US Patent 8390165 Synchronous motor drive system

Provided is a synchronous motor including a rotor having magnetic poles distributed circumferentially along a rotation direction of the rotor at equal intervals, and a stator having stator teeth arranged circumferentially along the rotation direction of the rotor, each tooth wound with a stator coil by concentrated winding. Every M consecutive stator teeth belong to one of stator teeth groups arranged at equal intervals. The M consecutive stator teeth in each stator teeth group are arranged at intervals different from the intervals of the magnetic poles of the rotor. The stator coils wound around the M consecutive stator teeth are connected to separate terminals. A motor driver supplies currents of different phases to the stator coils via the respective terminals.