压电超声换能器电负载调频特性研究

压电超声换能器由于具有较高的机械品质因数，因此对谐振频率的变化十分敏感。在负载、温度等工况因素影响下，超声换能器谐振频率会发生偏移，从而造成其出现工作性能下降甚至完全失效。提出一种电负载影响下的超声换能器等效电路，建立谐振频率与电负载的关系模型，并通过仿真以及试验进行验证。结果表明，这种电负载调频的压电超声换能器，可以有效地克服谐振频率偏移带来的性能损失问题，为新型超声加工系统的研制奠定了理论基础。

Characteristics of Piezoelectric Ultrasonic Transducer with Electric Load Modifying Frequency

Due to the high mechanical quality factor, piezoelectric ultrasonic transducers are sensitive to the change of the resonance frequency. When the ultrasonic transducers are affected by the loads, heat and other factors during working, the resonance frequency will change. This will result in the system's working ability dropping or even failure. The equivalent circuit of ultrasonic transducer with electric load is proposed. A mathematics model of the transducer's resonance frequency and the electric load is established, and proved by both simulation and experiment. The result shows that this kind of ultrasonic transducer can overcome the efficiency loss resulted from the change of resonance frequency. The conclusion is useful to the manufacturing of new ultrasonic machining systems.