Optimal Design Of A Driver Circuit For 30kA Hall Current Sensor

To satisfy the requirements on current measurement in ITER power experimental platform,a current sensor need to have all of these characteristics:it has the ability to measure direct current of 30kA;it isolates the measurement circuit from live conductor to be measured;it is easy for installation and disassembly;it has good precision and works steadily.According to the comparison among the common current sensor in modern industry,the zero-flux hall current sensor is an excellent choice to fulfill those requirements undoubtedly.Based on introduction to Hall effect,Hall element and Hall current sensor,the paper introduces and analyses the theory and circuit structure of zero-flux Hall current sensor,and gives some details and methods on circuit design to improve the performance of Hall sensor.Aiming to cover the shortages of the traditional drive circuit of zero-flux Hall current sensor,a digital drive circuit centered on DSP is designed.This drive circuit realizes the function of PI regulator and generating PWM driving signal and solve the problem of the difficulty in adjusting dead zone for PWM driving signal.Besides,the DSP processing circuit provides some practical function,such as over temperature protection,over voltage protection,communication with host computer and open loop test,and all of these make the system of Hall sensor more stable and more convenient for testing and monitoring by user.The experiment shows that this drive circuit transmits electromagnetic interference signal,and the interference signal have a great influence on the performance of the Hall sensor.According to analyzing the electromagnetic compatibility of the drive circuit,the paper lists out some measures of interference suppression from the aspects of interference source,coupling paths and victims.The oscillogram from experiment proves the effectiveness of those measures.The experiments show that the design of drive circuit is possible and with high stability.The data shows that the zero-flux Hall current sensor has the precision of 1.0 class,and the Hall sensor applies to the current measurement in ITER power experimental platform.