Design And Research On A New Piezoelectric Wind Energy Harvester And Its Interface Charging Circuit

Aiming at the problem about the low output efficiency of wind energy harvesters at low wind speed,this paper proposes a piezoelectric cantilever wind energy harvester with semi-annular bluff body structure,which is composed of a rectangular piezoelectric cantilever and a semi-annular bluff body installed at the free end of the cantilever.Compared with the traditional circular and rectangular cross-section bluff body,the semi-annular cross-section bluff body has stronger airflow obstruction due to the special concave structure,and the flow field near is more turbulent and the pressure field gradient is larger.So the bluff body and the piezoelectric cantilever beam have stronger galloping and higher output voltage.We used the finite element simulated method to analysis the wind speed and pressure distribution around the bluff body of semi-circular,circular and rectangular sections,respectively.The analysis results show that there is a stronger turbulent flow field and a larger pressure gradient near the semi-annular bluff body.In order to verify the advancement of the proposed structure,the output characteristics of wind energy harvesters with semi-circular,circular and rectangular bluff body at 0-6.5 m/s wind speed are tested.The experimental results show that the wind energy harvester with semi-annular bluff body has higher output voltage and power.At the low wind speed of 2m/s,the optimal output power of the presented harvester is 6.4 and 4.8 times than that of the wind energy harvesters with a circular and rectangular bluff body,respectively;when the wind speed is 6.5 m/s,the proposed harvester with semi-annular bluff body has an maximum output power of 0.482mW at an optimum load of 140k ?.·Not only that,this article also analyzes the basic principles of the four interface circuits in detail,and uses Multisim simulation software to establish simulation models of the four interface circuits,this article also compares the output characteristics and charging efficiency of the four interface circuits with a load,and designs Self-sensing synchronous charge extraction interface charging circuit,The charging efficiency of this circuit is 5.6 times that of the standard interface..The harvester structure proposed in the paper can also be applied to the fields of wave energy collection,wind speed measurement and the like.