Journal of Magnetism and Magnetic Mate

de

, H

a, K

8 D

Abstract

We have developed a system which transmits electric power and communication data simultaneously in a non-contact method using a

1. Introduction

extremely short, charging itself takes a long time, chargingstations are not widely available, and so on. Moreover,another major factor deterring the operation of EV is the

lack of technology to allow the general availability of non-

applied the system that transmitted the electric power andcommunication data based on Refs. [1,2] at the same time tothe charge system of an EV, and we also did basic research

ARTICLE IN PRESSthat conrmed the charge to the battery. In this paper, wereport on the excellent results obtained on our experimentswith a non-contact transformer.

0304-8853/$ - see front matter r 2006 Elsevier B.V. All rights reserved.

doi:10.1016/j.jmmm.2006.11.186

Corresponding author. Tel.: +8196 326 3447; fax: +81 96 326 5044.E-mail address: matsuda@cc.sojo-u.ac.jp (Y. Matsuda).Dangers accompanying the increase of vehicle produc-tion are the depletion of natural oil resources and thedestruction of the environment on a global scale throughvehicle exhaust emission. One solution to lessen theseproblems would be the widespread use of electric vehicles(EV). However, the general adoption of purely EV isadvancing rather slow. Some reasons contributing to thisdelay are that the mileage obtained for a single charge is

contact charging systems.In the course of our research, we have been aiming for the

realization of a non-contact charging method that could beeasily used not only at ones own garage, but also at publicparking lots, convenience stores, bus stops and at intersec-tions. It would be necessary to familiarize the system withboth the condition of the car battery to be charged as wellrelevant customer data. We have now developed a basicsystem that allows this interactivity. In the present study, weelectric shavers, electric toothbrushes, etc. Moreover, basic experiments are being conducted for applying this non-contact charging

system to electric equipments such as an electric vehicle (EV), which is a zero emission vehicle and environmentally excellent and will be

the transportation means of the next generation. The technology can also be applied in other electronic equipment, etc. However, since

the power supply route for these individual devices is independent, the supply system is complicated. EV also has to perform the

transmission of electric power and the transmission of information (data), such as the amount of the charge, in a separate system,

and thus is quite complicated. In this study, by performing simultaneously the transmission of electric power and information

(data) using magnetic coupling technology in which it does not contact, the basic experiment aimed at attaining and making unication

of a system simple was conducted, and the following good results were obtained: (1) Electric power required for load can be transmitted

easily by non-contact. (2) A signal can easily be transmitted bidirectionally by non-contact. (3) This system is reliable, and is widely

applicable.

r 2006 Elsevier B.V. All rights reserved.

PACS: 84.30.Jc; 84.30.Qi; 84.70.p

Keywords: Non-contact charging system; Magnetic couplingmagnetic coupling coil. Already, we are developing the fundamental technology of a non-contact charging system, and this is applied inNon-contact magnetic couplesystem for an

Y. Matsuda

Sojo University, 4-22-1, Iked

Available onlinerials 310 (2007) 28532855

power and data transferringlectric vehicle

. Sakamoto

umamoto 860-0082, Japan

ecember 2006

www.elsevier.com/locate/jmmm

ARTICLE IN PRESSsmY. Matsuda, H. Sakamoto / Journal of Magneti28542. Principle of the non-contact magnetic coupled power anddata transferring system

Because this system uses almost the same number ofparts as previous non-contact charge methods haveconsisted of, cost is one attractive advantage of ourelectromagnetic induction system for the transmissionof electric power and data. Fig. 1 shows the control, thedrive, and the main inverter circuit used in this experiment.Table 1 shows the parts list of this circuit. IC1 uses PICmicrocomputer 12F729 in Fig. 1 for the signal modulationand the inverter control. IR2110 is used for IC2 for thedrive of the main FET (S1,S2).Here, we explain the operation of the circuit of Fig. 1. A

signal of 100 kHz is oscillated by a PIC microcomputer.However, because the output voltage is 5V in the PICmicrocomputer, FET of the main circuit cannot be driven.Therefore, a special IR2110 is combined with the IC for

Fig. 1. Conguration of the experiment circuit.

Table 1

Circuit components

Component Specication

C1;C2 300V, 2200mFS1; S2 2SK1522IC1 PIC12F729(20MHz)

R1;R2 5:6OIC2 IR2110

IC3 78L05driving the gate. The program for the PIC microcomputeris rewritten to prevent the arm short-circuit of FET (S1,S2)in the main circuit, and the dead-time is adjusted. Thesignal is transmitted to IR2110 by using the RS232Cprogram used in PIC and PC at the time as thetransmission of the information signal. Fig. 2 (upperwaveform) shows the PCM input signal waveform of9600 bps input to PIC. After it modulates to 100 kHz whenthe PCM input signal is 1, and it modulates to 50 kHz whenthe PCM input signal is 0. Fig. 2 (lower waveform) showsthe waveform of the detachable coil when it is convertedinto the alternating current with the inverter. A very highefciency over 80% is obtained on a 2 kW output when thegap length is 100mm and the switching frequency is100 kHz.The input signal is modulated at the same time as the

power is transmitted to the secondary coil, being rectiedby the rectier and spreading as far as the output signaland the former PCM signal is demodulated. Adjustment of

Fig. 2. Waveforms of the input signal and coil.

and Magnetic Materials 310 (2007) 28532855the dead-time is performed while watching the shape of thewaveforms with adapted PIC software.As a more practical coupler, we examined the core

construction of the inductive charger of 2 kW assuming theoor of the car to be a steel plate 1120 1120 5mm3placed above the MnZn ferrite core in a 206mm higherposition. The ferrite core is assumed to be set on the earthoor, and the dimension is 1000 1000 10mm3. Fig. 3 isa simulation of the magnetic eld distribution in a crosssectional of the non-contact transformer depicted in Fig. 1.That the coupling coefcient increased through the effectsof an upper steel plate is evident.

3. Conclusion

In this paper, we describe the outline of the technologyfor the simultaneous transmission of electric power andbasic information through a non-contact system. In thepresent experiments, extremely excellent data were ob-tained.

References

[1] H. Sakamoto, et al., in: Proceedings of the IEEE INTELEC95, 1995,

pp. 330334.

[2] H. Sakamoto, et al., IEEE Trans. Magn. 32 (5) (1996) 4983.

ARTICLE IN PRESS

Fig. 3. Magnetic eld analysis around Power Transmission Coil (simulation result).

Y. Matsuda, H. Sakamoto / Journal of Magnetism and Magnetic Materials 310 (2007) 28532855 2855

Non-contact magnetic coupled power and data transferring system for an electric vehicleIntroductionPrinciple of the non-contact magnetic coupled power and data transferring systemConclusionReferences