计算机曲线拟合求压电换能器的特征频率及动态参量
EVALUATION OF CHARACTERISTIC FREQUENCIES AND DYNAMICAL PARAMETERS OF PIEZOELECTRIC TRANSDUCER BY CURVE FITTING
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摘要: 求压电换能器的特征频率及动态参量时通常采用“导纳圆图”的分析方法。测量“导纳圆”时,在换能器的共振频率附近只能测出几个频率点,因此从“导纳圆”上求得的特征频率为较粗糙的线性插值,误差较大,特别是在高Q值时更为明显。实际上,由这种方法确定串联、并联共振频率,电共振与反共振频率等较为困难。因此求与其相关的动态参数也同样困难,利用测量的频率、阻抗模量及幅角,采用计算机作曲线拟合的方法作数据处理,可求得换能器的全部特征频率以及对应的导纳值、机械及电品质因数、有效机电耦合系数等动态参量。在一定程度上提高了精度,编成通用程序后可提高工作效率。Abstract: According to the experimental data and by means of curve fitting an admittance graph of piezoelectric transducer has been worked out. From it the characteristic frequencies and dynamic parameters of the piezoelectric transducer are evaluated.