Analytical Computation of Torque-Speed Characteristics and Efficiency Map for PM Motors

This paper provides an analytical solution for designing a Brushless Permanent Magnet Synchronous Motor (BLPMSM) to compute its torque-speed characteristics and associated efficiency map. This approach combines the torque-speed computational algorithm with analytical open-circuit PM flux computation followed by EMF and torque computations. The torque-speed algorithm uses the Ferrari method to compute torque in MTPA and flux weakening regions. Subsequently, the efficiency map can be calculated for the entire speed range. The proposed comprehensive analytical approach can be useful for design optimisation in terms of significantly reducing computational efforts. Finite element analysis (FEA) is used to validate the analytical results.