Design optimization of a switched reluctance machine-based integrated starter/alternator for automotive applications

This paper presents findings from an optimal design study on a switched reluctance machine operating in both motoring and generating modes as automotive integrated starter/alternator. The design optimization approach employs an analytical lumped-parameter modelling of the switched reluctance machine in motor and generator operations, which is refined by finite-element magnetic field analysis of the machine and then implemented in MATLAB/Simulink environment. The objective function of the design optimization problem is the maximization of the average electromagnetic torque of the machine for motor operating mode under constraints on rotor speed, energy efficiency and torque ripple. Steady-state and dynamic simulation results for the optimally-designed switched reluctance machine in motoring and generating modes, as part of automotive integrated starter/alternator operation cycle, are also provided.