Improvement of Power Quality Using Backstepping Control Strategy for a Transformerless Dual-Stage Grid-Connected Photovoltaic System

Abstract

A nonlinear control of the active and reactive power for a photovoltaic system is presented in this paper. The generated power is injected into the electrical grid via transformerless single-phase voltage source inverter. The conception of the proposed controller is based on the backstepping approach to develop the inverter control laws. Additionally, the global asymptotic stability of the system is guaranteed using the Lyapunov stability approach. In order to examine the performance of the proposed controller, a comparative study has been established between the obtained results and those of the conventional linear controller under irradiance variation. As a result, the proposed controller presents better reference tracking and provides unity power factor. Moreover, the harmonic analysis demonstrates that the injected power into the electrical grid has an improved quality using the backstepping control approach.