| In recent years,piezoelectric energy collectors have received increasing attention due to their potential applications in self powered systems.However,problems such as low piezoelectric coefficient and narrow frequency band of traditional piezoelectric materials limit their practical applications.In this paper,the performance of x%Sm–（1-y）Pb(Mg1/3Nb2/3)O3-yPbTiO3（x=0,1,2,2.5,3;y=0.28,0.30,0.32,0.34）ceramics was studied and applied to piezoelectric energy collectors.The research is divided into two parts:The first part is the preparation and testing of x%Sm-PMN-yPT ceramics with different components.The second part is based on the operating environmental conditions of power grid transformers（SFSZ10-2400000/220）.Sm-PMN-PT ceramics are used as piezoelectric materials to participate in the design,preparation,and testing of piezoelectric energy collectors,providing energy for transformer wireless monitoring equipment,and verifying the feasibility of Sm-PMN-PT ceramic materials in the field of energy collection.In the first part,a series of x%Sm-PMN-yPT ceramics with different compositions were prepared by solid-state reaction method.The structure,dielectric,piezoelectric properties,and energy collection properties of ceramics were characterized and analyzed.The results show that compared to other components of Pure-PMN-yPT ceramics,Pure-PMN-32PT ceramics have higher piezoelectric coefficient((933≈778 p C/N),thickness direction electromechanical coupling coefficient（Kt=53%）,and piezoelectric voltage constant(g33=38.85×10-3Vm/N),energy conversion coefficient(d33×g33=30.22×10-12 m2/N),mechanical quality in non resonant state(FOMoff=6349.26×10-12 m2/N);The addition of Sm can effectively improve the density,piezoelectric performance,electromechanical coupling performance,and energy transfer coefficient of PMN-PT ceramics,which is more conducive to piezoelectric energy collection.After testing,it is determined that the optimal doping concentration of Sm is 2.5 wt.%.2.5%Sm-PMN-32PT has an ultra-high voltage electrical coefficient(d33≈1710 p C/N),and an energy conversion coefficient(d33×g33=56.81×10-12 m2/N)and the electromechanical coupling coefficient in the thickness direction（Kt=58%）.This component material is used as a piezoelectric material for piezoelectric energy collection devices through batch preparation.In the second part,firstly,the transformer environment was tested to determine the vibration frequency（100 Hz/200 Hz）and acceleration（0.5 g）.Secondly,the existing transformer wireless monitoring equipment was measured to determine the device size（not exceeding 88*35*60 mm）and power supply voltage（3V）.According to this size requirement,the device was designed and the fixture was prepared.Then,the piezoelectric vibrator was prepared according to the fixture requirements,and finally,the series parallel connection,charge and discharge tests were conducted.The results show that the 2.5%Sm-PMN-32PT ceramic used as a piezoelectric energy collector designed as a piezoelectric material has an open circuit voltage of 35.5 V at 200 Hz and 0.5 g,with a wide voltage frequency response.The open circuit voltage is above 30 V in the range of 200 to 203 Hz,and the optimal power is 8.11 m W,which occurs around 30kΩ.The energy density of the piezoelectric chip used in the piezoelectric array reaches 2.25 m W/cm3;This combination connects to the LTC-3588-1 energy conversion module and charges the1 F capacitor for 4.15 V in 203 min,which can provide 4.11 J of energy for back-end wireless communication devices and meet the self power supply requirements of communication devices.This work systematically analyzes the structure and electrical properties of PMN-PT ceramics.Through Sm doping modification,the piezoelectric properties of piezoelectric materials are significantly improved.Through the design and optimization of piezoelectric devices,the power generation performance of devices is significantly improved,which will promote the development of piezoelectric materials and energy collection devices,and has important significance for achieving self power supply of microelectronic devices. |
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