Abstract:Due to the nonlinear output characteristics of photovoltaic(PV) cells, this paper presents a comprehensive nonlinear control strategy apply to the single-stage grid-connected PV inverter. In this strategy, the active and reactive currents of the inverter are controlled decoupling exactly by nonlinear feedback linearization controller. The active disturbance rejection control is employed to the dc voltage regulator of the inverter, so the system mathematic modeling parameter error on the harmful effects of feedback linearization is compensated, and the control robust of the system is improved. With the active and reactive currents are exactly decoupling controlled and the voltage regulator has steady stability. A variable perturbation step maximum power point tracking(MPPT) technique, which based on the active current and the signal error of the dc voltage regulator, is designed to avoid miscalculation maximum power point of the PV array. The comprehensive nonlinear controller promotes effectively the control performance of the inverter by integrating the feedback linearization current loop, the active disturbance rejection voltage controller and variable perturbation step MPPT technique together. Simulation and experimental results show that the proposed strategy provides validity and feasibility.
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