中文摘要：

在分析超声换能器阻抗特性和电路匹配的基础上,对传统纯电感电容匹配电路模型进行电路仿真和阻抗分析,证明该模型在谐振频率附近有大范围的电抗变化,存在电路不稳定和电阻调节精度低的问题;提出＂电感-变压器＂阻抗匹配模型,通过电感和变压器分别调节换能器电阻和电抗,实现电路的精确匹配,以提高超声换能器阻抗匹配的精度和稳定性,并给出了理想的匹配条件和匹配参数。利用匝数可调的变压器和电感制作了超声换能器的匹配电路,对20.8 k Hz的变幅杆换能器进行了阻抗匹配的实验测量,结果证明这种＂电感-变压器＂阻抗匹配模型在谐振频率附近具有较小的电抗变化范围、较低的电阻变化率和较高的电抗调节精度,在超声换能器的自动阻抗匹配中具有良好的应用前景。

英文摘要：

Based on the analyses of impedance characteristics and matching circuit of ultrasound transducer, it is found that with the traditional inductance capacitance matching circuit, a wide range of reactance variation around the reso-nant frequency appears and causes the circuit stability and regulatory accuracy reduced. Therefore, a ‘transfor-mer-inductance’ matching model is proposed in this paper. The reactance and resistance can be regulated by the ad-justable inductance and transformer to improve the precision and stability of the matching circuit for ultrasonic trans-ducer, and the ideal matching condition and parameter are provided. In experiments, with the controllable transformer and inductance, a matching circuit is developed for an ultrasonic horn transducer with the center frequency of 20.8 kHz. It is proved that the matching circuit has a narrow impedance variation range with high reactance regulatory ac-curacy when the frequency is close to the resonance, which provides application potential in automatic impedance matching of ultrasonic transducer.