微加速度计机械与电学一体化仿真模型

Integrated Simulation Model for Mechanical and Electrical Parts in Micro-accelerometers

针对目前MEMS微加速度计机械和电路仿真各自脱节的现状,基于PSPICE软件,综合了敏感质量块机械、偏置电压静电力和接口电路3部分,提出了机械与电学一体化仿真模型。模型实现了敏感质量块大位移情形仿真,突破了已有仿真模型对该质量块的中点小位移近似。利用该模型,得到大位移情况下加速度计能承受的最大阶跃和脉冲加速度信号值,经过与经典理论公式比较,误差小于3%。进一步,通过在不同偏置电压开环模式下灵敏度仿真与实验值的比较,当敏感质量块处于小位移状态时,误差小于5%;处于大位移状态,小于10%。因此,仿真模型与经典理论公式以及实验值比较接近,可应用于微加速度计的仿真和物理过程再现,从而有助于该类微机械电子器件的进一步研究。

To cope with the separated situation of MEMS accelerometer＇ s simulation in mechanical and electrical parts,based on PSPICE software, an integrated simulation model was proposed, in which the sensing mechanical, bias voltage electric-static force and interface circuit parts were included. By the model, the simulation for large displacement of proof mass was achieved,which broke little displacement approximation in former simulation model. Through the comparison of maximum step and pulse acceleration response under large displacement condition, which are obtained by simulation model and classic formula respectively, it is indicated that the difference between them is less than 3%. Furthermore, the comparison was done with sensitivity test results in open loop mode. The comparison results show that the difference is less than 5% for large displacement situation and 3% for little displacement situation. Hence, the simulation model is close to classic formula and experiment results. As a result,it is hopeful for the model to be applied in the reappear of the accelerometer operation process, thus the model might being helpful in further research of that kind of MEMS device.