*2.7. Efficiency Calculation*

It is essential to know the losses of switched reluctance motor in order to calculate efficiency [34]. SRM losses calculation, especially the assessment of core losses, is a very difficult task mainly due to tha fact that flux wave-forms are non-sinusoidal and different from each other based on the sector that they are located in SRM's magnetic circuit. Moreover, core losses are dependent on the type of control and operating speed (*ω*). In a low speed region, it is acceptable to neglect the mechanical losses. Hence, losses may be calculated as:

$$Losses(\omega) = Core\,Losses + Copper\,Losses\tag{5}$$

Once the losses are known, the efficiency may be calculated by:

$$\eta = \frac{\omega T\_{\text{av}}}{\omega T\_{\text{av}} + Losses(\omega)} \tag{6}$$

In this paper, efficiency is calculated at the rated speed of 1000 rpm for all SRM designs candidates.
