Measurement of rare earth magnets at high temperatures

The work is about the magnetic characteristics of rare earth magnets at high temperatures. For the measurement of the demagnetization curve two test setups are designed and manufactured which allow inductive heating of the permanent magnets as well as the measurement of their magnetic properties and the adjustment of the PM working point. Non-coated permanent magnets made of different magnet materials which are typically used in permanent magnet machines are evaluated. The major aim of the work is to build up the measurement unit from off the shelf components. Moreover, an iterative procedure is presented to calculate the a priori unknown temperature dependent magnetic parameters with the help of measured air-gap flux density values. Different working points are evaluated and it is proved that the presented method can be used for different material samples and highly loaded magnets.