The Design Of High Accuracy Integrator System Based On FPGA

With the highly electrified modern society,people can not do without the application of various electrical appliances and electric power in science and technology,social production and even daily life.Electrical signals are more convenient to transform,amplify and transmit than other kinds of signals.Therefore,most of the non electric measurements are converted to electrical signals through certain means,such as various sensors,and then transmitted and measured.But the output of the sensor is often differential signal,so the integrator is one of the indispensable electronic devices in the electromagnetic measurement.In order to ensure the accuracy of measurement,we need to design integrators with high accuracy,low drift,good real-time and electromagnetic compatibility,and can work for a long time.The paper fully investigates the research status of integrators at home and abroad,and discusses the working principles of analog integrators,digital integrators,and modulo-integrators.And for the cause of integration error,an alternate integrator based on field programmable gate array(FPGA)was designed.A real-time compensating integrator is used as an integral unit,and two integrating units are used alternately.Finally,the two-way signal is stitched by the FPGA.By appropriately setting the alternating duty cycle,each integrator maintains the error within a small range when integrating the signal.The two integrators work alternately.When one integrator works,the other integrator discharges the integrated capacitance.The error will not accumulate for a long time,ensuring that the integrator circuit can work stably for a long time.According to the specific requirements and problems encountered in the test,the circuit board and the program are modified many times,and the prototype is finally determined.The 20 way alternating integrator participated in the EAST discharge test in 2017.The 2 way alternating integrator participated in the large current test,and the results showed good stability and consistency.Based on the alternating integrator,an error compensation integrator is designed.The integration error is compensated for the integrator using the closest integration period and the integral error function is approximated as a linear function.Between two adjacent half cycles,the error of the integrator in the latter half cycle is used to compensate the error function in the previous half cycle to effectively improve the accuracy of the integrator.