Permanent magnet assisted current superimposition variable flux machine

Electric and hybrid electric vehicles require traction motors that have a high power and efficiency over a wide rotation speed range . In order to satisfy these requirements and reduce the motor cost, variable flux reluctance motors (VFRMs) have been studied . Conventional VMFRMs have DC-field windings and armature windings. However, because there are two kinds of windings, the coil space factor decreases and the wiring becomes complicated . In order to solve these problems, we have developed a motor called the variable flux reluctance motor (CSVFRM) that does not have any DC-field coils, and instead uses current superimposition . In this paper, we propose a modified model whereby permanent magnets are introduced into the stator to increase the efficiency . The structure and operational principle of this machine are described and the N-T characteristics are computed by FEA.