Dynamic Eccentricity and Demagnetized Rotor Magnet Detection in Trapezoidal Flux (Brushless DC) Motors Operating Under Different Load Conditions

• Published in: IEEE transactions on power electronics Vol. 22; no. 5; pp. 2061 - 2069
• Main Authors: Rajagopalan, S., Roux, W., Habetler, T.G., Harley, R.G.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-09-2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aerodynamics; Applied sciences; Automotive engineering; Brushless dc (BLDC); Brushless DC motors; Brushless motors; Condition monitoring; D C motors; DC motors; Demagnetization; Demand; Eccentricity; Electric currents; electric machines; Electrical engineering. Electrical power engineering; Electrical machines; Electromagnets; Electronics; Exact sciences and technology; finite-element analysis (FEA); Ground, air and sea transportation, marine construction; Loads (forces); Magnetic flux; Magnetism; Miscellaneous; Motors; Road transportation and traffic; Rotors; Signature analysis; Simulation; Various equipment and components; varying load; Vehicle dynamics; Motor car; Unbalanced conditions; condition-monitoring; varying load; Finite element method; Brushless DC motors; Aerospace; Electric motor; Monitoring; High performance; finite-element analysis (FEA); Road vehicle; Brushless dc (BLDC); Magnet; eccentricity; Experimental study; Rotor; Fault currents; Electric machine; Automobile industry; Brushless machine; electric machines; System simulation; Diagnostic aid; Signature analysis; Alignment defect
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2007.904183

Brushless dc (BLDC) machines are finding increasing use in applications that demand high and rugged performance. Automotive and aerospace are some such areas where these machines may be used. In this context, condition monitoring of these machines would provide added value. This paper investigates the effect of several potential rotor faults on the current spectrum of BLDC motors with a view to develop an effective condition-monitoring scheme. The effect of load unbalances, misalignments, and varying load torques on the diagnosis of such machines is investigated. A method to estimate the strength of the rotor magnets is also provided. Simulation and experimental results are presented to substantiate that current signature analysis could be a viable tool for diagnosing the condition of BLDC machines.