Quasi-Z source inverter control of PV grid-connected based on fuzzy PCI

Abstract

Photovoltaic grid-connected inverter is an important interface between the photovoltaic power generation system and power grid. Its high-quality operation is directly related to the output power quality of the power grid. In order to further optimize the control effect of the quasi-Z source grid-connected photovoltaic inverter, a fuzzy proportional complex integral control (PCI) method was proposed for the current internal loop control. This method can eliminate the steady-state error, and has the characteristic of zero steady-state error adjustment for the AC disturbance signal of a specific frequency. The LCL filter is adopted in the grid-connected circuit, and the feedback capacitive current is taken as the control variable of the inner loop to form the active damping control method, which can not only effectively suppress the resonance of the LCL circuit, but also significantly inhibit the high-order harmonics in the grid-connected current. Finally, a system simulation model is built in MATLAB/Simulink to verify the superiority and effectiveness of the proposed method.