Design Of Device For Measuring Electric Power By Hall Element Multiplier

The Hall effect is widely used in the measurement of electrical parameters.At present,the experiment of Hall effect principle is also arranged in the university physics experiment class,but there is no experimental course about measuring the electric power of the Hall element multiplier.This thesis is to study this experiment,designed a set of experimental devices,which can be satisfied with the experimental operation and learning in the laboratory.Conventional power measurement is obtained by sampling the voltage and current separately,then using the CPU to obtain the product of voltage and current to obtain the instantaneous power,summing the instantaneous power with time and then averaging to obtain the power P.This way of separately collecting two electrical quantities,and then performing a large number of data summation calculations to obtain power,will bring a relatively large error.This paper presents a new method of measuring power,which is to calculate the electric power using a Hall element multiplier.A Hall element is placed in the cross section of the open magnetic ring,and the current to be measured passes through the magnetic ring.The current passing through the load is linear with the magnetic field B generated by it,and the magnetic field is measured to indirectly measure the currentI.The voltage U across the load generates a small current through the voltage dividing circuit as the operating current IS of the Hall element,and the operating current IS is linear with the load voltage U.It can be seen that the Hall voltage UH=KHISB output by the Hall element is linear with the power P=UI,that is,the Hall element power multiplier is constructed.It is not necessary to separately measure the magnitude of the voltage and current and then calculate the power.The Hall element power multiplier uses the linear relationship between the power and the Hall voltage to measure the magnitude of the Hall voltage,that is,the magnitude of the measured power.The direct measurement power method has higher accuracy.This paper first introduces the concept and development of Hall effect,then introduces the application of Hall effect in electrical parameter measurement,the method of conventional measurement of electric power and the new method and significance of Hall element to measure electric power.Secondly,the basic knowledge of Hall element and magnetic ring is introduced,the magnetic effect of current,Biot-Savart Law,the magnetic field generated by the current carrying straight wire,the magnetic conductive material and the magnetic field at the open magnetic ring.Then the overall design scheme of the experimental device is introduced.After that,the power supply circuit,the large current generation circuit,the Hall power multiplier,the voltage conditioning circuit,the microcontroller and the display module are respectively introduced.In the high current generating circuit part,The principle of transformer and current transformer is introduced respectively.In the voltage conditioning circuit part,the Instrumentation amplifier and the voltage and filter circuit are introduced.Finally,the measurement data of the experimental device is given.The least squares method is used to process and analyze the data.The power is measured by adjusting the voltage and current,and the measured power is compared with the theoretical power.The analysis results show the accuracy and feasibility of the experimental device The device is suitable for experimental teaching in university physics or electronics.