This paper examines the limits of power injected to the grid for the photovoltaic (PV) system. Usually, the PV system injects to the grid active power with reactive power equal to zero. However, it can inject/absorb both powers according to the grid demand and maintain the stability of the grid characteristics (voltage and frequency). The proposed system consists of two main controllers: the DC/DC boost converter to track the possible maximum power from the PV panels and the grid-tied three-phase inverter. The controllers are designed based on a nonlinear adaptive backstepping approach, sliding mode control and the vector control strategy. The robustness of the proposed techniques is ensured by considering parametric uncertainties as well as external disturbances. In the proposed control strategies, the sliding mode control presents a small number of parameters than the other strategies. The reactive power is proposed by the grid manager which is controlled via the inverter. The simulation results indicate clearly the robustness of the sliding mode control in terms of injecting active and reactive power into the grid and improving power quality as compared to a backstepping controller and vector control.

本文研究了为光伏 (PV) 系统注入电网的功率限制。通常，光伏系统以无功功率为零的有功功率注入电网。但是，它可以根据电网需求注入/吸收两种功率，并保持电网特性（电压和频率）的稳定性。所提出的系统由两个主要控制器组成：DC/DC 升压转换器（用于跟踪来自光伏电池板的可能最大功率）和并网三相逆变器。控制器的设计基于非线性自适应反步法、滑模控制和矢量控制策略。通过考虑参数不确定性以及外部干扰，确保了所提出技术的鲁棒性。在建议的控制策略中，与其他策略相比，滑模控制的参数数量较少。无功功率由通过逆变器控制的电网管理器提出。仿真结果清楚地表明了滑模控制在向电网注入有功和无功功率和改善电能质量方面的鲁棒性，与反步控制器和矢量控制相比。