A Novel Highly Efficient Torque-Sharing Algorithm for Dual Stator Winding Induction Machines for Various Speed Regions

This article proposes a novel and highly efficient torque-sharing algorithm for dual stator winding induction machines (DSWIMs). This algorithm introduces three modes of operation for DSWIMs based on the command speed and the required load power. Implementing this algorithm makes accurate flux calculation and control possible in very low-speed regions, including zero speed. In higher speed regions, if one of the winding sets is able to supply the required power solely, the other is switched
off
to augment the overall efficiency. In higher required powers, both winding sets cooperate to supply the load torque, and the required electromagnetic torque division between the two winding sets is fulfilled based on their power ratings. This guarantees overloading avoidance in various operation conditions. Moreover, the optimal flux condition is guaranteed in various speed regions free of the torque sharing. In addition, this algorithm is general and can be implemented in direct torque control and field-oriented control schemes in various reference frames. The proposed algorithm has been experimentally implemented in a 3.3-kW vector-controlled DSWIM drive system. In this flux and speed control system, the flux is controlled such that a search-based maximum torque per ampere (MTPA) algorithm is realized. The proposed MTPA strategy is insensitive to DSWIM parameters and load variations. The experimental results confirm the functionality of the proposed DSWIM drive system in various operation conditions.