高效功率传输的电容参数超声换能器的设计与分析

Design and Analysis of Capacitive Parametric Ultrasonic Transducer for Efficient Power Transfer

电容参数超声换能器(CPUT)由于不需要直流偏置或电荷充电的优势,已成为医用植入物、传感器网络和消费电子产品无线能量传输方面的研究热点。提出利用一维集总参数模型来研究CPUT的运行和参数设计。将CPUT等效为一个RLC谐振器中超声驱动的活塞电容C,进而产生两个耦合的非线性微分方程系统。利用Simulink进行方程的求解,获得电容电压、电路电流和活塞位移。在此基础上,研究了参数谐振阈值和声电转换效率。结果表明,这些性能指标与负载电阻、输入超声强度、超声频率、电极覆盖面积和间隙高度密切相关。当CPUT的阻抗与介质匹配并且驱动CPUT的工作频率略低于2ω_(oel)时,可以达到最佳的效率。这为进一步研究超声无线能量传输、能量收集和传感技术奠定基础。

Wireless energy transfer in medical implants, sensor networks, and consumer electronics is a hot research topic. Passive capacitance parameter ultrasonic transducers(CPUT)can be suitable for these applications because it does not require DC bias or permanent charging. The 1-D lumped parameter model is used to study the operation and parameter design of CPUT. The CPUT is equivalent to an ultrasonic driven piston C in an RLC resonator, which generates two coupled nonlinear differential equation systems. Simulink is used to solve the equation, and the voltage on the capacitor, the current in the circuit, and the displacement of the piston are obtained. On this basis, parametric resonance threshold and harmonic electric conversion efficiency are studied. The results show that the performance of CPUT is closely related to the load resistance, input ultrasonic intensity, ultrasound frequency, electrode coverage area, and gap height. Optimal efficiency can be achieved when the impedance of the CPUT matches with the impedance of the medium and the CPUT is driven at a frequency slightly below 2ω_(oel). These results lay a foundation for further research on ultrasonic wireless energy transfer, energy harvesting, and sensing.