Modeling and analysis of a wide-speed-range induction motor drive based on electronic pole changing

It has been previously demonstrated that an induction machine drive with contactorless pole changing can be achieved by reversing the current directions of certain stator coil groups. This paper compares the power and torque capability of this type of induction motor drive with conventional four-pole and two-pole induction machine drives. Based on the technique of vector space decomposition, the machine coupled-circuit model is transformed into a reference frame model. As a result of this transformation, the coupled coil group variables can be replaced by equivalent decoupled four-pole and two-pole dqO variables. This reference frame model facilitates the analysis and control of the machine drive, especially during transients, such as the pole-changing transition.