Hideaki Abe

Equivalent circuit of wireless power transmission with coil array structures

Wireless power transfer system with coil arrays which can supply to several apparatus at the same time is expected. In this case, only one or two primary coils under the secondary coil are excited. The electromotive force of the secondary coil is changed by the interval of primary coils and the number of the excited coils. In this paper, the effective equivalent circuit which could reproduce this behavior is presented.

A thin transformer realized by optimizing the resonance voltage of an active clamp soft-switching converter

This paper proposes a high frequency switching active clamp flyback converter which can reduce the height of the transformer and the size of the power supply. This is accomplished by applying an adequate resonance voltage lower than the absolute maximum rating of the drain to source breakdown voltage of the switching device. By using this approach we succeeded in reducing the height of the transformer and the size of the power supply to approximately half.

Load voltage stabilization of noncontact energy transfer using three resonant circuit

This paper is related to the noncontact energy transfer system which can stabilize the load voltage with no feedback control used three resonant circuits. This system which employs a detachable transformer for magnetic coupling has a leakage inductance. Therefore load voltage decreases greatly in proportion to load electric current. A feedback control circuit of the noncontact energy transfer system is more complicated than that of the contact energy transfer system. Namely, a noncontact energy transfer system with no-feedback system is expected for stabilization of the load voltage. A high efficiency noncontact energy transfer system requires several resonant circuits such as resonant inverter and resonant circuit for load matching. The authors found a novel method which minimizes the load voltage drop rate by using optimized capacitance value of above the resonant circuits.

Control method of wireless power transfer system for allowing coil position deviation

The purpose of this paper is to propose a new control method of wireless power transfer system that can maintain stable power supply even when the positions of the primary and secondary coil or distance between the two coils largely change. The new method will be done by adjusting the switching frequency to a frequency that can obtain the desired output. We confirmed the effectiveness of new wireless power supply control method through experimental result which show that the maximum horizontal position deviation that can obtain a 20W output is 2.8 times longer.

Resonance type short distance power transfer property for the structure parameter of the spiral coil

Recently wireless power transmission technology attracts attention. A method using magnetic resonant wireless power driven by about 10MHz, examination such as improvement of the transmission efficiency or the extension of the transmission distance is researched. On the other hand, we are interested in possibility of the reduction of the thickness of the antenna coil. In addition, we are studying high efficiency power transmission at short distance to reduce leakage magnetic flux. We investigated the structure parameter of the spiral type coil antenna that the transmission of the high efficiency could be possible in case of short distance. The control possibility of the transmission distance by the adjustment of this structure parameter was derived.