Transducerless position and velocity estimation in induction andsalient AC machines

This paper presents a viable transducerless rotor position and velocity estimation scheme for PWM inverter driven induction, synchronous, and reluctance machines with the capability of providing robust and accurate dynamic estimation independent of operating point, including zero and very high speeds, light and heavy loading. The injection of a balanced three-phase high frequency signal (500 to 2 kHz) generated by the inverter, followed by appropriate signal demodulation and processing combined with a closed-loop observer, enable the tracking of rotor magnetic saliencies from the machine terminals. Although rotor magnetic saliency is inherent within reluctance machines, and most synchronous machines, saliency in the induction machine is introduced via a modulation of the rotor slot leakage with minimal detrimental effects on the machine performance. Experimental verification for the induction machine is included     

Table-based PWM for all-digital RF transmitters

In this paper, a novel pulse-width modulator (PWM) for an all-digital PWM transmitter based on switching amplification is presented. In this approach, each symbol is represented by a sequence of pre-computed PWM pulse widths stored in a table that results in reduced error vector magnitude (EVM). A high-resolution pulse former is then used to build the bipolar radio frequency (RF) signal. Simulations and comparisons to other approaches reported in the literature under different oversampling ratios and finite time resolutions are presented. The impact of nonlinearities in the variable duty-cycle generator is also analyzed to demonstrate the robustness of the proposed technique.     

互联系统交流联络线随机功率波动幅值研究

跨省电网互联后,会产生各孤立电网所不具备的新功效。电网互联后可提高系统的供电可靠性及旋转备用效益、有利于优化发电结构、降低运行费用等。但是正常运行时跨省级互联系统交流联络线上存在随机功率随机波动的现象,这种功率波动影响跨省互联系统联络线上的传输功率,严重时会威胁到电网的安全稳定运行,研究了随机功率波动的机制,并通过PSASP软件仿真及EMS系统的实测数据,对基于系统静态频率特性,推导的关于跨省级互联系统交流联络线功率波动的公式进行了验证,分析了影响联络线功率波动在理论计算与实测数据中产生误差的原因,为制定抑制联络线功率波动的措施提供依据。     

正弦交流采样理论误差的估计

交流采样技术在多种智能化仪表中得到广泛应用。它的主要思想就是在一个周期内用若干个交流信号瞬时值描述该交流信号波形,并计算出有效值及其它有关参数。一个周期内对交流信号来样次数与由采样次数所带来的误差关系。对比从理论上作了探讨。     

基于特征增强的高分辨率人体姿态估计网络

在轻量级卷积神经网络进行高分辨率人体姿态估计时存在提取特征不充分,针对该问题,提出了一种基于特征增强的高分辨率人体姿态估计网络。首先利用空洞卷积补全操作提取图像特征,以避免特征信息丢失且保持模型参数基本不变;接着利用池化增强模块进行卷积提取特征的选择,以保留重要特征且减轻传统池化模块对提取特征造成的破坏;最后利用加强通道信息交互的深度可分离卷积模块进行特征提取,以保持该模块的参数量较少且能够提高其特征提取能力。在COCO2017数据集进行性能测试,本文算法和DiteHRNet30算法的AR值分别为77.9%和77.2%;在MPII数据集进行性能测试,本文算法和DiteHRNet30算法的PCKh值分别为32.6%和31.7%。实验结果表明,本文算法在人体姿态估计精度和算法复杂度之间能够达到较好的平衡。     

Analysis of estimation error of observer for disturbance torque and velocity

This paper analyzes some features of estimation error of the observer which estimates disturbance torque and velocity. This observer inputs the information of driving torque and current position, and outputs the information of disturbance torque and velocity. Although this observer is a practical tool to compose a robust control system, there has never been sufficient information to make the most of it. Thus the study to grasp some basic features of the observer is needed now. Also, it is very important to analyze the estimation error on it. This paper considers the estimation error caused by disturbance torque and observation noise because these seem to be the most significant causes. The result of analysis provides a practical way to select the pole allocation of the observer. Finally, the simulation and the experimental results are shown.     

交直流混联系统可靠性评估

首先使用容量卷积公式计算出HVDC系统的容量-概率模型,然后对经典有功调整模型进行扩展,以模拟HVDC线路用于远距离输电和系统互联等场合.为了避免交直流系统交流潮流计算后出现平衡机出力越限问题,在有功调整模型中考虑了系统的有功损耗,并在纯交流系统可靠性评估无功/电压线性化校正模型的基础上,提出了计及HVDC线路影响的调...     

Improved speed estimation in sensorless PM brushless AC drives

The application of flux-observer-based sensorless control to permanent-magnet brushless AC motor drives is described. Current methods of speed estimation are assessed, both theoretically and experimentally, and an improved method, which combines the best features of methods in which speed is derived from the differential of rotor position and from the ratio of the electromotive force to excitation flux linkage, is proposed. Its performance is verified experimentally.     

适应非光滑特性的交直流混合电力系统状态估计

交直流混合电力系统中的有载调压变压器(on-load-tap-changer, OLTC)和换流器模型存在大量限幅、死区等非光滑特性,如何处理换流器引入的分段函数约束是当前状态估计的研究难点。构建了OLTC的混合整数非线性(mixedintegernonlinearprogramming, MINLP)模型,通过控制二次侧电压水平得到OLTC挡位的估计值。针对换流器采用分段函数描述包含限幅、死区等下垂控制特性的问题,提出采用近似拟合函数将分段函数光滑化。与采用MINLP描述分段函数的方法相比,所提模型显著提高了计算效率。通过3节点和IEEE14节点交直流混合系统算例,验证了所提状态估计模型的正确性和实用性,同时分析了拟合系数对状态估计的影响。算例表明,所提模型增强了状态估计处理不良数据的能力,提高了对非光滑特性的适应能力,在保证计算精度的前提下能够提高状态估计的收敛性。     

An adaptive robust observer for velocity estimation in an electro‐hydraulic system

This paper proposes the design of an observer to estimate the velocity of an electro‐hydraulic system by using pressure measurements only. The difficulties involved in the design of an observer for such a system include the highly nonlinear system dynamics, severe parametric uncertainties such as large variation of inertial load and unmatched model uncertainties. In order to address these issues, a nonlinear model‐based adaptive robust observer is designed to estimate the velocity. The contributions of the proposed work is twofold. First, it introduces a novel coordinate transformation to reconstruct the velocity estimate. And second, from a structural viewpoint, the design has two important features: (i) an underlying robust filter structure, which can attenuate the effect of uncertain nonlinearities such as friction and disturbances on the velocity estimation, and (ii) an adaptation mechanism to reduce the extent of parametric uncertainties. Experimental results on the swing motion control of an electro‐hydraulic robot arm demonstrate the effectiveness of the proposed observer. Copyright © 2012 John Wiley & Sons, Ltd.     

面向过程的交流潮流模型新息图法状态估计

提出了一种处理相量测量单元(PMU)量测值的新方法.基于交流潮流模型下的新息图法状态估计,提出了一种过程的划分方法和面向过程的状态估计分析方法,它能提供一个时间过程内的特征运行状态.首先,根据是否有拓扑结构的变化将一个运行过程进行细分,完成过程的划分之后,可以得到表征过程内系统一般运行情况的期望运行状态,最大负荷和最小负荷时的极端运行状态.期望运行状态通过期望新息网络图来获得.IEEE-5节点系统用来说明本文所提方法的有效性.     

Methods of indirect estimation of motor velocity in VTC-IM systems

Methods of the indirect estimation of motor velocity in VTC-IM systems, including methods based on the calculation of motor differential equations and adaptive methods, are considered.     

数字化交—交变频器触发脉冲电路的研制

介绍了一种用于同步电机交流励磁系统中交—交变频器触发脉冲电路的工作原理及实用结果，并对其线路特点及工作过程作了详细的介绍和说明。     

Rotor position and velocity estimation for a salient-pole permanentmagnet synchronous machine at standstill and high speeds

This paper addresses self-sensing (“sensorless”) control of salient-pole permanent magnet synchronous motors (PMSMs). The major contribution of this work is the introduction of a simple-to-implement estimation technique that operates over a wide speed range, including zero speed. The technique achieves simplicity by decoupling the inherent cross-coupling in PMSMs. The technique utilizes the dependence of inductance on rotor position in interior permanent magnet machines to produce position and velocity estimates both for field orientation and for all motion control of the drives. The technique functions in a manner similar to a resolver and resolver-to-digital converter (RTDC) sensing system, whereby in the proposed technique the motor acts as the electromagnetic resolver and the power converter applies carrier-frequency voltages to the stator which produce high-frequency currents that vary with position. The sensed currents are then processed with a heterodyning technique that produces a signal that is approximately proportional to the difference between the actual rotor position and an estimated rotor position. This position error signal and a torque estimate are then used as inputs to a Luenberger style observer to produce parameter insensitive, zero lag, position and velocity estimates     

交直流混合系统状态估计算法研究与分析

采用最小二乘法对交直流输电系统的状态估计问题做了详细的分析和评价.在四种典型的交直流系统状态估计算法的基础上,增加了一类处理交直流系统之间关系的状态估计方法.针对五种算法对交流、直流系统的处理方法,采用一含有双端直流输电系统的14节点算例和一含有两条直流输电线路的300节点系统算例,进行多样本采样计算,从算法的优化效果,估计误差、迭代次数、对量测系统的适应性和计算速度等方面进行了详细的对比分析,总结了五种算法在不同的交流、直流系统量测配置情况下的计算性能,详细分析了几种算法的优缺点和实用性.针对电力系统状态估计的研究现状和现场需求,提出了直流系统状态变量的选取原则,对每个换流站只需选择两个状态变量即可,一个是直流电压,另一个是换流器控制角或换流变压器分接头.归纳出直流系统量测配置的特殊问题,即直流系统量测方程中必须包括无功量测或者触发角(熄弧角)量测,否则交直流混合系统状态估计发散的可能性比较大.     

交直流混合系统状态估计算法研究与分析

采用最小二乘法对交直流输电系统的状态估计问题做了详细的分析和评价。在四种典型的交直流系统状态估计算法的基础上,增加了一类处理交直流系统之间关系的状态估计方法。针对五种算法对交流、直流系统的处理方法,采用一含有双端直流输电系统的14节点算例和一含有两条直流输电线路的300节点系统算例,进行多样本采样计算,从算法的优化效果、估计误差、迭代次数、对量测系统的适应性和计算速度等方面进行了详细的对比分析,总结了五种算法在不同的交流、直流系统量测配置情况下的计算性能,详细分析了几种算法的优缺点和实用性。针对电力系统状态估计的研究现状和现场需求,提出了直流系统状态变量的选取原则,对每个换流站只需选择两个状态变量即可,一个是直流电压,另一个是换流器控制角或换流变压器分接头。归纳出直流系统量测配置的特殊问题,即直流系统量测方程中必须包括无功量测或者触发角（熄弧角）量测,否则交直流混合系统状态估计发散的可能性比较大。     

基于参数估计的工频交流信号过零时刻检测方法

智能电网调试工程中广泛应用数字化检测设备,其相位准确度可通过工频交流信号过零时刻检测装置转换成时间准确度的检测,而当前大多数工频交流模拟信号过零检测方法用于电网同期检测,其准确度均达不到微秒级要求。本方法通过对输入信号进行连续采样,分别使用峰值检测及Levenberg-Marquardt算法估计正弦模型的相对频率和相位参数,并根据模型及估计的参数计算准确的过零时刻。在MATLAB上实现了该算法及模拟环境,改变信号的采样频率、估计信号长度、谐波分量及信噪比等参数,分别对算法进行测试。仿真结果表明,该算法在采样频率100 ksps,拟合数据长度不小于104时,对谐波含量1%以内,信噪比40 d B以上的工频交流信号过零时刻的估计误差为1μs左右。     

Adaptive relative velocity estimation algorithm for autonomous mobile robots using the measurements on acceleration and relative distance

In this article, an adaptive algorithm is proposed for online velocity estimation of the autonomous mobile robots (AMRs) without positioning data received from a Global Positioning System (GPS) module or other means for odometry. Unlike the popular Kalman and particle filters that use the measurements on vectors of global (or local) position and acceleration of a mobile robot, the proposed adaptive relative velocity estimation (ARVE) algorithm requires the scalar value of measured distance to a beacon agent and also the measurement on acceleration vector, in order to generate an online estimation of the global velocity vector of a mobile robot. Combining the ARVE algorithm with the recently proposed adaptive relative position estimation (ARPE) algorithm provides a solution for online estimation of the translational states of a mobile robot without accessing the GPS data, which makes the package applicable in both indoor and outdoor environments. The stability of the ARVE algorithm is analyzed with LaSalle-Yoshizawa theorem. In addition, two simulation studies are provided to show the application of the proposed estimation package (ARVE+ARPE) for aerial AMRs in two cases corresponding to the stationary and moving beacon agents. In the simulation results, it is shown that the estimation package can be used in conjunction with the recently proposed adaptive model-free control (AMFC) algorithm to achieve desired tracking objective in autonomous movement of a quadrotor, without requiring the information on the internal dynamics of the robot.     

High-resolution infrared technology for soft-tissue injurydetection

Until recently, the application of infrared imaging to medicine has been limited by low-precision temperature measurement, low spatial resolution, a narrow field of view and the lack of image-processing ability. These shortcomings have been overcome and now modern cameras have the ability to accumulate many sequential images, thus permitting the study of dynamic phenomena. In this article we present several examples of soft-tissue injury and breast cancer detection where the use of appropriate image-processing algorithms substantially enhanced the diagnostic acumen of infrared imaging