Development Of Ultrasonic Wind Measurement System Based On Indirect Phase Difference Metho

As one of the most important green energy sources,accurate measurement of wind power is of great significance in the fields of wind power generation,transportation,and other fields.Traditional wind measuring instruments have small measurement range,short service life,and low accuracy.With the rapid development of electronic technology,ultrasonic anemometers have gradually become the mainstream wind measurement instruments.However,currently,instruments mostly use the time difference method for measurement,resulting in a large volume and protruding probes from the outside,which can affect the propagation of wind and cause shadow effects,thereby affecting measurement accuracy.Therefore,this paper proposes an indirect phase difference method for wind measurement,and develops a prototype system to achieve high accuracy and miniaturization of the instrument.The main research contents are as follows:(1)Aiming at the problem of shadow effects caused by the probes of existing ultrasonic anemometers,a vertically reflective array structure design is adopted,which hides the probes inside the instrument,allowing the downward emitted ultrasound to be received by adjacent probes after multiple reflections,which can increase the ultrasonic propagation path and reduce the instrument volume.Simulation of the system model using Fluent shows that the structure can effectively reduce the ultrasonic shadow effect.(2)An indirect phase difference method for wind measurement is proposed.Through waveform analysis of the echo signal,it is found that there is a false echo signal of about 700μs in front of the echo signal.Instead of processing it from the source of the echo signal,this article innovatively sets a delay of 800 μs after transmitting the signal,and then performs phase detection on the echo signal.Using the same method,the phase of the echo in the opposite direction is obtained and then subtracted,indirectly obtaining the true phase difference between the two echo signals,It effectively avoids the interference of false echo signals and provides a new method for ultrasonic wind measurement.(3)Based on the principle of ultrasonic wind measurement,the hardware circuit of the system is designed,including voltage conversion circuit,ultrasonic emission circuit,echo strobe circuit,signal conditioning circuit,temperature acquisition circuit,and communication circuit.Among them,the ultrasonic emission circuit adopts the method of direct driving by a single chip computer,which can reduce both power consumption and cost.A software program corresponding to the hardware circuit is written.When calculating the wind speed,the median average filtering algorithm is used to process the phase data,greatly improving the phase measurement accuracy.Finally,complete the assembly of the entire ultrasonic wind measurement system and conduct wind measurement data comparison experiments using a selfmade small wind tunnel and a Sigma AR856 anemometer.The experimental results show that the wind speed measurement error of this system is within ± 3%,and the wind direction measurement error is within ± 3°.