Coupled modeling method for vibration piezoelectric energy harvesting system

Abstract

The invention belongs to the field of vibration power generation of piezoelectric materials, and discloses a coupled modeling method for a vibration piezoelectric energy harvesting system. The coupled modeling method specifically comprises the following steps of: (S1) according to an equivalent analogical relation between mechanical quantity and electrical quantity, establishing an equivalent electrical model of a piezoelectric power generation structure; (S2) establishing a finite element model of the piezoelectric power generation structure, and estimating parameters of the equivalent electrical model;(S3) enabling stray capacitance and an interface circuit of the piezoelectric power generation structure to be equivalent to electrical impedance; and (S4) connecting the equivalent electrical model of the piezoelectric power generation structure with the equivalent electrical impedance, thereby establishing a coupling model of the vibration piezoelectric energy harvesting system. The coupled modeling method has the advantages that: firstly, the coupled modeling method is suitable for a cantilever beam piezoelectric power generation structure of any shape; secondly, a computing process is simple and amount of computation is small; and thirdly, the piezoelectric power generation structure and the interface circuit can be simultaneously optimized .

Description

technical field [0001] The invention belongs to the field of vibration power generation of piezoelectric materials, in particular to a coupling modeling method of a vibration piezoelectric energy harvesting system. Background technique [0002] With the rapid development of micro-electromechanical (MEMS), low-power circuit design and other technologies, the size and power consumption of wireless sensors are getting smaller and smaller, which makes it possible to capture other energy in the environment and convert it into electrical energy to meet the working needs of wireless sensors. This eliminates the need for an external power supply or battery power. In particular, vibration energy is ubiquitous in the environment. At present, vibration energy capture can be achieved through three methods: piezoelectric, electromagnetic and electrostatic. Among them, vibration piezoelectric energy capture has received the most attention because of its high energy density. , Easy to min...

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Problems solved by technology

However, due to the existence of the inverse piezoelectric effect of piezoelectric materials, there is a very tight coupling relationship between these parts in practice, that is, when the piezoelectric power generation structure is connected to the interface circuit, the interface circuit and the load will affect the vibration of the piezoelectric power generation structure state, and the change of the vibration state of the piezoelectric power generation structure will lead to a change in the output AC voltage, which will affect the overall conversion efficiency of the vibration piezoelectric energy harvesting system, which means that the separately optimized piezoelectric power generation structure is connected with the interface circuit Working together, the highest power conversion efficiency cannot be obtained, which is very unfavorable for practical applications

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