Servo loop design of capacitive MEMS accelerometer under high preload voltage

As a MEMS sensor working in the force feedback capacitive accelerometer system, the sensing mass of MEMS sensor is driven by the external acceleration, the differential modulating pulse voltage and the preload voltage. Under high preload voltage, the common servo loop design method of the capacitive MEMS accelerometer is invalid since the open loop system features can´t be obtained by experiments. The local closed-loop method for the aforementioned problem is proposed in this paper. Based on this method, the servo loop of the MEMS accelerometer under high preload voltage is designed. The tested results indicate that the local closed-loop method greatly improve the performance of the accelerometer.