压电超声换能器初级串联匹配新方法

Novel primary series matching scheme for piezoelectric ultrasonic transducer

在分析超声电源输出变压器的非理想性给压电超声换能器电端匹配带来不良影响的基础上,根据空芯变压器模型理论,提出了一种新型的压电超声换能器初级串联匹配法:取消常规的次级匹配电感,若由输出变压器和换能器所构成的整体负载在换能器机械谐振频率处呈感性,则可通过在输出变压器初级串接一个合适的电容实现功放电路和其负载间的共轭匹配,反之则串联一个合适的电感。性能对比实验表明,该匹配法较传统的次级串联电感匹配法进一步提高了匹配的准确度,能量的传递效果也得到改善。

The main reason for the matching performance degradation caused by the output transformer mounted on the ultrasonic generator was analyzed.Then,based on the theory of the air-core transformer model,a novel primary serial matching scheme for the piezoelectric ultrasonic transducer was developed.This scheme eliminates the traditional matching inductor mounted on the secondary coil.If the total load,which is composed of the output transformer and transducer,shows inductive impedance at the mechanical resonance frequency of the transducer,a series-wound suitable capacitor can achieve better performance than the traditional matching inductor-based scheme.Otherwise,a comportable series-wound inductor is needed.As a result of the above treatment,the state of conjugated matching between the supply amplifier and its load is reached.A series of texts demonstrate that,in comparison with the traditional secondary serial inductor matching scheme,the new scheme takes advantage in term of the matching precision and power transmission efficiency.