. Fig. AC bus k k V I S Fig. 4. Fig. 3. The position of two lines The equivalent circuit model of line impedance Z(k) = V I S () Fig f [Hz], c[m

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さゆりあいしま
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1 Evaluation and Suppression of Effect on Power Transfer Characteristics by Cable Impedance for Dynamic Wireless Power Transfer System Kodai Takeda, Student Member, Takafumi Koseki, Member Electric vehicle (EV) is an attractive technology because of its environment friendliness, but it has some drawbacks such as short driving range and huge battery. To solve these drawbacks, dynamic wireless power transfer (DWPT) has been proposed. In this paper, multi-paralleled DWPT system is assumed and cable impedance between consecutive primary coils is analyzed. This paper proposes a new method to evaluate an effect of the impedance, and we reveal that the impedance causes voltage drop and decrease in efficiency. Moreover, compensation method is proposed to reduce this voltage drop. Verification by numerical calculation shows that the proposed method can cancel almost all the voltage drop.,,,, Keywords: dynamic wireless power transfer, electric vehicle, cable, voltage drop, compensation for voltage drop Fig.. The schematic diagram of the system Fig.. A structure of dynamic wireless power transfer system. () () (3) Fig. (4) The University of Tokyo. 7-3-, Hongo, Bunkyo-Ku, Tokyo, Japan (5) (6) [ IV - ] C 07 IEE Japan

2 . Fig. AC bus k k V I S Fig. 4. Fig. 3. The position of two lines The equivalent circuit model of line impedance Z(k) = V I S () Fig f [Hz], c[m/s],λ[m] λ = c f 85 khz f = 85kHz,c = m/s λ 3.5km m m 3 () Litz 3 khz Litz Litz (8) (9) R line L line 3 C line [F/m] Litz r d ϵ r Fig.3 C line = πϵ r log ( d r r ) (3) C e [F/m] [ IV - ] C 07 IEE Japan

3 D D (3) πϵ r C e = log ( ) D r r (4) tan δ C ϵ r V[V] P c P c = πcv tan δ f (5) Fig. 5. ladder circuit network considering line impedance Table. The size of capacitance Parameter Capacitance Reactance C line 40pF 46.8 kω C e 40pF 46.8 kω R c R c = V (6) P c = πc tan δ f (7) Fig N Fig.5 N n k n K n K = [k k... k N ] (8) t V t P out (V t ) η (9) Fig. 6. The equivalent simple circuit model of line impedance η = t P out (V t ) VR(I S ) P line P idling P lineloss (i) P idlingloss (i) i P line = P lineloss (i) (0) i (9) P idling = P idlingloss (i) () i t 4 d 3r D.5r (3)(4) 85kHz Table. Fig Fig.5 Z in (n) 3 [ IV - 3] C 07 IEE Japan

4 Fig. 7. The equivalent circuit of PS Z in (N) = Z(k N ) + Z line () Z in (n) = + Z line ( n < N) (3) Z in (n+) + Z(k n ) Z in () P in V /R in () n V n V = Z in() Z line V (4) Z in () V n = Z in(n) Z line V n ( < n N) (5) Z in (n) n Vr n Vr = R line Z in () V (6) Vr n = R line Z in (n) V n ( < n N) (7) P line P idling N Vr i P line = (8) R i= line V i P idling = R (Z(0)) (9) i t 5. PS 5 PS 5 PS PS Fig.7 V ω L m R, R, L, L, C, C R L I, I Z L = jωl + R, M = ωl m, Z = jωl + jωc + R + R L V 0 = Z L jm jm Z I I (0) I, I (),() V I = () Z L + M Z jmv I = Z Z L + M () I S (3) I S = I + jωc V (3) Z(k) = + (4) Z L + M jωc Z 5 PS Q s = ωl /(R L + R ) k (5) C C L (7) C = C L (5) L Q sk 4 + C Y S (6) C 0 C (8) Q ωl R C (9) Y S = jωc + (6) jωl + R R = + j{(ω L + R )ωc ωl } (ωl ) + R 0 = (ω L + R )ωc ωl (7) C = ω L ( + ) (8) Q C = (9) ω L 4 [ IV - 4] C 07 IEE Japan

5 (a)system efficiency (b)transmitter voltage Fig. 8. Comparison between simulation results and numerical calculation results Table. The values for simulation Symbol Parameter Value V RMS input voltage V f Input voltage frequency 85 khz k 0 Coupling coefficient 0.0 R L Load resistance 3 Ω L Primary self inductance 6.58 µh R Primary coil resistance mω C Primary capacitance 533 nf L Secondary self inductance µh R Secondary coil resistance 60 mω C Secondary capacitance nf N Number of paralleled primary coils 0 Fig. 9. The circuit diagram with compensation capacitance (a)system efficiency (b)transmitter voltage Table 3. The values of line impedance Case L line [µh] R line [mω] C comp [µf] Case Case Case P out (30) P out = R L MI R + R L = 5 M R L Z L + M Z V (30) Table. k 0 0 n k i = 0(i n), k n = k 0 K n K n = [ k ] (3) k ()(3) 0.06mm 60strings Litz Table.3 case case case3 5 3 Fig. 0. (c)ratio of line loss numerical simulation results LTspice case,3 Fig Litz C comp Table.3 C comp = ω L line (3) Fig [ IV - 5] C 07 IEE Japan

6 Fig.0 η V t P lineloss /P in Fig.0(c) Litz 0.5 Fig.0(a)(b) case3 50 case w/ comp Wireless Charging, IEEE Trans. Ind. Electron., vol. 63, no. 0, pp , T. Takeuchi, D. Kobayashi, T. Imura, and Y. Hori, Fundamental Experiment on Dynamic Wireless Power Transfer Using Double-LCC, IEICE tech report, pp Chwei-Sen Wang, Oskar H. Stielau, and Grant A. Covic, Design Considerations for a Contactless Electric Vehicle Battery Charger, IEEE transactions on industrial electronics, Vol. 5, No. 5, pp , A.D. Podoltsev I. N. Kucheryavaya B. B. Lebedev Analysis of effective resistance and eddy-current losses in multiturn winding of high-frequency magnetic components IEEE Trans. on Magnetics vol. 39 no. pp H. Rossmanith M. Doebroenti M. Albach D. Exner Measurement and Characterization of High Frequency Losses in Nonideal Litz Wires IEEE Transactions on Power Electronics vol. 6 no. pp PS L. Chun R. Ganesh Jagendra J. T. Boys G. A. Covic Double-coupled systems for IPT roadway applications em IEEE J. Emerg. Select. Topics Power Electron. vol. 3 no. pp Mar. 05. X. Zhang, Z. Yuan, Q. Yang, Y. Li, J. Zhu, and Y. Li, Coil Design and Efficiency Analysis for Dynamic Wireless Charging System for Electric Vehicles, IEEE Trans. Magn., vol. 5, no. 7, pp. -5, S. Wolterink, P. Bauer, and S. Member, High Range On-line Electric Vehicles Powered by Inductive Power Transfer, F. Lu, S. Member, H. Zhang, and S. Member, Output Power Pulsation for Electric Vehicles, IEEE Trans. Ind. Electron., vol. 63, no. 0, pp , S. Zhou and C. Chris Mi, Multi-Paralleled LCC Reactive Power Compensation Networks and Their Tuning Method for Electric Vehicle Dynamic 6 [ IV - 6] C 07 IEE Japan

D IEEJ Transactions on Industry Applications Vol.137 No.11 pp DOI: /ieejias Circuit Analysis and Characterization of Contactles

D IEEJ Transactions on Industry Applications Vol.37 No. pp.85 86 DOI: 0.54/ieejias.37.85 Circuit Analysis and Characterization of Contactless Power Transfer System with Variable Impedance Jun Yamada, Student