交流分析

After specific analysis of this mode, the relationship between DC and AC load equivalent resistance and the circuit parameters selection strategy are concluded.

详细分析了断态下电路工作状况，得出直流等效电阻与交流负载等效电阻的关系，并给出了选取电路参数的经典方法。

The software and hardware realizing scheme of high performance, AC servo system based on the digital-analog mixed type of 16 bits high performance, single piece micro computer 80C196 is presented in this paper It expounds the theory and method of system design for industrial applications, and it also gives out the situation of system industrial applications Based on the analysis of the influential characteristics of servo system the method of improving the system precision, estimative model of loading torque and instantaneous velocity, compensative predictive control under low speed motion are dicussed in this paper.

论述了面向工业对象的系统设计原理与方法。并给出了本文系统工业应用的情况。在分析影响交流伺服系统性能的基础上，提出了改善系统精度的方法，给出了负载力矩和瞬时转速的估计模型，研究了低速运行时的补偿预测控制，提高了伺服系统低速稳定运行的范围。

To realize the management of the flexible subject categories and the database system, an cross-platform information management software has been developed, which also explored an intelligent functional module to fetch and analyze web information automatically.

本文在Linux系统下，编制了专题信息系统平台和管理工具：采用Web数据库技术，构建了后台的数据库系统；建立了前端网站系统(http：//159.226.63.156/metalnanol/)，包括专题信息库和各种检索功能与用户交流功能；建立了跨平台的信息管理工具，实现了灵活的专题信息分类管理、网络信息的自动获取与分析功能以及数据库各项管理功能。

First, the paper reviews the development and research of AC transfer speed system, introduces the different control strategy of transfer speed system for asynchronous motor, and discusses the basic principle of vector control system for asynchronous motor in detail,including the mathematics model and coordinate transformation of asynchronous motor, the fundamental equation of vector control, the estimation method of rotor flux, the system structure of vector control etc. Then, the paper lays stress on the fundamental principle, control algorithm and realization method in TMS320LF2407 of space vector pulse width modulation technology.

本文首先简述了交流调速系统的发展和研究重点，介绍了异步电机调速系统的不同控制策略，详细论述了异步电机矢量控制系统的基本原理：异步电机的数学模型和坐标变换、矢量控制的基本方程式、转子磁链的观测方法、矢量控制的系统结构等，并重点分析了空间矢量脉宽调制技术的基本原理、控制算法以及在TMS320LF2407中的实现方法。

The article makes a comparison among different types of bus, bus transmission signal and several familiar topologies of front-end converters and load-end converters. Finally, the half bridge converter with full-wave rectifier based on the high-frequency parallel-type AC bus bar is chosen as circuit structure and optimized. The working mode under different condition of the circuit is analyzed and a mathematical model is set up under continuous current mode. Simulation result is used as comparison.

通过对比不同类型的母线、母线传输信号以及各种常见的前端变换器拓扑和负载变换器拓扑，确定了基于并联型高频交流母线的半桥变换器加全波整流作为电路拓扑，并优化了电路的结构，分析了基于不同工作状态下的电路结构并建立电流连续模式的数学模型，并与软件仿真结果进行对比。

Due to the high reliability, high stability and low EMI criterions in auxiliary power supply systems, the half-bridge LLC resonant converter is selected for the front-end converter, the AC bus architecture and full-wave rectifier are as well utilized. The turns-ratio between the AC bus and load converter is 1:1. The effect of beads which are used in the load converters to the resonant circuit is analyzed.

根据辅助电源高可靠性、高稳定性、低电磁干扰、良好的高频隔离的要求，通过对不同拓扑类型的分析比较，选择半桥LLC谐振变换器作为前级变换器，交流母线和零式全波整流结构作为后级变换器，在母线和后级变换器的连接上采用1∶1的隔离变压器连接。

Communication just has progress, I announce China to guess the fundamental condition of guest net now, let everybody be analysed, is pattern of the profit inside the plan with original website feasible?

有交流才有进步，现在我公布一下中国猜客网的基本情况，让大家分析一下，网站原来的计划内盈利模式是否可行？

Nowadays, with the rapid development of the network, the Internet has become an important way for people to obtain, release and send messages. It also plays a key role in every field, such as in politics, economy, study and daily life. As known to all, forum is one of the well-known network services. It provides a "public" space for all the users to release and get messages, and allows users to discuss their interested topics together. The main functions of the forum system go as follows, user communication, user management, information inquiry and classification. Therefore, this paper plans to introduce the design and implementation of the forum for our school by using ASP+SQL Server2000. The ASP language has many advantages, for example, high security, relieving the load of the user's IE browser and improving the speed of communication. And the SQL Server2000 is a real multi-user, multi-thread database server.

在网络飞速发展的今天，Internet成为人们快速获取发布和传递信息的重要渠道，它在政治经济学习生活等各个方面发挥着重要的作用众所周知，论坛是当今网络中的知名服务之一它开辟了一块"公共"的空间供所有用户发表和读取信息，允许用户对自身感兴趣的话题展开讨论，从而起到集思广益的作用论坛系统的主要功能是：用户交流用户管理信息分类及查找等所以，经过分析，使用ASP+SQL2000的语言来开发本校园论坛ASP语言具有开发软件的特性，其优点是安全性能高，能减轻客户端浏览器的负担，提高交互速度而SQL Server2000是一个真正的多用户多线程SQL2000数据库服务器

Summarizing the influence and historical significance of the exchange in food culture between China and Foreign countries.

最后对饮食文化的传播情况进行分析，总结中外饮食文化交流的影响及历史意义。

Based on matrix analysis of motor and general theory of alternating current machines,3-phases induction synchronous motor is substituted for symmetrical 2-phases motor with even gas,then the equation for instantaneous torque of induction synchronous motor step motion is obtained.

文中采用了电机的矩阵分析方法，根据交流电机统一理论，将三相感应式同步电机用等效的具有均匀气隙的两相电机来代替，得出了感应式同步电机步进运动的瞬时转矩表达式。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。