光伏发电系统中三相逆变器不平衡控制的分析  

Analysis of three-phase inverter for photovoltaic power system under unbalanced load condition

作　　者：魏金成[1] 游芳[1] 郭筱瑛[2] 王嘉磊[1] 李清[1] 程华[3] 

机构地区：[1]西华大学电气信息学院,成都610039 [2]攀枝花学院电气信息工程学院,四川攀枝花617000 [3]中国民用航空总局第二研究所信息公司,成都610041

出　　处：《电测与仪表》2015年第6期61-65,88,共6页Electrical Measurement & Instrumentation

基　　金：四川省教育厅项目(12209580);太阳能光伏离/并网智能化控制逆变一体集成应用(2014CY-S-1-2)

摘　　要：针对光伏发电系统中离网三相逆变器工作在不平衡负载时的特点,文中详细分析了离网三相逆变器的拓扑电路结构及其相应的控制方法。分析了三相三桥臂逆变器主电路拓扑结构,引入了电容电流瞬时值反馈控制,同时还对三相逆变器经LCL滤波后的输出三相电压进行独立控制。通过对每相输出的交流电压与参考电压进行PI运算后再与电容电流进行K运算产生控制开关管的SPWM脉冲波,从而实现三相逆变器输出电压平衡。建立Matlab/Simulink仿真模型,仿真分析表明,文中采用的控制方法,在三相负载严重不平衡情况下,输出的三相电压不平衡度低,且带非线性负载能力强,从而保证逆变器在带任意不平衡负载时仍能维持三相平衡的输出电压。In view of the characteristic of the off-grid three-phase inverter with unbalanced load in the photovoltaic power system,this paper analyzed the circuit topology structure and its corresponding control method of the off-grid three-phase inverter in detail.The paper analyzed the topology structure of the three-phase three-leg inverter＇ s main circuit,introduced the instantaneous capacitor-current feedback control,and at the same time exerted split-phase control on the three-phase output voltage filtered by LCL.The PI operation was made between the output ac voltage of each phase and the reference voltage,and then the K operation was made between the output ac voltage of each phase and the capacitor current to produce SPWM pulse which could control the switch component,thus realizing balanced output voltage of the three-phase inverter.A Matlab/Simulink simulation model was constructed And the simulation analysis displayed that under serious imbalanced three-phase load,the control method proposed in this paper could ensure a lower imbalance degree of the three-phase output voltage and a stronger nonlinear load capacity so as to guarantee the balanced three-phase output voltage d under any unbalanced loads.

关 键 词：三相逆变器 电容电流控制 不平衡负载 独立控制 

分 类 号：TM464[电气工程—电器]