An alternative solution of automobile alternator with PM rotor machine

The proposed concept in this paper is about how to achieve flux control at higher speeds in automotive alternators with PM rotors. The use of high energy magnet (NdFeB) in the rotor helps to achieve high power density and high efficiency in the alternator. The PM flux control at high speed is done by implementing a mechanical flux weakening arrangement which uses a simple worm wheel and DC motor to perform this phenomenon of flux control. The open circuit and loaded performance of standard claw pole alternator for different field currents at various speeds has been predicted. The components of the mechanical arrangement which has been used for achieving rotation have been discussed. Further, a suitable variable flux permanent magnet machine (VFPM) is designed with the same dimensions as that of the standard claw pole machine. The open circuit performance of VFPM is predicted and is compared with the conventional machine.