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Spoke structure can increase the torque density of coaxial magnetic gear (CMG). However, the outer rotor can produce a large number of magnetic leakages. To improve the utility of PMs, a novel magnetic gear was proposed in this paper. The structure of the auxiliary flux modulator is a slotted iron yoke, and the slot angle is same as the stationary ring. Among, the permanent magnets (PMs) of inner rotor are adopted uneven block structure to improve air gap flux density. At the same time, the stationary ring adopts high-temperature superconducting (HTS) bulks, replacing the epoxy resin. In addition, Genetic algorithm (GA) is applied to calculate the optimal parameters of the proposed CMG. Finally, the air gap flux density and output torque of the magnetic gear a compared by the finite element method. The results show that the output torque of the proposed magnetic gear is effectively improved. [ABSTRACT FROM AUTHOR]

This paper proposes a novel high-temperature superconducting stator-excited axial-flux magnetic gear (HTS-SEAFMG) for the high-torque transmitting system. The proposed magnetic gear combines the merits of both HTS-excitation and stator-excitation. By using the HTS-excitation, a high air-gap flux density can be easily obtained, thus achieving the high torque density. The HTS-excitation windings are placed on the stator with a static seal of cooling Dewar which greatly reduces the manufacturing difficulty and the cost of refrigeration system compared with the dynamic seal. Thanks to the stator-excitation pattern, both the high-speed rotor and the low-speed rotor comprise only iron, thus contributing to the high mechanical reliability. The axially sandwich structure can also simplify its assembly in the high torque transmission applications. The dimensional parameter optimization and the electromagnetic performance evaluation are conducted by using the finite element method, respectively. The results show that the torque density of the proposed HTS-SEAFMG can reach 123 kNm/m3. Theoretical analysis and results are both given to verify the feasibility of the proposed HTS magnetic gear design. [ABSTRACT FROM AUTHOR]

This paper proposes a linear variable machine equipped with a set of field winding which is capable for adjusting the air-gap flux. As conventional variable reluctance machines, the proposed machine has a doubly salient structure and no permanent magnets or windings on the mover. The distinct feature of the proposed machine is that there are both the ac armature winding and the dc field winding in the stator. By inviting the dc field winding, the proposed machine not only has the flux control capability, but also realizes the bipolar operation. In this paper, the proposed machine design and its operating principle are presented and discussed. Then, a two-phase machine in modular design is dimensioned. By using the three-dimensional finite element analysis, both the steady and transient performances are quantitatively analyzed and evaluated. [ABSTRACT FROM PUBLISHER]

The quantitative interaction body force density was calculated in soft magnetic materials by using a freezing procedure of magnetization and virtual air-gap scheme, which were implemented by using the Finite Element Method. Until now, the virtual air-gap concept has been successfully applied to evaluating contact force and body force density in soft magnetic materials. When the generalized methods, methodologies with virtual air-gap scheme, are introduced, one can have an irregular force field, which seems to be random distribution of body force density. Even though this irregular pattern generates a correct global force and reasonable trend of mechanical deformation, it is quite difficult to predict the resultant deformation by the irregular force field. This irregular force field pattern is originated from the field direction to the finite element edge where the virtual air gap is inserted and an additional strong force arises with the outward normal direction. To remove this irregular pattern and evaluate an interaction body force density, the self-force density by the frozen magnetization should be withdrawn from the total body force density. To verify the proposed method, first, a critical magnetic system, which cannot be solved by the equivalent magnetizing source methods, were tested for evaluating the interaction body force density corresponding to the resultant mechanical deformations. After confirming the interaction force, two additional specific models were tested with the resultant mechanical deformations due to the different local force densities. [ABSTRACT FROM PUBLISHER]