Search Results (148)

Several applications require bidirectional power converters with high-voltage gain. While several topologies have been proposed, none of them exhibit Buck-Boost characteristics in both forward and reverse power transfer. Most proposals behave as a Boost converter in forward direction and as a Buck converter in the reverse direction. Therefore, this paper proposes a novel DC-DC bidirectional power converter that exhibits Buck-Boost characteristics in both power flow directions while providing very high wide voltage gain range. The proposed converter has, in addition, the ability to maintain continuous currents in the input and output. The theoretical analysis of the converter under bidirectional power flow conditions will be presented and examined, along with the design of its components. The validation of the characteristics and behavior of the proposed bidirectional power converter were tested in several laboratory experiments. The experimental results obtained from both power flow directions show agreement with the theoretical considerations. Full article

With the rapid advancement of hydrogen-based direct current microgrid (H₂-DCMG) technology, multi-port converters (MPCs) have emerged as the pivotal interface for integrating renewable power generation, energy storage, and diverse DC loads. This paper systematically reviews the current research status and development trends of isolated and non-isolated MPC topologies within hydrogen-based DC microgrids. Firstly, it analyses the interface requirements for typical distributed energy sources (DER) such as photovoltaics (PV), wind turbines (WT), fuel cells (FC), battery energy storage (BESS), proton exchange membrane electrolyzers (PEMEL), and supercapacitors (SC). Secondly, it classifies and evaluates existing MPC topologies, clarifying the structural characteristics, technical advantages, and challenges faced by each type. Results indicate that non-isolated topologies offer advantages such as structural simplicity, high efficiency, and high power density, making them more suitable for residential and small-scale microgrid applications. Isolated topologies, conversely, provide electrical isolation and modular scalability, rendering them appropriate for high-voltage electrolytic hydrogen production and industrial scenarios with stringent safety requirements. Finally, the paper identifies current research gaps and proposes that future efforts should focus on exploring topology optimization, system integration design, and reliability enhancement. Full article

Continuous advancements in power conversion techniques address the growing need for efficiency and adaptability in contemporary energy applications, including e-mobility, renewable energy, and energy storage systems. This work presents a review grounded in the fundamental topologies of power converters and subsequently analyzes their modern modifications and technological advances. Traditional structures such as Buck, Boost, Ćuk, and flyback converters remain effective solutions for voltage and current regulation; however, they exhibit limitations when extremely high voltage conversion ratios are required. These constraints have motivated the emergence of more sophisticated architectures capable of overcoming such challenges. In this context, the paper provides a novel characterization and comparative analysis of quadratic and bidirectional converter topologies, emphasizing their capability to efficiently achieve both high and low conversion ratios while minimizing component stress and avoiding extreme load cycles. Quadratic converters demonstrate high performance in nonlinear systems with significant energy demands, whereas bidirectional converters enhance energy management in applications requiring bidirectional power flow, such as electric vehicles and energy storage systems. Full article

This paper presents an innovative approach to the modeling and dynamic analysis of DC–DC converters in photovoltaic applications. Departing from traditional studies that focus on the transfer function from duty cycle to output voltage, this work investigates the duty cycle to input voltage transfer function, which is critical for accurate dynamic representation of photovoltaic systems. A notable contribution of this study is the integration of the PV panel behavior in the small-signal representation, considering a model-derived differential resistance for various operating points. This technique enhances the model’s accuracy across different operating regions. The paper also validates the effectiveness of this linearization method through small-signal analysis. A comprehensive comparison is conducted among several non-isolated converter topologies such as Boost, Buck–Boost, Ćuk, and SEPIC under both open-loop and closed-loop conditions. To ensure fairness, all converters are designed using a consistent set of constraints, and controllers are tuned to maintain similar phase margins and crossover frequencies across topologies. In addition, a gain-scheduling control strategy is implemented for the Boost converter, where the PI gains are dynamically adapted as a function of the PV operating point. This approach demonstrates superior closed-loop performance compared to a fixed controller tuned only at the maximum power point, further highlighting the benefits of the proposed modeling and control framework. This systematic study therefore provides an objective evaluation of dynamic performance and offers valuable insights into optimal converter architectures and advanced control strategies for photovoltaic systems. Full article

As a pivotal clean energy carrier for achieving carbon neutrality, green hydrogen technology has attracted growing global attention. This review systematically examines four mainstream water electrolysis technologies—alkaline electrolysis, proton exchange membrane electrolysis, solid oxide electrolysis, and anion exchange membrane electrolysis—analyzing their fundamental principles, material challenges, and development trends. It further classifies and compares power electronic converter topologies, including non-isolated and isolated DC–DC converters as well as AC–DC converter architectures, and summarizes advanced control strategies such as dynamic power regulation and fault-tolerant operation aimed at enhancing system efficiency and stability. A holistic “electrolyzer–power converter–control strategy” integration framework is proposed to provide tailored technological solutions for diverse application scenarios. Finally, the challenges and future prospects of green hydrogen across the energy, transportation, and industrial sectors are discussed, underscoring its potential to accelerate the global transition toward a sustainable, low-carbon energy system. Full article

This paper presents an enhanced non-isolated single-switch quadratic boost DC-DC converter. The proposed topology employs a single active switch, two inductors, two capacitors, and three diodes. The proposed design improves system reliability by replacing one of the active switches in a conventional cascaded boost converter with a diode. Two key features of this converter are its single switch, which simplifies operation, and the use of a lifting capacitor for voltage step-up. The reduced switch count and the use of Schottky diodes minimize switching losses and enhance overall efficiency. Comprehensive theoretical steady-state analysis under continuous conduction mode (CCM) is carried out to characterize the converter’s performance. Notably, at a 50% duty cycle, the converter achieves a voltage gain of four, while at a 70% duty cycle, it can reach a voltage gain of approximately 11. The proposed topology is validated through extensive simulations in MATLAB/Simulink (2023). In addition, a prototype with a 5 V input and 20 V output at a switching frequency of $50\mathrm{kHz}$ was constructed and tested. The experimental unit achieved an efficiency of about 85% at a 5 V input. The results confirm that the converter achieves high voltage gain and improved efficiency, making it well-suited for IoT and energy harvesting applications. Full article

A multi-port conversion system that connects photovoltaic (PV) arrays, battery energy storage (BES), and an electric vehicle (EV) to a single-phase grid offers a flexible solution for smart homes. By integrating Vehicle-to-Grid (V2G) and Vehicle-to-Home (V2H) technologies, the system supports bidirectional energy flow, optimizing usage, improving grid stability, and supplying backup power. The proposed four-port converter consists of an interleaved bidirectional DC-DC converter for high-voltage BES, a bidirectional buck–boost DC-DC converter for EV charging and discharging, a DC-DC boost converter with MPPT for PV, and a grid-tied inverter. Its non-isolated structure ensures high efficiency, compact design, and fewer switches, making it suitable for residential applications. A state-of-charge (SoC)-based power management strategy coordinates operation among PV, BES, and EV in both on-grid and off-grid modes. It reduces reliance on EV energy when supporting V2G and V2H, while SoC balancing between BES and EV extends lifetime and lowers current stress. A 7.5 kVA system was simulated in MATLAB/Simulink to validate feasibility. Two scenarios were studied: PV, BES, and EV with V2G supporting the grid and PV, BES, and EV with V2H providing backup power in off-grid mode. Tests under PV fluctuations and load variations confirmed the effectiveness of the proposed design. The system exhibited a fast transient response of 0.05 s during grid-support operation and maintained stable voltage and frequency in off-grid mode despite PV and load fluctuations. Its protection scheme disconnected overloads within 0.01 s, while harmonic distortions in both cases remained modest and complied with EN50610 standards. Full article

This article introduces a quadratic boost converter topology that has a low input current ripple compared to other quadratic boost traditional topologies. The proposed converter is inspired by the LCL filter; one of the inductors in the traditional converter is split into two inductors and a capacitor. The proposed converter has more components than its previous version, but two of its inductors are equivalent to the second inductor in the traditional quadratic boost, providing a non-increase in the size while reducing the switching ripple at the input current. These findings suggest that the proposed design is a viable alternative for applications where a quadratic gain is required while a small input current ripple is desirable. A comparative evaluation with a design showed the proposed converter reduced 20% in the stored energy of inductors and still has a reduction of more than 40% in the input current ripple. Simulation and experimental results are provided to demonstrate the principle of the proposition. Full article

This work introduces a non-isolated high step-up dc-dc interleaved boost converter combining magnetic coupling and voltage multiplier cells (VMCs). The proposed topology features a transformer with two primary windings of equal turns, interconnected to each other, enabling improved current sharing, and multiple secondary windings that contribute to extending the voltage gain. A three-winding coupled inductor is integrated into the design, while VMCs not only boost the output voltage but also significantly reduce the voltage stresses on the switches, eliminating the need for extreme duty ratios. The converter exhibits inherent modularity, allowing for voltage gain adjustments either through the turns ratio of the coupled inductor or by incorporating additional VMCs. An in-depth analysis of the topology is derived, and an experimental prototype rated at 48 V/400 V, 25 kHz, and 1 kW is implemented to verify and validate the theoretical claims, achieving an efficiency of 95.12% at full-load conditions. Full article

Given the decline in fossil energy reserves and the need for less pollution, achieving carbon zero is challenging in major industrial sectors. However, the emergence of large-scale hydrogen production systems powered by renewable energy sources offers an achievable option for carbon neutrality in specific applications. When combined with energy storage systems, static power converters are crucial in these production systems. This paper offers a comprehensive review of various power converter topologies, focusing on AC– and DC–bus architectures that interface battery storage units, electrolyzers, and fuel cells. The evaluation of DC/AC, AC/DC, and DC/DC converter topologies, considering cost, energy efficiency, control complexity, power level suitability, and power quality, represents a significant advancement in the field. Furthermore, the subsequent exploration of battery aging behavioral modeling, characterization methods, and real-time parameter estimation of the battery’s equivalent electrical circuit model enhances our understanding of these systems. Large-scale hydrogen production systems most often use an AC–bus architecture. However, DC–bus configuration offers advantages over AC–bus architecture, including high efficiency, simpler energy management, and lower system costs. In addition, MVDC or HVDC DC/DC converters, including isolated and non-isolated designs based on multiple cascaded DABs and MMC-type topologies, have also been studied to adapt the DC–bus to loads. Finally, this work summarizes several battery energy storage projects in the European Union, specifically supporting the large-scale integration of renewable energy sources. It also provides recommendations, discussion results, and future research perspectives from this study. Full article

Hybrid electric vehicles (HEVs) have gained significant attention for their superior energy efficiency and are becoming a predominant mode of urban transportation. The DC/DC converter plays a critical role in HEV energy management systems, especially in matching the voltage levels between the battery and DC bus. This paper proposes a novel high-gain DC/DC converter with a wide input voltage range based on coupled inductors. The innovation lies in the integration of a resonant cavity and the simultaneous realization of zero-voltage switching (ZVS) and zero-current switching (ZCS), effectively reducing both voltage/current stresses on the power switches and switching losses. Compared with conventional topologies, the proposed design achieves higher voltage gain without extreme duty cycles, improved conversion efficiency, and enhanced reliability. Detailed operating principles are analyzed, and design conditions for voltage stress reduction, gain extension, and soft switching are derived. The simulation model has been conducted in a PSIM environment, and a 300 W experimental prototype, implemented using a dsPIC33FJ64GS606 digital controller, has been established and demonstrates 93% peak efficiency at a 10 times voltage gain. The performance and practical feasibility of the proposed topology have been evaluated by both simulation and experiments. Full article

The research demonstrates, through simulation and laboratory validation, the development of a low-voltage DC-link (LVDC) back-to-back converter system that enables multi-frequency power transfer. The system operates in two distinct modes, which include a three-phase grid-connected converter transferring fundamental and 5th and 7th harmonic power to a three-phase residential inverter supplying a clean 50 Hz load and another mode that uses a DC–DC buck–boost converter to integrate a battery storage unit for single-phase load supply. The system allows independent control of each harmonic component and maintains a clean sinusoidal voltage at the load side through DC-link isolation. The LVDC link functions as a frequency-selective barrier to suppress non-standard harmonic signals on the load side, effectively isolating the multi-frequency power grid from standard-frequency household loads. The proposed solution fills the gap between the multi-frequency power systems and the single-frequency loads because it allows the transfer of total multi-frequency grid power to the traditional household loads with pure fundamental frequency. Experimental results and simulation outcomes demonstrate that the system achieves high efficiency, robust harmonic isolation, and dynamic adaptability when load conditions change. Full article

In this paper, a detailed review of electric vehicle (EV) charging station architectures is first presented, and then an optimal architecture suitable for a large MW-scale EV fast-charging station (EVFS) with multiple fast chargers is proposed and evaluated. The study examines various EVFS architectures, including those currently deployed in commercial sites. Most EVFS implementations use either a common AC-bus or a common DC-bus configuration, with DC-bus architectures being slightly more predominant. The paper analyzes the EV charging and battery energy storage system (BESS) requirements for future large-scale EVFSs and identifies key implementation challenges associated with the full adoption of the common DC-bus approach. To overcome these limitations, a novel multi-zone EVFS architecture is proposed that employs an optimal combination of isolated and non-isolated DC-DC converter topologies while maintaining galvanic isolation for EVs. The system efficiency and total power converter capacity requirements of the proposed architecture are evaluated and compared with those of other EVFS models. A major feature of the proposed design is its multi-zone division and zonal isolation capabilities, which are not present in conventional EVFS architectures. These advantages are demonstrated through a scaled-up model consisting of 156 EV fast chargers. The analysis highlights the superior performance of the proposed multi-zone EVFS architecture in terms of efficiency, total power converter requirements, fault tolerance, and reduced grid impacts, making it the best solution for reliable and scalable MW-scale commercial EVFS systems of the future. Full article

The constantly changing characteristics of sources, loads, and operating environments in microgrids aboard marine vessels warrant the need for the real-time and accurate transient state estimation of the various converters used for power flow management. This paper presents the digital twin development for a parameter-varying non-isolated DC-DC buck (step down) converter to demonstrate the potential of circuit identification and state estimation within a single digital twin model. The digital twin will utilize individual and parameter-specific NARX-RNNs in a centralized model to identify and adapt system state predictions relative to the most current configuration of the buck converter. Additionally, the model’s ability to maintain state estimation accuracy in the presence of circuit component variation will be demonstrated through simulated deviations from nominal values, and model versatility will be shown through testing a simulation-based model on physical hardware. This modular model, which is demonstrated through simulation and experimentation, can be adapted and scaled for additional circuit configurations. It has the potential to be integrated into real-time system monitoring and fault detection systems within multi-converter microgrid environments. Full article

This paper introduces a non-isolated ultra-high voltage gain topology using the combination of the coupled-inductor-based inverting buck-boost converter (IBB) and voltage multiplier (VM) structure. In the proposed converter, an ultra-high step-up voltage gain can be achieved with a small duty cycle thanks to a coupled inductor and VMs. The voltage stress and the losses of the switches in the proposed converter are even less than other conventional topologies. Unlike other coupled-inductor topologies, a large voltage spike caused by the leakage inductance of the coupled inductor is smoothed by the capacitor in the voltage multiplier. In addition, zero-voltage switching (ZVS) turn-on for the switches and zero-current switching (ZCS) turn-off for the diodes can be achieved with the energy stored in the leakage inductance. A 360 W (40 V/380 V) prototype converter is implemented to prove the advantages of the proposed converter, with a maximum efficiency of 98.4%. Full article