Design And Research On Ultrasonic Anemometer

With the rapid development of modern society, the energy problem has attracted widespread attention. Based on accurate measurement of the wind vector information, wind power is a new type of regeneration energy. Secondly, with the development of high-speed train systems, the safety of train operation has become increasingly prominent, especially along the railway gale, such as cave, tunnel and corners, where overturning accidents of trains may easily happen. Therefore real-time monitoring of the wind field along the railway will play a vital role in the safe operation. Moreover, modern meteorological monitoring is developing in the mode of unattended supervise. Therefore, the high reliability and maintenance-free wind measurement systems are of great importance.In this paper, we propose the design scheme of ultrasonic anemometer based on above requirements. The feasibility of the ultrasonic wind measurement system is verified by theoretical models and prototype. Firstly, we analyze the measurement model and calculation method of two-dimensional wind speed and wind direction, which is based on the principle of time difference. Secondly, the entire hardware design architecture of the system is given. In order to facilitate daily maintenances and get better electric isolation, design the hardware circuit including three modular units i.e., digital circuit unit, analog circuit unit and protective circuit unit. Thirdly, basic principles and flow diagrams of the system software design are illustrated. In order to form a complete measurement system, programs of ARM and CPLD are realized using Keil uVision3and Quartus Ⅱ10.1. Moreover, a specific algorithm of data averaging for measuring the critical wind direction is proposed, and a pulse modulation scheme to improve the quality of received ultrasonic signal is also provided.Finally, the actual functionalities and reliability of the ultrasonic anemometer are verified by electromagnetic compatibility testing and wind speed benchmark set test. Performance tests include:electromagnetic compatibility, high and low temperature, salt spray testing. Electromagnetic compatibility test includes four components:static, surge, electromagnetic fields and high-speed burst. Test results show that the ultrasonic anemometer is able to work properly in bad weather and severe electromagnetic environment. Wind direction and wind speed calibration of the system is used to verify the overall performance of the ultrasonic anemometer, with the final calibration results indicating precise measurement ability.