Research On Vibration Energy Collection Device Of Pavement Based On Thin Sheet Bending Piezoelectric Transducer

Pavement-based piezoelectric power-generation technology converts mechanical energy generated by traffic loads into electricity by embedding piezoelectric transducers in the pavement.Piezoelectric power generation technology is a kind of piezoelectric element attached to a certain structure to achieve energy collection and conversion technology.In this paper,according to the characteristics of pavement structure and traffic load,a piezoelectric energy collection device for collecting vibration energy of pavement is designed.The main contents are as follows:First of all,according to the good force-electric conversion characteristics of thin piezoelectric elements,it can not be directly applied to pavement capacity,it can not be directly applied to pavement structures.According to the different energy conversion modes of the piezoelectric transducers,two kinds of transducers,impact type and bending type,were designed and fabricated using thin sheet piezoelectric panel.The working principle of the two structures was analyzed,and the power generation performance of the two transducers was tested by establishing a comparative test,together with the laws of effect of variations in load conditions on the electricity production of the transducers.The test results show that the power generation performance and working stability of the bending transducer were better than those of the impact transducer under limited displacement and low frequency loading.Then,the bending piezoelectric transducer is made into a piezoelectric energy collecting device.The transducer is composed of 27 fixed piezoelectric sheets connected at both ends in parallel.The external casing uses a box-type structure with upper,middle and lower components.The transducer was embedded in a specimen with a typical pavement structure with compacted asphalt mortar as the base to create a power-generating pavement specimen for testing.Finally,the output performance tests of the piezoelectric energy harvesting device were carried out at indoor and outdoor sites,respectively.Indoor load test results show that open-circuit voltage increases with increased arousal frequency.As the displacement increases,the output power increases accordingly.When the vibration frequency of 10 Hz,the displacement is 2 mm,under the load resistance of 3 kΩ get maximum output voltage of30.17 V,the maximum output current 10.01 m A,maximum output power of 303.4 m W.The piezoelectric energy harvesting device for road is embedded in the actual asphalt pavement for performance test.The open-circuit voltage value increases with the increase of vehicle speed,and the open-circuit voltage value in the actual road test is higher than that in the indoor test.When the vehicle speed is 60 km/h,the maximum open circuit voltage value is91.0 V.The output power first increases with the increase in the external resistance value,reaches the maximum output power at optimal charge resistance,and then decreases the output power.Test results show that the vehicle’s speed has little effect on open-circuit voltage.Increasing axle load increases open-circuit voltage value and output power value.When the external load reaches 2000 Ω,axial load of 22.7 k N,the maximum output power of the device is 328.7 m W,the maximum output voltage is 26.44 V,the maximum output current is 12.4m A.Compared with the maximum output power of some existing piezoelectric power generation devices at home and abroad,the output power of the piezoelectric energy harvesting device designed in this paper is much higher than that of others.In a word,this new type of piezoelectric transducer provides a good prospect for the application of green energy in road engineering.