轻型直流输电技术作为一种新型输电技术，采用全控型大功率器件和脉宽调制技术，使得轻型直流输电技术具有自身的技术优势。由于轻型直流输电换流器的结构简单、体积小及功能强大，可以有效的弥补传统直流输电无法向无源网络系统供电的缺陷。因此，轻型直流输电技术已逐渐成为电力系统研究的热点。本课题主要研究向无源网络供电的轻型直流输电系统的动态模拟及仿真。 本课题根据三相两电平电压源换流器的拓扑结构，研究了轻型直流输电系统的结构、工作原理及功率传输特性，分析了整流换流器的SPWM调制触发原理及逆变换流器的SVPWM调制触发原理。通过系统电压、电流、P和Q的约束条件，建立电压源换流器 在dq0坐标系下的动态数学模型，确定轻型直流输电系统的控制策略及选取系统参数。 通过分析轻型直流输电系统的基本控制原理，设计了整流侧的定直流电压控制方式及逆变侧的定交流电压控制方式，完成了输电系统的内环电流与外环电压的双闭环控制结构，实现了d 轴、q 轴电流的独立控制，并利用模糊PID调节校正系统的直流侧电压。 利用Matlab/simulink 仿真软件，建立向无源网络供电的轻型直流输电系统的仿真模型及SVPWM 调制技术的仿真模型，获取系统有功功率、无功功率以及交直流系统的电压、电流仿真结果。仿真结果表明，SVPWM 调制方式有效的提高了直流电压的利用率，完成了有功、无功的相互独立控制。

As a new type of transmission technology, HVDC Light uses all-controlled power devices and the technology of pulse width modulation, which makes the HVDC light technology have its own technical advantages. HVDC Converter has the advantage of simple structure、small volume and strong function, which can effectively compensate for the defects of conventional HVDC to passive network power supply system. Therefore, HVDC Light technology has gradually become a hot spot of research in power system. The paper focuses on research of dynamic and simulation for HVDC Light system in passive networks. According to the topology of 3-phase and 2-level voltage source converter，the system structure, working principle and power transmission characteristic of the  HVDC Light are studied and the SPWM modulation trigger principle、inverter commutation of SVPWM trigger principle for rectifier converter are analyzed. Based on the constraints of the system voltage, current, P and Q, a dynamic mathematical model for the voltage source converter in dq0 coordinates is established and control strategy of HVDC Light system and the selection of the system parameters are studied. Based on the analysis of the basic control principle of the HVDC Light system, DC voltage control mode in rectifier side and AC voltage control mode are designed, the double closed-loop control structure of inner current and outer voltage for transmission system are established, the independent control of d axis and q axis electric current are achieved, and DC-side voltage are corrected in fuzzy PID control method. On the basis of Matlab/Simulink simulation software, simulation model of  HVDC Light system power supply to passive network and SVPWM Modulation technology are established, and the results of active power、reactive power, current voltage of DC system are obtained. The simulation results show that SVPWM modulation method effectively improves the utilization ratio of DC voltage and realizes the independently control for active and reactive power.