Reducing Dependency on Rotor Time Constant in a Rotor Flux Oriented Vector Controlled Induction Motor Drive Based on Its Static Model

This paper proposes a modified control algorithm for three phase squirrel cage induction motor. The proposed algorithm is based on the static or steady state model of a vectorcontrolled drive with rotor flux orientation and controls the machine dynamics over one fundamental cycle. The algorithm proposes current mode control on the direct axis and voltage mode control on the quadrature axis, unlike, state of the art vectorcontrolled drive where current mode control is used on both the axes. This offers two advantages. First, the control algorithm becomes independent of the rotor time constant, which is always varying, thereby reducing the dependency on rotor time constant of the motor. Second, one proportional integral controller is reduced in the control algorithm. The proposed scheme is validated through simulation using a fractional horse power squirrel cage induction motor. The proposed technique is also compared with the conventional vector control.