锁相环跟踪超声振动系统谐振频率的改进

Improving PLL tracking of ultrasonic vibration resonant frequency

摘要: 锁相式频率跟踪超声发生器的频率跟踪范围较小且易出现死锁现象,通常要人为重新启动,系统才能恢复跟踪状态,在应用时会带来麻烦。根据超声振动系统的等效电路研究其阻抗特性,并通过实验绘制换能器特性曲线,分析应用CD4046跟踪串联谐振频率容易造成死锁的具体原因,提出带解锁的频率跟踪系统的方案。实验结果表明此方案有较大的跟踪调节范围与较强的适应负载变化的能力,对超声发生器的具体应用有一定的参考意义。

Abstract: We discuss impedance characteristics of an ultrasonic vibration system.The causes of dead-locking in tracking series resonant frequency with CD4046 are analyzed.A new frequency tracking system with unlock circuit is proposed.Experimental results show that the new method can track series frequency of an ultrasonic vibration system in a wide frequency band,and adapt well to the mutative loads.It is of practical significance in the design of ultrasonic generators.