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Doubly salient electromagnetic machine (DSEM) can constitute a competitive rugged starter generator (SG) system. But under the traditional startup control method, the field current is set to the rated value regardless of speed or load torque conditions, and the phase currents are controlled with standard angle commutation, bringing in large power loss as well as non‐negligible torque ripple. To overcome these shortcomings, based on the established DSEM power loss calculation model, a currents distribution strategy is proposed according to the obtained quantitative relationship between DSEM power loss and field current under multiple speed and load torque conditions. Then, to identify the load torque for practical implementation, a novel torque observer is designed based on back propagation (BP) neural network algorithm. Afterwards, to further improve the startup torque performance, currents distribution with advanced angle commutation (AAC) strategy is put forward, where the optimal advanced angle is selected from a 3‐D lookup table to achieve the minimal commutation torque ripple. Under the proposed control strategies, DSEM power loss as well as the output torque ripple are desired to be decreased, the simulation and experimental results on a 12/8‐pole DSEM prototype verify the correctness and feasibility of the proposed strategies under multiple operating conditions. [ABSTRACT FROM AUTHOR]

This paper presents two novel designs of magnetic flux‐modulated mnemonic (MFMM) machines which incorporate magnetic gearing effect and flux‐mnemonic concept together. Both of these two machines can perform large torque production at low‐speed because of the magnetic gearing effect, and can readily achieve flexible flux‐controllability by temporarily applying current pulses to magnetise/demagnetise aluminium‐nickel‐cobalt magnets so as to expand the constant‐power region operation effectively. One machine has permanent magnets (PMs) on its rotor and outer stator which is referred as the dual‐layer PM MFMM (DPM‐MFMM) machine; bi‐directional field modulating effect is artfully incorporated in this machine to guarantee effective coupling between the magnetic fields excited by the armature windings and those excited by the two sets of PMs. The second machine employs all the PMs on the outer stator and the rotor is only made up of ferromagnetic segments. In other words, it is a single‐layer PM‐MFMM (SPM‐MFMM) machine, and the rotor carries the flux modulating poles. The configurations and working principles of both machines are discussed. The electromagnetic performances are comprehensively studied and quantitatively compared using finite element method (FEM). [ABSTRACT FROM AUTHOR]