The impact of structural dimensions and rotor pole numbers on the load and no-load torques of dual stator permanent magnet machine is investigated and presented in this work. Finite element analysis (FEA) is adopted in the prediction, since it exhibits higher computation accuracy compared to other methods such as analytical modelling and techniques, etc. Version 15.0 of MAXWELL/ANSYS-2D software is implemented in the entire computations. The considered structural dimensions include: rotor centrifugal size (Rth), aspect ratio (Sr), permanent magnet width (Mth), outer stator tooth width (Tth), rotor outer pole arc/pitch ratio (ϒ1) and rotor inner pole arc/pitch ratio (ϒ2). Also, model topologies having stator pole (S) and rotor pole (P) numbers i.e. 6S/10P, 6S/11P, 6S/13P and 6S/14P, are compared. The results show that the shaft torque and no-load torque would reasonably depend on the adopted machine’s structural dimensions; in addition to the impact of rotor pole number. More so, it is observed that the optimal output torque of a given machine may not necessarily occur at the same operating structural point with that of the required least no-load torque. Implementation of the optimum structural dimensions would result to largest average output electromagnetic torque from the machine. Moreover, practically all the most optimum results are obtained from the 6S/11P machine type. The useable average shaft torque from the simulated models is approximately: 2.33 Nm, 4.16 Nm, 3.75 Nm and 2.31 Nm, for the 6S/10P, 6S/11P, 6S/13P and 6S/14P categories, respectively. Similarly, least values of the no-load torque in the compared machine types are 1.2 Nm, 0.08 Nm, 0.04 Nm and 0.68 Nm i.e. for the 6S/10P, 6S/11P, 6S/13P and 6S/14P machine topologies.

A study on permanent magnet (PM) eddy current and core losses of dual-stator PM machines is investigated in this paper. The analyzed core losses include: the rotor core loss, stator core loss and the total core loss of the machines. Further, the effect of their different rotor pole number is also presented with quantitative comparison. Due to the relatively high electrical frequency of the analyzed 14-rotor pole machine, it gives the largest amount of PM eddy current loss. Similarly, the 13-pole machine exhibits the largest amount of total core loss amongst the compared machines. Although, the investigated machine having 4-rotor pole has a low core loss value, likely due to its low electrical frequency. However, it has the poorest efficiency amongst all, due to its very low output torque. Overall, largest torque density is obtained in the 13-pole machine at rated current condition.