Consequent pole permanent magnet machine with field weakening capability

The electromagnetic design procedure and laboratory test results are presented in this paper for a consequent pole permanent machine (CPPM) with field weakening capability. Due to its particular configuration, the CPPM allows one to easily control the air-gap flux in a wide range so that the speed range of the machine is increased. Two components of the flux: one-almost constant-coming from the permanent magnet located in the rotor surface of the machine, and the other-variable-coming from a field winding located in the middle of the stator, converge in the air-gap, characterizing the level of excitation of the machine. Preliminary 3D finite element analysis results establish that with 10% of the phase MMF, it is possible to vary the flux in a wide range. A 3 kW, 1000 to 3000 RPM velocity range, 8 pole and 32 AC volt generator using this configuration is tested to verify the flux control capability of this structure