A novel method for permanent magnet demagnetization fault detection and treatment in permanent magnet synchronous machines

Due to relatively high power density, negligible rotor losses, high efficiency, ease of control, and being almost maintenance free Permanent magnet synchronous machines (PMSM) are widely used in industrial applications. In this paper a new method of fault detection and treatment for 5-phase PMSM under partial demagnetization has been introduced. In the proposed technique various rotor demagnetization scenarios have been considered. As the optimum performance is of great importance in industrial applications the excitation of stator phases has been modified to attain the maximum output torque per input phase current in the event of demagnetization. Field reconstruction method has been used in conjunction with optimization methods to detect the fault and find the proper excitation.