电气类外文翻译3.docxVIP

文献传统上，交流电压变换是通过变压器的电磁感应实现的，随着现代社会的发展，地球资源的逐渐枯竭，为了实现人类社会的可持续发展，传统的采用大量铜、铁等贵金属的变压器将逐渐退出历史舞台，而由电力电子元件组成可调压ac/ac变换器来代替，这种斩波式调压电路具有高次谐波影响较小、功率因数高、动态影响快及具有宽的调压范围等优点,适用于工矿企业大量使用的间歇性负载异步电动机拖动机械的节能运行,具有一定的推广价值。交流斩波调压，一般有三种拓扑结构：1） 单管反串联双向电子开关斩控式交流调压。用二极管和igbt分别构成双向波开关和双向续流开关，用二组电感和电容分别组成低通输入、输出滤波器。这种连接igbt与二极管特性配合好，并可减小引线电感对换流的影响。该拓扑采用带电流检测的非互补控制方式，开关模式由电压极性决定，避免了调压中主开关和续流开关换相过程引起的共态运行，开关器件无换相过电压。该拓扑在热水器、静电除尘器中、小功率阻性负载应用中有较大的优势。2） 双开关斩控式交流调压电路。这种拓扑结构中，斩波开关和续流开关都是由四个独立的单功率开关反并联续流二极管构成，与单管反串联双向电子开关斩控式交流调压电路有异曲同工之妙，但结构上更加清晰明了，目前有文献报道它通过附加缓冲电路已应用在大功率场合。3） 单管双向电子开关斩控式交流调压电路。该拓扑为一种经济型单管交流调压电路，开关管对整流脉动输出电压进行斩波，从而达到调压目的。这种结构简单，无续流回路，且只有一路驱动信号。但这种电路只能用于阻性负载，所需的滤波电容比较大，且要求电容能通过较大的交流电流。由于电容积分效应，电路动态响应变慢，故其适用于成本低、性能要求不高、容量较小的交流调压中。交流斩波调压技术是一种新型的高性能的交流调压技术，在中小交流调压领域获得广泛应用。 为实现ac/ac电压变换，过去曾经用双向晶闸管的相控方法，来做恒频下的降压调节，由于晶闸管是半控元件，这样的调节会造成很大的电压畸变，产生谐波、消耗无功功率和功率因数变差，近年来人们已广泛利用全控型电力电子开关进行斩波控制来实现。绝缘栅双极型晶体管igbt是由mosfet和双极型晶体管复合而成的一种器件，其输入极为mosfet，输出极为pnp晶体管，因此，可以把其看作是mos输入的达林顿管。它融和了这两种器件的优点，既具有mosfet器件驱动简单和快速的优点，又具有双极型器件容量大的优点，因而，在现代电力电子技术中得到了越来越广泛的应用。在中大功率的开关电源装置中，igbt由于其控制驱动电路简单、工作频率较高、容量较大的特点，已逐步取代晶闸管或gto。但是在开关电源装置中，由于它工作在高频与高电压、大电流的条件下，使得它容易损坏，另外，电源作为系统的前级，由于受电网波动、雷击等原因的影响使得它所承受的应力更大，故igbt的可靠性直接关系到电源的可靠性。因而，在选择igbt时除了要作降额考虑外，对igbt的保护设计也是电源设计时需要重点考虑的一个环节。 literaturetraditionally, the ac voltage transform realizes through the electromagnetic induction of the transformer. with the development of modern society, the earth resources exhausted gradually. in order to realize the sustainable development of the human society, traditional transformer which use plenty of copper, iron those precious metal will gradually exit the stage of history, and replace by the ac/ac converter with power electronic, this chopping type surge higher harmonic circuit has the advantages such as less effect, power factor is high, the dynamic effect quickly and has regulating range wide, applicable to industrial and mining enterprises to use a load of intermittent asynchronous motor drag mechanical energy efficiency, and it has certain popular value.ac chopper surge, generally there are three kinds of topology structures:1).the single pipe the two-way series electronic switch cut controlled alternating voltage regulation. using diode and igbt a two-way switch and the wave respectively for two-way flow switch, with two groups of stray inductance and capacitance respectively low-pass input and output filter. a good connection for igbt and diode characteristics can reduce the influence of the inductor leads the exchange flow. the topology of the electric current detection using belt of complementary control mode, switch mode from voltage polarity decision, to avoid the surge in the switch and forwarding the flow switch commutation process of operation caused by the state, switching device without commutation overvoltage. this topology has greater load application advantages in water heater, electrostatic precipitator and small power resistance.2).double switch cut controlled alternating voltage regulation circuit. this topology structure, the chopper switch and forwarding the flow switch is made up of four independent single power switch the parallel free-wheeling diode structure, and the single pipe series two-way electronic switch cut controlled alternating voltage regulation circuit the same wonderful, but structure more clear, there are reports in the literature it through the additional buffer circuit has already been used in high power occasion.3) single pipe two-way electronic switch cut controlled alternating voltage regulation circuit. this topology is a cost-effective single pipe alternating voltage regulation circuit, switch tube rectifier pulse output voltage of the chopper, so as to achieve the purpose surge. this kind of structure is simple and no free-wheeling loop with only driving all the way to the signal. but this circuit can only be used for resistance load, the filter capacitance is bigger, and require capacitance can through the larger ac current. due to the capacitance integral effect, the dynamic response of the circuit become slow, so its applicable is to low cost, performance requirements with no high cost and the capacity of smaller alternating voltage regulation.ac chopper pressure regulating technology is a new type of high performance alternating voltage regulation technology, in small and medium-sized alternating voltage regulation field being widely applied. to realize the ac/ac voltage transform, people used to use two-way thyristor phased method, to do under the constant frequency adjust blood pressure, because the thyristor is half control components, such regulation could do a lot of voltage distortion, harmonic generation, consume reactive power and power factor becomes poor, in recent years people have widely use all-controlling power electronic switch control to realize the chopper.insulated gate bipolar transistor gate igbt compound a bipolar transistors mosfet into a device, the input is very mosfet, output is extremely pnp transistor. therefore, it can be as the input of mos darlington. it blends the advantages of the two devices. it has both the mosfet device driver simple and quick advantages and bipolar type device the advantages of large capacity. so in the modern society power electronic technology is getting more and more widely used.in high power switch power in the device, igbt has gradually replaced the thyristor or gto because its control drivi