Iron core losses: measurement and impact in induction motor vector control

In the present paper, the influence of iron core losses on the vector controlled induction motor performance is-presented. The equivalent iron core loss resistance is experimentally identified from no-load tests with PWM and sinusoidal supplies. The amount of detuning caused by the iron core losses is analysed for indirect rotor flux oriented control (RFOC) and stator flux oriented control (SFOC) of a voltage-fed induction machine. Based on simulation results, it is shown that the discrepancies between actual and imposed rotor flux, torque and errors in orientation angle are relatively important and must be compensated particularly for high performance applications. This is obtained by using a modified controller. The compensation adds to the system complexity.