压电谐振器是谐振式传感器和执行器的核心部件, 通常工作在共振和稳幅状态。采用一种锁相环(PLL)和自动增益(AGC)相结合的双闭环控制驱动电路, 分别实现了谐振器共振频率的跟踪激励和压电振子输出信号的稳幅控制。优化设计了双闭环电路中各元器件参数, 使得压电振子能稳定工作在谐振频率点。参照压电谐振器开环测试数据和闭环测试数据, 双闭环驱动电路能将谐振器相位锁定在59°(误差3°), 输出信号峰峰值稳定在12.8V(误差0.2V)。实验结果表明, 该电路设计能够达到稳定谐振器输出信号幅值和跟踪谐振器共振频率的目的。

Piezoelectric resonators, usually working at a resonant state with stable amplitude, are the core components of resonant sensors and actuators. As an approach to research the piezoelectric resonator driving circuit, a dual closed-loop control circuit is used to realize the resonant frequency tracking and the amplitude stabilizing through phase-locked loop (PLL) and automatic gain control (AGC). By optimizing the parameters of each component in the dual closed loop circuit, the piezoelectric resonator can work stably at the resonant frequency. The results of the open-loop experiment and the closed-loop experiment show that the dual closed-loop circuit can lock the resonator phase at 59°, and the error is less than 3°. The amplitude of output signal is controlled at 12.8V, and the error is less than 0.2V. The experimental results show that the circuit is capable of stabilizing the amplitude of the resonator output signal and tracking the resonant frequency of the resonator.