基于电压源换流器的高压直流输电系统混合调制方式

提出了一种适用于基于电压源换流器的直流输电系统的混合调制方式,可满足输电系统的暂态响应和稳态特性的需求。控制系统配置正弦脉宽调制(SPWM)和最小开关损耗2种调制方式:系统受到扰动或处于暂态时,采用响应速度快的SPWM,提高系统的暂态控制能力,改善暂态响应特性;系统处于稳态运行时,则采用最小开关损耗控制,提高系统运行的稳态特性和经济性。使用状态监测器监视系统状态,据此动态地选择合适的调制方式。描述了混合调制方式的基本原理,并基于PSCAD/EMTDC数字仿真软件,对该调制方式的控制效果进行了仿真验证。结果表明,所提出的混合调制方式具有良好的控制性能和稳态损耗特性,适于工程应用。

A Hybrid Modulation Method for VSC Type High Voltage Direct Current System

A hybrid modulation method is proposed for the HVDC system using voltage sourced converter(VSC) technology,which performs satisfactorily both in steady state and in dynamic state.The system can be controlled in two different pulse width modulation(PWM) modes,i.e.sinusoidal PWM(SPWM) and minimum switching losses PWM.When the system is under disturbance or in the transient state,the SPWM control with a faster response speed is used;in the static state,the minimum switching losses PWM control is used to achieve best economic performances.The system status is monitored and the control mode is selected accordingly.Simulation results using PSCAD/EMTDC indicate that the proposed method has satisfactory control capability and minimum power losses,and suits for engineering applications.