Demagnetization Modeling and Characteristic Analysis of Belt Conveyor Permanent Magnet Electric Roller Based on Back Electromotive Force

The demagnetization of permanent magnet electric roller of coal mine belt conveyor will reduce the comprehensive performance of electric roller. In serious cases, the belt conveyor will stop suddenly or burn down, leading to the failure of normal production and safety accidents on the site. In this paper, starting from the A-phase current and output torque angles under different degrees of loss of magnetic fault, the B–H curve is fitted by linear ratio, and the reverse electromotive force is modeled by numerical analysis method. A diagnosis method for the degree of demagnetization of permanent magnet electric roller on account of the mathematical model of back electromotive force is presented. In this paper, a 200 KW permanent magnet electric roller used in a mine is taken as the research object. The finite element model is established by ANSYS Electronics Desktop and the demagnetization simulation of model is carried out. The model of mathematics on account of the back electromotive force is compared with a model of finite element simulation, and the back electromotive force waveform of the two methods is basically the same, and the error is less than 5%. The mathematical model based on the reverse electromotive force proposed in this paper can accurately reflect the degree of loss of magnetization of the motor, and the calculation results are accurate, which is conducive to determining the state of the permanent magnet electric roller more effectively, and provides a theoretical basis for predicting and diagnosing the failure of loss of magnetization of the permanent magnet electric roller.