An Analytical Approach to Magnet Eddy-Current Losses for Interior Permanent-Magnet Synchronous Machines During Flux Weakening

This paper presents an analytical approach for evaluating the magnet eddy-current losses of interior permanent-magnet synchronous machines (IPMSMs) during flux weakening. To investigate the magnet eddy-current losses, an analytical method of the time-varying magnetic flux density in the magnet is proposed based on the armature reaction magnetic field analysis. According to the time-varying magnetic flux density, a coefficient is used to evaluate the magnet eddy-current losses during flux weakening. The coefficient can indicate how the major design parameters in an IPMSM affect magnet eddy-current losses during flux-weakening operation. Finite-element analysis was used to validate the proposed model and calculate the magnet eddy-current losses of IPMSM with different design parameters.