Development of a Novel Magnetic Circuit Model for Design of Premium Efficiency Three-Phase Line Start Permanent Magnet Machines With Improved Starting Performance

This paper presents challenges in an ongoing project related to the design of a premium efficiency three-phase line start permanent magnet synchronous motor (LSPMSM) and proposes an exclusive solution through development of a novel magnetic circuit model. Since the LSPMSM is rapidly replacing the conventional induction motors in industrial applications such as pumps, fans and conveyors which require the machine to operate under both frequent start-stop and steady-state conditions for a wide range of time, a trade-off has to be reached between their starting performance and efficiency post-synchronization. Until now this has only been possible with time consuming FEA based design methodology. Hence, understanding the need and scanty availability of literature on simplistic and yet precise magnetic circuit based design of three-phase LSPMSM, this manuscript proposes exclusively a novel magnetic circuit model to design LSPMSM with improved starting performance. Firstly, the aforementioned design issues have been illustrated using different machine configurations developed. Further, a detailed procedure to deal with the design issues with the help of the developed magnetic circuit model is discussed and validated by developing a machine where the trade-off has been reached.