A Novel Low Torque Ripple Hexagon Biased Flux Doubly Salient Permanent Magnet Motor
Mohammad Amirkhani, Behnam M. Mosammam, Mojtaba Mirsalim
Abstract
This paper proposes a new type of doubly salient permanent magnet (DSPM) motor in which the stator is in the shape of a hexagon and the PMs are placed between each stator module. This PM placement not only isolates the stator modules in a way that the phase-to-phase faults on the stator iron may be prevented and increases the fault tolerency of the inverter but also the permeance network of each phase is similar and lowers the torque ripple of the structure by injecting a pure sinusoidal excitation compared to DSPM structure. Moreover, the torque density per copper loss for this structure is improved compared to other structures. The efficiency and power factor of this structure is also increasingly improved compared to other biased-flux structures. The operation principle and design optimization of this structure using genetic algorithm is studied and explained. Furthermore, the electromagnetic performance of this structure including no-load, full-load, and overload capability is verified by finite element method. To better understand the superiority of the proposed structure a comparison study has also been conducted and the most important performance indexes of other hexagon or square envelope structures are also calculated.