Reducing the Resonant Frequency Difference of Piezoelectric Transformers Parallel System with Mechanical Coupling

Weidong Diao,Xinxin Liao,Zhihua Feng.

Link：https://www.tandfonline.com/doi/full/10.1080/07315171.2020.1799632

DIO:  10.1080/07315171.2020.1799632 

Abstract

The resonant frequency difference of piezoelectric transformers (PTs) with classical parallel connection could worsen system performance, then the mechanical coupling of PTs was proposed to avoid the disadvantage. Experimental results showed when the difference was relatively small, the performance of the classical parallel system and proposed mechanical coupling system was similar. However, when the difference increased, the maximum output power of classical parallel system at a temperature rise of 20 ℃ reduced by 32.6% and that of mechanical coupling system reduced by 7.7%. This indicated mechanical coupling was better than classical parallel connection in improving output power of PTs.

摘要

   传统的并联压电变压器的谐振频率差异会导致系统性能变差，本文提出了压电变压器的机械耦合方法进行改善。实验结果表明，当两个压电变压器谐振频率差异相对较小时，传统的并联系统与新提出的机械耦合系统的性能相近。当谐振频率差异增大时，传统的并联系统在温升为20℃时的最大输出功率降低了32.6%，机械耦合系统的最大输出功率降低了7.7%。这说明机械耦合方法在提高压电变压器输出功率方面优于传统的并联方式。

图1 提出的压电变压器机械耦合方法与传统的并联方法比较

   传统的压电变压器并联，两个压电变压器存在频率差异，提出压电变压器机械耦合能够避免频率差异。从实验结果可以看出，机械耦合方法优于传统的并联方式。

亮点：

1. 通过压电变压器的机械耦合，可以避免谐振频率差。            

2. 相同温升下，传统的并联压电变压器系统最大输出功率由于损伤降低了32.6%，而提出的机械耦合系统由于相同的损伤降低了7.7%。           

3. 与传统并联压电变压器系统相比，机械耦合压电变压器系统具有更强的抗损伤能力。