Applications research of sigma-delta modulator in high precision measurement system of motor current

Sigma-Delta AD conversion technology is widely used in high resolution applications, especially in high signal integrity and current isolation in AC motor current measurement system. The research proposes a Sigma-Delta AD conversion design for AC motor current measurement system. The research proposes a Sigma-Delta AD conversion design for AC motor current measurement system. The design can demodulate and filter the AD conversion signal, and the Sinc³ digital decimation filter is adopted to demodulate it by means of filtering and decimation. The Sinc³ digital decimation filter is designed by FPGA. It realizes the high-frequency filtering of output signal of the Sigma-Delta modulator and achieves high precision isolation sampling of motor current and meets the requirements of sampling accuracy and response speed of AC motor current measurement.