半导体的出现成为20世纪现代物理学其中一项最重大的突破，标志着电子技术的诞生。而由于不同领域的实际需要，促使半导体器件自此分别向两个分支快速发展，其中-个分支即是以集成电路为代表的微电子器件,特点为小功率、集成化,作为信息的检出、传送和处理的工具;而另-类就是电力电子器件，特点为大功率、快速化。1955年,美国通用电气公司发表了世界上第一个以硅单晶为半导体整流材料的硅整流器(SR) ，1957年又发表了全球首个用于功率转换和控制的可控硅整流器(SCR) 。由于它们具有体积小、量轻效率高、命长的优势，尤其是SCR能以微小的电流控制较大的功率,让半导体电力电子器件成功从弱电控制领域进入了强电控制领域、大功率控制领域。在整流器的应用上,晶闸管迅速取代了水银整流器(引燃管)，使得整流器固体化、 静止化和无触点化，并显著的节省能源。从1960年代开始,由普通晶闸管相继衍生出了快速晶闸管、光控晶闸管、不对称晶闸管及双向晶闸管等各种特性的晶闸管,形成一个庞大的晶闸管家族。
5SHY3545L0014
5SHY3545L0014
但晶闸管本身存在两个制约其继续发展的重要因素。一是控制功能 上的欠缺，普通的晶闸管属于半控型器件，通过闸极(控制极)只能控制其开通而不能控制其关断，导通后控制极即不再起作用，要关断必须切断电源，即令流过晶闸管的正向电流小于维持电流。由于晶闸管的关断不可控的特性,必须另外配以由电感、电容及辅助开关器件等组成的强迫换流电路,从而使装置体积增大，成本增加，而且系统更为复杂、可靠性降低。二是因为此类器件立足于分立器件结构，开通损耗大，工作频率难以提高,限制了其应用范围。1970年代末，随着可关断晶闸管(GTO) 日趋成熟，成功克服了普通晶闸管的缺陷，标志着电力电子器件已经从半控型器件发展到全控型器件。
5SHY3545L0014
5SHY3545L0014
However, thyristors themselves have two important factors that constrain their continued development. One is the lack of control function. Ordinary thyristors belong to semi controlled devices, and can only be controlled to turn on and not to turn off through the gate (control pole). After conduction, the control pole will no longer function, and to turn off, the power supply must be cut off, which means that the forward current flowing through the thyristors is less than the maintenance current. Due to the uncontrollable turn-off characteristics of thyristors, a forced commutation circuit composed of inductors, capacitors, and auxiliary switching devices must be additionally added to increase the device volume, increase costs, and make the system more complex and reduce reliability. The second reason is that such devices are based on discrete device structures, with high turn-on losses and difficulty in increasing operating frequency, which limits their application range. In the late 1970s, as turn-off thyristors (GTOs) became increasingly mature, they successfully overcame the defects of ordinary thyristors, marking the development of power electronic devices from semi controlled devices to fully controlled devices.
5SHY3545L0014
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