Multifault Observer Based Detection Method for Brushless DC Motors

A detection and identification method for high resistance connection faults and open phase fault in Brushless DC motors is presented. The method uses the current and speed residuals to detect the type of fault, the faulty phase and the severity of the fault in the case of high resistance connection. The residuals are made by comparing the measured signals and their estimates. These estimates are obtained with an observer which reconstructs the stator currents using only the rotor position signal. An observability analysis is included to show that it is possible to reconstruct the currents from the position measurement. Numerical simulations are presented to validate the proposed fault detection scheme.