Design optimization with improved torque performance of a new flux-intensifying PMSM using multilayer barriers for solar water pumps

Abstract

A novel flux-intensifying interior (FII) permanent magnet synchronous motor (PMSM) based on multilayer barriers in rotor structure with improved torque performance for solar water pump system is proposed here. The conventional interior (CI) PMSM generates maximum total torque on application of negative current along d-axis, resulting in an increment of demagnetization possibility of permanent magnets (PMs). Although flux-intensifying PMSMs solve this issue, their reluctance torque is lower due to the reduced saliency difference. This problem is solved by the presented FII-PMSM, which produces higher reluctance torque through specially designed barriers. Two types of barriers namely, inner and outer cutoff barriers are designed in rotor along quadrature axis. The inner barriers realize flux-intensifying effect while the outer cutoff barriers increase the saliency difference and hence the reluctance torque. Besides, the dimensions of barriers are optimized by using parametric optimization to maximize saliency difference and minimize torque ripples. The finite element methods based electromagnetic performances of FII-PMSM like inductance curves, torque profiles, airgap gap flux density, back electromotive force plots, efficiency map, output power map and PM flux density are obtained and compared with the CI-PMSM to show the superiority of presented motor.