Optimal design of a high-speed slotless permanent magnet synchronous generator with soft magnetic composite stator yoke and rectifier load

This paper presents a specific design methodology of a DC generation system using a high-speed slotless generator with surface-mounted magnets and soft magnetic composite (SMC) stator yoke connected to a rectifier. The method is based on an analytical design model of the machine, an electrical model of the machine–rectifier system and a non-linear optimization procedure. The coupling between both models is achieved by a specific correction mechanism during the iterative process that performs an efficient convergence of the optimization procedure. The machine design model is derived from an analytical computation of the two-dimensional magnetic field distribution created by the magnets, the armature currents and the stator eddy currents that circulate in the SMC material. It has been cross-validated by 2D finite element analysis. The design approach is applied to the specifications of a 1.5 MW, 18,000 rpm slotless permanent magnet generator with a rated DC output voltage of 1500 V.