PSEUDOROTOR-FLUX-ORIENTED CONTROL OF AN INDUCTION MACHINE FOR DEEP-BAR-EFFECT COMPENSATION

In an induction machine with deep rotor bars, the rotor parameters cha nge due to skin effect and saturation, and the skin effect is often mo deled as a ladder network. For the high-performance drive of an induct ion machine with deep bars, many sophisticated control strategies and machine models have been discussed. As a control strategy, a complicat ed airgap flux-oriented control scheme is mostly adopted, because it i s not possible to define a unique rotor flux in deep bar model. Howeve r, a unique pseudorotor flux can be defined, and it is straightforward to achieve independent control of pseudorotor flux and torque. This c ontrol scheme can be applied to, any nth multiple ladder network, In t his paper, it is described how a deep-bar effect of an induction machi ne can be negligible by performing the proper held-oriented control. B y using the concept of pseudorotor flux, the conventional rotor-flux-o riented control using equivalent rotor parameters is effective for dee p-bar and/or double-cage machines. The actual insulated gate bipolar t ransistor (IGBT) inverter systems with a high-precision torque transdu cer are implemented and thoroughly tested on a 250-hp induction machin e and a 5.5-kW double-cage induction machine to confirm their validity .