Performance analysis of multi-phase PM brushless DC motor drive system

The new technology permanent magnet motors have several advantages over the induction motor: most notably, they are smaller and more efficient. Recently permanent magnet BLDC motors and synchronous motors for warship propulsion are under development in Europe and America. Analysis of this paper shows that, applying asymmetric distributed multi 3-phase BLDC motors can simplify the converter system and reduce torque ripples in low speed. In order to optimize motors´ structure and their control methods, a mathematical model of those multi-phase BLDC motors is established in this paper. Certain simulation and experiment methods are presented based on the model. As an example, a double three-phase BLDC motor is detailedly analysed by authors, simulation and experiment results are in good agreement, which confirms the validity of the proposed methods.