An improved harvester available in scavenging energy from the operating environment with either weaker or stronger vibration levels is studied. To ensure the optimal harvester performance, a Cuk dc-dc converter is emp...An improved harvester available in scavenging energy from the operating environment with either weaker or stronger vibration levels is studied. To ensure the optimal harvester performance, a Cuk dc-dc converter is employed into the modulating circuit. This paper reports how this harvester scav- enges maximal energy from varying-level vibrations and store energy into an electrochemical battery. Dependence of the duty cycle upon the external vibration level is calculated, and it is found that: 1) for weaker vibrations, the charging current into the battery is smaller than the allowable current, and thus all the optimal output power of the harvesting structure can be absorbed by the battery. In this case, the duty cycle should be fixed at 1.86%; 2) for stronger external forcing, the allowable charging current of the battery is smaller than the optimal harvested current. This indicates that just a portion of the sca- venged energy can be accepted by the battery. Thus, the duty cycle should be decreased gradually with the increase of the vibration level. Finally the energy transmission process and the roles of each elec- tronic element are analyzed. It is shown that a Cuk converter can greatly raise the efficiency of such a harvester, particularly when subjected to a weaker ambient vibration.展开更多
Renewable energy has become important for electricity generation because of the high air pollution associated with conventional fossil-based energy systems.Conventional fossil-based power plants are gradually transiti...Renewable energy has become important for electricity generation because of the high air pollution associated with conventional fossil-based energy systems.Conventional fossil-based power plants are gradually transitioning by incorporating renewable energy sources,such as photovoltaic(PV)cells.In a PV system,an inverter converts DC power from solar panels to AC power required to serve common electrical loads.A conventional H-bridge inverter topology has several disadvantages,such as the voltage being not sinusoidal,switching the DC voltage and high common-mode voltage.The common-mode voltage can cause a large leaked capacitive current,which can result in undesirable operation in solar power applications.A common solution to this problem is the addition of a large filter to the input or output of an inverter.An inherent sinusoidal voltage source inverter based on a modified Cuk converter as its basic cell,which simultaneously generates a sinusoidal output voltage and a lower common-mode voltage,is proposed.The proposed topology does not require additional input or output filters.Analytical expressions are derived to confirm the operation of the proposed topology.Simulation results confirm the mathematical analysis.A laboratory-scale experiment is performed to verify the proposed inverter.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 10872074) the National Basic Research Program of China (Grant No. 2009CB724205)
文摘An improved harvester available in scavenging energy from the operating environment with either weaker or stronger vibration levels is studied. To ensure the optimal harvester performance, a Cuk dc-dc converter is employed into the modulating circuit. This paper reports how this harvester scav- enges maximal energy from varying-level vibrations and store energy into an electrochemical battery. Dependence of the duty cycle upon the external vibration level is calculated, and it is found that: 1) for weaker vibrations, the charging current into the battery is smaller than the allowable current, and thus all the optimal output power of the harvesting structure can be absorbed by the battery. In this case, the duty cycle should be fixed at 1.86%; 2) for stronger external forcing, the allowable charging current of the battery is smaller than the optimal harvested current. This indicates that just a portion of the sca- venged energy can be accepted by the battery. Thus, the duty cycle should be decreased gradually with the increase of the vibration level. Finally the energy transmission process and the roles of each elec- tronic element are analyzed. It is shown that a Cuk converter can greatly raise the efficiency of such a harvester, particularly when subjected to a weaker ambient vibration.
基金Supported by Institut Teknologi Bandung(Grant No.223/IT1.B07.1/TA.00/2022)。
文摘Renewable energy has become important for electricity generation because of the high air pollution associated with conventional fossil-based energy systems.Conventional fossil-based power plants are gradually transitioning by incorporating renewable energy sources,such as photovoltaic(PV)cells.In a PV system,an inverter converts DC power from solar panels to AC power required to serve common electrical loads.A conventional H-bridge inverter topology has several disadvantages,such as the voltage being not sinusoidal,switching the DC voltage and high common-mode voltage.The common-mode voltage can cause a large leaked capacitive current,which can result in undesirable operation in solar power applications.A common solution to this problem is the addition of a large filter to the input or output of an inverter.An inherent sinusoidal voltage source inverter based on a modified Cuk converter as its basic cell,which simultaneously generates a sinusoidal output voltage and a lower common-mode voltage,is proposed.The proposed topology does not require additional input or output filters.Analytical expressions are derived to confirm the operation of the proposed topology.Simulation results confirm the mathematical analysis.A laboratory-scale experiment is performed to verify the proposed inverter.
