General analytical model for calculating electromagnetic performance of permanent magnet brushless machines having segmented Halbach array

Since a Halbach array exhibits a number of attractive features, it has been increasingly applied to different market sectors, including aerospace, industrial, domestic, renewable and healthcare and so on. The need of fast global optimisation, cost-effective design and physical understanding of the relationship between parameters and performance requires a powerful analytical model. Hence, this study develops a general analytical model which is capable of predicting the electromagnetic performance of slotted/slotless permanent magnet (PM) brushless machines with both even- and odd-segment Halbach array, having different magnet remanence, magnetisation angle and arc for each single magnet segment. The emphasis has been on the magnetisation which is the key in analytical modelling of PM machines having a segmented Halbach array and its investigation. The validity of proposed analytical model is extensively examined by finite-element analyses, together with its applications for global optimisation and comparative study.