Research On Zero Drift Inhibition Of The Silicon Thermal Wind Sensor

Wind is a very important factor of meteorological elements,it plays a vital role both in the weather forecast and environmental monitoring.Lately,the study of anemometer with high-precision and portable has become the key point.Because of its advantage of miniaturization,microelectronic integration and high precision mass production,MEMS sensor has become the trend of the future sensors.This paper aims at the study of the zero drift in the same ambient temperature when the sensor working in the thermal temperature difference mode.The specific work is as follows:(1)In this paper a thermocouple coupling model of Ceramic package and a finite element simulation model of package error were established and analyzed.There are two manifestations of the zero drift.First of all,zero points are drifting with the wind speed.Secondly,on the same wind speed conditions,zero points are drifting with the wind direction.(2)A zero drift compensation method based on package error of ceramic substrate is proposed.The method used the result of a thermocouple coupling model of Ceramic package and a finite element simulation model of package error to realized a zero drift composition.Experiments show that the zero drift compensated sensor is working well,with the absolute error of the wind speed in low speed being less than ±0.3m/sand the error of the wind direction being less than ±2° and the relative error of the wind speed in high speed being less than ± 5%m/s and the error of the wind direction being less than ±2°.(3)MEMS thermal wind sensor has a variety of different working methods.The sensor mainly working on the constant temperature difference mode and the heat loss mode in this paper.And the sensor can simultaneously working on two modes.To improve the performance of the anemometer,this paper combined the two working modes’ output.Finally,it realized the wind speed accuracy of ±3%,angle accuracy of ± 2 °.This paper mainly deals with the problem of zero drift in the same ambient temperature and improving the performance of MEMS thermal wind sensor.Based on the thermocouple coupling model of the sensor and the finite element simulation of the package error of the ceramic substrate,a zero point compensation algorithm is proposed.And ultimately it has enhanced wind speed accuracy greatly.