模型，推导出考虑磁饱和时异步电机在同步旋转坐标系及静止坐标系下的方程，并做出了仿真结果，建立异步电机在非线性模型下的矢量控制调节器的PI参数设计，在实际应用中，若忽略电机电感的动态变化，可以根据当前的磁路饱和状态而在线修正电感参数，从而将非线性方程线性化，降低控制器的复杂度；考虑到电动汽车在起动和加速超车时需要电机有最大转矩输出，本文讨论在逆变器容量一定和电池供电能力有限的情况下电机最大转矩输出问题；推导了异步电机扩展降阶、离散卡尔曼滤波方程在线辨识转子时间常数和转子磁通，用于实现高性能的矢量控制算法，并给出了仿真结果；推导出了电动汽车恒转矩给定的闭环回馈制动系统，实现了电动控制模型和制动模型的统一，而且结合铅酸电池最大充电电流的要求，为制动转矩在线给定建立了数学模型；设计了基于双DSP系统的高性能矢量控制器软硬件框图，并以大量实验数据说明矢量控制在电动汽车应用的实际应用状况。

Under the limiting constrained conditions, an attempt to improve ship hull form of minimized wavemaking resistance is described by taking improved Michell integration as an object function and UV as an optimized design variable that is a mapping transformation function for the harmonizing and the fairing of the form variation.

在极限约束条件下，基于船体型值与UV度的映射函数，用UV度作为优化设计变量，以改进的Michel积分为目标函数，求得具有很好的协调性和工程光顺性的最小兴波阻力船型。

Electronic equipment categories: two core, three core insulated wire conduction test machine, an integrated plug-line tester, polarity tester, full-featured integrated precision wire tester, analog / digital storage oscilloscope, signal generator, the standard signal source, frequency dollars, Millivoltmeter distortion device,Miriam, LCR digital electric bridge, voltage tester, insulation resistance tester, grounding resistance tester, leakage current tester, electronic load, electric parameter measuring instrument, digital power meter, parameter measuring instrument transformers, transformer automatic testing system, transformers ring than phase tester, electrical safety parameter tester, variable frequency power supply, power supply, high-frequency shielding net room, temperature and humidity table, multimeter, power meter, tachometer, anemometer, coating thickness, coating thickness, vibration measuring instrument, the Composite test machines (motors, fans, hair dryer, lamps, fruit juice machine) and so on.

二芯、三芯线材绝缘导通测试机、插头线综合测试机、极性测试仪、全功能精密线材综合测试机、模拟/数字存储示波器、信号发生器、标准信号源、频率计、毫伏表、失真仪、抖晃仪、LCR数字电桥、耐压测试仪、绝缘电阻测试仪、接地电阻测试仪、泄漏电流测试仪、电子负载、电参数测量仪、数字功率计、变压器参数测量仪、变压器自动测试系统、变压器圈数比相位测试器、电器安全参数综合测试仪、变频电源、电源供应器、高频屏蔽网房、温湿度表、万用表、功率表、转速表、风速计、涂层测厚仪、镀层测厚仪、振动测量仪、综合测试机（马达、风扇、电吹风、灯饰、果汁机）等。

Actually, time is the only controllable variable in most single impulse resistance spot welding applications.

实际上，时间是在大多数单脉冲电阻点焊应用中唯一可以控制的因素。

Both results agree well basically. Based on Braginskii's formula for spark dynamic resistance, the nonlinear dynamic resistance of a spark gap used in a transmission line discharging circuit is calculated under the assumption of constant conductivity and variable conductivity.

基于Braginskii火花动态电阻公式，在假定火花开关电导率恒定与电导率渐变的条件下，利用传输线放电电路数值计算了气体火花开关的非线性动态电阻。

But it seems impossible to suppose that an agent could change the electrical resistance of a physical system without expending energy in the process, for to do this would necessitate changing the physical structure of the system, and that implies changing the positions of bits of matter on which forces are acting (think of turning the knob on a rheostat or variable resistor: one must expend energy to do this).

但是似乎不可能假设一个人能够改变物理系统的电子阻力而没有在这个过程中消耗能量，因为这样做会必然改变系统的物理结构，这会导致物质的the positions of bits的改变，在其中力起了作用。（考虑可变电阻器的按钮，做这个事情是要消耗能量的。

By considering wind resistance and wheel rolling resistance in vehicle single wheel brake model, the control technology of realizing the shortest brake distance has been studied by utilizing the optimal control theory, and the shooting methods based on initial variable guess technique has been provided to realize numerical calculation.

5在考虑风阻和轮胎滚动阻力的工况下，对以最短制动距离为目标的ABS控制律进行了研究，并利用基于初值猜测技术的打靶法进行了数值仿真。

In order to solve this problem,on the basis of analyzing the internal resistance of fuel cell and advantages of EIS method,a practical method of online measurement for fuel cell ohmic resistance ,namely alternating current variable frequency an.

为了解决这个问题，本文在对燃料电池内阻进行分析的基础上，结合电化学阻抗谱测试思想，提出了一种改进的燃料电池欧姆内阻在线测试法——交流变频调幅测量法，并基于高性能数字信号处理器设计了测试系统硬件电路和软件，得到了较好的测量效果。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。