Method of the poles position identification for brushless axial flux permanent magnet motor drive system

The following paper presents the method of poles position identification of the axial flux permanent magnet machine at zero and low speed. The identification is used for starting the motor in the demanded direction. The axial flux motor possesses a large number of poles which results in a small mechanical angle for magnet sector. The derived poles position identification by parallel current rate measurement i.e. PIPCRM method is simple and requires only one test before the driving current is produced. The paper presents the theory of the proposed poles position identification. The tests have been proved by laboratory tests on 40 kW/3000 rpm/16 poles axial flux permanent magnet motor operating as a brushless DC drive. The described PIPCRM method can be applied to other kinds of permanent magnet machines too