Patent ID: 7622840
Filing Date: 2009-11-24
Classification: H02K,H02P

Abstract:
1. An electric machine comprising: a rotational shaft; a rotor arranged coaxially with said shaft and having a plurality of salient poles which are arranged substantially equally spaced with each other in the circumferential direction; a stator stationarily arranged around said rotor and having a plurality of salient poles which are substantially equally spaced with each other and have thereon stator coils to be sequentially supplied with electricity for generating torque on said rotor; a sensor sending a signal indicating a state of charge of a battery, wherein said signal is used to determine required electricity generated from said electric machine; and a magnetizing member which is arranged on said shaft and offset from said rotor in the axial direction and capable of generating a magnetic field on said rotor to induce alternating magnetic flux on said stator coils when said magnetized rotor is rotated for generating electricity from said stator coils so as to charge said battery with said electricity, wherein: said rotor has no permanent magnet; and said magnetizing member is adapted so that strength of the magnetic field on said rotor may be adjusted to be larger as said required electricity is larger and to be smaller as said required electricity is smaller.