Hvdc light is a kind of new dc transmission technology developed from the traditional hvdc , with voltage source converter ( vsc ) and igbt as main components . the basic principles of vsvpwm are studied , and an approach to simulate vsvpwm based on pscad / emtdc is put forward in this thesis 轻型高压直流输电（ hvdclight ）技术是在传统直流输电基础上发展起来的一种新型输电技术，其主要部件是以绝缘栅双极晶体管构成的电压源换流器（ vsc ） 。
It has been shown that the performance of sige heterojunction bipolar transistor ( sige hbt ) in high frequency is much better than that of si bipolar junction transistor ( si bjt ) , and is better than that of algaas / gaas metal semiconductor field effect transistor ( algaas / gaas mesfet ) in some aspects Sige异质结双极晶体管（ sigehbt ）的高频性能大大优于si双极晶体管（ sibjt ） ，并在某些方面优于algaas / gaasmesfet ，所以sigehbt具有广阔的应用前景。
The factors limiting the frequency band of the wide - band amplifier are introduced . through analyzing the effects of the intrinsic parameters and parasitical on the frequency characteristics , a method of improving fr of mosfet by using short channel device and making mosfet work at the saturation region through raising vgs is put forward ; the effects of different kinds of circuit configurations on the frequency characteristics and the junction voltage on the voltage pattern circuit , current pattern circuit and frequency characteristics are analyzed . according to the linear theory of transconductance which is applied in the bit circuit , the current pattern amplifier circuit , current transfer circuit and output circuit which consist of mosfet and the wide - band amplifier composed of them are put forward 介绍了限制宽带放大器频带宽度的因素，通过分析mosfet的本征参数、寄生参数对频率特性的影响，提出了采用短沟器件、使mosfet工作在饱和区、抬高栅源电压等提高mosfet特征频率的方法；分析了不同电路组态对放大器频率特性的影响、节点电压对电压模电路、电流模电路频率特性的不同影响，根据应用于双极晶体管电路的跨导线性原理，提出了采用mosfet构成的电流模放大电路、电流传输电路、输出电路以及由它们所组成的宽带放大器，获得了良好的频率响应。
After the characteristics and development of excitation system of synchronous generators are analyzed , micro - computer regulating theory of excitation system is discussed , this dissertation presents a scheme of designing excitation system with programmable computer controller ( pcc ) and igbt , and pcc igbt excitation system of turbine generator is also developed according to the above mentioned 本文在全面分析同步发电机微机励磁装置特点及发展现状的基础上，论述了微机励磁调节的原理，提出基于可编程计算机控制器( pcc )控制的绝缘栅双极晶体管( igbt )励磁系统的设计方法，并在此基础上开发了基于pcc控制的水轮发电机igbt励磁系统。
