Disturbance observer based fuzzy sliding mode control of PV grid connected inverter

Abstract

In this paper, a disturbance observer based fuzzy sliding mode control (DOBFSMC) strategy is proposed for a single-phase PV grid-connected inverter. A disturbance observer is designed to estimate the system uncertainties in real time and a sliding mode controller that is designed with the output information of the disturbance observer is employed to control the output voltage of the DC-AC inverter, a fuzzy system is used to approximate the upper bound of the observation error between the actual disturbance and its observation value in order to improve the performance of the control system. The inverter has strong robustness since the disturbances can be adaptively compensated and the chattering is greatly reduced since the switching gain can be very small for the upper bound of observation error is estimated by the fuzzy system. Finally, simulation results verify the effectiveness of the proposed method