Variable Magnet Analysis of the Series Hybrid Permanent Magnet Magnetic Circuit with AlNiCo

The hybrid permanent magnet (PM) magnetic circuits have been widely used for the constant and variable magnetization state application of the PM machines. For the parallel type, there exists the severe cross-coupling effect, in which the low coercive force PMs tend to be demagnetized by the high coercive force PMs. To hold the operating point of the low coercive force PM, the flux barriers are designed to easy the cross-coupling effect and they inevitably lead to the complicated machine structure. To deal with this issue, the series hybrid PM magnetic circuit is employed. Based on two-dimensional finite element analysis, the no-load and on-load magnetic characteristic of the series hybrid PM magnetic circuit in the constant and variable magnetization state will be investigated in detail. A prototype magnetization device will be fabricated and corresponding test platform is built to validate the theoretical analysis.