Dynamic Loss Minimization Control of a 4-Pole/2-Pole Electronic Pole-Changing Induction Motor Using a Look-Up Table

A pole-changing motor with dual pole configurations can operate over an extended torque-speed region of operation. The higher pole configuration can be used for high torque in the low-speed region of operation, whereas at higher speeds an enhanced constant power speed region can be obtained with the lower pole configuration. The pole-changing can be accomplished electronically by changing the current directions in certain windings by using an inverter. This article discusses the current and flux dynamics associated with pole changing and presents a controller for the 4-pole/2-pole induction motor that initiates a pole change from one pole configuration to another with a power loss minimization method when the operating region overlaps for the two pole configurations. Simulation and experimental results using a look-up table-based loss-minimization approach are provided to validate the control method. The electronic pole-changing control results demonstrate a smooth torque transition while minimizing the motor loss.