Analytical Calculation Model for Inductance of Brushless DC Motor Under Bearing Fault

In a brushless DC motor (BLDCM), bearings are crucial components. During motor operation, when rolling bearings fail, the periodic variation of the air gap between the stator and rotor occurs, leading to changes in the air-gap permeance and subsequently altering the electromagnetic parameters of the motor. The winding inductance directly affects the parameters of the BLDCM control system. This paper presents the analytical equations for inductance under bearing faults, considering faults in the outer race, inner race, rolling elements, and cage. The validity of these equations is verified through numerical calculations. The results provide assistance for the motor control system.