Design And Application Of Piezoelectric-Electromagnetic Composite Energy Harvester

With the rapid development of low-energy,portable electronic devices,the conversion of vibration energy into electrical energy and supplying it to low-power electronic devices has become a current research hotspot.At present,the main types of vibration energy capturer are piezoelectric and electromagnetic.Piezoelectric energy traps have the characteristics of high output voltage and low output current,while electromagnetic energy traps have the characteristics of low output voltage and high output current.In this paper,we design a piezoelectric-electromagnetic energy capturer based on the low-frequency motion of the human body,hereinafter referred to as the "composite energy capturer",by combining the power generation principle of polyvinylidene fluoride(PVDF)material and the electromagnetic energy conversion principle.The energy capturer can be used to collect energy from various parts of the human body.It is simple,easy to operate and highly adaptable,and is effective in collecting low-frequency vibration energy generated by human motion.The full paper is summarised as follows.1.The research background and significance of this paper are explained.The current status of research on piezoelectric,electromagnetic and piezoelectric-electromagnetic energy capturers at home and abroad is briefly introduced,and a new composite energy captor is designed based on previous research.The basic principles of the piezoelectric and electromagnetic effects are analysed,the theoretical analysis of the two types of units is carried out,the factors affecting piezoelectric and electromagnetic power generation are analysed,a piezoelectric-electromagnetic coupling model is established from the electrical point of view,and the expressions for the output voltage and output power of the composite energy trap are deduced.2.Design the structure of the composite energy trap,establish the trap simulation model,use COMSOL finite element simulation software to simulate the vibration system and the piezoelectric cell,and investigate the influence of the piezoelectric cell base thickness,piezoelectric material thickness and the arch structure of the piezoelectric sheet on the output performance.Simulation analysis of the electromagnetic unit model was carried out to investigate the effects of coil length,wire diameter and permanent magnet related parameters on the electromagnetic unit.3.A prototype of the composite energy trap is machined,a vibration test platform is built and tests are carried out on the piezoelectric and electromagnetic cells respectively,and the test results are compared with the theoretical simulation results.The effect of the composite energy capturer in converting the mechanical energy of the human body into electrical energy was examined.The feasibility of applying the composite energy capturer to the human body for power generation was verified by applying the composite energy capturer prototype to the legs and hands and analysing its output performance.