一种新的无源性电压跌落发生器设计与实现

摘要

为了提高电压跌落发生器前级变流器模拟电网跌落故障时的稳定性及抗扰动性，提出了由直流电压外环加后级变流器微分电流前馈与无源性控制相结合的前级PWM变流器控制策略。以系统能量平衡为设计准则，建立PWM变流器能量函数，根据VSG控制目标，设计变流器无源控制率，微分电流前馈提高前级PWM变流器抵抗模拟不同类型电压跌落时的抗扰动性能。实验结果表明，控制策略能够提高VSG系统在电压对称和不对称跌落时的动态响应速度和抗干扰能力。%To improve the stability and disturbancerejection of the preceding stage converter of the voltage sag generator (VSG)when simulating grid dropout fault,this paper presents a PWMconverter control strategy which combines DC voltage outer loop plus differential current feed-forward of the backward stage converter with passivity-based control.It establishes an energy function of the PWMconverter with system energy balance as design criterion,and designs passivity-based control rate of the converter according to the VSG control target.The differential current feed-forward improves the disturbance rejection performance of the preceding stage PWM converter when different types of voltage sags are simulated.Experimental results show that the proposed control strategy can improve the speed of dynamic response and anti-jamming capacity of the VSG system in the cases of symmetric and asymmetric voltage sags.