Photovoltaic (PV) grid-connected system is nowa-days a well established industry. For PV inverters, European (EURO) efficiency and California Energy Commission (CEC) efficiency have been defined, as Figures of Merit (FoM) allowing easy PV inverter efficiency estimation, while including consideration on PV variability. This paper explores the applicability of weighted efficiencies for off-grid H2production system with DC-DC connection of the PV source, for both DC-DC converter, and electrolyzer. The study considers precise modeling of the system, and evaluation of its operation and efficiency over real scenario, with environmental data of three locations considered, with minute-based resolution, allowing precise simulation. Evaluation of EURO and CEC efficiencies for DC-DC converter and electrolyzer demonstrate the accuracy of the FoM with error lower than 1.23% and 3.70% respectively. It is finally recommended the use of weighted efficiencies for the evaluation of off-grid H2production systems, allowing fast and accurate comparison between different electrolyzer and DC-DC converter technologies while designing new plants.

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.

Differential-mode inverter is an attractive solution for photovoltaic (PV) microinverter applications since this structure allows to perform both voltage elevation and grid connection in a single conversion stage. In this paper a partial power differential mode inverter (PPDMI) is proposed. It is demonstrated that by using two partial power converter, the proposed solution allows to reduce the power rating of the structure by 15% in comparison to full-power structure. Moreover, averaged power processed by the converter is also reduced by 33%. In order to validate the proposed converter a PV microinverter realized with a flyback-based PPDMI has been simulated. The results show the attractiveness of the solution with estimated efficiency reaching 94.6%.

Budding yeast cells exist in two mating types, a and α, which use peptide pheromones to communicate with each other during mating. Mating depends on the ability of cells to polarize up pheromone gradients, but cells also respond to spatially uniform fields of pheromone by polarizing along a single axis. We used quantitative measurements of the response of a cells to α-factor to produce a predictive model of yeast polarization towards a pheromone gradient. We found that cells make a sharp transition between budding cycles and mating induced polarization and that they detect pheromone gradients accurately only over a narrow range of pheromone concentrations corresponding to this transition. We fit all the parameters of the mathematical model by using quantitative data on spontaneous polarization in uniform pheromone concentration. Once these parameters have been computed, and without any further fit, our model quantitatively predicts the yeast cell response to pheromone gradient providing an important step toward understanding how cells communicate with each other.

This paper presents an electrorefining plant operating with a photovoltaic dc-dc direct power interface. Different PV dc-dc power configurations are presented as alternative to partially feed the electrorefining process. The proposed power configuration is based on a multi-string dc-dc conversion system to achieve maximum power point tracking on each string, the electrorefining plant is fed through an interleaved isolated H-bridge dc-dc converter. The proposed configuration and control scheme are validated trough simulation results and tested under dynamic conditions.

This paper proposes a new power converter topology for the Wave Dragon multi-megawatt wave energy conversion platform. The current wave dragon power converter system is composed of several low-voltage two-level voltage source converters in back-to-back configuration; one per turbine-generator. Although this is a well known and proven technology, the use of distributed power electronic converters among all turbines does not bring any additional benefit in terms of efficiency and power quality. The proposed topology remains operating at low voltage and distributed at the generator side, but is combined at the grid side into a three-phase cascaded H-bridge (CHB) multilevel converter operating at medium voltage. This is achieved interfacing each PMSG through a low-voltage full bridge diode rectifier, followed by a boost dc-dc converter connected to the dc-link of the power cells of a 7-level CHB. The proposed configuration allows to concentrate the whole Wave Dragon platform into a single grid-tied converter with higher power quality and efficiency. Control schemes for both grid- and generator-side converters, and simulation results are presented in this paper.