Predictive Control of the Boost Inverter with Bypass Mode Connection for PV Microinverter Applications

In photovoltaic (PV) systems, the adoption of the single-stage microinverters present an attractive proposition. Unlike their two-stage counterparts, which consist of separate dc-dc and dc-ac conversion stages, single-stage microinverters simplify the conversion process by integrating both functions into a single unit. This combination offers advantages in terms of size, efficiency and overall system performance. In this context, the boost inverter with bypass mode connection emerges as an attractive alternative; however control challenges arise, particularly in the non-linearities inherent in these systems. The linearization process of the converter for conventional control strategies becomes complicated, promoting the exploration of alternative control approaches. This paper proposes a predictive control scheme for a Bypass Boost Inverter (BBI), addressing the aforementioned challenges. The control strategy employs a cascaded design, where the inner loop uses Finite Control Set-Model Predictive Control (FCS-MPC) to regulate inductor currents, indirectly controlling the output current for grid connection. The proposed control scheme is validated through simulations in PLECs software, demonstrating its performance in managing a PV panel. The results show good tracking of inductor current references and compliance with the standards for grid connection.