Dynamic resonant frequency ratio control for high-power piezoelectric devices

基于提出的谐振频率比控制方法，对高频交流开关短路进行了改进，设计了一种采用无源压电陶瓷片的多模朗之万超声换能器，通过控制谐振频率比，使换能器的两种纵向振动模式动态匹配，产生稳定的双频超声，为探索声悬浮、超声空化等声学领域的新应用提供了极大的帮助；并通过调节两种模式的输出准锯齿波位移，实现了精确驱动。样机通过动态谐振频率控制，实现了长期工作的稳定输出。

Based on the proposed resonant frequency ratio control method, we have improved the high-frequency AC switch short-circuit and designed a multimodal Langevin ultrasonic transducer with a passive piezoelectric ceramic piece.By controlling the resonant frequency ratio, the two longitudinal vibration modes of the transducer can be dynamically matched, and stable dual-frequency ultrasound can be produced, which is of great help for exploring new applications in acoustics such as acoustic levitation and ultrasonic cavitation.Furthermore, precise driving is achieved by adjusting the output quasi-sawtooth wave displacement of the two modes. By dynamic resonant frequency control, the prototype piezoelectric actuator achieves stable output under long-term operation.