工频与高频的分析

1、工频与高频的区别为什么工频UPS将被高频UPS所代替技术总是在发展的，新技术代替旧技术是历史的发展规律。然而，新旧之间的替代与转换一般并不是那么顺利，人类社会是这样，自然、科技领域也是这样。现在的电子技术已进入数字化时代，这是不可逆转的技术发展规律，各行各业迟早都要集中到这一条路上来，但就某一个时期来说发展是不平衡的，这中间有好多因素的影响，比如各自的技术发展水平不同，人员对新技术的认识和接受能力不同等等。具体到UPS领域又何尝不是如此。下边我给大家讲解一下工频机与高频机的区别及为什么工频机UPS将被高频UPS代替。一、 工频机UPS和高频UPS的一般概念  &#

2、160; 静止变换式工频机结构UPS技术出现在上个世纪70年代，毫无疑问在当时属尖端技术，几十年间也为电子电器技术领域作出了不朽的贡献。一般说任何技术的先进性是相对而言，任何先进的产品也有其一定的适用期。随着IT技术的出现与发展，工频机UPS组件暴露出它的缺点，比如体积大、重量大、功耗大和输入功率因数低等不利因素大大影响了它本身的可靠性。原来那种输入输出都在50Hz并且有输出变压器的老的电路结构就称作工频UPS；而这种输入输出电路都工作在20kHz以上且没有输出隔离变压器的电路就称为高频UPS。二、 高频UPS比工频UPS有哪些优点1、 输入功率因数高  

3、;  工频UPS一般在200kVA以下的输入电路都采用了可控硅6脉冲整流，输入功率因数不超过0.8，谐波电流有30%之大。如果再连接发电机，那么发电机的容量至少要3倍于UPS功率；如果是单相小功率UPS，发电机的容量至少要5倍于UPS功率。    任何容量的高频UPS的输入功率因数都可做到0.99甚至以上，谐波电流小于5%，前置发电机的容量理论上和UPS功率相同，大大缩减了投资和占地面积等。尤其是对市电的充分利用具有良好的经济意义和社会意义。    在同样指标下，比如要求输入功率因数为0.95以上时，工频UPS就必须外加谐波

4、滤波器或改为12脉冲整流，就是说前面要增加一个设备，再加上输出变压器，就比高频UPS多了两个环节。由于此二者的影响，使得工频UPS的效率比高频UPS低5%。在同样是100kW的容量时工频UPS每年要比高频UPS多消耗5万度电！这在中央号召节能减排的今天具有深远意义。3、 对外干扰小    干扰有两种，一种是听得到的机械噪声（工频中的变压器使用久了，硅钢结构松动后，一旦带载运行就会发出噪声，声音最大的可达到小型发电机的响声），一种是听不到的电噪声，这两种噪声工频UPS都有，形成了对设备和对人的伤害。电噪声影响机器的稳定度，机械噪声影响人的身心健康，降低工作

5、效率。    而高频UPS由于工作在20kHz以上，20kHz是人的耳朵听不到的频率，使工作环境安静下来。又由4、 体积小、重量轻    工频UPS由于有了输出变压器和适应50Hz的电感电容等低频器件使得体积重量都很大。比如山特200kVA工频UPS 重1380kg，而同是他的250kVA高频UPS 重量只有830kg。5.数字技术的应用    工频UPS刚开始是模拟技术，现在最高级的才发展到数字与模拟相结合的技术，模拟技术的可靠性要比数字技术低。而高频UPS技术一开始就是数字与模拟相结合的技术

6、，目前先进的已发展到全数字化技术，不言而喻，可靠性是很高的6. 对电网的适应能力强    工频UPS对于适应输入电压±15%的变化已很不易；而高频UPS甚至适应输入电压±30%左右的变化，这又大大延长了电池的寿命。7. 能将并机环流衰减到几乎为零   工频机UPS的并联就是变压器的直接并联,而变压器的直接并联最容易产生很大的环流,高频机UPS由于没有输出变压器,它们的并联可以看出这里的环流路径上处处是障碍,小于2V的电压差根本性不成环流。总之，高频UPS在性能上不但完全具备工频UPS的一切特性，而且还具备很多后者没

7、有的特点和功能。由此可见，高频UPS完全可以替代工频UPS而成为数字化时代的主流趋势。三、高频UPS与工频UPS的现状    因为高频UPS对技术与工艺以及生产手段的要求非常严格，一般不容易仿制，所以20kHz以上的高频UPS容量都小于100kVA，但目前仍有少数制造厂的技术真正过关，而且已显示出强大的生命力。在大功率范围虽然不能做到20kHz，但采用高频机结构，比如用IGBT高频整流（相对于50Hz而言），频率一般在15kHz以下，多数厂家已可做到200kVA，其中也有佼佼者，比如秀康10年前就可做到8kHz/480kVA，伊顿9395也可做到15kHz/120

8、0kVA，并已成为美国的军方指定产品。这说明高频结构UPS技术早已成熟。另外在我国军方和金融等重要部门也纷纷采用，并收到了良好的效果。因此工频结构UPS在这种情况下的日子会越来越艰难，好在是还有那么一批厂家的高频结构UPS没有过关，还得主推工频UPS，作为市场手段多说一些当前用工频UPS更合适之类的语言，多说一些工频机的好处和多找一些高频机的缺点均属正常现象，这可以理解，也可能是认识问题。但不要认为工频UPS技术永远不落后。从科学发展观来说，以后一段时间内无疑是高频UPS的市场。不可否认，高频UPS同样也有退出历史舞台的一天，当然那是后话。四、所谓两个发展方向   

9、; 现在有一种说法：高频UPS和工频UPS是两个发展方向。这就使人糊涂了：· 难道效率低的产品也是发展方向？难道节能减排还允许其反向产品发展？· 难道耗费资源和笨重的产品也是发展方向？    总之，这种观点不外乎说：高频UPS与工频UPS并存；节能减排与浪费能量和资源并存；先进与落后并存所谓技术上的并存应该是不可替代的，比如自行车虽然比汽车跑得慢，但它们在一定程度上是互相不可替代的；而这里的UPS技术却是可以完全替代的, 而且是顺理成章。    Difference between Frequency a

10、nd High-frequencywhy high-frequency UPS will replace of frequency UPS With the developing of society and science, new technology replace of old ones is always a rule. However, the replacement and switching between the new and old is not such easy. The electronic technology has already entered i

11、nto the digital age, and this is a develop principle that can not be changed. Now I would like to give some explanation why the frequency UPS will be replaced of by high-frequency UPS.1、general conception of high-frequency UPS and frequency UPSStable and convertible frequency inverter, which has onl

12、y 50HZ input and output frequency and has output transformer circuit, was invented in the 1970s,it is no doubt that at that time this was really very high technology and of course it made much contribution to the electronic field. Generally speaking, no matter how advanced a technology is, it is onl

13、y compared to say so because they have its own using period. With the exist and developing of IT technology, frequency UPS shows his disadvantage, such as bulky, high weight, high power consuming and low input power index, these drawbacks make people doubt its reliability. Naturally, there should be

14、 some new technology to replace of it, and thus there comes the high-frequency UPS, which has over 20 kHz input and output frequency and no transformer circuit. 2、 compared with frequency UPS, high-frequency UPS has lots of advantages1、high input power factor Generally, all the circuit of

15、frequency UPS under 200kVA use the SCR（Silicon Controlled Rectifier）6 pulse rectification and the input power factor is less than 0.8 while the harmonic current is 30%. If we connect with a generator, the capacity of the generator should be three times of the UPS power; and for those single-phase lo

16、w power UPS, it is at least five times. But for high-frequency UPS with any capacity, the input power factor can be as high as 0.99 and even higher while the harmonic current is less than 5%. If connected with generator, the capacity is theoretically the same as UPS power thus reduce the cost and oc

17、cupy. This point has good economic and social significance, especially for making full use of the AC power. 2、low self-power-consuming In the same situation, for example, if we need the input factor of a normal frequency UPS becomes over 0.95, we must connect a harmonic filter or changed it int

18、o 12 pulse rectification, thats to say, we need an extra equipment, and plus the transformer, there is totally two processes more than the high-frequency UPS. Because of these two factors, efficiency of frequency UPS is 5% less than high frequency ones. If we use UPS with 100kw capacity for one year

19、, frequency UPS will consume 50000 kWh AC power more than the high frequency ones. This has very deep meaning in recent society! 3、little interference UPS has two kinds of interference, one can be heard (machinery noise), but the others can not (Electrical noise). These two kinds of noise all e

20、xist in frequency UPS (especially, if used for a long time, the transformer will cause great machinery noise while working, and sometimes it can be as noisy as a small generator) and affect the equipment and human healthy. But for high-frequency ones, since the frequency is over 20 kHz (which can no

21、t be heard by human ear) and the input power factor is more than 0.99(which is almost linear), so there is nearly no interference caused. 4、small size and light Frequency UPS has is very heavy because it has output transformer and some low frequency components (LC) which adapt to the 50Hz. Lets

22、 take 200kVA UPS for an example, frequency ones weight 1.38KG while high-frequency ones is only 0.83KG. 5、Application of digital technologyAt the very beginning, frequency UPS only use simulation technology and combination of digital and simulation technology is the highest one, but high-freque

23、ncy ones use digital technology once it exists. Its no doubt that this kind of product will have more reliable quality. 6、Better adaptability to the AC power networkIt is not easy for frequency UPS to adapt the 15% change of the power network but high-frequency UPS can adapt even a 30% change,

24、and this would extend the battery life. 7、can reduce the parallel operation circulation to minimum The parallel connection of frequency UPS is actually the direct parallel connection of transformer, which will easy to cause high circulation; but high-frequency UPS cause no circulation when the

25、voltage is less than 2V because there is no output transformer and it has obstruction almost everywhere in the circuit.In short, high-frequency UPS not only have all the features that frequency UPS has, but even has much more new functions that the latter one doesnt have. So, it is definitely that t

26、he former will replace of the the latter and become the main solution in this field.3、 status of high-frequency UPS and frequency UPSAlthough the high-frequency UPS has very strict requirement for technology and production way and not easy to copy, but there is still several factories has quali

27、fied technology and showed great vitality. For high power ones, although can not reach 20kHz but if use high-frequency structure （generally the frequency is under 15kHz）, such as IGBT high-frequency rectification（Relatively to the 50Hz）, many factories can make it 200kVA; whats more, some factories

28、even do it better, for example, Xiukang can make it as 8kHz/480kVA ten years ago; Eton 9395 also realizes 15kHz/1200kVA which has been chosen as U.S. military specified products. All these show that high-frequency structure of UPS technology is already mature. In addition, this kind of technology is

29、 also used in some important government department in China, like military and financial, and already received good results.So the frequency UPS will have a more difficult situation. Fortunately, there are still some factories with unqualified technology and they need to promote it. Thus as a sales strategic, saying some good words for frequency UPS and some bad words for the other one is un