Control Strategy for a Multiphase Lundell-Alternator/Active-Rectifier System in 14V Automotive Power Systems

This paper presents a novel control strategy for a conventional six-phase Lundell alternator fed at the output with a MOSFET-based active-rectifier. The signal references for the controller are calculated from a cost-function aiming to minimise the alternator stator copper losses in an effort to maximise the alternator-rectifier system overall efficiency. The system is initially simulated and tuned in Matlab/Simulink and then experimentally verified. Steady-state efficiency results from experimental measurements of the alternator/rectifier system are compared against a standard passive rectifier. The results indicate a better overall efficiency compared to the passive rectifier, for an alternator speed of up to approximately 5000 rpm, corresponding to city driving.