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In this paper, a new permanent magnet (PM) linear motor is proposed. This motor has a special structure with complementary stator flux, which helps to reduce the flux leakage and improve the utilization of the PM. The PMs are installed in a leaning manner, which increases the effective area of the PMs and enhances the field excitation. Hence, the force density of the motor can be improved and it will be, especially suitable for applications within a limited space. The motor structure and working principle are first explained. The design of the motor is then comprehensively investigated. An electromagnetic optimization method based on tabu search algorithm and finite-element method is proposed for the motor to improve its force density. [ABSTRACT FROM AUTHOR]

A novel gearless and brushless power-split transmission system is proposed for a variable speed constant frequency wind power generation application. The key is to design a special hybrid axial–radial flux focusing structure, which has an improved utilization of permanent magnet (PM) materials. This design integrates the merits of two popular concepts—the direct-drive PM generator and the doubly fed induction generator. It is direct driven, with high torque density and in the meanwhile, it needs only a partial-scale converter. To improve the stability of the system, five phase currents are used for the control winding. A time stepping finite-element method is used to analyze the dynamic performance of the proposed system. [ABSTRACT FROM AUTHOR]

This paper presents a novel gearless and brushless power split transmission system for variable-speed constant-frequency wind power generation application. The core element of this system is a novel axial-flux doubly fed dual-rotor permanent magnet machine. The key of the design is to utilize the flux modulation principle to modulate the magnetic flux in an axial-flux machine and use doubly fed stator winding to control the rotor rotation. This design combines the merits of direct-drive machines and doubly fed generators. As the mechanical problems related to brushes, slip rings, and gear boxes are successfully overcome, the operational reliability of the system is improved. The stator winding of the proposed system can be directly connected to the power grid, and the power rating of its associated frequency converter is reduced. Time-stepping finite-element method is used to analyze the dynamic performance of the proposed system. [ABSTRACT FROM AUTHOR]