This paper proposes a new battery management system (BMS) based on a master-slave control mode for multi-cell li-ion battery packs. The proposed BMS can be applied in li-ion battery packs with any cell number. The w...This paper proposes a new battery management system (BMS) based on a master-slave control mode for multi-cell li-ion battery packs. The proposed BMS can be applied in li-ion battery packs with any cell number. The whole system is composed of a master processor and a string of slave manager cells (SMCs). Each battery cell corresponds to an SMC. Unlike the conventional BMS, the proposed one has a novel method for communication, and it collects the battery status information in a direct and simple way. An SMC communicates with its adjacent counterparts to transfer the battery information as well as the commands from the master processor. The nethermost SMC communicates with the master processor directly. This method allows the battery management chips to be implemented in a standard CMOS ( complementary metal-oxide-semiconductor transistor) process. A testing chip is fabricated in the CSMC 0.5 μm 5 V N-well CMOS process. The testing results verify that the proposed method for data communication and the battery management system can protect and manage multi-cell li-ion battery packs.展开更多
A new type strongly gain coupled (GC) DFB laser and a new type self alignment spot size converter (SA SSC) are proposed and successfully fabricated.The strongly GC DFB laser is monolithically integrated with the ...A new type strongly gain coupled (GC) DFB laser and a new type self alignment spot size converter (SA SSC) are proposed and successfully fabricated.The strongly GC DFB laser is monolithically integrated with the SA SSC with three step epitaxies.A high single mode yield and large side mode suppression ratio is obtained from the strongly GC DFB laser.A near circle far field pattern is obtained by using the SA SSC.展开更多
Formal verification is playing a significant role in IC design.However,the common models for verification either have their complexity problems or have applicable limitations.In order to overcome the deficiencies,a no...Formal verification is playing a significant role in IC design.However,the common models for verification either have their complexity problems or have applicable limitations.In order to overcome the deficiencies,a novel model-WGL(Weighted Generalized List)is proposed,which is based on the general-list decomposition of polynomials,with three different weights and manipulation rules introduced to effect node sharing and the canonicity.Timing parameters and operations on them are also considered.Examples show the word-level WGL is the only model to linearly represent the common word-level functions and the bit-level WGL is especially suitable for arithmetic intensive circuits.The model is proved to be a uniform and efficient model for both bit-level and word-level functions.Then based on the WGL model,a backward-construction verification approach is proposed,which reduces time and space complexity for multipliers to polynomial complexity(time complexity is less than O(n3.6)and space complexity is less than O(n1.5))without hierarchical partitioning.Both the model and the verification method show their theoretical and applicable significance in IC design.展开更多
GPS/Dead-reckoning navigation system for autonomous underwater vehicle (AUV) is introduced, which includes navigation overall architecture, hardware and software structure. Dead-reckoning theory is presented in detail...GPS/Dead-reckoning navigation system for autonomous underwater vehicle (AUV) is introduced, which includes navigation overall architecture, hardware and software structure. Dead-reckoning theory is presented in details. And the strong tracking Kalman filter and Singer model are applied to handle the imprecise navigation mode, which can improve the navigation system’s precision and reliability. Finally, the sea experiments which include autonomous search mission in an unknown area and long distance motion are conducted to demonstrate the reliability and feasibility of the navigation system.展开更多
The paper presents a new architecture composed of bit plane-parallel coder for Embedded Block Coding with Optimized Truncation (EBCOT) entropy encoder used in JPEG2000. In the architecture, the coding information of e...The paper presents a new architecture composed of bit plane-parallel coder for Embedded Block Coding with Optimized Truncation (EBCOT) entropy encoder used in JPEG2000. In the architecture, the coding information of each bit plane can be obtained simultaneously and processed parallel. Compared with other architectures, it has advantages of high parallelism, and no waste clock cycles for a single point. The experimental results show that it reduces the processing time about 86% than that of bit plane sequential scheme. A Field Programmable Gate Array (FPGA) prototype chip is designed and simulation results show that it can process 512×512 gray-scaled images with more than 30 frames per second at 52MHz.展开更多
Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x) integrated electrode for ...Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x) integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2) under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2) under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2) for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2) at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.展开更多
A new power estimation method is proposed for base station(BS) in this paper.Based on this method,a software platform for power estimation is developed.The proposed method models power consumption on different abstrac...A new power estimation method is proposed for base station(BS) in this paper.Based on this method,a software platform for power estimation is developed.The proposed method models power consumption on different abstraction levels by splitting a typical base station into several basic components at different levels in the view of embedded system design.In particular,our focus is on baseband IC(Integrate Circuit) due to it's the dominant power consumer in small cells.Baseband power model is based on arithmetic computing costs of selected algorithms.All computing and storage costs are calibrated using algorithm complexity,hardware architecture,activity ratio,silicon technology,and overheads on all hierarchies.Micro architecture and IC technology are considered.The model enables power comparison of different types of base stations configured with different baseband algorithms,micro architectures,and ICs.The model also supports cellular operators in power estimation of different deployment strategies and transmission schemes.The model is verified by comparing power consumption with a real LTE base station.By exposing more configuration freedoms,the platform can be used for power estimation of current and future base stations.展开更多
The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to impr...The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to improve the conductance characteristic. In thisprocession, the conductive particles interact to each other. In this paper, we describe theconductance of the doped polymer by Monte Carlo method. The results accord with the experimentsquite well. It can be concluded that there is an evident change of doped polymer from nonconductorto metal.展开更多
A novel magnetic integrated controllable reactor of transformer type(CRT)has the advantages of simple structure,flexible assembly,convenient maintenance and practicability.To analyze its operation characteristics accu...A novel magnetic integrated controllable reactor of transformer type(CRT)has the advantages of simple structure,flexible assembly,convenient maintenance and practicability.To analyze its operation characteristics accurately,we establish corresponding equivalent mathematical model considering magnetic leakage based on magnetic circuit and circuit dualistic transformation method.The distribution of magnetic leakage field of each winding is analyzed qualitatively,and the analytical calculation formulas of magnetizing inductance and leakage inductance of each winding are derived.Based on this,the analytical calculation formulas of short-circuit impedance and winding current of CRT under different working conditions are derived.The field-circuit coupling finite element model of the magnetic integrated CRT is established to simulate the current of each winding under different working conditions.The results show that the analytical calculation results of each winding current have good consistency with the finite element calculation results,indicating the validity of CRT equivalent mathematical model and correctness of the analytical formulas of leakage inductance,short-circuit impedance and winding current of CRT.The working winding current of CRT is increasing gradually with the operation of control winding in turn to realise the transition of CRT compensation capacity from zero to a rated value.展开更多
The choice of meter data acquisition methods has important significance for the electric energy management. Based on the comprehensive analysis of several meter data acquisition methods, this paper assess the performa...The choice of meter data acquisition methods has important significance for the electric energy management. Based on the comprehensive analysis of several meter data acquisition methods, this paper assess the performance of each one by analytic hierarchy process. We can draw a conclusion by calculating" The local automatic meter reading, the prepaid electric energy metering and the remote automatic meter reading have almost the same performance. They are better than the manual meter reading and the vehicle mounted mobile automatic meter reading. So we can choose any one of the three. Among them, the prepaid electric energy metering performs best. This can be a reference for grid company' s decision.展开更多
A fully integrated CMOS bio-chip is designed in a SMIC 0.18μm CMOS mixed signal process and successfully integrated with a novel bio-nano-system. The proposed circuit integrates an array of 4 × 4 (16 pixels) o...A fully integrated CMOS bio-chip is designed in a SMIC 0.18μm CMOS mixed signal process and successfully integrated with a novel bio-nano-system. The proposed circuit integrates an array of 4 × 4 (16 pixels) of 19μm × 19μm electrodes,a counter electrode, a current mode preamplifier circuit (CMPA) ,a digital decoding circuit,and control logics on a single chip, It provides a - 1.6- 1.6V range of assembly voltage,Sbit potential resolution, and a current gain of 39.8dB with supply voltage of 1.8V. The offset and noise are smaller than 5.9nA and 25.3pArms,respectively. Experimental resuits from on-chip selective assembly of 30nm poly (ethylene glycol) (PEG) coated magnetic nano-particles (MNPs) targeted at biosensor applications are included and discussed to verify the feasibility of the proposed circuits.展开更多
An integrated micro positioning xy-stage with a 2mm × 2mm-area shuttle is fabricated for application in nano- meter-scale operation and nanometric positioning precision. It is mainly composed of a silicon-based x...An integrated micro positioning xy-stage with a 2mm × 2mm-area shuttle is fabricated for application in nano- meter-scale operation and nanometric positioning precision. It is mainly composed of a silicon-based xy-stage,electrostatics comb actuator,and a displacement sensor based on a vertical sidewall surface piezoresistor. They are all in a monolithic chip and developed using double-sided bulk-micromachining technology. The high-aspect-ratio comb-driven xy-stage is achieved by deep reactive ion etching (DRIE) in both sides of the wafer. The detecting piezoresistor is located at the vertical sidewall surface of the detecting beam to improve the sensitivity and displacement resolution of the piezoresistive sensors using the DRIE technology combined with the ion implantation technology. The experimental results verify the integrated micro positioning xy-stage design including the micro xy-stage, electrostatics comb actuator,and the vertical sidewall surface piezoresistor technique. The sensitivity of the fabricated piezoresistive sensors is better than 1.17mV/μm without amplification and the linearity is better than 0. 814%. Under 30V driving voltage, a ± 10vm single-axis displacement is measured without crosstalk and the resonant frequency is measured at 983Hz in air.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
As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, t...As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on Zn O and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.展开更多
The boost type power supplies are widely used in portable consumer electronics to step up the input voltage to adapt for the high voltage applications like light-emitting diode(LED) driving and liquid crystal display(...The boost type power supplies are widely used in portable consumer electronics to step up the input voltage to adapt for the high voltage applications like light-emitting diode(LED) driving and liquid crystal display(LCD) biasing.In these applications,a regulator with small volume,fewer external components and high efficiency is highly desired.This paper proposes a projected off-and on-time boost control scheme,based on which a monolithic IC with an on-chip VDMOS with 0.2 Ω on-state resistance RDS-ON was implemented in 1.5 μm bipolar-CMOS-DMOS(BCD) process.A 12 V,0.3 A boost regulator prototype is presented as well.With projected off-time and modulated on-time in continuous conduction mode(CCM),a quasi fixed frequency,which is preferred for ripple control,is realized.With projected on-time and modulated off-time in discontinuous conduction mode(DCM),pulse frequency modulation(PFM) operation,which is beneficial to light load efficiency improvement,is achieved without extra control circuitry.Measurement results show that an efficiency of 3% higher than that of a conventional method under 0.5 W output is achieved while a step load transient response comparable to that of current mode control is maintained as well.展开更多
基金The Key Science and Technology Project of Zhejiang Province(No.2007C21021)
文摘This paper proposes a new battery management system (BMS) based on a master-slave control mode for multi-cell li-ion battery packs. The proposed BMS can be applied in li-ion battery packs with any cell number. The whole system is composed of a master processor and a string of slave manager cells (SMCs). Each battery cell corresponds to an SMC. Unlike the conventional BMS, the proposed one has a novel method for communication, and it collects the battery status information in a direct and simple way. An SMC communicates with its adjacent counterparts to transfer the battery information as well as the commands from the master processor. The nethermost SMC communicates with the master processor directly. This method allows the battery management chips to be implemented in a standard CMOS ( complementary metal-oxide-semiconductor transistor) process. A testing chip is fabricated in the CSMC 0.5 μm 5 V N-well CMOS process. The testing results verify that the proposed method for data communication and the battery management system can protect and manage multi-cell li-ion battery packs.
文摘A new type strongly gain coupled (GC) DFB laser and a new type self alignment spot size converter (SA SSC) are proposed and successfully fabricated.The strongly GC DFB laser is monolithically integrated with the SA SSC with three step epitaxies.A high single mode yield and large side mode suppression ratio is obtained from the strongly GC DFB laser.A near circle far field pattern is obtained by using the SA SSC.
基金Sponsored by the National Natural Science Foundation of China(Grant No.69973014and60273081)the Natural Science Foundation of Heilongjiang Province(Grant No.F0209)HEU Foundation(Grant No.HEUF04088).
文摘Formal verification is playing a significant role in IC design.However,the common models for verification either have their complexity problems or have applicable limitations.In order to overcome the deficiencies,a novel model-WGL(Weighted Generalized List)is proposed,which is based on the general-list decomposition of polynomials,with three different weights and manipulation rules introduced to effect node sharing and the canonicity.Timing parameters and operations on them are also considered.Examples show the word-level WGL is the only model to linearly represent the common word-level functions and the bit-level WGL is especially suitable for arithmetic intensive circuits.The model is proved to be a uniform and efficient model for both bit-level and word-level functions.Then based on the WGL model,a backward-construction verification approach is proposed,which reduces time and space complexity for multipliers to polynomial complexity(time complexity is less than O(n3.6)and space complexity is less than O(n1.5))without hierarchical partitioning.Both the model and the verification method show their theoretical and applicable significance in IC design.
文摘GPS/Dead-reckoning navigation system for autonomous underwater vehicle (AUV) is introduced, which includes navigation overall architecture, hardware and software structure. Dead-reckoning theory is presented in details. And the strong tracking Kalman filter and Singer model are applied to handle the imprecise navigation mode, which can improve the navigation system’s precision and reliability. Finally, the sea experiments which include autonomous search mission in an unknown area and long distance motion are conducted to demonstrate the reliability and feasibility of the navigation system.
基金Supported in part by the "863" Program (No.2003 AA1ZB10)
文摘The paper presents a new architecture composed of bit plane-parallel coder for Embedded Block Coding with Optimized Truncation (EBCOT) entropy encoder used in JPEG2000. In the architecture, the coding information of each bit plane can be obtained simultaneously and processed parallel. Compared with other architectures, it has advantages of high parallelism, and no waste clock cycles for a single point. The experimental results show that it reduces the processing time about 86% than that of bit plane sequential scheme. A Field Programmable Gate Array (FPGA) prototype chip is designed and simulation results show that it can process 512×512 gray-scaled images with more than 30 frames per second at 52MHz.
文摘Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x) integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2) under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2) under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2) for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2) at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.
基金The finance supporting from National High Technical Research and Development Program of China(863program)2014AA01A705
文摘A new power estimation method is proposed for base station(BS) in this paper.Based on this method,a software platform for power estimation is developed.The proposed method models power consumption on different abstraction levels by splitting a typical base station into several basic components at different levels in the view of embedded system design.In particular,our focus is on baseband IC(Integrate Circuit) due to it's the dominant power consumer in small cells.Baseband power model is based on arithmetic computing costs of selected algorithms.All computing and storage costs are calibrated using algorithm complexity,hardware architecture,activity ratio,silicon technology,and overheads on all hierarchies.Micro architecture and IC technology are considered.The model enables power comparison of different types of base stations configured with different baseband algorithms,micro architectures,and ICs.The model also supports cellular operators in power estimation of different deployment strategies and transmission schemes.The model is verified by comparing power consumption with a real LTE base station.By exposing more configuration freedoms,the platform can be used for power estimation of current and future base stations.
文摘The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to improve the conductance characteristic. In thisprocession, the conductive particles interact to each other. In this paper, we describe theconductance of the doped polymer by Monte Carlo method. The results accord with the experimentsquite well. It can be concluded that there is an evident change of doped polymer from nonconductorto metal.
基金Weinan Science and Technology Plan Project(No.2020ZDYF-JCYJ-177)General Special Scientific Research Projects of Education Department of Shaanxi Provincial Government(No.21JK0582)+2 种基金Young and Middle-aged Scientific and Technological Talents Project of Shaanxi Railway Institute(No.KJRC202001)Scientific Research Fund Project of Shaanxi Railway Institute(No.KY2021-34)Science and Technology Innovation Team of Shaanxi Railway Institute(No.KJTD201901)。
文摘A novel magnetic integrated controllable reactor of transformer type(CRT)has the advantages of simple structure,flexible assembly,convenient maintenance and practicability.To analyze its operation characteristics accurately,we establish corresponding equivalent mathematical model considering magnetic leakage based on magnetic circuit and circuit dualistic transformation method.The distribution of magnetic leakage field of each winding is analyzed qualitatively,and the analytical calculation formulas of magnetizing inductance and leakage inductance of each winding are derived.Based on this,the analytical calculation formulas of short-circuit impedance and winding current of CRT under different working conditions are derived.The field-circuit coupling finite element model of the magnetic integrated CRT is established to simulate the current of each winding under different working conditions.The results show that the analytical calculation results of each winding current have good consistency with the finite element calculation results,indicating the validity of CRT equivalent mathematical model and correctness of the analytical formulas of leakage inductance,short-circuit impedance and winding current of CRT.The working winding current of CRT is increasing gradually with the operation of control winding in turn to realise the transition of CRT compensation capacity from zero to a rated value.
文摘The choice of meter data acquisition methods has important significance for the electric energy management. Based on the comprehensive analysis of several meter data acquisition methods, this paper assess the performance of each one by analytic hierarchy process. We can draw a conclusion by calculating" The local automatic meter reading, the prepaid electric energy metering and the remote automatic meter reading have almost the same performance. They are better than the manual meter reading and the vehicle mounted mobile automatic meter reading. So we can choose any one of the three. Among them, the prepaid electric energy metering performs best. This can be a reference for grid company' s decision.
文摘A fully integrated CMOS bio-chip is designed in a SMIC 0.18μm CMOS mixed signal process and successfully integrated with a novel bio-nano-system. The proposed circuit integrates an array of 4 × 4 (16 pixels) of 19μm × 19μm electrodes,a counter electrode, a current mode preamplifier circuit (CMPA) ,a digital decoding circuit,and control logics on a single chip, It provides a - 1.6- 1.6V range of assembly voltage,Sbit potential resolution, and a current gain of 39.8dB with supply voltage of 1.8V. The offset and noise are smaller than 5.9nA and 25.3pArms,respectively. Experimental resuits from on-chip selective assembly of 30nm poly (ethylene glycol) (PEG) coated magnetic nano-particles (MNPs) targeted at biosensor applications are included and discussed to verify the feasibility of the proposed circuits.
文摘An integrated micro positioning xy-stage with a 2mm × 2mm-area shuttle is fabricated for application in nano- meter-scale operation and nanometric positioning precision. It is mainly composed of a silicon-based xy-stage,electrostatics comb actuator,and a displacement sensor based on a vertical sidewall surface piezoresistor. They are all in a monolithic chip and developed using double-sided bulk-micromachining technology. The high-aspect-ratio comb-driven xy-stage is achieved by deep reactive ion etching (DRIE) in both sides of the wafer. The detecting piezoresistor is located at the vertical sidewall surface of the detecting beam to improve the sensitivity and displacement resolution of the piezoresistive sensors using the DRIE technology combined with the ion implantation technology. The experimental results verify the integrated micro positioning xy-stage design including the micro xy-stage, electrostatics comb actuator,and the vertical sidewall surface piezoresistor technique. The sensitivity of the fabricated piezoresistive sensors is better than 1.17mV/μm without amplification and the linearity is better than 0. 814%. Under 30V driving voltage, a ± 10vm single-axis displacement is measured without crosstalk and the resonant frequency is measured at 983Hz in air.
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.
基金supported by the National Basic Research Program of China(Grant No.2015CB351900)National Natural Science Foundation of China(Grant Nos.11222220,11320101001,11090331 and 11227801)Tsinghua University Initiative Scientific Research Program
文摘As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on Zn O and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.
基金Project (No.90707002) supported by the National Natural Science Foundation of China
文摘The boost type power supplies are widely used in portable consumer electronics to step up the input voltage to adapt for the high voltage applications like light-emitting diode(LED) driving and liquid crystal display(LCD) biasing.In these applications,a regulator with small volume,fewer external components and high efficiency is highly desired.This paper proposes a projected off-and on-time boost control scheme,based on which a monolithic IC with an on-chip VDMOS with 0.2 Ω on-state resistance RDS-ON was implemented in 1.5 μm bipolar-CMOS-DMOS(BCD) process.A 12 V,0.3 A boost regulator prototype is presented as well.With projected off-time and modulated on-time in continuous conduction mode(CCM),a quasi fixed frequency,which is preferred for ripple control,is realized.With projected on-time and modulated off-time in discontinuous conduction mode(DCM),pulse frequency modulation(PFM) operation,which is beneficial to light load efficiency improvement,is achieved without extra control circuitry.Measurement results show that an efficiency of 3% higher than that of a conventional method under 0.5 W output is achieved while a step load transient response comparable to that of current mode control is maintained as well.