一种微机械谐振传感器的驱动控制

Modeling and numerical simulation control of a MEMS resonant sensor

微机械谐振式传感器广泛使用静电自激驱动,自激驱动反馈环路有非线性环和线性环,线性环路电路结构复杂,调节参数多,易引入噪声,影响传感器的分辨率。以微机械谐振式加速度计为研究对象,建立加速度计的数值仿真模型并采用静电自激驱动;反馈环路采用非线性环,并利用函数描述法分析传感器系统的稳定性。数值仿真实验表明:在封装品质因数大时,非线性反馈环构成的自激驱动电路需系统等效电路中线性环节和非线性环节满足三个条件,同时非线性部分的高阶谐波响应影响相位平衡,会造成系统谐振频率和振动幅度的偏差。

Electrostatic self-excited drive is widely used in MEMS resonant sensors.The feedback loop is linear loop and nonlinear loop.The linear loop circuit structure is complex,and it is easy to introduce noise,which affects the resolution of the sensor.In this paper,the micromechanical resonant accelerometer is taken as the research object,the numerical simulation model of the accelerometer is established,and the electrostatic self-excited driving is adopted,and the nonlinear loop is adopted in the feedback loop,and the stability of the sensor system is analyzed by using the function description method.The numerical simulation results show that on the occasion of high quality factor,the self-excited driving of nonlinear feedback loop works when the use of function description method meets three conditions,meanwhile,the high-order harmonic response of nonlinear part will affect the phase balance,resulting in the uncertainty of vibration amplitude and resonance frequency.