LAUSR

In this article, the efficiency function of the permanent-magnet (PM) machines is reconstructed by the quantitative loss expressions. Then, the efficiency function is used to quantitatively analyze the maximum efficiency point and the specific high-efficiency region. General principles of improving the maximum efficiency and the regulation of the specific high-efficiency region for PM machines are investigated. First, the loss expressions of PM machines, which vary with the speed and the current, are presented. Moreover, an accurate efficiency function is established to calculate the efficiency map of PM machines quickly. Furthermore, the maximum efficiency point and the specific high-efficiency region of PM machines are derived, as well as their variation principles with loss distributions are studied. Furthermore, a 12-slots 10-poles PM machine and a 48-slots 22-poles PM machine are designed to verify the analytical results. Subsequently, their electromagnetic performances and the efficiency maps are calculated and compared by the finite-element method. Finally, both PM machines are prototyped and experimental results are given for validations.