Influence of magnetic load on can loss and performance in canned permanent magnet synchronous machines

The rotating magnetic field of the air gap in the canned permanent magnet synchronous motor (CPMSM) cuts the stationary can sleeve, which causes can loss and reduces the drive-system efficiency. At present, the researches on suppressing can loss and improving the CPMSM efficiency has encountered a bottleneck. In this paper, the influence of magnetic load on the can loss and performance of the CPMSM is comprehensively investigated by controlling the current angle in the finite element model. It is found that the can loss decreases, and the CPMSM efficiency increases gradually with the decline of magnetic load. In addition, a parameter called the forced energy index (FEI) that can reflect the comprehensive performance of the CPMSM is defined. The results shows that the FEI and power factor of the CPMSM are optimal when the zero d-axis current control is adopted. Finally, a PMSM prototype is manufactured, and the load experiment was carried out to verify the effectiveness of the given research.