Control Strategies Proposals in Grid-Connected Converters: Balancing Inverter Output Current Limitation and Power Injection

This paper offers a comprehensive analysis of interconnecting a converter to the electrical grid through an LCL filter, focusing on the control strategy and its alternative approaches. The control strategy includes an external power control mechanism, translating power into a constrained reference current. Additionally, an internal current controller utilizing state feedback is implemented. The study investigates multiple strategies to strike a balance between limiting the inverter output current and precisely injecting power into the grid. Different techniques are assessed, some prioritizing effective limitation of inverter output current but facing challenges in achieving the desired power injection. Conversely, alternative methods efficiently inject the desired power but encounter difficulties in guaranteeing a limited inverter output current. Moreover, this paper conducts simulations to compare the behavior of these strategies under uncertainties in electrical parameters and during weak grid scenarios. The simulations underscore the pivotal role of this mechanism in significantly enhancing the efficiency and reliability of the converter connected to the grid.