Abstract
Piezoelectric energy harvester (PEH) is emerging as a novel device which can convert mechanical energy into electrical energy. It is mainly used to collect ambient vibration energy to power sensors, chips and some other small applications. This paper first introduces the working principle of PEH. Then, the paper elaborates the research progress of PEH from three aspects: piezoelectric materials, piezoelectric modes and energy harvester structures. Piezoelectric material is the core of the PEH. The piezoelectric and mechanical properties of piezoelectric material determine its application in energy harvesting. There are three piezoelectric modes, d31, d33 and d15, the choice of which influences the maximum output voltage and power. Matching the external excitation frequency maximizes the conversion efficiency of the energy harvester. There are three approaches proposed in this paper to optimize the PEH’s structure and match the external excitation frequency, i.e., adjusting the resonant frequency, frequency up-converting and broadening the frequency bandwidth. In addition, harvesting maximum output power from the PEH requires impedance matching. Finally, this paper analyzes the above content and predicts PEH’s future development direction.
Highlights
In recent years, wireless sensor network technology has been widely used in environmental monitoring, health care, urban temperature detection, agricultural production and other fields [1,2,3,4,5,6].The main power supply for sensor nodes still relies on chemical battery, which offers limited energy storage
There are still problems that limit the application of Piezoelectric energy harvester (PEH): (1) the power loss in rectification circuit caused by the low output voltage [18]; (2) the narrow working frequency bandwidth of the energy harvester [9,19,20]; and (3) the mismatch of the frequency between the PEH and the environment [21,22]
In 2004, Sodano et al [23] first developed the model of the PEH, which consists of cantilever beam, piezoelectric material and electrodes
Summary
Wireless sensor network technology has been widely used in environmental monitoring, health care, urban temperature detection, agricultural production and other fields [1,2,3,4,5,6]. There are still problems that limit the application of PEH: (1) the power loss in rectification circuit caused by the low output voltage [18]; (2) the narrow working frequency bandwidth of the energy harvester [9,19,20]; and (3) the mismatch of the frequency between the PEH and the environment [21,22]. The following section introduces a general model of energy harvester and describes the research progress of PEHs from three aspects: piezoelectric materials, piezoelectric modes and energy harvesters’ structure.
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