Research on a Novel Magnetic-Geared Machine with High Power Density

Magnetic-geared machine can achieve high torque at low speed, which has potential prospect in direct-drive application. This paper proposes a novel axial-flux magnetic-geared machine, in which PM excitation exists in PM rotor and modulating ring. The novel machine can offer the advantage of higher power density and improve power factor effectively. The operating principle is presented and the impact of key geometrical parameters on air-gap flux density is investigated. To evaluate the advantage of the proposed machine, a comparison is made with a conventional one with respect to electromagnetic performances. Results show that the power density and power factor of the proposed machine are 5.3 kW/L and 0.85, respectively. Compared with the conventional one, the proposed machine can effectively improve power density and power factor by 36% and 41%, respectively.