Enhancement of power quality for a transformerless single-phase grid-connected photovoltaic system using backstepping control approach

This paper presents a nonlinear control of the active and reactive power for a photovoltaic system. This latest is connected into the grid via transformless voltage source inverter. The design of the controller is based on the Backstepping approach to establish the inverter control laws. An analysis based on Lyapunov stability approach is developed to guarantee the global asymptotic stability of the system. In order to verify the effectiveness of the proposed controller, the obtained results are compared with those of the conventional linear controllers under changing in solar irradiance. The results show that the proposed control laws provide better performance in terms of references tracking and unity power factor. Furthermore, the harmonic performance and total harmonic distortion revealed that the power quality injected into the electrical network are enhanced using the Backstepping control strategy.