Balancing Supercapacitor Voltages in Modular Bidirectional DC–DC Converter Circuits

At present, passive balancing methods dominate energy storage applications, however, they suffer from a long balancing duration. In this article, we took advantage of a modular architecture, where several modular power converters replace a central dc–dc converter for fast charging and balancing of a supercapacitor stack. A strategy has been proposed to control how power is shared among the converters during the charging period in order to balance the supercapacitors. However, some converters enter control saturation due to voltage differences between supercapacitors caused by their nonuniform conditions and characteristics. The originality of this article lies in taking into account the saturation by modifying an energy-based strategy to correct the power shares and make balancing the supercapacitors possible. Simulation and experimental case studies were used to demonstrate the strategy\u27s performance and limitations

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Energy Management for Grid-Tied PV Systems Using Particle Swarm Optimization

The main purpose of an Energy Management System (EMS) is to determine the hourly energy dispatch of the microgrid and the main utility grid. An optimization algorithm is needed in order to minimize the cost of operating the distributed generations in a microgrid. This paper is focused on developing an EMS model that can determine the hourly optimal operating strategies of each distributed generation in the microgrid system with regard to energy cost minimization, system constraints, and better utilization of renewable energy resources through daily load demand. The proposed system utilized Particle Swarm Optimization. Its effectiveness was demonstrated using a full-day load demand profile of a grid-connected microgrid as the case study

Feasibility Study of a Hybrid Renewable Energy System for a Remote Rural Community Using HOMER Pro

As the Philippines strives towards energy security, there remains the concern for reliable and stable electricity in rural areas due to the lack of access to the main grid and the high cost of expansion. Standalone energy systems in rural areas can increase energy security from local renewable sources such as solar, wind, and water resources. This study modeled and designed a hybrid renewable energy system (HRES) in a remote rural community using HOMER Pro simulations. The goal is to assess the feasibility of integrating solar and wind energy resources with the existing micro-hydro power plant to provide 24/7 electricity in the community. A techno-economic assessment and an implementation strategy of the HRES are presented in this paper. Results show that the optimal HRES configuration has an additional cost of energy of PHP 3.98 per kW and includes 84-kW solar PV panels, 84 batteries, and a 27-kW converter. These can be integrated into the existing 10-kW micro-hydro power system. Together with the hardware technical specifications and system configuration, this contribution provides cost calculations, and has identified approaches to add to the overall system\u27s long-term sustainability