【作者】 陈超；

【导师】 张章；

【作者基本信息】 合肥工业大学 ， 集成电路工程（专业学位）， 2020， 硕士

【摘要】 随着无线传感网络的快速发展,市场上出现了一系列低功耗植入式或可穿戴设备,而传统电池的体积大小和续航问题已经成为延长设备寿命的重大瓶颈,因此人们考虑采用传感器实现对外界能量的收集。能量收集技术可以利用外界自然能量转换成电能实现持续供电,而在诸多外界能量中,振动能存在能量密度高,来源广泛的优点,因此本文选择采用压电传感器实现振动能量收集。压电传感器可以将振动能通过压电效应产生交流信号。本文在悬臂梁压电式振动能量收集接口控制电路研究基础上,提出了一款基于电容同步开关收集的冷启动压电能量收集系统,有效提高能量转换效率,并利用转换之后的电能为整个系统供电,该系统有基于电容同步开关收集接口控制电路工作前和工作后两种工作情况。论文主要从以下几个方面展开工作:（1）首先调研了国内外学者的学术研究,详细介绍了不同的压电能量收集接口控制电路的优缺点并进行设计改进,接着介绍了压电传感器的基本原理,分析相应的压电效应与方程推导,提出压电传感器的悬臂梁物理结构与电学结构。重点分析了传统的全桥整流器、同步电荷提取电路、基于电感串联同步开关收集电路、基于电感并联同步开关收集电路以及基于电容同步开关收集电路的工作过程,推导出各自的输出电压以及输出功率并进行比较。（2）本文提出并设计了基于电容同步开关收集冷启动压电能量收集系统,在没有外部电压的情况下,实现系统内部自供电。整个系统主要包括有源AC-DC整流器、高压模块、控制模块和冷启动模块,文中详细介绍了各模块电路图并分析其工作原理。整个系统内部电源由输出储能电容提供,在V_DD未达到工作电压时,接口控制电路不工作,系统作为全桥整流器工作,冷启动电路开启提高开路电压。当V_DD达到工作电压,接口控制电路的各个模块启动,大幅度提高能量转换效率,冷启动电路关闭。（3）使用了Cadence公司的Spectre仿真软件,根据理论模型设置了合适的系统电路参数,对各个模块进行了功能仿真,并得到了系统的翻转效率波形图。与其他接口控制电路相比,基于电容同步开关收集冷启动压电能量收集电路可以在增加收集效率的同时减少设计面积。仿真结果表明,电压V_PT翻转效率达到了66.36%,在4.5V的开路电压供电下,输出功率比值达到5.5倍,高于采用电感整流技术,并可以实现冷启动自供电功能。更多还原

【Abstract】 With the rapid development of wireless sensor networks,a series of low-power implantable or wearable devices have appeared on the market.The size and life of traditional batteries have become a major bottleneck in extending the life of devices.Therefore,people are considering adopting transducers to achieve the collection of external energy.Energy harvesting technology can use the external natural energy to convert it into electrical energy for continuous power supply.Among many external energy sources,vibration energy has the advantages of high energy density and wide range of sources.Therefore,this paper chooses to use piezoelectric transducers to achieve vibration energy harvesting.Piezoelectric transducers can use vibration to generate AC signals through piezoelectric effect.Based on the research of the cantilever piezoelectric vibration energy harvesting interface controlled circuit,this paper proposes a cold-start piezoelectric energy harvesting system with synchronous switch harvesting on capacitors to efficiently improve energy conversion efficiency,and uses the converted energy to power the entire system,which has two working situations before and after the synchronous switch harvesting on capacitors interface controlled circuit.The paper mainly works from the following aspects:（1）Firstly,the academic research of domestic and foreign scholars was investigated,the advantages and disadvantages of different piezoelectric energy harvesting interface controlled circuits and the design improvements were introduced in detail.Then the fundamental of piezoelectric transducer is introduced,and the corresponding piezoelectric effects and equations are analyzed.The physical structure and electrical structure of the cantilever piezoelectric transducer are proposed.This paper focuses on analyzing the working process of traditional full-bridge rectifier,synchronous electrical charge extraction circuit,series-synchronous switch harvesting on inductor circuit,parallel-synchronous switch harvesting on inductor circuit,and synchronous switch harvesting on capacitors circuit,and derives the output voltages and output power respectively and compares them.（2）This paper proposes and designs an synchronous switch harvesting on capacitors cold-start piezoelectric energy harvesting system,to achieve self-power supply in the system without external voltage.The whole system mainly includes active AC-DC rectifier,high-voltage module,controlled module and cold-start module.The circuit diagram of each module is described in detail and its working principle is analyzed.The internal power supply of the entire system is provided by the output energy storage capacitor.When V_DDdoes not reach the working voltage,the interface controlled circuit does not work,and the system works as a full-bridge rectifier.The cold-start circuit is turned on to increase the open circuit voltage.When V_DDreaches,each module of the interface controlled circuit is started,which greatly improves the energy conversion efficiency,and the cold-start circuit is closed.（3）Appropriate system circuit parameters were set according to the theoretical model with Cadence’s Spectre.This paper performs functional simulation for each module,and the waveform diagram of the system’s flipping efficiency was obtained.Compared with other interface controlled circuits,synchronous switch harvesting on capacitors cold-start piezoelectric energy harvesting circuit can reduce the design area while increasing the flipping efficiency.The simulation results show that the flipping efficiency of voltage V_PThas reached 66.36%.The output power ratio reaches 5.5 times under the open-circuit voltage of 4.5V,much higher than that using inductive rectification technology,and the function of cold-start self-power supply can be realized.更多还原