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.

Analysis and performance of a three-phase single-stage SEPIC differential-mode inverter (DMI) using a discontinuous modulation scheme (DMS) are presented in this paper. Since the DMS was previously suggested in many inverter topologies to reduce the voltage stress of utilized switching devices and enhance inverter efficiency, a simple design process to integrate DMS into the SEPIC DMI is proposed in this work. With this modulation strategy, the discontinuity of the duty cycle for one-third of the entire grid frequency cycle thoroughly minimizes the conduction losses and switching losses into the SEPIC converters. Also, it is noted that the voltage stress is significantly reduced in passive elements as well as switching devices. Furthermore, the compensation of the negative sequence harmonic components is maintained without adding extra sensors. The inverter operation along with mathematical analysis of the DMS and grid current control is presented. A PSIM simulator is used to evaluate the behavior of the proposed modulation strategy. Finally, a comparison with the conventional continuous modulation scheme (CMS) is performed for a better assessment.

PV microinverters are the preferred choice for the integration of PV systems in rooftop applications. Among them, single stage microinverters are gaining more attention in the last years due to their inherent advantages, where differential mode inverters have been one of the mainstream proposed architectures. In this context, dual boost inverters (DBI) appears as a very attractive alternative, however, control issues and efficiency are still challenges to solve. To overcome these issues, the DBI with bypass switches and half-cycle modulation has been proposed, in order to increase the efficiency and suppress PV leakage currents. In this paper, a simple and efficient control scheme for the DBI with bypass switches is proposed. In order to validate the proposed control scheme, the DBI with bypass switches is simulated operating as PV microinverter under dynamic test conditions.

Power Optimizers are a trending solution for photovoltaic (PV) applications since they allow high energy yield performing energy conversion and distributed maximum power point tracking (DMPPT). Because of its benefits in terms of efficiency, component rating and power density, partial power converter (PPC) is a very attractive solution to operate as power optimizers. In this paper, a new reconfigurable Full-bridge-based PPC is proposed. The reconfigurable scheme allows to take advantage of both step-up PPC of Type I, and step-down PPC of Type II. In order to enlarge the operation range, the proposed converter can also be reconfigured as a classical full-power converter. Theoretical analysis of the converter is provided and simulation results show the correct operation of the proposed reconfigurable PPC, and validate its effectiveness and performances.