The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Junichi Itoh - One of the best experts on this subject based on the ideXlab platform.
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a maximum Power Density design method for nine switches matrix converter using sic mosfet
IEEE Transactions on Power Electronics, 2016Co-Authors: Kazuhiro Koiwa, Junichi ItohAbstract:This paper presents a matrix converter design for achieving maximum Power Density using a SiC device based on a front-loading design. To design the matrix converter to achieve maximum Power Density, the conduction loss and the switching loss of the matrix converter are theoretically derived and validated by simulation and experiment. Based on these formulas, the relationship between the efficiency and Power Density are revealed by using a Pareto–Front curve in order to solve the tradeoff problem between the Power Density and the efficiency. Moreover, in order to promote the widespread use of the matrix converter instead of a BTB system, it is quantitatively evaluated that the Power Density in the matrix converter is increased by 4.19 kW/dm3 in comparison to the BTB system. Moreover, the Power Density of the matrix converter that uses a SiC-MOSFET (ROHM) as the switching device with natural air cooling is 95.0% (2.1 kW/dm3) of the calculated maximum Power Density. Thus, the Power Density of the matrix converter is improved by 57.5% by the maximum Power Density design method. Based on the results, the design method for a high Power Density ac–ac direct converter is established according to the requisite specifications.
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Evaluation of a maximum Power Density design method for matrix converter using SiC-MOSFET
2014 IEEE Energy Conversion Congress and Exposition (ECCE), 2014Co-Authors: Kazuhiro Koiwa, Junichi ItohAbstract:This paper discusses a maximum Power Density design for a matrix converter using SiC device based on front loading design. In order to design the matrix converter at maximum Power Density, the conduction loss and the switching loss of the matrix converter are derived theoretically. Based on these equations, the relationship between the efficiency and Power Density are discussed by Pareto-front curve in order to solve the tread-off problem between the Power Density and the efficiency. From the experimental results, the maximum efficiency is 98.3% with two phase modulation at 3.9-kW output Power and 25-kHz switching frequency (Devices: SiCMOSFET BSM00003A ROHM). Moreover, the maximum Power Density of the matrix converter reaches 2.12 kW/dm (the design value is 2.22 kW/dm) with a natural air cooling. Thus, the design method of a high Power Density AC-AC converter using a matrix converter is established according to the specifications.
Lingen Chen - One of the best experts on this subject based on the ideXlab platform.
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Power Density analysis and optimization of an irreversible closed intercooled regenerated brayton cycle
Mathematical and Computer Modelling, 2008Co-Authors: Lingen Chen, Junhua Wang, Fengrui SunAbstract:In this paper, Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is optimized for an irreversible closed intercooled regenerated Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of the theory of thermodynamic optimization. The analytical formulae for dimensionless Power Density and efficiency, as functions of the total pressure ratio, the intercooling pressure ratio, the components (the regenerator, the intercooler, the hot- and cold-side heat exchangers) effectiveness, the compressor and turbine efficiencies, the heat reservoir temperature ratio, and the temperature ratio of the cooling fluid in the intercooler and the cold-side heat reservoir, are derived. The optimum dimensionless Power Density is obtained by optimizing the intercooling pressure ratio. The maximum dimensionless Power Density is obtained by searching the optimum heat conductance distributions between the hot- and cold-side heat exchangers for a fixed total heat exchanger inventory and fixed heat conductance distributions of the regenerator and the intercooler, and by searching the optimum intercooling pressure ratio. When the optimization is performed with respect to the total pressure ratio of the cycle, the maximum dimensionless Power Density can be maximized again, and a double-maximum Power Density and the corresponding optimum total pressure ratios are obtained. The effects of the heat reservoir temperature ratio, the temperature ratio of the cooling fluid in the intercooler and the cold-side heat reservoir, the efficiencies of the compressors and the turbine, and the total heat exchanger inventory on the optimum Power Density, the maximum Power Density, and the double-maximum Power Density and the corresponding optimal total pressure ratio are analyzed by numerical examples. In the analysis, the heat resistance losses in the four heat exchangers, and the irreversible compression and expansion losses in the compressors and the turbine are taken into account.
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Power Density optimisation of endoreversible closed intercooled regenerated brayton cycle
Journal of The Energy Institute, 2007Co-Authors: Lingen Chen, J H Wang, Fengrui SunAbstract:AbstractIn the present paper, the Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is optimised for an endoreversible closed intercooled regenerated Brayton cycle coupled to constant temperature heat reservoirs in the viewpoint of finite time thermodynamics (FTT). The analysis shows that the cycle dimensionless Power Density can be optimised by searching the optimum heat conductance distributions between the hot- and coldside heat exchangers for a fixed total heat exchanger inventory and fixed heat conductance distributions of the regenerator and the intercooler, and by searching the optimum intercooling pressure ratio. When the optimisation is performed with respect to the total pressure ratio of the cycle, the maximum dimensionless Power Density can be maximised again, and a double maximum Power Density and the corresponding optimum total pressure ratio are obtained. The effects of some design parameter on the maximum Power Density and the corresponding pe...
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Power Density Optimization for an Irreversible Regenerated Closed Brayton Cycle
Physica Scripta, 2001Co-Authors: Lingen Chen, Jun-ling ZhengAbstract:In this paper, the Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is taken as objective for performance optimization of an irreversible regenerated closed Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulae about the relations between Power Density and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the regenerator, the irreversible compression and expansion losses in the compressor and turbine, and the pressure drop loss in the piping. The maximum Power Density optimization is performed by searching the optimum heat conductance distribution corresponding to the optimum Power Density among the hot- and cold-side heat exchangers and the regenerator for the fixed total heat exchanger inventory. The influence of some design parameters, including the temperature ratio of the heat reservoirs, the total heat exchanger inventory, the efficiencies of the compressor and the turbine, and the pressure recovery coefficient, on the optimum heat conductance distribution and the maximum Power Density are provided. When the heat transfers between the working fluid and the heat reservoirs are carried out ideally, the analytical results of this paper become those obtained in recent literature. The Power plant design with optimization leads to smaller size including the compressor, turbine, and the hot- and cold-side heat exchangers and the regenerator.
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Power Density analysis of an endoreversible closed Brayton cycle
International Journal of Ambient Energy, 2001Co-Authors: Lingen ChenAbstract:SYNOPSIS In this paper, the Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is maximised for an endoreversible closed Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite time thermodynamics (FTT) or entropy generation minimisation (EGM). The effects of heat transfer and engine sizes were included in the analysis. The results showed that the efficiency, at the maximum Power Density, is always greater than that at maximum Power output, and that Power Density optimisation leads to a smaller and more efficient Brayton cycle. When heat transfer is carried out ideally, the results of this paper match those obtained in recent literature.
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Power Density Optimization for an Irreversible Closed Brayton Cycle
Open Systems & Information Dynamics, 2001Co-Authors: Lingen ChenAbstract:In this paper, the Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is taken as objective for performance optimization of an irreversible closed Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulas about the relations between Power Density and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the irreversible compression and expansion losses in the compressor and turbine. The maximum Power Density optimization is performed by searching the optimum heat conductance distribution corresponding to the optimum Power Density of the hot- and cold- side heat exchangers for the fixed heat exchanger inventory. The influence of some design parameters on the optimum heat conductance distribution, the maximum Power Density, and the optimum pressure ratio corresponding to the maximum Power Density are provided. The Power plant design with optimization leads to a higher efficiency and smaller size including the compressor, turbine, and the hot- and cold-side heat exchangers.
Kazuhiro Koiwa - One of the best experts on this subject based on the ideXlab platform.
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a maximum Power Density design method for nine switches matrix converter using sic mosfet
IEEE Transactions on Power Electronics, 2016Co-Authors: Kazuhiro Koiwa, Junichi ItohAbstract:This paper presents a matrix converter design for achieving maximum Power Density using a SiC device based on a front-loading design. To design the matrix converter to achieve maximum Power Density, the conduction loss and the switching loss of the matrix converter are theoretically derived and validated by simulation and experiment. Based on these formulas, the relationship between the efficiency and Power Density are revealed by using a Pareto–Front curve in order to solve the tradeoff problem between the Power Density and the efficiency. Moreover, in order to promote the widespread use of the matrix converter instead of a BTB system, it is quantitatively evaluated that the Power Density in the matrix converter is increased by 4.19 kW/dm3 in comparison to the BTB system. Moreover, the Power Density of the matrix converter that uses a SiC-MOSFET (ROHM) as the switching device with natural air cooling is 95.0% (2.1 kW/dm3) of the calculated maximum Power Density. Thus, the Power Density of the matrix converter is improved by 57.5% by the maximum Power Density design method. Based on the results, the design method for a high Power Density ac–ac direct converter is established according to the requisite specifications.
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Evaluation of a maximum Power Density design method for matrix converter using SiC-MOSFET
2014 IEEE Energy Conversion Congress and Exposition (ECCE), 2014Co-Authors: Kazuhiro Koiwa, Junichi ItohAbstract:This paper discusses a maximum Power Density design for a matrix converter using SiC device based on front loading design. In order to design the matrix converter at maximum Power Density, the conduction loss and the switching loss of the matrix converter are derived theoretically. Based on these equations, the relationship between the efficiency and Power Density are discussed by Pareto-front curve in order to solve the tread-off problem between the Power Density and the efficiency. From the experimental results, the maximum efficiency is 98.3% with two phase modulation at 3.9-kW output Power and 25-kHz switching frequency (Devices: SiCMOSFET BSM00003A ROHM). Moreover, the maximum Power Density of the matrix converter reaches 2.12 kW/dm (the design value is 2.22 kW/dm) with a natural air cooling. Thus, the design method of a high Power Density AC-AC converter using a matrix converter is established according to the specifications.
Fengrui Sun - One of the best experts on this subject based on the ideXlab platform.
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Power Density analysis and optimization of an irreversible closed intercooled regenerated brayton cycle
Mathematical and Computer Modelling, 2008Co-Authors: Lingen Chen, Junhua Wang, Fengrui SunAbstract:In this paper, Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is optimized for an irreversible closed intercooled regenerated Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of the theory of thermodynamic optimization. The analytical formulae for dimensionless Power Density and efficiency, as functions of the total pressure ratio, the intercooling pressure ratio, the components (the regenerator, the intercooler, the hot- and cold-side heat exchangers) effectiveness, the compressor and turbine efficiencies, the heat reservoir temperature ratio, and the temperature ratio of the cooling fluid in the intercooler and the cold-side heat reservoir, are derived. The optimum dimensionless Power Density is obtained by optimizing the intercooling pressure ratio. The maximum dimensionless Power Density is obtained by searching the optimum heat conductance distributions between the hot- and cold-side heat exchangers for a fixed total heat exchanger inventory and fixed heat conductance distributions of the regenerator and the intercooler, and by searching the optimum intercooling pressure ratio. When the optimization is performed with respect to the total pressure ratio of the cycle, the maximum dimensionless Power Density can be maximized again, and a double-maximum Power Density and the corresponding optimum total pressure ratios are obtained. The effects of the heat reservoir temperature ratio, the temperature ratio of the cooling fluid in the intercooler and the cold-side heat reservoir, the efficiencies of the compressors and the turbine, and the total heat exchanger inventory on the optimum Power Density, the maximum Power Density, and the double-maximum Power Density and the corresponding optimal total pressure ratio are analyzed by numerical examples. In the analysis, the heat resistance losses in the four heat exchangers, and the irreversible compression and expansion losses in the compressors and the turbine are taken into account.
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Power Density optimisation of endoreversible closed intercooled regenerated brayton cycle
Journal of The Energy Institute, 2007Co-Authors: Lingen Chen, J H Wang, Fengrui SunAbstract:AbstractIn the present paper, the Power Density, defined as the ratio of Power output to the maximum specific volume in the cycle, is optimised for an endoreversible closed intercooled regenerated Brayton cycle coupled to constant temperature heat reservoirs in the viewpoint of finite time thermodynamics (FTT). The analysis shows that the cycle dimensionless Power Density can be optimised by searching the optimum heat conductance distributions between the hot- and coldside heat exchangers for a fixed total heat exchanger inventory and fixed heat conductance distributions of the regenerator and the intercooler, and by searching the optimum intercooling pressure ratio. When the optimisation is performed with respect to the total pressure ratio of the cycle, the maximum dimensionless Power Density can be maximised again, and a double maximum Power Density and the corresponding optimum total pressure ratio are obtained. The effects of some design parameter on the maximum Power Density and the corresponding pe...
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Efficiency of an Atkinson engine at maximum Power Density
Energy Conversion and Management, 1998Co-Authors: Lingen Chen, Junxing Lin, Fengrui SunAbstract:In studies of finite-time thermodynamics, most performance analyses concern the maximum Power output and the corresponding efficiency for heat engines. In this paper, instead of just maximizing Power for a cycle, the Power Density (the ratio of the Power to the maximum specific volume in the cycle) is maximized for an Atkinson engine. The results showed that the efficiency at maximum Power Density is always greater than that at maximum Power, and the design parameters at maximum Power Density lead to smaller and more efficient Atkinson engines with larger pressure ratios.
Jia Wang - One of the best experts on this subject based on the ideXlab platform.
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the fast optimal voltage partitioning algorithm for peak Power Density minimization
International Conference on Computer Aided Design, 2010Co-Authors: Jia WangAbstract:Increasing transistor Density in nanometer integrated circuits has resulted in large on-chip Power Density. As a high-level Power optimization technique, voltage partitioning is effective in mitigating Power Density. Previous works on voltage partitioning attempt to address it through minimizing total Power consumption over all voltage partitions. Since Power Density significantly impacts thermal-induced reliability, it is also desired to directly mitigate peak Power Density during voltage partitioning. Unfortunately, none of the existing works consider this. This paper proposes an efficient optimal voltage partitioning algorithm for peak Power Density minimization. Based on novel algorithmic techniques such as implicit Power Density binary search, the algorithm runs in O(n log n + m2 log2 n) time, where n refers to the number of functional units and m refers to the number of partitions/voltage levels. Our experimental results on large testcases demonstrate that large amount of (about 9.7x) reduction in peak Power Density can be achieved compared to a natural greedy algorithm, while the algorithm still runs very fast. It needs only 14.15 seconds to optimize 1M functional units.
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ICCAD - The fast optimal voltage partitioning algorithm for peak Power Density minimization
2010 IEEE ACM International Conference on Computer-Aided Design (ICCAD), 2010Co-Authors: Jia WangAbstract:Increasing transistor Density in nanometer integrated circuits has resulted in large on-chip Power Density. As a high-level Power optimization technique, voltage partitioning is effective in mitigating Power Density. Previous works on voltage partitioning attempt to address it through minimizing total Power consumption over all voltage partitions. Since Power Density significantly impacts thermal-induced reliability, it is also desired to directly mitigate peak Power Density during voltage partitioning. Unfortunately, none of the existing works consider this. This paper proposes an efficient optimal voltage partitioning algorithm for peak Power Density minimization. Based on novel algorithmic techniques such as implicit Power Density binary search, the algorithm runs in O(n log n + m2 log2 n) time, where n refers to the number of functional units and m refers to the number of partitions/voltage levels. Our experimental results on large testcases demonstrate that large amount of (about 9.7x) reduction in peak Power Density can be achieved compared to a natural greedy algorithm, while the algorithm still runs very fast. It needs only 14.15 seconds to optimize 1M functional units.
