This paper introduces a new multilevel converter topology for a hybrid HVDC system comprising line-commutated converter (LCC) and voltage source converter (VSC). Among the existing modular multilevel ...converter (MMC) topologies for the hybrid HVDC, a mixed MMC structure with half-bridge submodules (HBSMs) and full-bridge submodules (FBSMs) has characteristics of reduced system cost, low operation loss, but still keeping capability to cope with dc short-circuit fault. However, it is very difficult for the conventional hybrid MMC structure to balance the submodule capacitor voltages under dc-bus voltage sliding since each MMC arm is a mixture of HBSMs and FBSMs. To solve the defect of the conventional hybrid MMC structure, an asymmetric mixed MMC, in which one arm is made of series-connected HBSMs and other arm is made of FBSMs, is devised. The proposed asymmetric MMC can regulate the dc-bus voltage freely without uncontrollable submodule capacitor voltages. The problems of the conventional MMC structure and the validity of asymmetric MMC are verified by both computer simulation and experimental results.
On hybrid k-ideals in semirings Elavarasan, B.; Muhiuddin, G.; Porselvi, K. ...
Journal of intelligent & fuzzy systems,
01/2023, Letnik:
44, Številka:
3
Journal Article
Recenzirano
Many uncertainties arise in real-world problems, making them impossible to solve using conventional approaches. Researchers all over the world have developed new mathematical theories like fuzzy set ...theory and rough set theory to better understand the uncertainties that occur in various fields. Soft set theory, which was recently introduced, offers a novel approach to real-world problem solving by removing the need to set the membership function. This is helpful in resolving a variety of issues, and much progress is being made these days. Recently, Jun introduced the concept of a hybrid structure, which blends the concepts of a fuzzy set as well as a soft set. In this paper, we define the hybrid k-sum and hybrid k-product of k-ideals of semiring and investigate their properties. We illustrate with an example that the hybrid sum and hybrid product of two k-ideals are not always hybrid ideals. We also describe semiring regularity constraints in terms of hybrid k-ideal structures.
In this paper, a multiinput dc-dc converter is proposed and studied for hybrid electric vehicles. Compared to conventional works, the output gain is enhanced. Fuel cell (FC), photovoltaic panel, and ...energy storage system are the input sources for the proposed converter. The FC is considered as the main power supply, and roof-top PV is employed to charge the battery, increase the efficiency, and reduce fuel economy. The converter has the capability of providing the demanded power by load in absence of one or two resources. Moreover, the power management strategy is described and applied in a control method. A prototype of the converter is also implemented and tested to verify the analysis.
This paper is concerned with the simultaneous optimal component sizing and power management of a fuel cell/battery hybrid bus. Existing studies solve the combined plant/controller optimization ...problem for fuel cell hybrid vehicles (FCHVs) by using methods with disadvantages of heavy computational burden and/or suboptimality, for which only a single driving profile was often considered. This paper adds three important contributions to the FCHVs-related literature. First, convex programming is extended to rapidly and efficiently optimize both the power management strategy and sizes of the fuel cell system (FCS) and the battery pack in the hybrid bus. The main purpose is to encourage more researchers and engineers in FCHVs field to utilize the new effective tool. Second, the influence of the driving pattern on the optimization result (both the component sizes and hydrogen economy) of the bus is systematically investigated by considering three different bus driving routes, including two standard testing cycles and a realistic bus line cycle with slope information in Gothenburg, Sweden. Finally, the sensitivity of the optimization outcome to the potential price decreases of the FCS and the battery is quantitatively examined.
•Preparation of hybrid nano-composites and nanofluids.•Stability measurement and enhancement methods of hybrid nanofluids.•Factors affecting thermal conductivity of hybrid nanofluids.•Mechanisms ...involving in thermal conductivity enhancement of hybrid nanofluids.•Correlations to predict thermal conductivity to hybrid nanofluids.
Innumerable studies are conducted on nanofluids containing single type nanoparticles and attributes of such colloidal mixture have been well elucidated and prospected. Furtherance in nano-composites has entitled production of hybrid nanomaterials (nanoparticles) and remarkable researchers are exploring hybrid nanofluid characteristics. The cardinal objective of this study is to provide a comprehensive review on thermal conductivity of hybrid nanofluids by overviewing experimental, numerical and ANN (artificial neural networking) studies. Assorted factors that affect thermal conductivity such as nanoparticle type, concentration of nanoparticles, types of base fluid, size of nanoparticle, temperature, addition of surfactant, pH variation and sonication time are analyzed in present paper. Additionally, synthesis of hybrid nano-composites, preparation of hybrid nanofluids, approaches for stability measurement and enhancement, methods of thermal conductivity measurement and reasons for thermal conductivity enhancement are discussed. Miscellaneous empirical correlations developed by researchers for thermal conductivity prediction of hybrid nanofluids are also compiled and presented. Results suggest that enhancing temperature and concentration increases thermal conductivity and proper selection of hybrid nanoparticles plays a prime role in attaining stability of hybrid nanofluids.
The main purpose of this article is to develop the energy management for off-road hybrid vehicle with cyber-physical approach. Three main endeavor make this paper different from the existing relevant ...literature. First, a hybrid energy storage system (HESS) is utilized in an off-road hybrid vehicle to study its potential benefits over conventional use of only a battery or ultracapacitor (UC) packs. The main potential advantages of coupling a UC and a battery pack are in reducing cost, space, and weight. Second, an average power based model predictive control is proposed to solve the energy management of the vehicle with multiple energy sources without any priori information of the drive cycles. After modeling, the optimization problem with multiobjective that takes battery life into account is introduced. Finally, a comparison study is presented to analyze the benefits of the HESS in off-road hybrid vehicles over vehicles equipped with only a UC or a battery pack. The results show that using an HESS in off-road hybrid vehicles reduces the total cost, space, and weight. More specifically, the cost of the energy storage system (ESS) is decreased by 36% and 32.5% compared to only battery and only UC ESS, respectively.
This paper proposes a new decentralized power management and load sharing method for a photovoltaic based islanded microgrid consisting of various photovoltaic (PV) units, battery units and hybrid ...PV/battery units. Unlike the previous methods in the literature, there is no need to communication among the units and the proposed method is not limited to the systems with separate PV and battery units or systems with only one hybrid unit. The proposed method takes into account the available PV power and battery conditions of the units to share the load among them. To cover all possible conditions of the microgrid, the operation of each unit is divided into five states and modified active power-frequency droop functions are used according to operating states. The frequency level is used as trigger for switching between the states. Efficacy of the proposed method under different load, PV generation, and battery conditions is validated experimentally in a microgrid lab prototype consisting of three units.
This paper proposes a modular multilevel converter (MMC) based switched reluctance motor (SRM) drive with decentralized battery energy storage system for hybrid electric vehicle applications. In the ...proposed drive, a battery cell and a half-bridge converter is connected as a submodule (SM), and multiple SMs are connected together for the MMC. The modular full-bridge converter is employed to drive the motor. Flexible charging and discharging functions for each SM are obtained by controlling switches in SMs. Multiple working modes and functions are achieved. Compared to conventional and existing SRM drives, there are several advantages for the proposed topology. A lower dc-bus voltage can be flexibly achieved by selecting SM operation states, which can dramatically reduce the voltage stress on the switches. Multilevel phase voltage is obtained to improve the torque capability. Battery state-of-charge balance can be achieved by independently controlling each SM. Flexible fault-tolerance ability for battery cells is equipped. The battery can be flexibly charged under both running and standstill conditions. Furthermore, a completely modular structure is achieved by using standard half-bridge modules, which is beneficial for market mass production. Experiments carried out on a three-phase 12/8 SRM confirm the effectiveness of the proposed SRM drive.
Under the complicated driving conditions, the sharp acceleration and deceleration actions would cause the high-rate charge and discharge current of electric driving system in hybrid electric vehicle ...(HEV), which brings about a serious impact on the battery lifetime. The hybrid energy storage system (HESS) combined with battery and ultracapacitor (UC), would be a possible solution to this problem. For HEV with HESS, in addition to improving fuel economy, realizing the protection of battery is also an important objective. However, improving one aspect performance may sacrifice another aspect performance. The tradeoff between multiple optimization objectives remains a challenge for energy management design. Aiming at this problem, a multi-objective optimization energy management strategy based on velocity prediction for a dual-mode power split HEV with HESS is proposed in this paper. Firstly, to get the precise predictive input sequence, generalized regression neural network (GRNN) is used to predict future velocity. Secondly, the power distribution of dual-mode power spilt HEV with HESS is described as a rolling optimization problem in the prediction horizon of model predictive control (MPC). A new cost function considering the fuel consumption and the protection of the battery is brought forward, and the optimization problem is solved using Pontryagin's minimum principle (PMP). Moreover, the Powell-Modified algorithm is introduced to execute the solving process of PMP. Finally, the proposed strategy is verified by comparing it with four other strategies under four different driving cycles. Compared to the rule-based strategy, the proposed strategy reduces root mean square (RMS) of battery current and fuel consumption by up to 18.5 % and 18.9 %, respectively.
•Multi-objective optimization strategy is proposed for a dual-mode power split HEV.•The predictive control model is described with Pontryagin's Minimum Principle.•Power distribution over prediction horizon is solved using the Powell-Modified algorithm.•The performance is verified through the comparison among different methods.
Breast cancer is the most prevalent non-cutaneous malignancy in women, with greater than a million new cases every year. In the last decennium, numerous diagnostic and treatment approaches have been ...enormously studied for Breast cancer. Among the different approaches, nanotechnology has appeared as a promising approach in preclinical and clinical studies for early diagnosis of primary tumors and metastases and eradicating tumor cells. Each of these nanocarriers has its particular advantages and drawbacks. Combining two or more than two constituents in a single nanocarrier system leads to the generation of novel multifunctional Hybrid Nanocarriers with improved structural and biological properties. These novel Hybrid Nanocarriers have the capability to overcome the drawbacks of individual constituents while having the advantages of those components. Various hybrid nanocarriers such as lipid polymer hybrid nanoparticles, inorganic hybrid nanoparticles, metal-organic hybrid nanoparticles, and hybrid carbon nanocarriers are utilized for the diagnosis and treatment of various cancers. Certainly, Hybrid Nanocarriers have the capability to encapsulate multiple cargos, targeting agents, enhancement in encapsulation, stability, circulation time, and structural disintegration compared to non-hybrid nanocarriers. Many studies have been conducted to investigate the utilization of Hybrid nanocarriers in breast cancer for imaging platforms, photothermal and photodynamic therapy, chemotherapy, gene therapy, and combinational therapy. In this review, we mainly discussed in detailed about of preparation techniques and toxicological considerations of hybrid nanoparticles. This review also discussed the role of hybrid nanocarriers as a diagnostic and therapeutic agent for the treatment of breast cancer along with alternative treatment approaches apart from chemotherapy including photothermal and photodynamic therapy, gene therapy, and combinational therapy.
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