The Development And Design Of Current Sensor Based On The Shunt

Current sensor is the most common measurement in the field of Electrical Measurement.At the present stage,there are some sensors that are wildly used include Hall Current Transformer,Current Transformer,Shunt and Rogowski Coil Current Transducer,etc.These current sensors have their own advantages and disadvantages.For example,the Hall Current Transformer is difficult to meet precision measurement requirements at the whole frequency band and the Current Transformer is only suited to test the current signal what is near the range of the power grid frequency.Now,there are more requirements to the current sensors especially in the measurement field what is so complex electromagnetic environment.Under the condition of meeting the measurement band it requires that the current sensors should have the high linearity within the whole frequency band,the stable accuracy of measurement and the strong ability of resisting electromagnetic interference.So it has very important practical significance that developing a new type current sensor which owns the high stability and the strong ability of resisting electromagnetic.According to the deeply researching on the advantage and disadvantage of the various current sensors,the paper proposed a new design ideal and target of the current sensor.It has designed the module of sampling current which is based on the shunt,the module of electrical isolation which take a high precision linear optical coupling as core and the module of voltage offset.Through selecting the higher precision ADC and the digital signal processor of TMS320F2812,then make sure the overall structure.Getting the simulation analysis by using the software of Multisim for the circuit of sampling and isolation,the circuit of the signal conditioning and the overall circuit.According to the needs of the sensor's linearity and accuracy,the overall structure has been established by selecting the appropriate the devices' parameters.The simulation of this system is proposed when input the DC and the AC signal,and the simulation studies are carried out,as a result,the feasibility of this scheme is proved by simulation results.Based on the development board of QQ2812 DSP,through the software designing the function of data acquisition is accomplished in CCS integrated development environment including the main program,the system's initialization program,the interrupt program and the ADC conversion program.Finally,the pritical circuit has been tested by using the signal generator and the oscilloscop.The ideal linearity and precision has gotten by calculated the experimental data.After analysis on the circuit,getting the minimal phase errors between the input signal and the output signal.These results has proved that this new tpye current sensor has the good performance of the practical application.