摘要
针对光伏系统工作在低功率状态下LCL滤波器的滤波效果变差的问题,提出一种根据逆变器瞬时输出功率改变开关频率的控制策略.首先,分析LCL滤波器各参数的设计方法,采用单级光伏并网逆变结构,在基于电网电压定向的矢量控制(VOC)的基础上建立频率控制环,以确定当前功率状态下开关管的最佳开关频率.其次,分析频率环中功率鉴定器、频率鉴定器和频率滞环比较器的设计方法.最后,通过实验对比传统固定开关频率控制和自适应开关频率控制的并网电流波形.实验结果表明:该自适应开关频率控制方法能降低并网电流畸变率,有效改善并网电能质量,控制策略具有可行性和有效性.
Aiming at the problem that the filtering effect of LCL filter becomes worse when the photovoltaic system works at low power,this paper presents a control strategy to change the switching frequency according to the instantaneous output power of the inverter.Firstly,by analyzing the design method of each parameter of LCL filter,a single-stage photovoltaic grid-connected inverter structure is used to establish the frequency control loop based on grid voltage oriented vector control(VOC)to determine the optimal switching frequency under the current power state.Secondly,the design methods of power detector,frequency detector and frequency hysteresis comparator are analyzed in detail.Finally,the grid-connected current waveforms of traditional fixed-switching frequency control and adaptive switching frequency control are compared by experiments.The experimental results show that the adaptive switching frequency control method can reduce the grid-connected current distortion rate and effectively improve the grid-connected power quality.The control strategy is feasible and effective.
作者
潘健
李坤
廖冬初
PAN Jian;LI Kun;LIAO Dongchu(Hubei Key Laboratory for High-Efficiency Utilization of Solar Energy and Operation Control ofEnergy Storage System,Hubei University of Technology,Wuhan 430068,China)
出处
《华侨大学学报（自然科学版）》
CAS
北大核心
2019年第2期226-231,共6页
Journal of Huaqiao University(Natural Science)
基金
国家重点研发计划重大专项(2018AAA056)
国家自然科学基金资助项目(51677058)
关键词
光伏并网
逆变器
开关频率
LCL滤波器
频率环
电能质量
photovoltaic grid connection
inverter
switching frequency
LCL filter
frequency loop
power quality
