Control of the Induction Machine in the Field Weakening Range

A Hybrid DTC-DSC Drive for High Performance Induction Motor Control

“…9. However, the generation of the reference flux is slightly different when compared to the conventional method [21], where the flux magnitude has a step reduction of 13.4% as the motor speed reaches its reference (ω m,2 ). This reduction is to ensure that the output torque can be well-regulated to its reference with the proper level of flux reference as reported in [22].…”

“…12. The basic DTC uses the conventional flux weakening method, where the variation of the reference flux is inversely proportional to the motor speed [21]. Note that, the base speed for each scheme is defined as the maximum speed at which the maximum torque can be retained under the rated flux condition.…”

Improved torque response by tuning of the magnetizing inductance under field weakening operation region [of induction motors]

“…The former doesn't includes the magnetizing inductance and the latter includes that. + The torque in stalor flux reference frame (4) …”

“…Nevertheless, the flux level must decreased above base speed, then the dynamic Performance of the controller is deteriorated. Therefore, the improvement of the system performance and the maximum torque operation has been studied [4]-[SI. The conventional method that is to vary the rotor flux reference in proportion to the inverse of the rotor speed has the limitation that is caused by the neglecting the dynamics of the rotor circuit.…”

“…The flux calculation corrects the slip gain and commands the correct field current. But the machine model is complicated because of need of the correct parameters such as inductance ratios, stator resistance, and derivatives of stator currents [4]. In state space model, the torque constant is determined by rotor flux and the rotor time constant.…”