**4. Finite Element Analysis of a Symmetrical Rotor**

A variety of numerical methods are available for the analysis of electromagnetic torque. These include, the virtual work method, the Maxwell stress tensor method, the nodal force method, and the Coulomb virtual work method, which are all methods used to analyze the cogging torque of PMBLDC motors. For the determination of cogging torque, precise field solutions are required. That is to say that a sophisticated mesh discretization is vital in FEA analysis, just as a dependable physical model is crucial for analytical calculations.

This section describes the outcomes of the 3D FEA analysis of the examined PMBLDC motor with the symmetrical rotor. Cogging torque can be determined numerically using the FEA method. Without a prototype, FEA is a powerful and viable tool for defining the performance of a given design [27,28]. The main target of this work was to decrease the cogging torque by using the magnet displacement method.

A 12-slot, 4-pole PMBLDC motor was considered as the motor for which the cogging torque was determined analytically using the FEA method. Further, on the basis of the FEA analysis, a comparative study was performed to compare the effect of the magnet shifting with the symmetrical structure. Figure 5 shows the conventional rotor with symmetrical magnets. Table 3 shows the FEA results for the symmetrical structure.

**Figure 5.** Conventional rotor with symmetrical magnets.


