Lack of inertia is one problem urgent for the stability of hybrid ac/dc system. In this paper, a comprehensive inertial control strategy is proposed for stability improvement of the hybrid ac/dc ...microgrid. The unified inertia index is introduced to evaluate the holistic inertia level of the hybrid microgrid. Besides, the coupling relationship between ac and dc nanogrid is discussed based on the power balance, which serves as the base of mutual inertial support. The characteristics of distributed generations (DGs) are analyzed, based on which the comprehensive inertial support is designed for various DGs respectively and adaptively divided into two responses: the local support and the cross-grid support. The proposed strategy takes full use of the rotational kinetic energy of wind turbine generator (WTG), and exploits the power capacity of distributed hybrid energy storages (HESs), which improves the global stability and dynamic performance of the hybrid microgrid during power disturbance. The performance of the proposed control strategy is validated by the simulation cases with different operating scenarios.
We developed a conceptual framework that describes the key role of ecosystem services in urban ecological infrastructure. From this framework we analyze how research on ecosystem services has been ...addressed in cities of Latin America and the Caribbean, in order to discuss their incorporation into policies of urban planning, in the context of nature-based solutions and sustainable development goals. Mexico, Brazil, Chile, Colombia and Argentina represent 90% of research in urban ecosystem services, all of them except Colombia had carried out studies considering green, blue and gray-hybrid infrastructures. However, green-hybrid infrastructure clustered most of the studies. Ecosystem service supply component and intermediate beneficiaries are the most studied. Our results show that most studies have not been developed from the perspective of the biophysical, sociocultural or economic assessment of ecosystem services, on the contrary we recognized or deduced them from proxy variables found within the studies. Our findings suggest that the study of urban ecosystem services in Latin America and the Caribbean is in development and has begun to increase in the last decade. However, we found that the incorporation of urban ecosystem services in urban planning is low, but at the same time, it is in a promising development related to the application of innovative actions such as nature-based solutions and in support of the new global urban agenda.
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•In 2050, 90% of population in Latin American and the Caribbean will be urban.•We integrated ecosystem services and urban ecological infrastructure in a framework.•Five countries represent the 90% of the research in urban ecosystem services (UES).•Green and blue-hybrid infrastructure have been the most studied in Latin cities.•Urban planners should use results of studies made in context different from UES.
Drive modes are driver-selectable pre-set configurations of powertrain and certain vehicle parameters. Plug-in hybrid electric vehicles typically feature the special options of drive modes that can ...affect the hybrid energy source management system; for example, electric vehicle mode (which draws fully on battery) and charge sustaining mode (which utilizes internal combustion engine to charge the battery while propelling the vehicle). This paper studies an optimization problem to enable the driver to select the appropriate drive modes for fuel minimization. We develop the optimization algorithms that optimize the decisions of drive modes based on trip information and, integrated with path planning to find an optimal path, considering intermediate filling and charging stations. We further provide an online algorithm that is based on the revealed trip information. We evaluate our algorithms empirically on a Chevrolet Volt, which shows significant fuel savings.
An SOFC-Engine hybrid power generation system is evaluated using exergetic and exergoeconomic analysis methods to determine measures for improving its efficiency and cost effectiveness. The system is ...a combination of a solid oxide fuel cell (SOFC) and an internal combustion engine; the engine burns the anode offgas and produces additional power, thus improving the electrical efficiency of the overall system.
The exergetic analysis, on the SOFC-Engine hybrid system, identifies the location, magnitude, and sources of thermodynamic inefficiencies (exergy destructions and exergy losses) in the system; the largest exergy destruction takes place within the internal combustion engine, followed by the heat exchangers, and the SOFC stack. Through the exergoeconomic analysis, the cost structure of the SOFC-Engine hybrid system is revealed, and the exergoeconomic factor of each component is quantified. The highest exergoeconomic factor of 93% is observed in the SOFC stack, implying that reducing the equipment cost of SOFC is of high importance to reduce the final product of the overall system. On the other hand, the fuel/water preheater shows the lowest exergoeconomic factor of 7%, meaning that improving its thermodynamic efficiency is more important for that component. Concerning the internal combustion engine, a well-balanced exergoeconomic factor of 52% is calculated.
•An SOFC-Engine hybrid system is analyzed using exergetic and exergoeconomic analyses.•The SOFC-Engine hybrid shows the highest efficiency among all analyzed systems.•The largest exergy destruction takes place on the internal combustion engine.•Through the exergoeconomic analysis, measures for the cost reduction are suggested.
•A new damper, which can achieve different damping modes, is applied to vehicle suspension.•The hybrid dynamics of the air suspension with the new damper are modeled using MLD systems.•The optimal ...control of the switching sequences of the damping modes is achieved by MPC method.
This paper presents the hybrid modeling and the model predictive control of an air suspension system with damping multi-mode switching damper. Unlike traditional damper with continuously adjustable damping, in this study, a new damper with four discrete damping modes is applied to vehicle semi-active air suspension. The new damper can achieve different damping modes by just controlling the on-off statuses of two solenoid valves, which makes its damping adjustment more efficient and more reliable. However, since the damping mode switching induces different modes of operation, the air suspension system with the new damper poses challenging hybrid control problem. To model both the continuous/discrete dynamics and the switching between different damping modes, the framework of mixed logical dynamical (MLD) systems is used to establish the system hybrid model. Based on the resulting hybrid dynamical model, the system control problem is recast as a model predictive control (MPC) problem, which allows us to optimize the switching sequences of the damping modes by taking into account the suspension performance requirements. Numerical simulations results demonstrate the efficacy of the proposed control method finally.
A switched-capacitor bidirectional dc-dc converter with a high step-up/step-down voltage gain is proposed for electric vehicles with a hybrid energy source system. The converter presented has the ...advantages of being a simple circuit, a reduced number of components, a wide voltage-gain range, a low voltage stress, and a common ground. In addition, the synchronous rectifiers allow zero voltage switching turn-on and turn-off without requiring any extra hardware, and the efficiency of the converter is improved. A 300 W prototype has been developed, which validates the wide voltage-gain range of this converter using a variable low-voltage side (40-100 V) and to give a constant high-voltage side (300 V). The maximum efficiency of the converter is 94.45% in step-down mode and 94.39% in step-up mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.
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•Novel hybrid nanostructures have multi-functional features.•Organic and inorganic hybrid nanostructures have renewed applications in nanomedicine.•Applications include combination ...chemotherapy, gene therapy, immunotherapy, imaging.
Hybrid nanostructures are nanocomposites constructed from at least two different types of materials to imbibe the individual advantages while overcoming individual shortcomings and forming one nanostructure with superior properties not possessed by single component nanostructures. Organic and inorganic hybrid nanostructures are a class of promising nanocomposites that possess interesting biological and physicochemical properties, making them highly attractive in biomedical applications. Recently, organic hybrid nanostructures such as hybrid lipid-based systems, hybrid polymeric nanoparticles, micelles, dendrimers and inorganic hybrid nanostructures such as metal nanoparticles, hybrid carbon nanomaterials, hollow mesoporous silica nanoparticles, hybrid magnetic nanoparticles and layered double hydroxides nanosheets and organic–inorganic hybrid nanostructures are developed for implementation in nanomedicine. Numerous studies have been conducted to investigate the employment of hybrid nanostructures in biomedical fields for gene therapy, chemotherapy, immunotherapy, combination chemotherapy, imaging platform, photodynamic and photothermal therapy. Novel hybrid nanostructures with multi-functional features have been evolved. This review summarizes the recent development and applications and directs the future perspective of hybrid nanostructures in biomedical applications.
The efficiency of Hybrid Electric Vehicles (HEVs) may be substantially increased if the energy of the exhaust gases, which do not complete the expansion inside the cylinder of the internal combustion ...engine, is efficiently recovered by means of a properly designed turbogenerator and employed for vehicle propulsion; previous studies, carried out by the same authors of this work, showed a potential hybrid vehicle fuel efficiency increment up to 15% by employing a 20 kW turbine on a 100 HP rated power thermal unit. The innovative thermal unit here proposed is composed of a supercharged engine endowed with a properly designed turbogenerator, which comprises two fundamental elements: an exhaust gas turbine expressly designed and optimized for the application, and a suitable electric generator necessary to convert the recovered energy into electric energy, which can be stored in the on-board energy storage system of the vehicle. In these two parts, the realistic efficiency of the innovative thermal unit for hybrid vehicle is evaluated and compared to a traditional turbocharged engine. In Part 1, the authors present a model for the prediction of the efficiency of a dedicated radial turbine, based on a simple but effective mean-line approach; the same paper also reports a design algorithm, which, owing to some assumptions and approximations, allows a fast determination of the proper turbine geometry for a given design operating condition. It is worth pointing out that, being optimized for quasi-steady power production, the exhaust gas turbine considered is quite different from the ones commonly employed for turbocharging application; for this reason, and in consideration of the required power size, such a turbine is not available on the market, nor has its development been previously carried out in the scientific literature. In the Part 2 paper, a radial turbine geometry is defined for the thermal unit previously calculated, employing the design algorithm described in Part 1; the realistic energetic advantage that could be achieved by the implementation of the turbogenerator on a hybrid propulsion system is evaluated through the performance prediction model under the different operating conditions of the thermal unit. As an overall result, it was estimated that, compared to a reference traditional turbocharged engine, the turbocompound system could gain vehicle efficiency improvement between 3.1% and 17.9%, depending on the output power level, while an average efficiency increment of 10.9% was determined for the whole operating range.
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