Study On The Output Stability Of Silicon Thermal Wind Sensor

With the growing technology,Internet of Things,artificial intelligence and other technology development are inseparable from the sensor support.MEMS sensors,with their portability,low power consumption,low cost and other advantages,have become an increasingly important role in many fields.Meteorological monitoring is of great significance to agriculture,forestry,industry and other fields,and it is also closely related to people's daily life.Wind speed monitoring is one of the important aspects of meteorological monitoring,Compare to the traditional anemometer,MEMS wind speed sensor has an unparalleled advantage.In this paper,a kind of silicon thermal wind speed sensor is introduced,and its output characteristics are studied.The reason of the output instability caused by the chip structure,the signal detection circuit and the control circuit of the sensor are studied.The improvement of the signal detection circuit and the control circuit of the program are put forward,and test validation,the specific work of this paper are as follows:(1)In this paper,the output characteristics of the silicon thermal wind speed sensor are studied.It is found that the fluctuation range of the sensor output data is larger than that of the sensor in the case of stable wind speed,that is,the sensor output is unstable.In terms of the structure of the sensor chip,the signal detection circuit and a control circuit the reasons are analyzed.The noise voltage of the thermocouple in the sensor chip,the offset voltage of the AD623,the quantization noise of the analog digital replacement module,the noise of the power supply module,and the temperature drift characteristics of the microcontroller are all factors that affect the output stability.While the power supply module output noise and temperature drift characteristics are the most important factors.(2)In order to improve the output stability of silicon thermal wind speed sensor,this paper has developed the scheme from hardware and software.In terms of hardware,the power supply circuit to improve the noise immunity is designed,that is,the filter circuit in the power supply output module is improved,while the temperature drift compensation circuit is designed to suppress the temperature drift.In the software aspect,the digital filtering algorithm is discussed,the clipping filter algorithm and the weighted recursive average filtering algorithm are fused,and the limiting weighted recursive filtering algorithm is proposed,and the limit amplitude value in the algorithm is experimented and discussed.(3)In this paper,the hardware scheme and the software scheme are tested and analyzed.The hardware scheme can reduce the fluctuation range of the sensor output to the original half at the stable wind speed,but it still exceeds the sensitivity.Combined with hardware solutions and software solutions,in the stable wind speed sensor output fluctuation range is less than the sensor sensitivity,thereby further improving the sensor output stability.