基于TMS320F2812的异步电机变频调速系统设计与应用

针对空压机中大功率异步电机费电问题,为实现节能需对电机变频凋速。文中介绍了用于电机控制的芯片的最新发展状况,讨论了基于TMS320F2812的异步电机变频调速系统在空压机控制中的硬件设计,介绍了各部分硬件电路的实现。通过电压空间矢量方法实现了对异步电机的变频控制。实践表明,该系统有较高的灵活性和稳定性,适合于复杂的无传感器矢量控制和直接转矩控制算法的实现。     

变频IC用于矢量控制系统

本文阐述了基于调频调压配合控制原理的矢量控制系统的工作原理。该系统很好地解决了一般变频调速系统难于实现电机在各种运转情况下磁通恒定的问题。采用变频IC实现SPWM控制信号的产生,使整个系统的硬件电路得以简化。采用工控PC机控制,使矢量控制思想易于实现,并且工作可靠。该系统具有良好的性能。     

基于神经元的变频调速系统自适应PID控制

针对矢量控制变频调速系统,对神经元控制和常规PID控制进行分析和研究,提出了一种基于神经元的变频调速系统自适应PID控制,具有一定的实用价值.     

MATLAB在SVPWM变频调速系统中的应用

运用MATLAB／SIMULINK对SVPWM变频调速系统建立仿真模型，这些模型包括：交流异步电机、矢量变换、空间矢量调制波输出。仿真和实验结果表明：本文研究的空间矢量变频调速系统的硬件和软件配置方案合理，基本达到了预期的目标，在仿真和实验负载条件下能够进行变频调速；电压输出波形符合理论分析结论，电流输出为三相对称正弦波，转速符合最少拍控制要求，基本无振荡。     

基于DSP的异步电机SVPWM调速系统研究与实现

以TMS320F2812型DSP为控制核心,搭建了异步电机电压空间矢量脉宽调制（SVPWM）控制系统。通过对异步电机控制原理的分析,本文中用Matlab／Simulink平台对异步电机矢量控制系统进行仿真,完成了三相异步电机矢量控制系统硬件和软件设计。最后详细介绍了SVPWM控制系统的调试过程,并完成了异步电机调速系统的研究。     

TMS320F240在同步电机变频调速中的应用

介绍了基于TMS320F240控制芯片的同步电机变频调速系统。该系统采用矢量控制思想．选用TMS320F240控制芯片及其它外围电路构成同步电机变频调速的硬件系统，变频调速系统的电流、电压、采样电路及检测保护等电路和控制方法，从而实现同步电机电压和频率的可调。     

异步电机矢量控制系统DSP软件设计

本文运用矢量控制并结合空间电压矢量调制技术,开发了以TI公司的电机控制专用DSP芯片TMS320LF2407为核心的、低成本、调速性能好的变频调速系统,设计了控制系统的软件部分,给出了矢量控制系统软件流程和各子模块的具体实现.     

交流异步电机调速系统

随着科学技术的飞速发展,我国各行业电机变频调技术应用越来越广,本文就交流异步电机变频调速原理和变频调速技术分类做了分析,并通过分析变频调速系统对异步电机的影响来阐述研究交流异步电机变频调速系统的重要性。     

基于FPGA的全数字化交流变频调速系统

提出一种基于FPGA的全数字化交流变频调速系统。该系统以80C196KC和F1)GLA为控制核心，并运用矢量控制和空间矢量PWM算法来实现变频调速。     

电力拖动系统交流异步电机变频调速自动控制

为解决传统电力拖动系统交流异步电机变频调速控制波特率低的问题,研究电力拖动系统交流异步电机变频调速自动控制方法。采集电力拖动系统交流异步电机变频调速控制信号,同步转换控制信号与数据,建立变频调速控制数据通信协议,计算变频调速控制频率,实现电力拖动系统交流异步电机变频调速自动控制。设计实例分析,结果表明,实验组控制波特率明显高于对照组,能够提高电力拖动系统交流异步电机变频调速自动控制性能。     

Effective solution of certain problems of theory of schedulings of nets

Cybernetics and Systems Analysis -     

变电站一次设备喷涂PRTV用量的分析

对国网宁夏电力检修公司宁安运维站近2年来一次设备喷涂PRTV用量的统计数据进行分析整理,得出各类一次设备按照标准要求喷涂PRTV时的用量估算值,并针对现存作业中存在的问题,提出相应解决方案。     

Complexity of families of learning algorithms and estimation of the nonrandomness of extraction of empirical regularities

The paper presents a general approach to the evaluation of the complexity of classes of algorithms, so-called pVCD-method. To develop this method, all the examined families of models of empiric generalization were restricted to classes implementable on computers and, wider, by examining their partially recursive representations. Within the framework of the algorithmic approach, the concept of Kolmogorov’ complexity of algorithms for the recognition of properties or the extraction of regularities is proposed. The method proposed to evaluate the nonrandomness of the extraction of empirical regularities is based on this concept.     

Analysis of microdensitometric data in terms of probability of cleavage of DNA

Computer-aided analysis of autoradiographic films of DNA fragments is presented. The Powell least-squares procedure is used for optimization of parameters for components of complex densitometric curves. Since each densitometric spectrum may be divided for several non-overlapped blocks of bands, there is no upper limit on the number of parameters which must be optimized. Eight shapes for the component bands are utilized: symmetric and asymmetric Gauss and Cauchy functions, direct, symmetric and asymmetric product of Gauss function and inverse of Cauchy function, and log-normal function. The probability of DNA cleavage is calculated with correction for multiple cuts. The methods presented was applied to detailed analysis of densitometric spectra of a 21-bp DNA restriction fragment and allowed for direct correlation between structural microheterogeneity of DNA and the resulting cutting pattern. This method should facilitate the analysis of densitometric data from antibiotic-induced cleavage of DNA and footprinting experiments.     

联合收割机脱粒滚筒恒速智能控制器设计

研究了轴流式联合收割机的控制问题,给出了联合收割机脱粒滚筒的数学模型,介绍了基于模式识别的智能控制原理,建立了联合收割机脱粒滚筒恒速控制模型,设计了基于模式识别的智能恒速控制器.应用Matlab/Simulink进行了控制器仿真,其结果表明,将基于模式识别的智能控制应用于联合收割机脱粒滚筒的恒速控制,其过渡过程平稳、响应速度快、无超调、无振荡并且无稳态误差.     

An estimate of numbers of terms of semicycles of delay difference equations

In this paper, we study the semicycles of oscillatory solutions of the delay difference equation y_n+1 − y_n + p_ny_n-k = 0, where p_n is a sequence of nonnegative real numbers and k is a positive integer. Upper bound of numbers of terms of semicycles are determined in the case when

Our results improve and complement known results in literature.     

Complexity of approximation of 3-edge-coloring of graphs

The problem to find a 4-edge-coloring of a 3-regular graph is solvable in polynomial time but an analogous problem for 3-edge-coloring is NP-hard. To make the gap more precise, we study complexity of approximation algorithms for invariants measuring how far is a 3-regular graph from having a 3-edge-coloring. We show that it is an NP-hard problem to approximate such invariants with an error O(n1−ε), where n denotes the order of the graph and 0<ε<1 is a constant.     

Modifications of the method of variation of parameters

In spite of being a classical method for solving differential equations, the method of variation of parameters continues having a great interest in theoretical and practical applications, as in astrodynamics. In this paper we analyse this method providing some modifications and generalised theoretical results. Finally, we present an application to the determination of the ephemeris of an artificial satellite, showing the benefits of the method of variation of parameters for this kind of problems.