Performance comparison between two-phase-on and three-phase-on operation of Brushless DC drives

A comparison between two-phase-on (2PO) and three-phase-on operation (3PO) for Three-phase Brushless DC machines (BLDCs) is presented in this paper. It aims to highlight the different BLDC exploitation achievable by means of 3PO compared to that obtainable by 2PO. For this purpose, two different control strategies are considered, i.e. a traditional 2PO-based and a 3PO-based, whose main details are briefly analyzed and discussed. Subsequently, they are compared to each other referring to the case of a BLDC. The comparison reveals improved BLDC performances achievable by means of 3PO in terms of averaged torque, torque ripple and Joule losses reduction, especially at high-speed operation.