Sensorless induction machine based integrated starter alternator for the 42 V powernet for automobiles

This paper presents sensorless induction machine based integrated starter alternator (ISA) scheme for the 42 V powernet for automobiles. Proposed scheme provides solution for cost and reliability issues related to position encoder based ISA systems in automobiles. The stator voltages of induction machine that need for rotor flux estimation, are constructed from DC bus voltage and reference signals of space vector modulator with necessary correction to compensate errors due to device drops and dead time. This allows elimination of two voltage sensors and that leads further cost reduction of the system. Dynamics and efficiency of the proposed integrated starter alternator were investigated by means of modeling and prototype system. The simulation and experimental results of sensorless operation of the proposed ISA in motoring and generation modes are presented in this paper.