Indirect field-oriented torque control of induction motor considering magnetic saturation effect: error analysis

This study investigates the causes and calculation formulas of steady-state torque and rotor flux errors, when an induction motor considering magnetic saturation effect is controlled by standard indirect field-oriented control algorithm. First, two reasons that causing the errors are analysed. One is mutual inductance mismatch between controller and motor. Another is rotor flux orientation deviation, resulting in the failure of decoupling of the magnetising and torque-producing currents. Then, the equations for calculating steady-state errors (orientation error, rotor flux error and torque error) are derived. The errors are related to reference torque, reference rotor flux and mutual inductance deviation. In addition, the characteristic maps of errors with respect to reference values are drawn. The accuracy and correctness of derived equations are validated by simulation and experimental results.