NPC三电平虚拟同步机桥臂故障容错模型预测控制  

Fault-tolerant Model Predictive Control for Bridge Arm of NPC Three-level Virtual Synchronous Generator

作　　者：金楠 肖晗 谢欢 武洁 JIN Nan;XIAO Han;XIE Huan;WU Jie(College of Electrical and Information Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China)

机构地区：[1]郑州轻工业大学电气信息工程学院,郑州450002

出　　处：《电源学报》2024年第2期147-157,共11页Journal of Power Supply

基　　金：国家自然科学基金资助项目(U2004166);河南省重点研发与推广专项(科技攻关)资助项目(202102210103)。

摘　　要：虚拟同步机VSG(virtual synchronous generator)通过模拟同步机特性为新能源并网提供惯性和阻尼。然而,电力电子开关器件高频开关过程中可能会发生断路故障,导致输出电流波形严重畸变,影响电网安全稳定运行。针对中点箝位型NPC(neutral point clamped)三电平VSG桥臂故障问题,提出一种中点电压均衡的VSG容错模型预测控制策略。分析NPC三电平VSG单相桥臂故障后运行机理,在开关器件故障后利用直流侧电容组成虚拟桥臂,重构为VSG桥臂故障容错结构。建立故障情况下预测电流模型,重构故障状态空间电压矢量,将直流侧中点电容电压引入容错模型代价函数,减小电容电压波动,实现VSG桥臂故障容错运行。实验结果表明,在开关器件发生故障后,NPC三电平VSG能容错连续运行,验证了所提模型预测容错控制策略的有效性,提高了VSG运行可靠性。A virtual synchronous generator(VSG)can provide inertia and damping for the grid connection of new en-ergy by simulating the characteristics of a synchronous generator.However,a circuit breaking fault may occur in the process of high-frequency switching of power electronic switching devices,which will lead to a serious distortion of out-put current waveform and affect the safe and stable operation of power grid.In this paper,a VSG fault-tolerant model predictive control strategy based on neutral point voltage equalization is proposed to solve the fault problem of neutral point clamped(NPC)three-level VSG bridge arm.The operation mechanism of NPC three-level VSG single-phase bridge arm after fault is analyzed.The DC-side capacitor forms a virtual bridge arm after the switching device fault,which is reconstructed as a VSG bridge arm fault-tolerant structure.Under fault conditions,a current predictive model is estab-lished,and the space voltage vector in a fault state is reconstructed.The neutral point capacitor voltage on the DC-side is introduced into the cost function of fault-tolerant model to reduce capacitor voltage fluctuations and realize the fault-tolerant operation of VSG bridge arm.Experimental results show that the NPC three-level VSG can operate continuously after the switching device fault,which verifies the effectiveness of the proposed model predictive fault-tolerant control strategy and improves the operation reliability of VSG.

关 键 词：虚拟同步机 容错模型 模型预测控制 中点钳位型变换器 代价函数 

分 类 号：TM464[电气工程—电器]