Ayiguzhali Tuluhong

Conventional virtual synchronous generators (VSGs) employ fixed inertia and damping parameters, resulting in insufficient adaptability to varying operating conditions. Moreover, virtual inertia may cause active-power overshoot and dynamic oscillations and slow down the transient response. To address these issues, a fractional-order VSG control strategy with fuzzy adaptive inertia and damping regulation is proposed. A small-signal model of the active-power loop is established to analyze the oscillation mechanism and the effects of key parameters on system dynamics. A fractional-order inertia element is introduced to improve the power-frequency dynamic response, while a fuzzy controller adjusts the virtual inertia and damping coefficients online according to the system dynamic state. The proposed strategy is validated under multiple operating conditions, together with sensitivity and robustness analyses. Simulation results show that, compared with the conventional VSG, the proposed strategy reduces the active-power overshoot ratio from 38.84% to 0.95% under an active-power reference variation. Under a grid-frequency disturbance, the maximum power deviation and maximum frequency deviation are reduced by 1.710 kW and 0.0374 Hz, respectively. Further simulations under varying operating conditions demonstrate that the proposed strategy maintains good dynamic performance and robustness. The proposed method achieves a favorable balance among power-oscillation suppression, frequency support, and robustness, providing an effective control solution for grid-connected photovoltaic-storage systems with high renewable-energy penetration.

Large-scale photovoltaic (PV)–hydrogen production systems are increasingly regarded as a promising solution for mitigating renewable energy curtailment and supporting the transition toward low-carbon energy systems. However, when connected to weak grids, such systems often suffer from insufficient voltage–frequency support capability and pronounced Direct current (DC) bus voltage fluctuations, which limit their operational stability and practical deployment. To address these challenges, this paper proposes a dual virtual motor coordinated control strategy for PV-based hydrogen production systems, integrating a grid-forming virtual synchronous generator (VSG) with a virtual DC motor (VDCM). By exploiting the complementary dynamic characteristics of grid-side converters and hydrogen production loads, the proposed approach enhances grid support capability while simultaneously providing inertia and damping to the hydrogen production DC bus without relying on additional physical energy storage. Dynamic response analysis is conducted to investigate the influence of virtual inertia and damping parameters on system stability. Simulation results under weak-grid conditions demonstrate that the proposed strategy effectively improves frequency and voltage support performance and significantly suppresses DC bus voltage fluctuations during load and power disturbances. The proposed control framework offers a practical and scalable solution for improving the operational robustness of PV–hydrogen production systems, contributing to the reliable integration of renewable energy and the development of green hydrogen infrastructure.

Grid-connected PV inverters (GCPI) are key components that enable photovoltaic (PV) power generation to interface with the grid. Their control performance directly influences system stability and grid connection quality. However, as PV penetration increases, conventional controllers encounter difficulties in managing nonlinear dynamics and weak-grid conditions. This paper reviews both conventional and artificial intelligence (AI)-based control methods for GCPI. It compares their performance characteristics, application scenarios, and limitations and summarizes current research progress and remaining challenges. The potential and issues of applying AI to enhance system intelligence are also highlighted. Finally, future development trends are discussed, emphasizing high efficiency, strong adaptability, and intelligent integration in GCPI technologies.

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.

With the continuous proliferation and development of renewable energy technologies, three-level converters have gained widespread application due to their lower output harmonics and higher output voltage. However, in practical applications, multilevel converters inevitably encounter issues such as common-mode voltage (CMV) and neutral-point voltage (NPV) imbalance, which significantly affect system stability and operational lifespan. This paper investigates the root causes of neutral-point voltage fluctuations and common-mode voltage generation. It provides an analysis and summary of solutions for CMV suppression and NPV balancing, focusing on space vector modulation (SVM) strategies, carrier-based modulation techniques, modulation waveform approaches, and intelligent control methods. Furthermore, the paper explores future development trends, aiming to provide valuable insights for subsequent theoretical research and practical applications.

As an important piece of equipment in photovoltaic power generation systems, the bidirectional DC-DC converter plays a vital role in improving the conversion efficiency of photovoltaic power generation system. The energy transfer in PV systems heavily relies on efficient bidirectional DC-DC converters. To ensure stable operation, converters with high reliability and power density are required. This paper introduces the basic principles and topologies of bidirectional DC-DC converters and provides a comparative analysis. And it examines the characteristics of the converters’ control schemes and switching strategies, summarizes the existing research findings and current issues. Finally, it looks ahead to the future development trends of bidirectional DC-DC converters in PV systems.

As a clean energy source, hydrogen not only helps to reduce the use of fossil fuels but also promotes the transformation of energy structure and sustainable development. This paper firstly introduces the development status of green hydrogen at home and abroad and then focuses on several advanced green hydrogen production technologies. Then, the advantages and shortcomings of different green hydrogen production technologies are compared. Among them, the future source of hydrogen tends to be electrolysis water hydrogen production. Finally, the challenges and application prospects of the development process of green hydrogen technology are discussed, and green hydrogen is expected to become an important part of realizing sustainable global energy development.

Transnational cooperation in international corporations has become an important force in promoting the economic development of countries, and corruption in cross-cultural business has an important impact on the sustainable development of international cooperation. Based on the construction field, this study applies evolutionary game theory to the microlevel to investigate the corrupt behavior of international corporations from reputation perspectives, taking into account their reputation and cooperation behaviors. The findings indicate that the sensitivity of each party involved in the corruption behavior differs concerning international reputation, and a heightened reputation of the supervisory company can effectively curb the corrupt behavior of subcontracting. Additionally, the behavior of the general contracting company shows a sense of inertia, while the three main parties—general contracting company, supervisory company, and subcontracting company—exhibit multistage decision-making characteristics as their international reputation gradually improves. Through the lens of multinational enterprise cooperation and the development of the construction industry, this study aims to address the constraints faced by the construction industry in various countries and identify potential solutions. Furthermore, it provides insights into key issues related to international engineering corruption governance.

Operational inefficiencies in healthcare buildings and sustainability issues have become increasingly prominent. The root cause of this phenomenon is the irregular and incomplete structured data related to hospital user activities and spaces that are difficult to resolve using traditional manual methods. In order to solve this problem, an automated mapping approach is presented for hospital user activity and space. Using the Revit API technology and the C# language on the Visual Studio platform, a program for automated mapping is developed. It achieves the automatic mapping of hospital user activities and spaces, along with automatic calculation of utilization rates. An illustrative case study is conducted, focusing on the activity data and building space utilization of healthcare users at Shanghai Renji Hospital. The results indicate that (1) This method can realize the automatic combination of hospital user activities and hospital spaces, and hospital administrators can optimize the utilization rate of hospital spaces quickly and accurately. (2) This approach is highly adaptable, especially to changes in hospital user activities and hospital spatial data. (3) This method promotes the sustainable development of healthcare buildings and has great practical application value.