Analysis and Comparison of the Dynamic Response of Direct and Indirect Rotor Flux Control Applied to an Asymmetrical Two-Phase Induction Motor

This paper discusses two methods for asymmetrical two-phase induction motor control. The direct rotor field oriented control (DRFOC) and the indirect rotor field control (IRFOC) methods are investigated. Both control strategies were implemented in the same hardware with little modifications in the control algorithm. However, the intrinsic model asymmetry causes extra coupling between the stator windings. To use the field-orientated method, the asymmetry must be eliminated by using a transformation based on the mutual inductances. Experimental investigation was carried out and a comparative analysis of the performance of the two methods of control is presented. Based on experimental results of the DRFOC and IRFOC control systems, it is shown that the speed control and the flux control present a fast response even under load disturbance. In addition, the complexity for implementing both systems is identical. Although some questions were raised concerning the use of such transformation, it is still a viable solution as is demonstrated by the results.