A pole changing vernier machine with consequent pole rotor

Abstract

This paper presents a consequent pole changing vernier machine (CPCVM) for variable speed application such as electric vehicles. The proposed topology works as a 48-pole vernier machine with a consequent pole rotor in the low speed region. In this mode, the machine provides high torque and high efficiency. Also, the machine uses less amount of magnet volume than a surface permanent magnet machine. However, in high speed region, the poles of the machine are changed and the machine switches to permanent magnet synchronous machine (PMSM) mode that provides high efficiency in the high speed region. Therefore, the machine combines the advantages of a consequent pole vernier machine and a conventional PMSM in a single topology. The variable speed range of the machine is extended by pole changing operation. The merits of the proposed topology are investigated by finite element analysis and the feasibility of the machine is confirmed for variable speed operation.