Abstract: In view of the serious temperature rise caused by the internal rotor permanent magnet synchronous motor(PMSM) with interior permanent magnet at high speed, the 35 kW PMSM with the "one" type and "V" type magnetic pole structures are introduced. Based on the same mass and blocks of permanent magnets, the magnetic flux on the surface of the permanent magnet and its change under the weak magnetic condition are analyzed by the finite element method and analytical method. The eddy current losses and characteristics in the motors with two magnetic pole structures are explored at different speeds, weak magnetic angles and demagnetization currents under the same weakening field condition. The eddy current losses of the motor with "V" type magnetic pole structure is larger than that of the motor with "one" type magnetic pole structure under the same weakening field condition. Finally, the prototype is fabricated and tested to verify the effectiveness of the finite element model, which provides a reference for the eddy current losses of permanent magnet synchronous motor under weakening field conditions.

Key words: permanent magnet synchronous motor(PMSM), weak magnetic condition, eddy current loss, finite element analysis(FEA)