【正文】 to the large size, then miniputers high cost and reliability of this idea is not reality. Now, with microprocessorbased protection function of similar size, speed, workmanaging machine greatly exceed the storage capacity of miniputer, therefore, make use of the relay protection sets polymerizingkettle time is ripe, this is the development direction of the microputer relay protection. Tianjin University has developed with microprocessorbased protection device with an identical structure reform polymerizingkettle of relay protection device. This device has several advantages: (1) 486PC machine can meet all the functions of the current and future demands of microputer protection function. (2) dimension and structure and the current protection device, exquisite workmanship, shockproof, prevent overheating, preventing electromagic interference ability is strong, can run in very bad working environment, cost can be accepted. (3) using STD bus or PC bus, hardware modular, for different protection can be arbitrarily choose different modules, flexible configuration, easy extension. The microputer relay protection device, puterized is irreversible trend. But how to better satisfy power system, how to further improve the reliability of the relay protection, and how to obtain more economic benefit and social benefit, still must specifically indepth research. 820 works The puter work information and data munication tool has bee the mainstay of the information age, make human production technology and social life of the fundamental changes have taken place. It is deeply affect all industries, as well as various industry provides powerful means of munication. So far, in addition to the differential protection disoperation and protection of the relay protection device, all can only protect the 桂林電子科技大學(xué)畢業(yè)設(shè)計(jì)英文資料 翻譯 6 electricity installation reaction. Protection function is limited, reduce accidents resection fault ponents. This is mainly due to the lack of data munications. Strong Foreign had put forward the concept of protection system, which was mainly refers to the safety automatic device. Because of the relay protection function not only fault ponents and limit resection impact accident (this is to ensure priority), the safe and stable operation of the whole system. This requires each protection unit can be altogether I、 Conclusion Discussed above in the switching regulator of a variety of conservation, and introduces a number of specific ways to achieve. Of a given switching power supply is concerned, but also protection from the whole to consider the following points: 1) The switching regulator used in the switching transistor in the DC security restrictions on the work of regional work. The transistor switches selected by the manual available transistors get DC safe working area. According to the maximum collector current to determine the input value of overcurrent protection. However, the instantaneous maximum value should be converted to the average current. At rated output current and output voltage conditions, the switch of the dynamic load line does not exceed a safe working area DC maximum input voltage, input overvoltage protection is the voltage value. 2) The switching regulator output limit given by the technical indicators within. Work within the required temperature range, the switching regulator39。 二、極性保護(hù) 直流開關(guān)穩(wěn)壓器的輸入一般都是未穩(wěn) 壓直流電源。 三、程序保護(hù) 開關(guān)穩(wěn)壓電源的電路比較復(fù)雜 ,基本上可以分為小功率的控制部分和大功率的開關(guān)部分。為了不使該限流電阻消耗過多的功率，以致影響開關(guān)穩(wěn)壓器的正常工作 ,而在開機(jī)暫態(tài)過程結(jié)束后，用一個(gè)繼電器自動(dòng)短接它 ,使直流電源直接對(duì)開關(guān)穩(wěn)壓器供電。為此 ,要求在開機(jī)這一段時(shí)間內(nèi) ,開關(guān)調(diào)制電路輸出給開關(guān)三極管基極的脈寬調(diào)制驅(qū)動(dòng)信號(hào)，能保證開關(guān)三極管由截止逐漸趨于正常的開關(guān)狀態(tài)，故而要加設(shè)開機(jī)保護(hù)以配合軟啟動(dòng)。但是 ,根據(jù) 開關(guān)穩(wěn)壓器的特點(diǎn) ,這種保護(hù)電路的輸出不能直接控制開關(guān)三極管 ,而必須使過電流保護(hù)的輸出轉(zhuǎn)換為脈沖指令 ,去控制調(diào)制器以保護(hù)開關(guān)三極管。輸入 電源的極性保護(hù)電路可以跟輸入過電壓保護(hù)結(jié)合在一起 ,構(gòu)成極性 保護(hù)鑒別與過電壓保護(hù)電路。另外，穩(wěn)壓管存在著參數(shù)的離散性，型號(hào)相同但過電壓起動(dòng)值卻各不相同，給調(diào)試帶來了困難。特別在升壓型 或反相升壓型的直流開關(guān)穩(wěn)壓器中欠電壓的保護(hù)是跟過電流保護(hù)緊密相關(guān)的，因而更加重要。亦可將溫度繼電器置于開關(guān)三極管的附近，一般大功率管允許的最高管殼溫度是 75℃，調(diào)節(jié)溫度整定值為 60℃。它亦可以用作功率晶體管的過熱保護(hù)，晶體開關(guān)管的基極電流被 n 控制柵型熱晶閘管 TT201旁路，開關(guān)管截止，切斷集電極電流 ,防止過熱。采用 32 位微機(jī)芯片并非只著眼于精度，因?yàn)榫仁?A/D 轉(zhuǎn)換器分辨率的限制，超過 16 位時(shí)在轉(zhuǎn)換速度和成本方面都是難以接受的；更重要的是 32 位微機(jī)芯片具有很高的集成度，很高的工作頻率和計(jì)算速度，很大的尋址空間，豐富的指令系統(tǒng)和較多的輸入輸出口。這種裝置的優(yōu)點(diǎn)有： (1)具有 486PC 機(jī)的全部功能，能滿足對(duì)當(dāng)前和未來微機(jī)保護(hù)的各種功能要求。繼電保護(hù)的作用也只限于切除故障元件，縮小事故影響范圍。但是 ,這個(gè)瞬時(shí)最大值應(yīng)轉(zhuǎn)換為電流的平均值。聲警適用于整機(jī)比較復(fù)雜、電源部分又裝在不顯眼的地方 ,它可以給工作人員以有效的故障告警 。 所以必須全面系統(tǒng)地考慮開關(guān)電源各種保護(hù)措施，確保開關(guān)電源的正常工作和高效率與高可靠性。通過邏輯控制 電路使相應(yīng)的開關(guān)三極管截止的方案顯得既靈敏方便又經(jīng)濟(jì)。過電流保護(hù)則可根據(jù)最大輸出電流來確定。這就要求每個(gè)保護(hù)單元都能共 九、結(jié)語 以上分別討論了在開關(guān)穩(wěn)壓器中的各種保護(hù)方式 ,并介紹了一些具體實(shí)現(xiàn)的方法。但對(duì)如何更好地滿足電力系統(tǒng)要求，如何進(jìn)一步提高繼電保護(hù)的可靠性，如何取得更大的經(jīng)濟(jì)效益和社會(huì)效益，尚須進(jìn)行具體深入的研究。在計(jì)算機(jī)保護(hù)發(fā)展初期，曾設(shè)想過用一臺(tái)小型計(jì)算機(jī)作成繼電保護(hù)裝置。華中理工大學(xué)研制的微機(jī)保護(hù)也是從 8 位 CPU，發(fā)展到以工控機(jī)核心部分為基礎(chǔ)的 32 位微機(jī)保護(hù)。根據(jù) p型控制柵熱晶閘管 (TT102)的特性，由 RT 值確定該器件的導(dǎo)通溫度， RT 越大，導(dǎo)通溫度越低。 七、過熱保護(hù) 開關(guān)穩(wěn)壓器的高集成化和輕量小體積，使其單位體積內(nèi)的功率密度大大提高，電源裝置內(nèi)部的元器件對(duì)其工作環(huán)境溫度的要求也相應(yīng)提高。簡(jiǎn)單的欠電壓保護(hù)如圖 6 所示。常用的方法是晶閘管短路保護(hù)。 五、過電壓保護(hù) 開關(guān)穩(wěn)壓器的過電壓保護(hù)包括輸入過電壓保護(hù)和輸出過電壓保護(hù)。由于晶體管的熱容量小 ,普通保險(xiǎn)絲一般不能起到保護(hù)作用 ,常用的是快速熔斷保險(xiǎn)絲。這可用開機(jī)程序控制電路來保證。在開機(jī)瞬間 ,濾波電容器會(huì)流過很大的浪涌電流 ,這個(gè)浪涌電流可以為正常輸入電流的數(shù)倍。最簡(jiǎn)單的極性保護(hù)電路如圖 1 所示。晶體管和集成器件耐受電、熱沖擊的能力較差。 switching power supply will be damaged. Polarity protection purposes, is to make the switching regulator only when the correct polarity is not connected to DC power supply regulator to work at. Connecting a single device can achieve power polarity protection. Since the diode D to flow through switching regulator input total current, this circuit applied in a lowpower switching regulator more suitable. Power in the larger occasion, while the polarity protection circuit as a procedure to protect a link, save the power required for polarity protection diodes, power consumption will be reduced.