Design And Implementation Of Low-power MEMS Thermal Wind Sensor And Portable Weather Instrument

Meteorological monitoring is widely used in agriculture,industry,military,transportation,energy and other fields.The monitoring elements include temperature,air pressure,humidity and wind speed and direction,among which wind speed and direction occupies an important position.In recent years,with the development of MEMS technology and IC technology,MEMS thermal wind sensors with small size and low power consumption have been developed rapidly,which have high market application value.The laboratory has many years of experience in MEMS thermal wind sensor research.There are complete solutions for sensor chip substrate material selection,chip structure design and chip drive circuit research,but the overall power consumption of the final designed sensor system is relatively high.Based on the laboratory's existing research results on low-power MEMS thermal wind sensor chips and sensor system software CTD control schemes,this paper makes improvements to the control methods and detection methods of sensor chips to ensure measurement accuracy and stability.The power consumption of the sensor system is significantly reduced,and the heating efficiency of the sensor chip is greatly increased.The design of a new portable weather meter based on the wind sensor is developed to solve the problem that the existing portable weather meter products cannot balance high precision and portability.The main work of this dissertation are described as follows:1.A software CTD control scheme for directly measuring temperature difference is proposed.Using the combination of switching power supply and digital potentiometer to design the heating control circuit of the sensor chip effectively reduces the power loss of the non-heating components in the original circuit and greatly improves the heating efficiency of the sensor chip.By testing the sensor system,the system power consumption is greatly reduced.2.A software CTD control scheme with hardware comparison temperature difference is proposed.On the basis of the direct measurement of the temperature difference scheme,the structure of the temperature difference measurement circuit is modified,the heating element and the temperature measurement element are connected to the bridge,and the heating voltage of the sensor chip is adjusted according to the voltage value output by the comparator.The stability of the heating voltage of the sensor in this scheme has an increase of 73.7%.Through the test of the sensor system,the wind speed measurement range of the sensor system is 0?20m/s,the measurement accuracy is <±(0.5m/s+5%v),the measurement range of the wind direction is0?359°,and the measurement accuracy is <± 5°,The maximum power consumption of the sensor system is 142mW,which is 64.5% lower than the original solution in the laboratory.3.Carried out the design and implementation of a new portable weather instrument.The portable weather meter is separated from the wind sensor,and it is connected to the low-power MEMS thermal wind sensor through a wired way to realize data communication.The portable weather meter is mainly used to measure the temperature and humidity,air pressure,wind speed,wind direction and other meteorological parameters,and record the positioning information during the measurement.It can realize real-time information viewing,data curve display,historical data query,positioning information display and other functions.After the whole machine test,the total power consumption of the portable weather instrument system is 2.32W,the working time is 85 minutes,the meteorological information and positioning information can be collected correctly,the LCD display works well and it is easy to use.