Performance deterioration in indirect vector controlled induction motor drives due to iron losses

The paper evaluates the consequences of iron loss representation omission in control systems of indirect vector controlled induction machines. Iron loss is at first measured experimentally, by supplying four different induction machines (0.75 kW, 1.1 kW, 4 kW and 7.5 kW) fed from a PWM inverter and from a sinusoidal supply. The results of the experiments are then used in the analysis of detuning effects in steady-state operation of indirect rotor, air gap and stator flux oriented induction machines, introduced by iron loss. Operation in the constant flux region is discussed and all the four machines are encompassed by the analysis. It is shown that errors in the orientation angle and discrepancies between actual and commanded flux and torque values are relatively significant for the 1.1 kW and 4 kW machines