The purpose of this study is to use magnetic field of 50/60 Hz up to 0.2 mT for energy source. This paper focuses on magnetic energy harvesting from electrical appliances which can be also used for power consumption m...The purpose of this study is to use magnetic field of 50/60 Hz up to 0.2 mT for energy source. This paper focuses on magnetic energy harvesting from electrical appliances which can be also used for power consumption monitoring. The magnetic energy harvesting device consists of an energy harvesting module, Cockcroft-Walton circuit and storage capacitor. First of all, typical magnetic fields around several electrical appliances are investigated. In order to harvest 10 mJ energy, the shape of magnetic flux concentration flange in energy harvesting module and number of steps in Cockcroft-Walton circuit are considered. From experimental results, magnetic energy harvesting of 17 mJ from a refrigerator is successfully demonstrated.展开更多
After people or vehicles press, piezoelectric ceramics can send a weak and unstable alternating current. According to this characteristic, we made feet pressing energy collection and utilization device based on piezoe...After people or vehicles press, piezoelectric ceramics can send a weak and unstable alternating current. According to this characteristic, we made feet pressing energy collection and utilization device based on piezoelectric ceramics. The two parts of this device includes energy storage and utilization. In terms of storage, the energy collection module, can deposit AC sent by piezoelectric ceramics in the super capacitor after rectification. In terms of utilization of energy, the device achieve a variety of usage： through the USB interface, it can supply power for different equipments, replace the mobile station of train stations and realize the function of saving the electricity as the night corridor induction lamp, combined with vibration module design and programmable timer. The whole structure is supported by an acrylic plate, which saves cost and have good durability. This device implements the storage and usage of idle feet pressing energy. In conclusion, it is helpful to provide a new idea for people＇ s low carbon lives and has a quite broad application prospect.展开更多
Piezoelectric energy harvesting is widely used to scavenge vibration energy in the environment.For some vibration sources with fixed frequency,cantilevered harvester can generate the energy effectively,so the optimiza...Piezoelectric energy harvesting is widely used to scavenge vibration energy in the environment.For some vibration sources with fixed frequency,cantilevered harvester can generate the energy effectively,so the optimization theory for cantilevered harvester in such an application is needed.In this article,we present the theoretical and experimental studies of the cantilevered piezoelectric energy harvester with a fixed resonance frequency.An analytical model based on energy method is used to estimate the open-circuit voltage and generated energy.Considering that the harvester may be subjected to the static force or steady-state sinusoidal vibration excitation,static and dynamic analysis is performed for device structure to achieve efficient energy.In the analysis,the effects of geometrical dimension on the energy harvesting performance are discussed comprehensively.Eventually,a prototype is designed and fabricated using(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT)single crystal with ultrahigh piezoelectric properties and coupling factor.Performances of the cantilever with different clamped length are evaluated under sinusoidal vibration excitation,proving the good consistency between experimental results and theoretical prediction.The established analysis can provide useful guidelines for the structure design of cantilevered piezoelectric energy harvester with a fixed resonance frequency.展开更多
文摘The purpose of this study is to use magnetic field of 50/60 Hz up to 0.2 mT for energy source. This paper focuses on magnetic energy harvesting from electrical appliances which can be also used for power consumption monitoring. The magnetic energy harvesting device consists of an energy harvesting module, Cockcroft-Walton circuit and storage capacitor. First of all, typical magnetic fields around several electrical appliances are investigated. In order to harvest 10 mJ energy, the shape of magnetic flux concentration flange in energy harvesting module and number of steps in Cockcroft-Walton circuit are considered. From experimental results, magnetic energy harvesting of 17 mJ from a refrigerator is successfully demonstrated.
文摘After people or vehicles press, piezoelectric ceramics can send a weak and unstable alternating current. According to this characteristic, we made feet pressing energy collection and utilization device based on piezoelectric ceramics. The two parts of this device includes energy storage and utilization. In terms of storage, the energy collection module, can deposit AC sent by piezoelectric ceramics in the super capacitor after rectification. In terms of utilization of energy, the device achieve a variety of usage： through the USB interface, it can supply power for different equipments, replace the mobile station of train stations and realize the function of saving the electricity as the night corridor induction lamp, combined with vibration module design and programmable timer. The whole structure is supported by an acrylic plate, which saves cost and have good durability. This device implements the storage and usage of idle feet pressing energy. In conclusion, it is helpful to provide a new idea for people＇ s low carbon lives and has a quite broad application prospect.
基金supported by the Natural Basic Research Program of China("973"Program)(Grant No.2013CB632902)the National Natural Science Foundation of China(Grant Nos.51332009,51372258,11304333 and 51272268)
文摘Piezoelectric energy harvesting is widely used to scavenge vibration energy in the environment.For some vibration sources with fixed frequency,cantilevered harvester can generate the energy effectively,so the optimization theory for cantilevered harvester in such an application is needed.In this article,we present the theoretical and experimental studies of the cantilevered piezoelectric energy harvester with a fixed resonance frequency.An analytical model based on energy method is used to estimate the open-circuit voltage and generated energy.Considering that the harvester may be subjected to the static force or steady-state sinusoidal vibration excitation,static and dynamic analysis is performed for device structure to achieve efficient energy.In the analysis,the effects of geometrical dimension on the energy harvesting performance are discussed comprehensively.Eventually,a prototype is designed and fabricated using(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT)single crystal with ultrahigh piezoelectric properties and coupling factor.Performances of the cantilever with different clamped length are evaluated under sinusoidal vibration excitation,proving the good consistency between experimental results and theoretical prediction.The established analysis can provide useful guidelines for the structure design of cantilevered piezoelectric energy harvester with a fixed resonance frequency.
