Test Analysis And Improvement Of The Effect Of Temperature Drift And Zero Point Stability On The Performance Of Thermal Wind Speed Sensor

The development of science and technology makes people's quality of life improved at the same time, it also brings the adverse factors such as environmental problems that may endanger public safety. Which haze and other weather directly affect the quality of life of the public, to enhance the incidence of various respiratory diseases. Wind speed and wind direction, as the core of meteorological elements, play a very important role in the detection of meteorological environmental problems. The zero stability of the thermal wind direction sensor and the temperature drift are the factors that affect the accuracy of the measurement.In this paper, a new type of MEMS wind speed and wind direction sensor with pulse width modulation is adopted. The main contents of the study are as:the design of control circuit, through the feedback control to change the heating resistance heating voltage pulse width duty cycle, so that the system to achieve constant temperature difference mode. Adopting different detection principle to different wind speed. When the wind speed is lower than the software setting threshold value, the measured value of the output thermal temperature difference is higher than the set threshold value. Analysis on the causes of the influence of the zero point stability of the sensor. Through design pressure circuit makes the sensor chip surface heat field tends to balance; through the design of using pulse width modulation control circuit, makes the system each initialization remained stable after, no zero drift; wind speed value growth of voltage signal has zero drift, this paper analyzes the principle are the possibility of zero stability. After testing the wind speed error caused by zero drift in the wind speed 20m/s value is about 4%. The solution of temperature drift is the precondition for the sensor to work under different conditions. Changing the environment temperature of constant temperature difference control principle was measured, in the temperature range of the system, the variation of constant temperature maximum is only 1?. According to the principle of thermal temperature difference detection, the output voltage curve offset is small, and the temperature drift error is about 2.3%. For heat loss detection principle, heating voltage pulse width for duty ratio with temperature changes affect larger, through the analysis of the data obtained a simple formula to compensate the temperature drift, after compensation for the system measured wind speed deviation is about 3.6% meet the performance index of the system.Through the analysis of the factors affecting the stability of the zero point and the compensation of temperature drift, the performance of the wind speed and direction sensor is achieved.