【正文】 電流與負(fù)載的工作情況有關(guān)，從這個(gè)意義上講，其電流將不是唯一可控的，同時(shí)由于直流側(cè)電流不能突變，負(fù)載必須為電流提供通路，同一時(shí)刻必須有兩相導(dǎo)通，所以PWM式電流源型逆變電路采用兩相導(dǎo)通的方式。同時(shí)，并聯(lián)在中間直流回路上的高阻值電阻，還起到固定放電電阻的作用，用于牽引變流器非正常關(guān)閉后直流支撐電容和二次諧振電容的固定放電。、諧振吸收回路諧振吸收回路是一個(gè)諧振電路，由諧振電容器和置于主變壓器中的諧振電抗器組成，用來(lái)過(guò)濾中間直流回路中兩倍于輸入電壓頻率的能量流產(chǎn)生的紋波。如果在正半波時(shí)，S2或S3兩個(gè)IGBT開(kāi)關(guān)中的一個(gè)處于開(kāi)通狀態(tài)，變壓器次邊繞組處于短路狀態(tài)，電流開(kāi)始上升。 如果圖 2中的②和③重疊后， 在示波器上就會(huì)出現(xiàn)圖 中的④波形圖。在整流電路輸出電壓、功率保證的情況下，主要是對(duì)紋波電壓的要求。216。 PWM 整流器的理想模型來(lái)說(shuō)明 PWM 變流電路的基本功能： PWM整流器，AC/DC 變流器為 PWM 整流電路的主電路，輸入部分由電網(wǎng)電動(dòng)勢(shì)u 和交流側(cè)電感 L 組成，輸出部分則是由負(fù)載電阻和負(fù)載電動(dòng)勢(shì)功組成(電動(dòng)勢(shì)是由負(fù)載電感產(chǎn)生)。IGBT的開(kāi)通與斷開(kāi)與輸入電抗器共同作用產(chǎn)生了與輸入電壓相位一致的正彈性弦電流波形，這樣就消除了二極管整流產(chǎn)生的諧波。 變流器電路原理圖、四象限整流器在牽引變流器中，四象限整流器設(shè)計(jì)成變流器模塊的形式。4）冷卻系統(tǒng)特點(diǎn)。此外，控制系統(tǒng)還采用了直接轉(zhuǎn)矩控制技術(shù)、再生制動(dòng)技術(shù)、TCN網(wǎng)絡(luò)技術(shù)等先進(jìn)的控制技術(shù)。表1 .1 各種調(diào)速方法的比較調(diào)速方法變頻率f改變轉(zhuǎn)差率s變極對(duì)數(shù)雙饋電動(dòng)機(jī)晶閘管串級(jí)調(diào)速轉(zhuǎn)子串級(jí)電阻調(diào)速液力偶合器調(diào)速電動(dòng)機(jī)類(lèi)型異步電動(dòng)機(jī)繞線轉(zhuǎn)子異步電動(dòng)機(jī)繞線轉(zhuǎn)子異步電動(dòng)機(jī)繞線轉(zhuǎn)子異步電動(dòng)機(jī)籠型異步電動(dòng)機(jī)多速異步電動(dòng)機(jī)功率范圍/KW數(shù)千國(guó)內(nèi)已達(dá)到2400以上30~20004~數(shù)千30~數(shù)千~100調(diào)速范圍5：1~10:12:1~4:12:1~4:12:15:12:1~4:1轉(zhuǎn)速變化率小低速時(shí)大較小大大較小平滑性能好好好好好有級(jí)轉(zhuǎn)矩特性恒轉(zhuǎn)矩恒功率恒轉(zhuǎn)矩恒轉(zhuǎn)矩恒轉(zhuǎn)矩恒轉(zhuǎn)矩或恒功率效率（%）90以上95以上80~901s1s70~90功率因數(shù)~~~~~投資費(fèi)用高較高較高低一般低適用場(chǎng)合輥道、高速傳動(dòng)及風(fēng)機(jī)水泵等分機(jī)、水泵等風(fēng)機(jī)、水泵等頻繁起動(dòng)、短時(shí)低速運(yùn)行。該方式既可次同步調(diào)速，有可以超同步調(diào)速；但缺點(diǎn)是僅適應(yīng)于繞線轉(zhuǎn)子異步電動(dòng)機(jī)4 變極調(diào)速 該調(diào)速方式通過(guò)改變定子繞組的接法去改變極對(duì)數(shù)，進(jìn)而實(shí)現(xiàn)有級(jí)調(diào)速；若對(duì)高電壓大功率電動(dòng)機(jī)進(jìn)行調(diào)速，對(duì)所采用的轉(zhuǎn)換開(kāi)關(guān)的要求比較高，一般采用油浸式或真空式開(kāi)關(guān)。串級(jí)調(diào)速有電子串級(jí)和電機(jī)串級(jí)兩種方式。從調(diào)速的本質(zhì)來(lái)看，不同的調(diào)速方式無(wú)非是改變交流電動(dòng)機(jī)的同步轉(zhuǎn)速或不改變同步轉(zhuǎn)兩種。 電動(dòng)機(jī)外觀圖電動(dòng)機(jī)有兩大部分組成：定子和轉(zhuǎn)子定子：定子是電動(dòng)機(jī)靜止不動(dòng)的部分。全部電氣部件均是絕緣的，且所用絕緣材料均為H級(jí)或F級(jí)，絕緣性能好，耐熱性能好。異步電動(dòng)機(jī)的工作點(diǎn)可以很方便地進(jìn)行平滑調(diào)節(jié)，以實(shí)現(xiàn)最大可能的粘著利用，不會(huì)出現(xiàn)粘著中斷的情況。 16 PWM逆變器原理。s education practice is to seize against four wind this focus on centralized solve outstanding problems asked County, township leadership and leading cadres of the four winds, the disadvantages of the style, scale behavior to a large scale investigation, overhaul, cleaning greatly. At the same time, respond to the concerns of the masses, safeguard the interests of the masses, pay attention to solve practical problems, solve the people around the unwholesome tendencies especially on eat, take the card, Yong lazy luxury, extravagance and waste fees, privileges and other issues, timely and effective, without any discount to solve, to improve the style of real implementation of the requirements of real to the grassroots, real let group Benefit the public.(a) focus on solving the four winds outstanding issuesThe central and provincial requirements, the county leadership and leading cadres of key performance concept is not correct, do not dare to play, to engage in image project, political project, a leadership guide, a set of ideas, orders and prohibitions, and a policy, there are countermeasures county. The units directly under the heavy focus on solving Yung lazy drag, buck passing skin, work is not implemented, the service is not active. The dynamic problem of law enforcement and supervision departments and window units, service industry mainly solve the door hard, ugly face, something difficult, and arbitrary charges, fines, levies, and breach of privilege, chinakayao, not the problem of law. The township, street The collar of leading bodies and leading cadres to solve key does nottheir own conditions to develop the correct road, the maximum to avoid investment risk, gain profit.(three) vigorously promote the brand. To establish brand awareness, awareness of the use of brand, brand value, brand acquisition performance, enhance the petitive strength. Concentrated manpower, careful planning, packaging and publicity of a number of unique, market influence and coverage of the brand, the implementation of key breakthroughs, to enhance the petitive strength, walking business road the petition of alienation and characteristics, the pursuit of stability and development of the market.(four) to promote the integration of resources. To further broaden their horizons, effective integration of resources within the group, the city resources, other industries and regional resources, mutual trust, mutual benefit, seeking winwin principle, in the framework of national policies and regulations, strict inspection and argumentation, legal consultation, examination and approval procedures, strict regulation of economic activities, attract injection the social investment to the industry group, to achieve leveraging the development, ensure that the value of stateowned assets.(five) to strengthen the construction management personnel. Strengthen the management of education and training of cadres and workers of the existing business, firmly establish the concept of the market, enhance the sense of crisis to adapt to market petition, the sense of urgency, improve the ability to respond to market petition, improve management and operation of the market. At the same time, according to the need of industrial development, vigorously the introduction of highquality management management personnel, and strive to build a highquality professional management team, hard work, and promote the entire workforce knowledge structure, age structure, structure optimization and upgrading ability, enhance core petitiveness, adapt to the need of market petition.(six) seriously study the policy for policy. Serious research about social support the development of cultural undertakings in the country and the XX policy, especially the policy of industrial development, financial investment policy, financial policy and tax policy, and actively seek policy, projects and funds, enterprise and industry group mission to promote leapfrog development.、摘 要HXD1C型電力機(jī)車(chē)，運(yùn)行穩(wěn)定、可靠，能滿(mǎn)足該型電力機(jī)車(chē)的運(yùn)用要求，實(shí)現(xiàn)模塊化，通用化，降低了機(jī)車(chē)運(yùn)營(yíng)和維護(hù)成本。s mass line educational practiceAccording to the ce