LCL型电流控制的光伏并网系统研究

Study of the PV Grid-connected Generation System Based on Capacitive Current Control with LCL Filter

对于光伏发电系统,并网电流中含有较多的高次谐波和较大的谐波畸变率值。采用LCL型电容电流控制的方法,既可以控制单位功率因素并网提高并网质量,又可以抑制由于LCL滤波器引起的低频谐振。LCL型电容电流与电感电流结合构成双闭环控制回路,可以防止单闭环控制回路可能出现不稳定等问题。给出LCL电路的解耦模型,进一步优化并网电能质量。实验仿真主要比较LC型滤波器和LCL型滤波器,比较仿真结果中的并网输出波形和谐波畸变率值,验证了LCL型电流控制的正确性。

In PV grid-connected power generation system,the grid-connected current contains many high order harmonics and larger harmonic distortion values. By using LCL type of capacitive current control method,the unit power factor can be controlled, and the grid-connected quality can be improved; in addition, the low frequency resonance caused by LCL filter can also be suppressed. The dual closed - loop control constituted by LCL capacitive current and inductive current can even prevent the unsteadiness of the single closed - loop control loop. The decoupling model of LCL circuit is given to further optimize the grid-connected energy quality. The LC filter and LCL filter are mainly compared in experimental simulation, the grid -connected output waveform and harmonic distortion value in simulation result are also compared ; the correctness of the LCL current control is verified.