基于互相关的小型化低功耗超声波风速风向仪设计

Miniaturized Low Power Ultrasonic Anemometer Based on Cross-correlation

超声波风速风向仪具有无转动部件,响应快,精度高的优点,但体积大、功耗高、成本高成为限制超声波风速风向仪广泛使用的主要因素。为了便于超声波风速风向仪的推广和使用,本文采用国产FPGA(Field Programmable Gate Array)并结合FIR(Finite Impulse Respond)滤波器以及互相关检测算法设计了一款超声波风速风向仪,探头之间的距离仅为80 mm,感风面积仅为传统超声波风的1/10,使得省级风洞均可计量检定。整机经过风洞实测,每秒钟可完成50次风速风向测量,在0~5 m/s时风速最大测量误差为±0.3 m/s,5~20 m/s时风速最大测量误差为±0.5 m/s,20~30 m/s风速测量最大误差为±5%,稳定风速下风向测量最大误差为±1°以内,总功耗为0.2 W(仅为传统超声波风功耗的1/20)。通过实测数据发现,FPGA结合数字滤波及互相关检测算法相比于传统的DSP(Digital Signal Processor)超声波风速风向仪能明显缩小体积,降低成本功耗。

Ultrasonic anemometers are widely acclaimed for their non-rotating parts,rapid response,and high precision in measuring wind speed and direction.However,the traditional ultrasonic anemometers with a large physical footprint,substantial power requirements,and considerable cost impede their extensive utilisation.To overcome these challenges and facilitate the widespread adoption of ultrasonic anemometers,this study presents a cutting-edge design featuring a domestically produced Field Programmable Gate Array(FPGA)integrated with Finite Impulse Response(FIR)filters and cross-correlation detection algorithms.The FPGA-based ultrasonic anemometer design offers clearly noticeable advantages.By reducing the distance between transducers to 80 mm and limiting the sensing region to just 1/10 of traditional ultrasonic anemometers,this compact configuration allows for accurate calibration in some provincial-level wind tunnels.Rigorous wind tunnel tests are conducted to evaluate the performance of the ultrasonic anemometers,demonstrating the instrument’s capability to measure wind speed and direction up to 50 times per second.In terms of measurement accuracy,the performance of this ultrasonic anemometer is tested in a wind tunnel,demonstrating its capability to meet specific measurement requirements for both low and high wind speeds.For wind speeds from 0 to 5 m/s,the maximum measurement error remains within±0.3 m/s.In the range of 5 m/s to 20 m/s,the maximum error is±0.5 m/s.For wind speeds between 20 m/s and 30 m/s,the maximum error is±5%.Under stable wind conditions,the maximum error for wind direction measurement is within±1°.Additionally,the power consumption of the ultrasonic anemometer is significantly reduced to 0.2 W,only 1/20 of the consumption of traditional ultrasonic anemometers with Digital Signal Processors(DSP).The integration of FPGA technology,FIR filters,and cross-correlation detection algorithms into the ultrasonic anemometer design contributes remarkably to improvements in size,cost,and power consumption compared to conventional DSP-based ultrasonic anemometers.The compact size and decreased power requirements make the FPGA-based ultrasonic anemometer an ideal choice for applications necessitating compactness,cost-effectiveness,and energy efficiency.Its potential for widespread utilisation in diverse fields is highly promising.The presented FPGA-based ultrasonic anemometer design surmounts the limitations associated with traditional models.Its compactness,reduced power consumption,and cost-effectiveness make it a compelling solution for accurate wind speed and direction measurements in various practical applications.Comprehensive wind tunnel tests substantiate its precision and reliability,bolstering its potential for widespread adoption and utilisation in diverse fields.