A Brushless Hybrid Excited Motor Based on Field Modulation Theory

This article proposes a novel brushless hybrid excited (HE) motor, in which both armature and field windings are located on the stator, and permanent magnets (PMs) are housed on the rotor. The key difference is that a special consequent-pole rotor structure is adopted, in which every two PMs are separated by a rotor tooth. So, when dc current is fed into the field winding, the produced stationary wound field can be modulated by the rotor teeth to generate rotary wound field harmonics. Thus, an effective HE operation can be achieved due to the interaction between the synchronous rotating PM field and the wound field harmonics. The motor configuration is introduced first. Then, the operating principle is discussed by the magnetic field modulation theory. By finite element analysis (FEA), the electromagnetic performances are calculated and analyzed. The results verify the validity of the theoretical analysis.