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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]