Single — Stage three — Phase grid — Connected photovoltaic system with maximum power tracking and active and reactive power control based on nonlinear control

Nowadays, due to the high-scale penetration of photovoltaic systems, reliable and efficient photovoltaic grid-connected systems using the advances of power electronics and advanced control techniques are desirable. In this paper, using the general structure for synchronous dq0 frame, a single-stage three-phase grid-connected photovoltaic inverter with a nonlinear control strategy is developed to generate maximum power of the photovoltaic array regardless of the atmospheric conditions, without the necessity of a DC-DC converter. This scheme can simultaneously compensate for reactive power, thus; maintaining the unity power factor on the grid side. A Lyapunov analysis is developed to prove the stability of the system and boundedness of signals in the closed loop system. Simulation results demonstrate the control objectives are met along with the effectiveness and robustness of the nonlinear controller in the proposed control scheme.