Hybrid Sliding Mode-Backstepping Control for Robust MPPT Extraction of Photovoltaic Systems in Grid-Connected Microgrids

Abstract

This study provides an innovative method for developing an effective nonlinear control solution for a gridconnected photovoltaic (PV) system, utilizing a hybrid Sliding Mode-Backstepping (SMC-BSC) control scheme. The proposed control scheme achieves three objectives at the same time (maximum power point tracking (MPPT), stabilization of DC bus voltage, and injection of quality electrical power) while providing an effective interface between the PV array and a DCDC boost converter while maintaining uninterrupted inductor current flow via backstepping control technique with an addition of sliding mode to improve robustness against uncertainties due to changes in variable parameters or environmental conditions. The AC -side of the PV system includes the use of a voltage-source inverter operating in the synchronous dq reference frame for regulation of the DC-link voltage, as well as maintaining a unity power factor by preventing reactive power exchange. The overall closed-loop system’s stability is guaranteed through a Lyapunov analysis to verify the state variables reach equilibrium within a bounded settling interval of the sliding surface and asymptotic stability at equilibrium points. Results from the simulation show how quickly the new control method responds, produces less chattering noise, accurately tracks current, produces stable active power output and produces zero reactive power to the grid during changes in solar irradiance level.