基于平滑切换的不平衡工况下直驱风机故障穿越控制策略  

Smooth Switching Based Fault Ride-through Control Strategy for Direct-driven Wind Turbine Under Unbalance Condition

作　　者：万子镜 田震 王伟[3] 查晓明[1,2] 黄萌 刘思杰[1,2] WAN Zijing;TIAN Zhen;WANG Wei;ZHA Xiaoming;HUANG Meng;LIU Sijie(Hubei Key Laboratory of Power Equipment&System Security for Integrated Energy,Wuhan 430072,China;School of Electrical Engineering and Automation,Wuhan University,Wuhan 430072,China;NARI Technology Co.,Ltd.,Nanjing 211106,China)

机构地区：[1]综合能源电力装备及系统安全湖北省重点实验室,湖北省武汉市430072 [2]武汉大学电气与自动化学院,湖北省武汉市430072 [3]国电南瑞科技股份有限公司,江苏省南京市211106

出　　处：《电力系统自动化》2023年第19期138-146,共9页Automation of Electric Power Systems

基　　金：国家重点研发计划资助项目(2022YFB2402703)。

摘　　要：目前已有的风电机组故障穿越控制策略和相关标准主要针对三相平衡故障或仅考虑不平衡工况下的单一控制目标,文中重点研究了直驱风机并网系统在三相不平衡故障下的多目标协同故障穿越控制策略。首先,在不平衡工况下网侧逆变器瞬时功率模型的基础上,分析了传统控制策略下直驱风机输出电流三相不平衡、有功功率与无功功率二倍频振荡及其导致的直流母线电压波动机理。为了实现不平衡故障下的多目标协同控制,提出了基于最小二乘法的最优电流设定值求解方法。此外,考虑到故障过程中网侧变流器直流电压环对电流控制的钳制作用,提出了一种基于状态跟随的平滑切换控制策略以减小切换过程的暂态冲击,即故障穿越期间直流电压控制从网侧变流器平滑切换至机侧变流器。与传统故障穿越控制策略相比,所提故障穿越控制策略可以同时实现对不平衡电流、有功及无功功率波动的有效抑制,避免了单独控制有功或无功功率振荡时易出现的电流指令值饱和现象,提高了直驱风机故障穿越控制性能。最后,利用PSCDAD/EMTDC仿真验证了所提控制策略的有效性和优越性。The existing fault ride-through control strategies and related standards for wind turbines mainly consider three-phase balanced faults or a single control objective under unbalanced conditions.This paper focuses on the multi-objective cooperative fault ride-through control strategy for the grid-connection system of direct-driven wind turbines with three-phase unbalance faults.Firstly,based on the instantaneous power model of the grid-side inverter under unbalance conditions,the three-phase unbalance of direct-driven turbine output current,two-fold frequency oscillation of active power and reactive power and the mechanism of the resulting DC bus voltage fluctuation under the traditional control strategy are analyzed.To achieve the multi-objective cooperative control with unbalance faults,this paper proposes a solving method for the optimal current setting value based on the least squares method.Besides,considering the clamping effect of the DC voltage control loop of the grid-side converter on the current control,a smooth switching control strategy is proposed based on the state following to reduce the transient shock of the switching process,i.e.,the DC voltage control is smoothly switched from the grid-side converter to the generator-side converter during the fault ridethrough process.Compared with the conventional fault ride-through control strategy,the proposed fault ride-through control strategy can simultaneously achieve effective suppression of unbalanced currents,and active and reactive power fluctuations,while avoiding the saturation of current command value that tends to occur when active or reactive power oscillations are controlled separately,which improves the fault ride-through control performance of direct-driven wind turbines.Finally,PSCDAD/EMTDC simulations are carried out to verify the effectiveness and superiority of the proposed control strategy.

关 键 词：直驱风机 故障穿越 不对称故障 三相不平衡 多目标协同 最小二乘法 平滑切换控制 

分 类 号：TM315[电气工程—电机]