Speed estimation for very low speed systems

This paper discusses the problem of speed estimation in very low speed servo systems. Speed estimation can be easily done by such conventional tools as tachometers, observers, numerical differentiation, and so on. However, speed estimation for very low speed systems still includes some engineering problems regarding precision. This paper proposes a simple way to derive a speed estimate by using the output difference over a long period of time and the sequence of inputs during the same period. We have also verified this method through an experiment on a hydraulic servo system. © 1999 Scripta Technica, Electr Eng Jpn, 126(4): 63–69, 1999     

Two novel low power and very high speed pulse triggered flip‐flops

Two novel low power and high‐speed pulse triggered flip‐flops were presented in this paper. Short circuit current was controlled, and race condition between pull‐up and pull‐down branches was removed, which caused reduction of power consumption. On the other hand, the number of stack transistors in the discharging path was reduced which decreased delay of the flip‐flops. The first proposed flip‐flop reduced the number of transistors and the second proposed flip‐flop used conditional data mapping and removed floating node of the first flip‐flop. Post‐layout simulation result showed that the first proposed flip‐flop reduced 21% of power delay product and the second proposed flip‐flop reduced 16% of power delay product in comparison with other flip‐flops in 50% of data switching activities. Copyright © 2014 John Wiley & Sons, Ltd.     

一种高频动态磁滞回线的PSpice电路模型研究

根据Jiles-Atherton铁磁磁滞理论和Hammerstein结构宏模型提出了一种高频动态磁滞回线的PSpice电路模型.将二阶低通滤波器插入Jiles-Atherton数学模型的等效PSpice电路中,追踪磁滞回线随频率的变化,近似地模拟高频动态磁滞回线.经实验论证,用该PSpice电路模型仿真所得磁滞回线与实...     

基于SOC的磁性材料磁滞回线测量仪

对磁滞回线的测量原理做了简单的介绍,提出了基于SOC(片上系统)实现磁滞回线测量的新方法及其具体实现方案。实验结果表明该测量仪与传统的测量仪相比,大大地改善了系统的性能。     

一种实用的微机型转速信号装置设计方案

从设计角度提出了一种实用的微机型转速信号装置设计方案     

一种实用的微机型转速信号装置设计方案

从设计角度提出了一种实用的微机型转速信号装置设计方案.     

Development of a new off-line test procedure for low voltage rotating machines fed by adjustable speed drives (ASD)

Using adjustable speed drives employing fast switching components to supply low voltage asynchronous motors may be detrimental to their reliability in some cases. The premature failures of the insulating materials are often attributed to the existence of partial discharges (PD) in the windings. Nevertheless, a clear evidence of any PD existence in such systems is far from being established. Also, their location may not be in the turn-to-ground or phase-to-phase insulation but in the turn-to-turn insulation due to the voltage waveforms, and as such, the classical AC test is no longer applicable. The aim of this paper is to present an off-line test procedure capable of overcoming this problem. The results of the test carried out on the representative population of different motors are presented.     

基于神经网络的双馈风电机组转速PID控制仿真

为了提高双馈风电机组的转速控制性能,采用了基于BP神经网络的PID控制方案和基于RBF神经网络辨识的PID控制方案,在推导出双馈风电机组暂态电势恒定情况下随风速变化的二阶转速调节模型基础上,分别编制仿真程序,对风电机组转速控制进行了跟踪仿真分析.针对上述两种方案的缺陷,提出了基于RBF网络辨识的单神经元网络PID控制和基于RBF网络辨识的BP神经网络PID控制两种改进控制方案,达到了优化风电机组转速控制性能的目的.     

基于最小二乘支持向量机的风力发电机组风速软测量

风力发电机组的有效风速无法直接测得.依据辅助变量与主导变量之间的数学关系,建立风力机有效风速最小二乘支持向量机软测量模型:通过对辅助变量的测量和计算,可得到风力机有效风速的估计值.实现风力发电机组的有效风速软测量.计算机仿真结果表明.最小二乘支持向量机软测量模型具有泛化能力强和计算效率高的优点:能够满足风速的大范围变化和风力发电机组控制实时性的要求.     

Design of an automatic gain control loop for high speed communication

This paper presents the design of an automatic gain control (AGC) loop for high-speed communication systems, which can be used in wired, wireless, or optical receiver. The design is performed in 130 nm SiGe BiCMOS technology. A Gilbert cell-based variable gain amplifier is designed, which shows approximately linear gain control with respect to the gain control voltage. The variable gain amplifier is followed by two fixed gain cascode amplifiers. Then, a full wave rectifier-based peak detector is designed and analyzed. To reduce the peak detector error, a compensation technique is applied. Finally, an operational amplifier is designed, which is used as voltage adder and comparator. The designed AGC loop is simulated with sinusoidal and pseudorandom binary sequence (prbs) input signal with high frequency signal of 1 to 30 GHz. The simulation results of the AGC loop show that a gain tuning range of 47 dB (−7 to 40 dB) is obtained in this design. It is also seen that the reference signal can be varied from 50 to 200 mV. This AGC works in the input voltage signal range between 3 mV peak and 230 mV peak, and the power dissipation of is 79 mW.     

转速闭环变频调速系统的建模与调节器参数设计

对通用变频器和异步电动机组成的转速闭环变频调速系统 ,提出一种系统建模与调节器参数设计的方法 ,并给出了设计实例和实验结果。     

半导体换流低速磁阻电动机的速度控制

介绍了半导体换流低速磁阻电动机的结构及换流原理,提出了该种电机的开环调速控制方法,并给出了样机实验结果及结论。     

Sensorless vector control of induction motors at very low speed using a nonlinear inverter model and parameter identification

The performance of vector-controlled induction motor drives without a speed sensor is generally poor at very low speed. The reasons are offset and drift components in the acquired feedback signals, voltage distortions caused by the nonlinear behavior of the switching converter, and the increased sensitivity against model parameter mismatch. New modeling and identification techniques are proposed to overcome these problems. A pure integrator is employed for stator flux estimation which permits high-estimation bandwidth. Compensation of the drift components is done by offset identification. The nonlinear voltage distortions are corrected by a self-adjusting inverter model. A further improvement is a novel method for online adaptation of the stator resistance. Experiments demonstrate smooth steady-state operation and high dynamic performance at extremely low speed.     

双闭环直流调速系统的工程设计与典型系统

介绍了双闭环直流调速系统的工程设计方法与典型系统的关系，并设计举例。     

A wide range delay locked loop for low power and low jitter applications

In this paper, a design of analog delay locked loop is introduced in which new techniques are applied to eventually increase operating frequency range and reduce jitter considerably. In this design, all blocks of a delay locked loop including a voltage controlled delay line, charge pump, and loop filter are accurately designed. A new delay cell is proposed with wide delay range, in which increase of delay range results in using fewer cells, and consequently the power consumption will decrease. Current mirror techniques and feedback in the proposed charge pump also cause higher current matching and better jitter performance. This delay locked loop, which is designed with TSMC 0.18‐μm CMOS technology, has a wide frequency range from 217 to 800 MHz. It consumes maximum 3.4‐mW and minimum 2.6‐mW power dissipation in source voltage of 1.8 V, which is suitable for low power applications. It also has an appropriate lock time that is at least equal to 3 clock cycles at 217 MHz and at most 25 clock cycles at 800 MHz. Jitter performance in this delay locked loop is improved significantly: RMS jitter is 0.65 ps at 800 MHz and 2.54 ps at 217 MHz. Moreover, its maximum peak‐to‐peak jitter is equal to 5.17 ps, and its minimum peak‐to‐peak jitter is equal to 1.39 ps at 217 and 800 MHz, respectively.     

基于COT-SSD的变转速滚动轴承微弱故障诊断

针对背景噪声干扰及转速波动工况下滚动轴承微弱故障识别困难这一问题,提出一种结合计算阶次追踪(COT)和奇异谱分解(SSD)的新型诊断方法。利用COT算法对采集的原始时域信号进行等角度重采样,继而利用SSD算法对重采样角域信号进行处理,通过自适应构建的轨迹矩阵的奇异值分解重组,将角域信号从高频至低频分解为若干个奇异谱分量,利用融合峭度指标筛选最佳奇异谱分量,选定最佳分量后对其进行进一步的包络解调运算,最终通过分析包络阶次谱中幅值突出的成分来准确判定滚动轴承运行状态。滚动轴承内外圈故障实测信号分析结果表明,所提方法能够有效提取出变速工况下滚动轴承的微弱故障特征信息。     

光伏并网逆变器空间电压矢量双滞环电流控制新策略

提出了一种适用于三相光伏并网逆变器的双滞环电流控制改进算法。根据逆变器线电流与功率器件开关状态的关系,对线电流实行解耦控制,利用双滞环来判断参考空间电压矢量的位置,结合锁相环电路对输出的开关状态进行检测,构成频率闭环控制。最后利用Matlab/Simulink工具箱和3 kW实验平台对双滞环控制算法进行验证。结果表明,该算法保留了传统滞环控制电流跟踪响应快、有限流能力的优点,同时也有效地克服了开关频率变化不固定、开关损耗较大等问题。     

光伏并网逆变器空间电压矢量双滞环电流控制新策略

提出了一种适用于三相光伏并网逆变器的双滞环电流控制改进算法.根据逆变器线电流与功率器件开关状态的关系,对线电流实行解耦控制,利用双滞环来判断参考空间电压矢量的位置,结合锁相环电路对输出的开关状态进行检测,构成频率闭环控制.最后利用Matlab/Simulink工具箱和3 kW实验平台对双滞环控制算法进行验证.结果表明,该算法保留了传统滞环控制电流跟踪响应快、有限流能力的优点,同时也有效地克服了开关频率变化不固定、开关损耗较大等问题.     

CY5液压机构控制回路技术改进

针对生产实践中CY5液压机构“完全零压状态”下控制回路失效的状况,提出了技术改进方案,并对技改方案的优缺点进行了比较。