Study on Accurate 3D Magnetic Field Measurement System

The existed magnetic field measurement systems have some shortcomings just as poor accuracy and automation. Most of them can only achieve one or two dimensions´ measurement. The research of accurate 3D magnetic field measurement system is introduced. The 3D magnetic field sensor is made by six Hall devices which are attached to six surfaces of a cube respectively. The output signals of Hall devices are amplified by differential amplifiers and send to data acquisition system. The influence of the surround temperature to Hall device´s input resistance is compensated using voltage proportional method which is achieved by sampling the Hall sensor´s output voltage and the voltage drop on the sampling resistance alternatively. The measurement result is calculated from the proportion of them, thus constant current source is no longer necessary for the measurement system. Experiments prove that the system´s error is 0.5 percent. The system is used to measure the magnetic fields of magnetic levitation vehicle.