Study of Copper Loss by Inter Turn short fault of Interior Permanent Magnet Synchronous Motor

The winding of the motor stator coil can be faulted due to high voltage, high temperature stress and etc. In the ITF (Inter Turn Fault) winding, large fault current, ohmic loss, and excessive winding heat are induced. As a result, fault aggravation and machine burning might happen unless adequate fault diagnosis and management are equipped. By limiting the copper loss by the ITF, the faulted motor could operate without aggravation till the adequate fault management action is performed. In this paper, an IPMSM (Interior Permanent Magnet Synchronous Motor) ITF tolerant drive method by limiting internal copper loss is proposed. The copper loss by the ITF is made simple for the proposed method and analyzed with various current, speed, and output torque condition. By maximizing the output torque with minimum IPMSM copper losses, MTPL (Maximum Torque Per Loss) operation point is suggested. Compared with the MTPA (Maximum Torque Per Ampere) the MTPL is more efficient operation point with ITF. To verify the proposed method, experiment studies are performed with an IPMSM with an ITF. The results show the feasibility and practicality of the proposed method.