外接LC电路的可调压电换能器的频率特性

压电换能器往往因受到温度与负载的影响,导致其谐振频率、反谐振频率和机械品质因数等特征参数发生变化。通过在压电换能器中设计用于调节的压电陶瓷片,并在调节压电陶瓷片两端外接电负载,可以实现压电换能器的频率调节,修正由于温度和负载导致的频率漂移。基于压电换能器的Mason等效电路,建立外接LC调节电路的压电换能器的谐振频率、反谐振频率模型,分析LC调节电路中调节电感对频率调节特性的影响;通过实验研究外接LC调节电路对可调压电换能器机械品质因数的影响,并验证调节电感对频率调节特性的影响。理论分析和实验研究的结果表明:随着调节电感的增大,调节电容对频率的调节灵敏度提高,可调压电换能器的频率调节宽度拓宽,但也会使压电换能器的机械品质因数降低。合理选择调节电感和调节电容能兼顾频率调节宽度和机械品质因数的要求。此研究可为后续自适应压电换能器的频率调节系统设计提供指导。 

Frequency characteristics of a regulatable piezoelectric transducer with external LC circuit

Piezoelectric transducers are often affected by temperature and load,resulting in changes in their characteristic parameters such as resonance frequency,anti-resonance frequency and mechanical quality factor.By designing the piezoelectric ceramics for regulation in the piezoelectric transducer,and connecting the electrical load at both ends of the regulating piezoelectric ceramics,the frequency regulation of the piezoelectric transducer can be realized,and the frequency drift caused by temperature and load can be corrected.Based on the Mason equivalent circuit of piezoelectric transducer,the resonant frequency and anti-resonant frequency models of piezoelectric transducer with external LC regulating circuit are established,and the influence of regulating inductance in LC regulating circuit on frequency regulation characteristics is analyzed.The influence of external LC regulating circuit on the mechanical quality factor of regulatable piezoelectric transducer is studied by experiments,and the influence of regulating inductance on frequency regulation characteristics is verified.The results of theoretical analysis and experimental studies show that as the regulating inductance increases,the regulating sensitivity of capacitance on frequency increases and the frequency regulation width of the regulatable piezoelectric transducer widens,but it also reduces the mechanical quality factor of the piezoelectric transducer.The reasonable selection of the regulating inductor and the regulating capacitor can balance the requirements of frequency regulation width and mechanical quality factor.This study can provide guidance for the design of subsequent frequency regulation systems for adaptive piezoelectric transducers.