A Parallel Hybrid Excited Machine Using Consequent Pole Rotor and AC Field Winding

Abstract

Hybrid excited (HE) machines with both permanent magnet (PM) and field winding excitations, inherit the benefits of PM machines and improve the flux regulation capability. This paper proposes a novel consequent pole HE (CPHE) machine. The PM pole pair and the iron pole are alternately placed on the rotor, while both the armature winding and ac field winding are located on the stator slots, which achieve the brushless excitation. Since the flux of the field winding goes through the iron poles, the PM and field winding exhibit parallel magnetic paths, which is favorable for the flux regulation and avoids the irreversible demagnetization of the PMs. In this paper, the operating principle of the proposed CPHE machine is illustrated. Moreover, the electromagnetic performance, including back electromotive force, torque, and flux regulation range considering different coil pitch of field winding is analyzed by finite-element analysis. It is demonstrated that the proposed machine exhibits flexible flux regulation capability, which is suitable for applications requiring wide speed range operation or voltage regulation.