Modeling and Classification of Stator Inter-Turn Fault and Demagnetization Effects in BLDC Motor Using Rotor Back-EMF and Radial Magnetic Flux Analysis

Abstract

This paper shall carry out unique study and investigation on the individual and combined effect of Stator Inter-turn Fault (SITF) and rotor demagnetization effects in a Surface Mounted Permanent Magnet (SPM)-type Brushless Direct Current (BLDC) motor. Comprehensive modeling of fault is accomplished using the well-established fault modeling techniques such as Electrical Equivalent Circuit (EEC), Magnetic Equivalent Circuit (MEC), Numerical Methods (NMs) and hybrid modeling-based approaches. The extensive study of SITF conditions using an Improved Winding Function Theory (IWFT) gives better analysis to winding inductance $L_{S}$ , under fault conditions, while modeling the demagnetization effects using MEC and NM based approaches gives more realistic magnetic field quantities. The outcomes obtained are further remodeled in the developed hybrid model of a BLDC motor to study the steady state performance of a machine in terms of rotor back-EMF, $E_{B}$ and radial magnetic flux density $B_{g}$ . The characteristic performance accomplished through the hybrid model system possess better accuracy with less computational time and therefore finds suitability among efficient and fast diagnosis technique feasible for industrial applications. The significant detectable changes in $E_{B}$ and $B_{g}$ under subjected fault conditions, assist in detection, identification and classification of faults in BLDC motor. By obtaining the similar outcome experimentally and under the load conditions, the proposed study on the classification of fault is validated.

Keywords

• Brushless direct current (BLDC) motors
• demagnetization
• electrical equivalent circuit (EEC)
• finite element (FE) method
• improved winding function theory (IWFT)
• numerical methods (NMs)