Power Enhancement for AC Hybrid Excitation Brushless Generator Using Hybrid-Pole Rotor

In this paper, a novel alternating current hybrid excitation brushless generator (AC-HEBG) structure with hybrid-pole rotor is proposed, which exhibits higher power density compared with the consequent-pole AC-HEBG. The hybrid-pole AC-HEBG has the same combinations of slot and pole, field winding pole pair, and permanent magnet (PM) usage as the consequent-pole AC-HEBG, but has different PM rotor structure. Firstly, the structure of the consequent-pole and hybrid-pole AC-HEBG are introduced, and the 3<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> harmonic field enhancing principle of the hybrid-pole AC-HEBG is expounded. Then, the flux regulation principle, as well as the influence of rotor salient pole arc on the flux regulation capability are investigated and analyzed. It is found that compromises should be made between the output power and flux regulation range. Moreover, the proposed hybrid-pole AC-HEBG is compared with the consequent-pole AC-HEBG in terms of no-load back electromotive force and DC voltage, on-load power and external characteristic, loss and efficiency. Finally, a hybrid-pole AC-HEBG prototype is built to validate the theoretical analysis.