LCL滤波光伏并网逆变器控制策略

为了探讨光伏并网逆变系统控制策略,消除并网电流谐波,研究了LCL滤波和电容电流内环、并网电流外环的双闭环控制规律;设计了光伏并网逆变系统,该系统采用LCL滤波,选用双闭环控制提高系统稳定性;针对传统PI控制的特点,改进传递函数,减小调试范围。该系统综合了双闭环控制、PI控制的优点,仿真试验验证了该系统的线电压波形稳定,静态误差较小,动态响应能力较强,显示该控制系统的优越性,表明了该系统能较好提高并网电流质量,控制策略有效可行。

Control strategy of photovoltaic grid-connected inverter based on LCL filter

In order to study the control strategy of the photovoltaic grid-connected inverter,eliminate the current harmonics,the control laws of LCL filter and double closed loop of the capacitor current inner loop and grid connected current outer loop were studied.A system of grid connected inverter is designed,using LCL filter,with double closed loop to improve system stability. According to the characteristics of the traditional PI control,the improved transfer function is adopted to reduce the scope of com- missioning.The system combines the advantages of the double closed loop and PI control.The simulation results verify that the waveform of the line voltage is stable,the static error is small and the dynamic response ability is better.Those show the system is effective to improve the quality of the net current,and this control strategy is feasible.