This paper presents a comparative study of modulation strategies for a full-bridge based unidirectional step-down partial power converter (PPC), focusing on a newly proposed Buck Modulation (BM) scheme. Unlike traditional Phase-Shift Modulation (PSM), BM disables transformer utilization by applying identical PWM signals to all switches in the converter’s full-bridge, effectively converting the topology into an equivalent buck converter. Thermal simulations were conducted to evaluate efficiency performance across different transformer turns ratios and load conditions. Results demonstrate that BM achieves superior efficiency at light loads when the transformer ratio is below unity, and consistently outperforms PSM across the entire power range when the ratio exceeds unity. Furthermore, BM offers a wider and more flexible operating voltage range.

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.

This paper proposes a DC-coupled PEM electrolyzer current control scheme combined with an Input Capacitors Voltage Balancing (ICVB) strategy for a three-channel interleaved dual buck converter topology, aimed at low-carbon hydrogen production. Input capacitors voltage imbalance can lead to improper operation of the interleaved dual buck converter topology, potentially damaging the power components. To address this issue, a control scheme featuring differential operation is proposed to regulate the input voltages, alongside the current control of the electrolyzer, directly influencing the amount of hydrogen produced. By controlling 5 out of 6 inductor currents, it is possible to leave one degree of freedom to control the voltage balance of the input capacitors, indirectly controlling the remaining current due to the operating principle of the topology. Simulation results are presented to validate the proposed control scheme for the proposed system with a nominal power of 1MW.

Electric vehicle (EV) charging infrastructure is critical, especially considering the exponential increase in electric vehicle adoption over the last decade, leading to a surge in demand for charging stations. However, it is not just about increasing their number; consideration should also be given to the reliability and availability of these chargers. Several factors can affect power converter reliability, many of which have been studied independently of the application. Nevertheless, in addition to those EV chargers are subjected to unique controls and operation that depend on the different battery charging profiles that have been proposed. This work analyzes the impact of different load profiles on semiconductors, using a total of four different load profile strategies. The results show that there is a very similar impact on damage among the most mainstream charging profiles. However, the Pulse Charging (PC) profile stands out as one that accumulates more semiconductor damage, reducing EV charger reliability.

Electromobility has experienced rapid expansion, where electric vehicle (EV) battery and charging processes are of great importance. Charging profiles have been proposed to enhance charging speeds while improving battery lifetime. However, more research is needed in relation to their impact on the charging infrastructure. This paper analyzes the impact of the charging profile over the global efficiency of the power converter of the fast charging station. Both full and partial charges are considered, and four types of charging profiles and variants, for a total of 12 charging profiles are considered. Results of this study show significant efficiency differences depending on the charging profile, being the classical Constant Current Constant Voltage (CCCV) at low charging rate the most efficient charging profile, while Pulse Charging (PC) leads to the lowest. The dependence of the global efficiency of the power converter with the corresponding charging time is also analyzed.

Electromobility has been growing rapidly in recent years, as a result of green and sustainability policies that promote it, but its growth has been hampered by having less autonomy than combustion vehicles, not being able to directly replace them especially in heavy-duty electric vehicles powertrains. The main objective of this work is to propose an improvement to an already implemented Bidirectional Dual-Active-Bridge (DAB) Partial Power Converter (PPC) topology, seeking to boost efficiency by testing different modulations. The modulation study applied to PPC is interesting in order to identify the cases where the RMS current in the transformer is minimized. Results of the study shows that efficiency of the DAB-based PPC can be optimized by using the correct modulation, with a possible maximum efficiency of 99.41% at 6.526 kW.

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.

DC microgrids have been gaining importance in modern power grids. Thanks to its DC nature, photovoltaic (PV) energy generation fits perfectly as a renewable source for DC microgrids. In this context, DC-DC converters are used to interconnect the PV source with the DC bus of the microgrid. This paper proposes a new transformerless partial power AC-link converter which can be used for this purpose. Unlike traditional partial power converters, the proposed solution does not require the use of a transformer. A reduced dynamic average model of the new converter is presented and detailed operation of the proposed converter is given, along with simulation results, to validate the converter’s behavior. Results on a 6.5 kW PV system show a maximum efficiency of 98.7%, confirming the interest of the proposed transformerless partial power AC-link converter in a DC microgrid.

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%.

This paper presents a comparison of buck-boost partial power converters (PPC) for the DC-DC conversion stage of an electrical vehicle (EV) fast charging station. By using a DC-DC buck-boost structure, the proposed fast charger can operate with wide output voltage range. The proposed topology can be used to charge either 400V or 800V batteries. Since the PCC only processes a fraction of the total power, high efficiency is obtained. Two different buck-boost PPC topologies are compared. First structure consider two-quadrant switches in order to obtain bipolar voltage, while the second structure uses an unfolding bridge to change the voltage polarity. Results show that the first solution with two-quadrant switches allows better efficiency. The proposed converter operation is then evaluated for fast charging applications for both 400V and 800V batteries, showing high efficiency up to 99%, making the proposed solution very attractive for fast charging application.

In photovoltaic (PV) systems, module level power electronics has focused a lot of attention in the last years. The microinverter, also known as AC module, has shown to be an interesting solution. For this purpose, PV microinverter architectures with pseudo DC-link consisting in a DC-DC converter followed by an unfolding inverter have been analyzed as good alternatives. This paper proposes a new push-pull based pseudo DC-link microinverter. Simulation results are provided to validate the behavior of the proposed microinverter. Comparison with the classical interleaved flyback pseudo DC-link microinverter is given to show the interest of the proposed structure. Results show improvement in terms of conversion efficiency and power quality.

This paper proposes an interleaved partial power converter (PPC) for the DC-DC conversion stage of electric vehicles (EVs) fast charging stations. The proposed converter topology is based on the H-bridge DC-DC converter. PPC allows the converter to process only a fraction of the total power, the rest being bypassed and directly supplied to the load. This increases the converter efficiency, as only a portion of the power goes through the converter, thus increasing its efficiency. The principle of operation of the proposed PPC is theoretically analyzed. Simulations of the behavior of the proposed PPC are provided for the charging of an EV battery. Results show the good behavior of the proposed system. It is in particular verified that the proposed converter only process a fraction of the power around 36% for the entire output power range. Comparison with a classical full power converter is provided showing that the proposed topology leads to a significant improvement in terms of conversion efficiency, from 95.1% to 98.3%.

In order to increase the conversion efficiency in photovoltaic (PV) systems, different configurations and topologies were developed. Depending on the application, the converters used for grid connection are built using one or two conversion stages. The advantages of the converters with a DC-stage are mainly the distributed maximum power point tracking algorithm per PV string or PV module and, when required for grid connection, the possibility of voltage elevation. However, the conversion efficiency is lower than configurations with a single-stage as the central inverter. Therefore, the proposed work presents a Partial Power DC-DC converter (PPC) which process part of the entire system power, and the remaining power is directly supplied to the output side. A topology is proposed and the details of its operation are explained based on the operating principle. Simulations are performed in order to evaluate the converter performance.