A Back-Stepping Sliding Mode Control Strategy Based on Extended Observer for Photovoltaic Grid-Connected Inverter

In the photovoltaic power generation system, the grid-connected inverter is an important link to realize system connection with the electricity grid, but the existence of various interferences of the external environment and the system itself brings a series of problems. In this paper, the circuit of the LCL is used to filter of photovoltaic grid-connected inverter output, and step-sliding mode control and the extended state observer are combined to complete the tracking control of the inverter system. Three state variables of the control strategy are the output voltage of inverter system its first and second derivative, back-stepping and sliding mode control are combined, and the extended state observer is designed to estimate the composite interference, then its output compensates to the back-stepping sliding mode controller. The effectiveness of the control strategy is proved by the simulation of photovoltaic grid-connected inverter system in Matlab.