外文翻译-----恒压供水的控制与节能的探索

毕业设计(论文)翻译资料

课题名称：S7-200 PLC控制的变频 调速恒压供水系统设计

毕业设计(论文)起止时间：

2007 年 3 月 1 日～ 6 月 10 日(共 17 周)

指导教师：

报告日期：

The control and Energy-saving of automatic Water Supply System

Abstract: Based one simple analysis of the methods for water supply used domestically and abroad, this paper discusses the principe and system’s structure of automatic water supply system by using frequency conversion speed regulation in detail. Then the system’s advantages are discussed and some key problems that should be pay attention to designing are presented.

Keyword: Frequency conversion speed regulation; water supply with stable pressure: PID regulator.

1、Foreword

At present , supply water in residential area and life of the skyscraper of our country generally adopt the way common frequently . It has heavy energy consumption, high noise ,and there has a great deal of questions in the source of water, such as secondary pollution etc. And it is a kind of comparatively ideal mode to adjust the watersupply device controlled rapidly with frequency conversion .Entering the middle and later periods of the 1990s, as the speed technology of frequency conversion achieves more development becomes perfect, the way of the full-automatic constant pressure that based on this technology supplied water has already been widely used in the developed country , and is becoming riper.

In recent years, author has made some real work on rapidly to the transformation in frequency conversion supply water design and construction of control system , have accumulated some experience, and has formed the view on some questions. The reason why the energy-conserving principle frequency conversion of the water pump system of speed adjustment becomes popularized , is mainly because that it has a better energy- conserving result. To pump system of frequency conversion, the water pump after adjusting the speed has functional relation of the following:

Q1/Q2 =n1/n2 (1) H1/H2 = (n1/n2)2 (2) of the type. Q1, Q2 represents the flow before and after the speed for the water pump respectively; N1, n2 represents the rotational speed before and after the speed for the water pump respectively; H1, H2 represents the lift before and after the speed for the water pump respectively .

According the above:H1/H2=(f1/f2)2 Namely real lift of a water pump is power the square of frequency in direct radio. Therefore changing the power supply frequency of the electrical machinery of water pump through the frequency converter , can control supporting water pressure strength of the water pump . 2 constant pressure as Fig. 1 shows supply water of the automatically controlled frequency conversion water -supply system principle block diagram. P1 is the give pressure value, p2 for the actual pressure value had examined from the pipeline of the pressure sensor, PID regulator passes the error operation of the two value, and through controlling the frequency output of the frequency converter, thus make the pressure of the pipeline remain throughout on establishing value p1.

This system can measure users' instantaneous water pressure adjust automatically , regulate the amount of quantity of supplying water and operation conditions of the electrical machinery in view of the above. Can according to give water pressure strength to set for and control pressure value which needed , make the equipment in the constant pressure state all the time, can know from load characteristic of electrical

machinery axle power and its the third power of in direct radio rotational speed of electrical machinery mixed, that is p1/p2=(n1/n2)3. For example, as the frequency converter output frequency for 35Hz (establish as 50Hz at most), that is to say that the actual rotational speed is 70% o'clock of specified rotational speed, the power consumption of the governor is 0.73 =0.343, account for specified 35%. That is to say , the water pump is always in constant pressure and turn the working state of matching the way into the flow , is it is it keep to exceed to dispel and backset current have work loss. Constant speed transfer with frequency conversion speed axle power change curve as Fig. 2 shows , relatively can know, it is the most obvious that frequency conversion adjusts the energy-conserving result of speed way.

2、Case analyse

Constant pressure is it regulate flow of water to the purpose to up to constant pressure through suiting well rapidly in frequency conversion to supply water, the goal that it controls finally is the water pressure. Controlling the target has non-linear , lagging characteristics. The quality of PID regulator performance , has determined the quality of the water -supply system to a great extent When the system is during the course of starting and stopping, or the pressure establishing value changes by a large margin , because there is a very great deviation within short time, no matter the controll algorithm of PID regulator adopts the increment type or the position type, its total mark one will fetch the cistern , water pump group (1M , 2M ) and complement the fittings to form relevantly. The core of this system is that frequency conversion adjusts the speed switch board, it monitors the pressure of the pipe network in real time through the pressure sensor , and change into the electric signal and offer the frequency converter to to make operation, through the controlling commonly of frequency converter , programmable controller PLC and relay array, adjust the system of supplying water rapidly after forming perfect full-automatic frequency conversion. Frequency converter is various in kind, for instance the types , such as Mitsubishi , Fuji , three Kenya and ABB ,etc.. Generally often select the pumps , special-purpose series of air blower for use. Whether take …… 此处隐藏：15051字，全部文档内容请下载后查看。喜欢就下载吧 ……