The power and voltage levels of renewable energy resources is growing with the evolution of the power electronics and switching module technologies.For that,the need for the development of a compact and highly efficie...The power and voltage levels of renewable energy resources is growing with the evolution of the power electronics and switching module technologies.For that,the need for the development of a compact and highly efficient solid-state transformer is becoming a critical task in-order to integrate the current AC grid with the new renewable energy systems.The objective of this paper is to present the design,implementation,and testing of a compact multi-port solid-state transformer for microgrid integration applications.The proposed system has a four-port transformer and four converters connected to the ports.The transformer has four windings integrated on a single common core.Thus,it can integrate different renewable energy resources and energy storage systems.Each port has a rated power of 25 kW,and the switching frequency is pushed to 50 k Hz.The ports are chosen to represent a realistic industrial microgrid model consisting of grid,energy storage system,photovoltaic system,and load.The grid port is designed to operate at 4.16 k VAC corresponding to 7.2 kV DC bus voltage,while the other three ports operate at 500 VDC.Moreover,the grid,energy storage and photovoltaic ports are active ports with dual active bridge topologies,while the load port is a passive port with full bridge rectifier one.The proposed design is first validated with simulation results,and then the proposed transformer is implemented and tested.Experimental results show that the designed system is suitable for 4.16 k VAC medium voltage grid integration.展开更多
Recently, reactivity controlled compression ignition (RCCI) has been proposed inorder to achieve a higher thermal efficiency with lower emissions than conventional combustion. In RCCI mode, as the fuel types and their...Recently, reactivity controlled compression ignition (RCCI) has been proposed inorder to achieve a higher thermal efficiency with lower emissions than conventional combustion. In RCCI mode, as the fuel types and their combinations affects the reactivity stratificationinside cylinder, thus combustion control, in present study, iso-propanol was evaluated as lowreactivity fuel (LRF) when petroleum diesel, commercial biodiesel and their blends were highreactivity fuels. It is of great importance that iso-propanol and biodiesel be used together inRCCI mode, as they significantly affect the in-cylinder stratification due to their high octane/cetane number. Therefore, the reactivity controlled compression ignition (RCCI) combustioncharacteristics was investigated in a diesel research engine using iso-propanol, petroleumdiesel, biodiesel and their blends as fuels. Tests were conducted on varying loadings (from20% to 60% of max torque) and premixed ratios of LRF (Rp Z 0, 0.15, 0.30, 0.45, and0.60) at a constant engine speed of 2400 rpm. Results, which were compared with conventionaldiesel combustion (CDC), showed that, as the premixed ratio (Rp) of low-reactivity fuel (isopropanol) increased, ignition delay (ID) period prolonged while combustion duration (CD) and rate of pressure rise (RoPR) reduced assisted to reduce NO emissions and smoke opacity in theexhaust. NO and smoke opacity reduced simultaneously for biodiesel-propanol combinationsup to 40% under 20% load and 0.60 premixed ratio of LRF compared to CDC. Propanol premixed ratio of 0.30 at 60% load was found to be optimum concerning lowest emissions. In conventional mode, HC emissions reduced by up to 52% when biodiesel and its blends with dieselfuel are used, whereas they increased significantly in RCCI mode. According to overall results,it is concluded that RCCI performed better than CDC at entire load.展开更多
基金supported by the National Science Foundation under Grant No.1650470,GRAPES I/UCRC program。
文摘The power and voltage levels of renewable energy resources is growing with the evolution of the power electronics and switching module technologies.For that,the need for the development of a compact and highly efficient solid-state transformer is becoming a critical task in-order to integrate the current AC grid with the new renewable energy systems.The objective of this paper is to present the design,implementation,and testing of a compact multi-port solid-state transformer for microgrid integration applications.The proposed system has a four-port transformer and four converters connected to the ports.The transformer has four windings integrated on a single common core.Thus,it can integrate different renewable energy resources and energy storage systems.Each port has a rated power of 25 kW,and the switching frequency is pushed to 50 k Hz.The ports are chosen to represent a realistic industrial microgrid model consisting of grid,energy storage system,photovoltaic system,and load.The grid port is designed to operate at 4.16 k VAC corresponding to 7.2 kV DC bus voltage,while the other three ports operate at 500 VDC.Moreover,the grid,energy storage and photovoltaic ports are active ports with dual active bridge topologies,while the load port is a passive port with full bridge rectifier one.The proposed design is first validated with simulation results,and then the proposed transformer is implemented and tested.Experimental results show that the designed system is suitable for 4.16 k VAC medium voltage grid integration.
基金The Scientific and Technological Research Council of Turkey(TUBITAK)is greatly acknowledgment for financial support with project numbered 118M650.
文摘Recently, reactivity controlled compression ignition (RCCI) has been proposed inorder to achieve a higher thermal efficiency with lower emissions than conventional combustion. In RCCI mode, as the fuel types and their combinations affects the reactivity stratificationinside cylinder, thus combustion control, in present study, iso-propanol was evaluated as lowreactivity fuel (LRF) when petroleum diesel, commercial biodiesel and their blends were highreactivity fuels. It is of great importance that iso-propanol and biodiesel be used together inRCCI mode, as they significantly affect the in-cylinder stratification due to their high octane/cetane number. Therefore, the reactivity controlled compression ignition (RCCI) combustioncharacteristics was investigated in a diesel research engine using iso-propanol, petroleumdiesel, biodiesel and their blends as fuels. Tests were conducted on varying loadings (from20% to 60% of max torque) and premixed ratios of LRF (Rp Z 0, 0.15, 0.30, 0.45, and0.60) at a constant engine speed of 2400 rpm. Results, which were compared with conventionaldiesel combustion (CDC), showed that, as the premixed ratio (Rp) of low-reactivity fuel (isopropanol) increased, ignition delay (ID) period prolonged while combustion duration (CD) and rate of pressure rise (RoPR) reduced assisted to reduce NO emissions and smoke opacity in theexhaust. NO and smoke opacity reduced simultaneously for biodiesel-propanol combinationsup to 40% under 20% load and 0.60 premixed ratio of LRF compared to CDC. Propanol premixed ratio of 0.30 at 60% load was found to be optimum concerning lowest emissions. In conventional mode, HC emissions reduced by up to 52% when biodiesel and its blends with dieselfuel are used, whereas they increased significantly in RCCI mode. According to overall results,it is concluded that RCCI performed better than CDC at entire load.
