Research on the Modelling of a Single-winding Bearingless Permanent Magnet Brushless DC Motor

Abstract

This paper studies the radial suspension force mathematical model of a single-winding bearingless permanent magnet brushless DC motor, which provides a theoretical basis for the precise control of a single-winding motor. First, the physical structure of the single-winding BL-BLDC motor and the principle of radial suspension force generation are introduced. Then, the equivalent magnetic circuit method is used to establish the electromagnetic relationship inside the motor and the virtual displacement method is used to derive and calculate the mathematical model of the radial suspension force. The radial suspension force of the motor is composed of the force generated by the suspension force winding and the unbalanced magnetic pull force generated by the motor rotor deviating from the center position. Finally, the finite element analysis software is used to model and simulate the single-winding motor to analyze the change of the suspension force amplitude under different currents and the influence of different eccentric displacements on the unbalanced magnetic tension of the motor. The results show that the error between the simulation results obtained by the FEA and the theoretical calculation results of the mathematical model is small, which verifies the correctness of the radial suspension force mathematical model of the single-winding BL-BLDC motor.