矩问题

词组短语

problem of moments

与矩问题相关的网络例句 [注：此内容来源于网络，仅供参考]

For Hu invariant moment having no scale invariance, two modified algorithms are proposed: one is based on the normalized central moment coming from the concept of image square and the other is based on constructing a new invariant moment.

主要贡献如下： 1。针对离散情况下Hu不变矩特征仅仅具有平移、旋转不变性，不具有比例不变性的问题，提出了两种改进算法：一种是从图像正方形概念演变而来的归一化中心矩的修正；另一种是重新构造新的不变矩特征。

This paper analyzes the relation between the generalized moment problem and its dual problem, and gives the solution to some generalized moment problems.

分析了广义矩问题及其对偶问题的关系，获得了求解广义矩问题的方法。

The magnetic moment problem of the composite particle has been reviewed in this talk ; The effect due to the magnetic moment of leptons and stratons will be put forward for discussion if describing them as composite particles; In particular, the measured gyromagnetic ratios have been shown that it is consistent with the prediction in QED exactly; Finally, there is a possibility, which is described in a simple model, that the compositeness of stratons and leptons is not contradictory with the experiment...

在这个报告里，我们回顾了复合粒子系统的磁矩问题，分析了如果描述层子和轻子为复合粒子，磁矩问题将会带来的影响。特别是轻子的g-2值在实验上有精确的测量与量子电动力学的准确计算相当好的一致，最后从一个简单的模型讨论表明存在着可能性，轻子、层子是复合的，然而又与目前的实验相一致。

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。

In view of special applications of multi-pole magnetic permanent torque motor used for precise numerical control rotary table, motors with higher torque density and lower torque ripple s are needed.

针对精密数控转台伺服直接驱动用多极永磁力矩电机的特殊应用问题(要求电机有较大的转矩密度且较小的转矩波动)，在分析该种电机的特殊结构的基础上，提出一种新型不等齿顶宽结构，以提高绕组利用系数，加大电机的转矩密度；并采用转子斜极的方法，可在有效消除转矩波动的同时，电机仍保持较高的绕组利用系数。

In view of special applications of multi-pole magnetic permanent torque motor used for precise numerical control rotary table, motors with higher torque density and lower torque ripples are needed.

针对精密数控转台伺服直接驱动用多极永磁力矩电机的特殊应用问题(要求电机有较大的转矩密度且较小的转矩波动)，在分析该种电机的特殊结构的基础上，提出一种新型不等齿顶宽结构，以提高绕组利用系数，加大电机的转矩密度；并采用转子斜极的方法，可在有效消除转矩波动的同时，电机仍保持较高的绕组利用系数。

The flux hysteresis controller was ignored in the constant torque region and an improved method was proposed to make the estimation of torque easier.The proper stator voltage space vector was selected based on the output of the torque hysteresis controller and the sector which the current rotor flux locates in.

摘 要：针对无刷直流电机直接转矩控制中磁链观测困难、控制复杂等问题，提出了一种应用于无刷直流电机二二导通方式下的新型直接转矩控制方法：在电机基频以下调速时，略去了常规的磁链观测控制环节，改进了转矩计算方法，通过转矩滞环控制选择所施加的空间电压矢量。

A new brushless DC motor DTC scheme was studied to solve those problems associated with direct torque controlof brushless DC motor,such as difficulty to control flux and complexity to estimate torque.The flux hysteresis controller was ignored in the constant torque region and an improved method was proposed to make the estimation of torque easier.The proper stator voltage space vector was selected based on the output of the torque hysteresis controller and the sector which the current rotor flux locates in.

摘 要：针对无刷直流电机直接转矩控制中磁链观测困难、控制复杂等问题，提出了一种应用于无刷直流电机二二导通方式下的新型直接转矩控制方法：在电机基频以下调速时，略去了常规的磁链观测控制环节，改进了转矩计算方法，通过转矩滞环控制选择所施加的空间电压矢量。

The torque ripple in direct torque control system of permanent magnet synchronous motor is analyzed. To decrease the torque ripple in PMSM DTC, a PMSM DTC system based on the strategy of modulating the time of voltage vector is proposed .

讨论了永磁同步电机直接转矩控制转矩脉动问题，针对永磁同步电机直接转矩控制存在较大脉动转矩的缺点，提出了一种模糊调节电压矢量作用时间的永磁同步电机直接转矩控制策略。

This paper introduces the control principle of the direct torque control system of an asynchronous motor, and proposes a new strategy to solve the problem of the large torque ripple and current ripple. The Matlab 6.5 simulation shows that it can solve the problem efficiently.

本文介绍了直接转矩控制系统的控制原理，并针对基于直接转矩控制的异步电动机运行时存在较大的电流及转矩脉动问题，提出一种新的控制方案，并基于Matlab 6.5对这种新方法进行仿真，仿真结果表明该方案能有效的解决电流及转矩脉动的问题。

与矩问题相关的网络解释 [注：此内容来源于网络，仅供参考]

problem of geometrical construction：几何准问题

problem of fixed points 不动点问题 | problem of geometrical construction 几何准问题 | problem of moments 矩问题

k statistic k：统计量

k samples problem k样本问题 | k statistic k统计量 | k th moment k阶矩

moment：力矩

正确理解力偶(couple)的概念,比较力与力偶,力矩(moment)与力偶矩的异同,学习正确列写平衡方程. 本章为静力学重点内容. 重点讲述求解平衡问题的方法步骤. 详细叙述力系简化(reduction)理论,主矢(principal vector)与主矩(principal modem)概念,

moment：矩

是驱动力矩(moment)太小,还是片架移动阻尼(damp)太大?我们分析问题从简单入手,考虑到驱动电路的参数一般不会随意变化,而片架的机械运动系统可能随时间变化而磨损变化,所以着重检查了片架的导轨和轴承,发现其中有个轴承因磨损较大,

generalized truncated second-order moments method：广义截断二阶矩法

波浪力纵向分布:longitudinal distribution of wave forces | 广义截断二阶矩法:generalized truncated second-order moments method | 二阶边值问题:Second-order boundary value problems

Pauli：包立

1911年有人建议所有的基本磁矩都能分解成整数的分枝,这就是后来所谓"外思磁子的肇始,虽然并不正确,包立(Pauli)在1920年还是再度把这个问题提出来,使这单位磁矩被藉著波耳的原子来给予物理上的阐释,

problem of moments：矩问题

problem of geometrical construction 几何准问题 | problem of moments 矩问题 | problem of prime twins 孪生素数问题

problem of prime twins：孪生素数问题

problem of moments 矩问题 | problem of prime twins 孪生素数问题 | problem on obstacle 障碍问题

trigonometric moment problem：三角矩问题

trigonometric function 三角函数 | trigonometric moment problem 三角矩问题 | trigonometric polynomial 三角多项式

voltage：控制电压

因为是控制电压(Voltage)与频率(Frequency)之比,称为U/f控制. 恒定U/f控制存在的主要问题是低速性能较差,转速极低时,电磁转矩无法克服较大的静摩擦力,不能恰当的调整电动机的转矩补偿和适应负载转矩的变化;其次是无法准确的控制电动机的实际转速.