Driving performance evaluation of interior permanent magnet (IPM) motor using circuit parameter estimation

This paper deals with the method of driving performance evaluation of interior permanent magnet (IPM) motors with 6-pole NdFeB magnets rotor and 9-slot stator. The circuit parameters of IPM motor such as Ld(d-axis inductance), Lq(q-axis inductance), torque and speed are investigated using 2-d finite element analysis(FEA) in each current value with phase angle condition. The low speed region below the based point presents speed-torque curve according to limited current in constant torque condition for maximum torque-per-ampere (MTPA) control. On the other hand, the high speed region above the based point draws speed-torque curve according to frequency and current angle variation in limited current and voltage for field-weakening control. This curve shows that suitable driving region to drive the IPM motors.