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A separate-stator modular machine with biased flux is proposed in this paper. In this machine, the windings and the permanent magnets are located in two separate parts of the stator, which favors the heat dissipation and magnetic saturation reduction of the machine. With the specially designed stator structure, a biased flux can be introduced to flexibly regulate the excitation field by injecting a zero-sequence current into the phase windings, so that a wide operation speed range can be achieved. Moreover, a modular structure is adopted to simplify the automated manufacture assembly. In this paper, the machine configuration and the working principle are first illustrated. The effect of the design parameters on its torque capability is then investigated. A coupled electromagnetic-thermal optimization method based on the genetic algorithm and finite-element method is proposed to improve the torque performance of the machine. [ABSTRACT FROM AUTHOR]

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]

This paper presents a shoe-sole-embedded power harvester which can extract power from walking to charge portable or mobile electronic devices. The core component of the design is a combination of a trans-rotary magnetic gear (TRMG) and a disk-type axial-flux permanent magnet (AFPM) generator. The key idea is to convert linear foot motion into rotation using the TRMG, so that the AFPM can be driven to generate electric power. The proposed energy harvester has a high power density due to its electromagnetic nature. Moreover, by integrating a TRMG, it eliminates the mechanical problems caused by the conventional transmission mechanisms, which also makes it compact in size. Besides introducing its structure and working principle, the design procedure is presented and its performance is analyzed using the finite-element method. [ABSTRACT FROM PUBLISHER]

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]

Compared with mechanical gears, a magnetic gear (MG) has many merits by virtue of its contactless feature, high efficiency and inherent overload protection. In this paper, a novel MG with intersecting shaft axes based on the flux modulation effect is proposed. Compared with previous MGs, the transmission direction of the novel MG can be designed very flexibly and it also has good competitive edge in relation to the use of permanent magnets, which enables it to have a relatively high-torque density. The working principle and performance are validated by an example design using finite element method. The effects of the dimensional parameters on the torque performance are analyzed. It is also verified that the torque density can be further improved by adopting a flux concentration configuration in its rotor design. It is concluded from the torque per unit volume density performance that the novel MG is very promising as a substitute to conventional gears. [ABSTRACT FROM AUTHOR]

A novel electrical continuously variable transmission (E-CVT) system for hybrid electric vehicles is presented. The merits of the system, which is comprised of a magnetic gear (MG) integrated permanent magnet brushless machine, are its compactness, light weight, very high torque density, and simple structure. The integrated MG is ingeniously used to greatly amplify its output torque. It serves the functions of both power splitting and coupling. The drawbacks of mechanical gears or brushes in traditional systems are overcome. A design method based on finite element method for maximizing the torque output of the machine is presented and the performance of the machine in the E-CVT system is validated. [ABSTRACT FROM AUTHOR]