Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security and process monitoring. However, their lifetime remains very limited by battery capacity. Through the use of piezoelectric e...Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security and process monitoring. However, their lifetime remains very limited by battery capacity. Through the use of piezoelectric energy harvesting techniques, ambient vibration can be captured and converted into usable electricity to create selfpowering WSN which is not limited by finite battery energy. This paper investigates analytically and experimentally the performance of a WSN powered by a Piezoelectric Energy Harvesting System (PEHS) and a material block-level modeling considering most key energy consumption of a wireless sensor node in a star topology network is proposed. By using real hardware parameters of existing components, the proposed model is used to evaluate the energetic budget of the node. The sensor node performance is evaluated regarding transmit packet size, duty cycle and the number of nodes that can be deployed. From the spectral properties of the available vibration inside two moving vehicles (automobile and train), the maximal recoverable power for each type of vehicle is estimated. Using a PEHS based on a cantilever beam optimized for low-frequency applications, 6 mW power is recovered in the case of the train while a 12.5 mW power is reached in the case of the automobile. It is observed that the sink may not operate with the recovered energy. However, the sensor node can sense and transmit data with a maximum size of 105.5 kbits when the duty cycle is 4 × 10<sup>-15</sup>. It is also achieved that the node is most effective when the measured physical phenomena vary slowly, such as the variations in temperature due to thermal inertia. Considering an optimized PEHS based on non-linear processing, it is shown that the sink can operate for 190% improvement of the recovered power.展开更多
The low power and narrow speed range remain bottlenecks that constrain the application of small-scale wind energy harvesting.This paper proposes a simple,lowcost,and reliable method to address these critical issues.A ...The low power and narrow speed range remain bottlenecks that constrain the application of small-scale wind energy harvesting.This paper proposes a simple,lowcost,and reliable method to address these critical issues.A galloping energy harvester with the cooperative mode of vibration and collision(GEH-VC)is presented.A pair of curved boundaries attached with functional materials are introduced,which not only improve the performance of the vibration energy harvesting system,but also convert more mechanical energy into electrical energy during collision.The beam deforms and the piezoelectric energy harvester(PEH)generates electricity during the flow-induced vibration.In addition,the beam contacts and separates from the boundaries,and the triboelectric nanogenerator(TENG)generates electricity during the collision.In order to reduce the influence of the boundaries on the aerodynamic performance and the feasibility of increasing the working area of the TENG,a vertical structure is designed.When the wind speed is high,the curved boundaries maintain a stable amplitude of the vibration system and increase the frequency of the vibration system,thereby avoiding damage to the piezoelectric sheet and improving the electromechanical conversion efficiency,and the TENG works with the PEH to generate electricity.Since the boundaries can protect the PEH at high wind speeds,its stiffness can be designed to be low to start working at low wind speeds.The electromechanical coupling dynamic model is established according to the GEH-VC operating principle and is verified experimentally.The results show that the GEH-VC has a wide range of operating wind speeds,and the average power can be increased by 180%compared with the traditional galloping PEH.The GEH-VC prototype is demonstrated to power a commercial temperature sensor.This study provides a novel perspective on the design of hybrid electromechanical conversion mechanisms,that is,to combine and collaborate based on their respective characteristics.展开更多
With the rapid development of low-power communication technology and microelectronics technology, wearable and portable embedded health monitoring devices, micro-sensors, and human body network positioning devices hav...With the rapid development of low-power communication technology and microelectronics technology, wearable and portable embedded health monitoring devices, micro-sensors, and human body network positioning devices have begun to appear. For seeking reliable energy sources to replace battery on these devices, it is of great significance for developing low power products to explore the research of piezoelectric effect in conversion of human motion into electricity. Based on the different human motions, the existing technology of piezoelectric energy harvester (PEH) is firstly classified, including PEHs through heel-strike, knee-joint, arm motion, center of mass. The technology is then summarized and the direction of future development and efforts is further pointed out.展开更多
The lower electromechanical performance of lead-free piezoelectric materials remains a critical bottleneck impeding their ability to replace lead-based materials in energy harvesting.To overcome this predicament,here,...The lower electromechanical performance of lead-free piezoelectric materials remains a critical bottleneck impeding their ability to replace lead-based materials in energy harvesting.To overcome this predicament,here,we propose a multiscale reconfiguration design to tailor the intricate coupling between the structure and properties of(K,Na)NbO_(3)-based piezoelectric materials.The multiphase coexistence,local structural heterogeneity,enhanced crystal anisotropy,and acceptor doping yielded(K,Na)NbO_(3)-based ceramics with a harmonious balance between the piezoelectric coefficient and the dielectric constant.As a result,the(K,Na)NbO_(3)-based textured ceramics demonstrate exceptional piezoelectric properties,including a piezoelectric charge coefficient(d_(33))of 551 pC·N^(-1)and a piezoelectric voltage coefficient(g_(33))of 54.2 mV·m·N^(-1).The energy harvesting devices exhibit an ultrahigh instantaneous output power(P_(out))of 4.85 mW and an instantaneous output power density(P_(D))of 70.2μW·mm^(-3).This work provides valuable insights into the design and development of high-performance lead-free piezoelectric ceramics and significantly advances the potential of(K,Na)NbO_(3)-based ceramics as viable replacements for Pb(Zr,Ti)O_(3)-based ceramics in energy harvesting applications.展开更多
Piezoelectric energy harvesters(PEHs)fabricated using piezoceramics could convert directly the mechanical vibration energy in the environment into electrical energy.The high piezoelectric charge coefficient(d_(33))and...Piezoelectric energy harvesters(PEHs)fabricated using piezoceramics could convert directly the mechanical vibration energy in the environment into electrical energy.The high piezoelectric charge coefficient(d_(33))and large piezoelectric voltage coefficient(g_(33))are key factors for the high-performance PEHs.However,high d_(33)and large g_(33)are difficult to simultaneously achieve with respect to g_(33)=d_(33)/(e_(0)e_(r))and d_(33)=2Qe_(0)e_(r)P_(r).Herein,the energy harvesting performance is optimized by tailoring the CaZrO_(3)content in(0.964−x)(K_(0.52)Na_(0.48))(Nb_(0.96)Sb_(0.04))O_(3)-0.036(Bi_(0.5)Na_(0.5))ZrO_(3)-xCaZrO_(3)ceramics.First,the doping CaZrO_(3)could enhance the dielectric relaxation due to the compositional fluctuation and structural disordering,and thus reduce the domain size to~30 nm for x=0.006 sample.The nanodomains switch easily to external electric field,resulting in large polarization.Second,the rhombohedral-orthorhombic-tetragonal phases coexist in x=0.006 sample,which reduces the polarization anisotropy and thus improves the piezoelectric properties.The multiphase coexistence structures and miniaturized domains contribute to the excellent piezoelectric properties of d_(33)(354 pC/N).Furthermore,the dielectric relative permittivity(ε_(r))reduces monotonously as the CaZrO_(3)content increases due to the relatively low ion polarizability of Ca^(2+)and Zr^(4+).As a result,the optimized energy conversion coefficient(d_(33)×g_(33),5508×10^(−15)m^(2)/N)is achieved for x=0.006 sample.Most importantly,the assembled PEH with the optimal specimen shows the excellent output power(~48 mW)and lights up 45 red commercial light-emitting diodes(LEDs).This work demonstrates that tailoring ferroelectric/relaxor behavior in(K,Na)NbO_(3)-based piezoelectric ceramics could effectively enhance the electrical output of PEHs.展开更多
Understanding the characteristics of cloud water resource(CWR)and precipitation efficiency of hydrometeors(PEh)is imperative for the application of CWR in Northwest China.The atmospheric precipitable water(PW)in all f...Understanding the characteristics of cloud water resource(CWR)and precipitation efficiency of hydrometeors(PEh)is imperative for the application of CWR in Northwest China.The atmospheric precipitable water(PW)in all four seasons and clouds and PEh in summer were studied with ERA-5 and CloudSat data in this region.The results show that topography,especially in the Tibetan Plateau,exerts significant impacts on the precipitation and PW in summer,since large amounts of clouds are distributed along the mountain ranges.The study region is divided into four typical areas:the monsoon area in eastern Northwest China(NWE),the Qilian Mountains area(QM),the Tianshan Mountains area(TM),and the Source of Three Rivers area(STR).Over the four areas,cloud top height(6.3 km)and cloud base height(3.3 km)over NWE are higher,and precipitating clouds are thicker(7 km)in the single-layer clouds.Liquid water content decreases with increasing altitude,while the ice water content first increases and then decreases.Liquid water path is higher over NWE(0.11 kg m^(−2))than over TM and STR(0.05 kg m^(−2)),and the ice water path is mainly concentrated within the range of 0.025–0.055 kg m^(−2).The PEh values are distributed unevenly and affected evidently by the terrain.Although the PEh values in the four typical areas(0.3–0.6)are higher than those in other regions,the CWR is relatively abundant and has a higher exploitation potential.Therefore,it is well-founded to exploit CWR for alleviating water shortages in these areas of Northwest China in summer.展开更多
文摘Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security and process monitoring. However, their lifetime remains very limited by battery capacity. Through the use of piezoelectric energy harvesting techniques, ambient vibration can be captured and converted into usable electricity to create selfpowering WSN which is not limited by finite battery energy. This paper investigates analytically and experimentally the performance of a WSN powered by a Piezoelectric Energy Harvesting System (PEHS) and a material block-level modeling considering most key energy consumption of a wireless sensor node in a star topology network is proposed. By using real hardware parameters of existing components, the proposed model is used to evaluate the energetic budget of the node. The sensor node performance is evaluated regarding transmit packet size, duty cycle and the number of nodes that can be deployed. From the spectral properties of the available vibration inside two moving vehicles (automobile and train), the maximal recoverable power for each type of vehicle is estimated. Using a PEHS based on a cantilever beam optimized for low-frequency applications, 6 mW power is recovered in the case of the train while a 12.5 mW power is reached in the case of the automobile. It is observed that the sink may not operate with the recovered energy. However, the sensor node can sense and transmit data with a maximum size of 105.5 kbits when the duty cycle is 4 × 10<sup>-15</sup>. It is also achieved that the node is most effective when the measured physical phenomena vary slowly, such as the variations in temperature due to thermal inertia. Considering an optimized PEHS based on non-linear processing, it is shown that the sink can operate for 190% improvement of the recovered power.
基金the National Natural Science Foundation of China (Nos. 11802091and 12172127)the Hunan Province Science and Technology Innovation Program of China(Nos. 2020JJ3019 and 2019RS2044)the Scientific Researchof Hunan Provincial Department of Education of China (No. 21A0463)
文摘The low power and narrow speed range remain bottlenecks that constrain the application of small-scale wind energy harvesting.This paper proposes a simple,lowcost,and reliable method to address these critical issues.A galloping energy harvester with the cooperative mode of vibration and collision(GEH-VC)is presented.A pair of curved boundaries attached with functional materials are introduced,which not only improve the performance of the vibration energy harvesting system,but also convert more mechanical energy into electrical energy during collision.The beam deforms and the piezoelectric energy harvester(PEH)generates electricity during the flow-induced vibration.In addition,the beam contacts and separates from the boundaries,and the triboelectric nanogenerator(TENG)generates electricity during the collision.In order to reduce the influence of the boundaries on the aerodynamic performance and the feasibility of increasing the working area of the TENG,a vertical structure is designed.When the wind speed is high,the curved boundaries maintain a stable amplitude of the vibration system and increase the frequency of the vibration system,thereby avoiding damage to the piezoelectric sheet and improving the electromechanical conversion efficiency,and the TENG works with the PEH to generate electricity.Since the boundaries can protect the PEH at high wind speeds,its stiffness can be designed to be low to start working at low wind speeds.The electromechanical coupling dynamic model is established according to the GEH-VC operating principle and is verified experimentally.The results show that the GEH-VC has a wide range of operating wind speeds,and the average power can be increased by 180%compared with the traditional galloping PEH.The GEH-VC prototype is demonstrated to power a commercial temperature sensor.This study provides a novel perspective on the design of hybrid electromechanical conversion mechanisms,that is,to combine and collaborate based on their respective characteristics.
文摘With the rapid development of low-power communication technology and microelectronics technology, wearable and portable embedded health monitoring devices, micro-sensors, and human body network positioning devices have begun to appear. For seeking reliable energy sources to replace battery on these devices, it is of great significance for developing low power products to explore the research of piezoelectric effect in conversion of human motion into electricity. Based on the different human motions, the existing technology of piezoelectric energy harvester (PEH) is firstly classified, including PEHs through heel-strike, knee-joint, arm motion, center of mass. The technology is then summarized and the direction of future development and efforts is further pointed out.
基金sponsored by the National Natural Science Foundation of China(Nos.52032007 and 52502151)the Natural Science Foundation of Shanghai(No.25ZR1404008).
文摘The lower electromechanical performance of lead-free piezoelectric materials remains a critical bottleneck impeding their ability to replace lead-based materials in energy harvesting.To overcome this predicament,here,we propose a multiscale reconfiguration design to tailor the intricate coupling between the structure and properties of(K,Na)NbO_(3)-based piezoelectric materials.The multiphase coexistence,local structural heterogeneity,enhanced crystal anisotropy,and acceptor doping yielded(K,Na)NbO_(3)-based ceramics with a harmonious balance between the piezoelectric coefficient and the dielectric constant.As a result,the(K,Na)NbO_(3)-based textured ceramics demonstrate exceptional piezoelectric properties,including a piezoelectric charge coefficient(d_(33))of 551 pC·N^(-1)and a piezoelectric voltage coefficient(g_(33))of 54.2 mV·m·N^(-1).The energy harvesting devices exhibit an ultrahigh instantaneous output power(P_(out))of 4.85 mW and an instantaneous output power density(P_(D))of 70.2μW·mm^(-3).This work provides valuable insights into the design and development of high-performance lead-free piezoelectric ceramics and significantly advances the potential of(K,Na)NbO_(3)-based ceramics as viable replacements for Pb(Zr,Ti)O_(3)-based ceramics in energy harvesting applications.
基金This work was supported by the National Natural Science Foundation of China(Nos.52072150 and 51972146)the China Association for Science and Technology(Young Elite Scientists Sponsorship Program)the State Key Laboratory of New Ceramics and Fine Processing Tsinghua University(No.KF202002).
文摘Piezoelectric energy harvesters(PEHs)fabricated using piezoceramics could convert directly the mechanical vibration energy in the environment into electrical energy.The high piezoelectric charge coefficient(d_(33))and large piezoelectric voltage coefficient(g_(33))are key factors for the high-performance PEHs.However,high d_(33)and large g_(33)are difficult to simultaneously achieve with respect to g_(33)=d_(33)/(e_(0)e_(r))and d_(33)=2Qe_(0)e_(r)P_(r).Herein,the energy harvesting performance is optimized by tailoring the CaZrO_(3)content in(0.964−x)(K_(0.52)Na_(0.48))(Nb_(0.96)Sb_(0.04))O_(3)-0.036(Bi_(0.5)Na_(0.5))ZrO_(3)-xCaZrO_(3)ceramics.First,the doping CaZrO_(3)could enhance the dielectric relaxation due to the compositional fluctuation and structural disordering,and thus reduce the domain size to~30 nm for x=0.006 sample.The nanodomains switch easily to external electric field,resulting in large polarization.Second,the rhombohedral-orthorhombic-tetragonal phases coexist in x=0.006 sample,which reduces the polarization anisotropy and thus improves the piezoelectric properties.The multiphase coexistence structures and miniaturized domains contribute to the excellent piezoelectric properties of d_(33)(354 pC/N).Furthermore,the dielectric relative permittivity(ε_(r))reduces monotonously as the CaZrO_(3)content increases due to the relatively low ion polarizability of Ca^(2+)and Zr^(4+).As a result,the optimized energy conversion coefficient(d_(33)×g_(33),5508×10^(−15)m^(2)/N)is achieved for x=0.006 sample.Most importantly,the assembled PEH with the optimal specimen shows the excellent output power(~48 mW)and lights up 45 red commercial light-emitting diodes(LEDs).This work demonstrates that tailoring ferroelectric/relaxor behavior in(K,Na)NbO_(3)-based piezoelectric ceramics could effectively enhance the electrical output of PEHs.
基金Supported by the National Natural Science Foundation of China(41775139)Ministry of Science and Technology of China(2016YFE0201900 and GYHY201406033)China Meteorological Administration(ZQC-R18169/RYSY201904).
文摘Understanding the characteristics of cloud water resource(CWR)and precipitation efficiency of hydrometeors(PEh)is imperative for the application of CWR in Northwest China.The atmospheric precipitable water(PW)in all four seasons and clouds and PEh in summer were studied with ERA-5 and CloudSat data in this region.The results show that topography,especially in the Tibetan Plateau,exerts significant impacts on the precipitation and PW in summer,since large amounts of clouds are distributed along the mountain ranges.The study region is divided into four typical areas:the monsoon area in eastern Northwest China(NWE),the Qilian Mountains area(QM),the Tianshan Mountains area(TM),and the Source of Three Rivers area(STR).Over the four areas,cloud top height(6.3 km)and cloud base height(3.3 km)over NWE are higher,and precipitating clouds are thicker(7 km)in the single-layer clouds.Liquid water content decreases with increasing altitude,while the ice water content first increases and then decreases.Liquid water path is higher over NWE(0.11 kg m^(−2))than over TM and STR(0.05 kg m^(−2)),and the ice water path is mainly concentrated within the range of 0.025–0.055 kg m^(−2).The PEh values are distributed unevenly and affected evidently by the terrain.Although the PEh values in the four typical areas(0.3–0.6)are higher than those in other regions,the CWR is relatively abundant and has a higher exploitation potential.Therefore,it is well-founded to exploit CWR for alleviating water shortages in these areas of Northwest China in summer.
