CA2147259A1 - Contactless battery charging system - Google Patents

Abstract

A contactless recharging system (10, 100, 200, 300) and method for recharging a battery storage device (12) onboard an electric vehicle (14, 106, 302) has a primary converter station (20, 102, 202, 304) for converting power from a power source (16) into high frequency power at a selected charging rate. The vehicle has a secondary converter (32, 150, 306) for converting high fre-quency power into DC power to charge the battery. The converters are coupled together by a contactless coupling of a conductor loop (30, 104, 308, 420, 430) and a coupling link (25, 25', 110, 205, 310, 310', 310") forming a coaxial winding transformer. The coupled link and loop carry a communication indicating the selected charging rate of the battery. The link has a magnetic core (40; 50; 112; 318, 320, 322 and 324) and a core-mounted conductor (45; 55; 120; 326, 328, 330 and 332) at least partially sur-rounded by the core. The core-mounted conductor selectively at least partially surrounds a portion of the loop to transfer power therebetween. The core-mounted conductor is coupled to one of the converters, and the loop is coupled to the other converter.

Description

~0 94/09544 -1- 2 1 4 7 2 ~ ~ Pcr/us93/0997s CON'rACTLESS BATTERY CHARGING SY~ ;M
d of the In~nlioll The present invention relates generally to battery le. I~ging systems, and more particularly to an improved cnnt~tle-cc battery l~h~u~iug system, such as rnay be used in 5 electric vehicles and the like to enhance safety, reliability and user convenience.
Given the ~ r . ' proliferation of electric vehicles, it will be n~ to have a distributGd and ~ea -'ly ~li~ ~_hiuyl~g confil5~ 'nn, located at, for instance, the vehicle operator's IG '-' -~, place of business, parking garages, recharge stations, and the like. In ~ .,g the ~li~ system that willbe , ' ~ on a large scale 10 basis, the i~. consid~,. . are initial cost, operating cost, reliability, and user safety.
Using currently available technology, the most likely a~ ua~h for battery IGcl~ g would be a conductor metal-to-metal contact in a plug and socket arrangement supplying Clt~ .y current (AC) or direct current (DC) power to the vehicle. Charging would be acco~li~hcd by the vehicle operator physically making the cnnn~tinn between the 15 vehicle and the power supply outlet. Given the high currents and voltages required to recharge electric vehicles for op~rnti.-n, this cnnn~tion by an untrained and l-n~l~illecl operator could create I - ~ hazards, particularly if no means were provided for a quick n- ~ "r d;- ~n~ l of the vehicle from the charging source. Fu~ e, the need for providing charging ol,~oli ^c at distributed locations as '-tn~3 above, would be i r ~ t~A by these 20 same cnn~rnc Other dl....: ' include higher curb weight for the electric vehicle, wear and tear of high current exposed contacts, as well as the safety issues, particularly under fault modes and owner misuse. More i~.i Iy, the public perception of reduced safety with live high power contacts may adversely impact ~u~lu ~ e of electric vehicles. The high 25 pl~* li~y that ' ds and safety o~ onC, such as Underwriters Laboratories, may require galvanic isolation between an AC power source and the vehicle battery, raises the prospect that e~pensive isolated cou~_,t~ would be necded.
Thus, a need e~ists for a cnntn^tlP-cc battery l~chsrgmg system, such as may be usGd to provide power to electric vehicles, which is directed toward ove.~ullllg, and not 30 s ~^epti~'^ to, the above l ~ nc and disadvantages.
S~ ~ of the In~nliu~t According to one aspect of the present invention, a cnnt~ tl~occ l~~l~.~uug system and method for ,~ch&l~siug an energy storage device onboard an electric vehicle has a primary converter for converting power from a power source into high fiG lu~n~ ~ power. A
35 ~cond..l~ converter on board the vehicle is coupled to the battery for converting high rl~u~n. ~ power into charging power supplied to the energy storage device. The primary and secondal~ cuuie.~ are coupled together by a cnn~^tle-cc coupling of a c~ or loop and a coupling link forming a c~a~ial winding t ~ ,u~,.. The coupling link has a magnetic core W094/09544 23 ~rl253 -2- PCI/US93/0997 and a core-mounted c~ .r at least partially surrounded by the magnetic core. The core-mounted conductor selectively at least partially surrounds a portion of the conductor loop to transfer power 1' ~l~een. The core-mounted cn~ tor is coupled to either the primary or the ~Il~l.y converter, with the conductor loop being mounted to the other of the primary 5 and the secondary c.,ll~rc.t~
An overall object of the present invention is to provide a battery t;ch~ g system and method for use in l~ch4pillg electric vehicle batteries.
A further object of the present il.~_.tion is to provide a coupling link for coupling an electric vehicle with a power source.
An r~lAiti~ -I object of the present invention i6 to provide a battery hglllg system which enhances user safety, increases convenience, decreases lech~ g time, and hl. l~s battery recharge efficiency and battery life over earlier systems.
Another object of the present invention is to provide a battery .ccl~;mg system for electric vehicles which has high reliability and may be installed and used at a 15 reacnnal~le cost.
The present invention relates to the above features and objects individually as well as collectively. These and other objects, features and ~ . of the present invention will become apparent to those skilled in the art from the following description and drawings.
Brief Description of the Drswin~s Fig. I is a partially ' c rear elevational view of one form of a c~ tP~tlrcg l.~l~l~h g system of the present invention for l~1~5hlg an energy storage device, such as a battery on-board an electric vehicle;
Fig. 2 is a radial sectional view of one form of a: r ~1 e coupling link of Fig. l;
Fig. 3 is a radial sectional view of one form of an alternate separable couplinglink of the present invention;
Fig. 4 is a ' - block diagram of one form of the c~n-Pctl~-cc rechaiging system of Fig. 1;
Fig. 5 is a partially s-' c rear elc '--n~l view of an alternate form of a 30 co~ tl~cc r~l~.~;hlg system of the present invention;
Fig. 6 is a radial sectional view of one form of a separable coupling link of Fig. 5;
Fig. 7 is a crL~--- c block diagram of one form of the crln~Pctlecc l~chalglug system of Fig. 5;
Fig. 8 is a partially s~h~ ic rear cl~ nq1 view of another alternate form of a cn~ thcc ~ il-g system of the present il-~ r~n Fig. 9 is a partially c5h~onr. ~ic and partially cutaway rear elevational view of an irn-l alternate form of a cnntprtlr-cc 1~ ' ~mg system of the present invention;

2 1 ~ 7 2 ~ ~ PCI`/US93/0997~

Fig. 10 is a partially h c top plan view of one form of a s r ~ flc coupling link ~u~ uudillg one forrn of a cnnA~ctor loop of Fig. 9;
Fig. 11 is a cross-sectional front el~ ~ ' nn view taken along lines 11--11 of Fig. 10;
Fig. 12 is a ,~ c diagram of a fluid cooling system for use with the link of Fig. 10;
Fig. 13 is a cross-sectional front elel t:nn viewof the link shown open for receiving the loop of Fig. 10;
Fig. 14 is a front elevation view of one form of an alternate embodiment of a coupling link of the present invention shown open for receiving the loop of Fig. 10;
Fig. 15 is a front elevation view of one form of another alternate embodiment of a coupling link of the present invention shown open for receiving the loop of Fig. 10; and Figs. 16 and 17 are front elevation views of the link of Fig. 10 shown ~ulluuu.lillg two alternate forms of conductor loops of the present invention.
Detailed D~ , of the Preferred Emb~d-Several alternate emhoAil-~P.ntc of a cnntsrtl~o-cc charging system are illustrated below for charging an energy storage device. The emh(!Aim~n~c are illustrated in terms of charging a DC battery 12 on board an electric vehicle. It is apparent to those skilled in the art, that the cnntsr~ cc charging systems described herein may be used for charging other energy storage devices and - ' s, such as mobile robots Ind space vehicles.
First Embc l Fig. 1 illustrates an Pn-hoAimPn- of a c~ntsrtl~-cc ~ ;hlg system 10 cuu;,llu~kd in ~c4. ' -~ with the present invention for supplying charging power for 5h~g an energy storage device, such as a battery system or battery 12 of an electric vehicle 14. While the energy storage device is illustrated for si~licily as a battery 12, it is apparent that the l~l~u~;hlg systems described herein may be used to recharge any other type of energy storage device, such as a ~ Al~c~ing magnetic energy storage device, an el~;llu ~ - lic flywheel,and the like. It is apparent that the electric vehicle embodiment is provided merely by way of e~ample herein and this system may be used with any electrical load having internal or onboard energy storage capability.
The l~L,u2 hlg system 10 receives power from an electrical power source 16, via conductors 18. The power source 16 may be a single phase or a polyphase ~It~ ting current (AC) source or a direct current (DC) source as desired for a particular application. A
primary cuu~ ,r, such as a high fl~u_ncy current source converter 20, converts power received from the source 16, such as AC power at a line freL~u~u~ (60 Hz in the United States) to a high fl~u~,u~, for instance, on the order of 2-50 kHz. The u~. nn of the various .~ , of the l~l~ging system 10, such as primary converter 20, is .1;~ A, WO 94/09~S44 ~ 7 ~ 5 9 PCI /US93/0997 further below after an overview of the operational interrelationship between the various co~,u~ .
The high f.~u~.u~ ~ AC power from the primary converter 20 is delivered by a tethering cùu.lu.ilor or tether 22 to coupling means, such as a coupling sheath or link 25 5 described further below (see Figs. 2 and 3). The link 25 is configured to clamp onto a secondary power pickup conductor loop 30 mounted to vehicle 14. The term ccnt-qrtlP-c.c ac used herein means without any electrical contact between two conductors, other than magnetic coupling between the condu.;tc,.~. When link 25 is coupled with conductor loop 30, the structure thusly forrned is referred to herein as a coal~ial winding t. '(Jllu~,. (CWT) and may 10 be analyzed using various theoriec firom the current-t.~ru~ r field.
The secondary loop 30 is coupled to a s~onda- y converter 32. The converter 32 convertc the high f~G4u~uc~ AC power received from the primary converter 20 via link 25 and loop 30 into charging power, which is used to charge the vehicle battery 12. This charging power may be either AC or DC power or a colul,.n~.lion thereof, such as AC power15 ~-y~ ~d over a DC waveform. The particular type of charging power used in a given on is dictated by the energy requirements of the particular energy storage device being ._Lu ~d.
The rech~;iug system 10 may be operated by a method similar to a conventional gas pump at a roadside service station. The vehicle driver parks vehicle 14 20 adjacent to the primary co...r~,.le. 20 and couplec the tethered imk 25 with the power pickup loop 30 mounted to vehicle 14. After rnanually clqn~riny link 25 to the vehicle power pickup 30, the primary, ;e.lel includes control logic which verifies that the circuit is correct before begi ~ing delivery of the high fiGuu~ucy AC power. The high fiGuu~u~;y AC power received by pickup 30 from link 25 is co..~_.lGd into charging power by the secondary converter 32 and 25 used to charge the battery 12.
Referring to Fig. 2, an illustrated PmL~imPn~ of the coupling link 25 is shown coupled with the cnn~ rtr~r loop 30 to form a CWT. The link 25 includes a ~ LIe magnetic core 40, illllc~rP~e~ as being split into two core portions or SG~ tS 42 and 42', which are pivoted together at hinge 44. The core sPgmPntC 42 and 42' may be joined by a 30 variety of other means (not shown) and openable by motion in other manners, such as by rnotion rather than pivotal motion, or some coulL ' nn thereof. Furthermore, the coupling of link 25 with loop 30 rnay be P~romplicLP~I by an opening type of motion by loop 30 (not shown) to receive link 25.
The link 25 also has a core-mounted con-lu-,lor 45, illustrated as being split 35 into two conductor portions or sc~5 u~u~ 46 and 46'. In the illustrated P,mL~irnPnt, c. udu~lu~
45 is a solid tubular member, such as of copper. However, it is apparent that a plurality of discrete c~ ^tors may be used to form c~n~ rt~r 45, for instance, with the discrete co~du~ evenly distributed about the inner surface of the core to provide a ~Jb~ ;qlly ~094/095 5 ~ I17259 unifonn distribution of current. Each of the conductor segments 46 and 46' are carried by core se~ t~ 42 and 42', respectively. With link 25 closed, as shown in Fig. 2, there are two mini~l air gaps where core Y~, 42 and 42' abut. Also with linlc 25 closed, conductor 45 defines an interwinding region 48 within link 25. With the cn..~l~J l~,r loop 30 located in the S ~Ji.. g region 48, an interwinding space S _ay be defined as between the conductor loop 30 and the core-unted cn~ t~r 45.
When the link 25 is energized, i - .c current (not shown) flows in opposite directions through the con.lu-;lvr loop 30 and the core-mounted conductor 45. That is, when the current is flowing in cnnAuctr,r loop 30 in a direction into the paper, current is 10 flowing in cnnA~rtor 45 in a direction oriented out of the paper.
While omitted for clarity in the Fig. 2, the cr~ ct(-r loop 30 is an insulated conductor having an inner portion of a conductive material surrounded by an outer layer of an insulative material. Similarly, the conductor 45 is also of a conductive material surrounded by jnelll on (not shown). The c~ Qr 45 includes jnclll on adjacent the interwinding region 15 48 and between the cvu.lu.;ti.le portion of conductor 45 and the core 40. The core 40 also hac jnc~ inn (not shown) around its outer pe"~h~-y. ~AAitinn~lly, the core 40_ay have an outer covering (not shown) of a resilient, and durable material to protect the link 25 from damage during use.
Referring to Fig. 3, an alternative emhoAim~nt of the link in Fig. 1 is shown 20 as link 25'. The link 25' includes a ~,.ual '~ or split core 50, ill~strated as having two core 52 and 54. The core segment 52 carries a core-mounted C~ndU~ 55, illustrated as a C-channel member, for instance of solid copper. It is apparent that cn~-A- ~-~u, 55 _ay also be cv~lise~d of a plurality of discrete members as described above for cn~ 45 of Fig. 2.
Referring to Fig. 1, the core-unted cnnA~ctnr 55 _ay be coupled to the pri_ary converter 25 20 by a cnr.-l~ (not shown) within tether 22.
The core segment 54 is preferably mounted to the vehicle 14 on a ~.
basis. Core ~ t~ 52 and 54 are each configured to abut one another to form a flu~c p~
of magnetic _aterial having two mini~l air gaps where core ~ 42 and 42' abut. When the two core sc~;.--- --~ 52 and 54 are brought together into -b~ t, this flw~ path surroun~c 30 the cr~nA~rtor loop 30.
The illustrated condu,lur 30 passes freely in front of the core segment 54, e~rt~nAing through the interwinding region to ~ nting points (not shown) on the vehicle 14, and then electrically coupling to the co..~..ler 32. Alternatively, the cr..~ lul loop 30 m ay be supported from core segment 54 by a support (not shown) of an insulative _aterial. When the 35 core sc~ 52 and 54 are drawn together as shown in Fig. 3, they define lL~ l~t~ an ~.-uJil~g region 58 ~ ~lly ~u~vullJing an a~ial portion of the con~lu~lvr loop 30.
In o~. nn, a ' l latching . ' or device (not shown) _ay be used to secure the two core ~;..- --'~ 52 and 54 together. However, when energized, the two W0 94/09~44 ~ 9 -6- PCI /US93/0997 core scO~ t~ 52 and 54 are adv O_~usly drawn together by the ~tPn~-fgn~ magnetic forces, as are the core ~o..~ 42 and 42' of Fig. 2, when the net currents flowing through the 30 and 55 are opposing. In other words, when the flw~ in each core segment is flowing in the same direction, these magnetic forces will draw the core ~O..~ together.
5 Conversely, when the flu~es in each core segment are opposed, the core ~_O.-~ will be repelled from one another. These attractive forces adv g~u~ly assist in ini~i ' g, and g the coupling joint of the core ~ O,-~ , and thus, of the condu. tor s~O.. -.
Funh~ e, by using opposing flu~ flows, the forces may be used to repel the core scO~,It~
and provide for controlled dPCourling of the charging link.
10 Fig. 4 illustrates a method of o~ nn of primary convener 20 and s~ond~ y converter 22, with the link 25 and conductor loop 30 shown ~hPmo~ lly. The appl~described herein uses power electronics to optimize system pe.l~ and to meet currently realized practical design considerations. In the illustrated embodiment, the power source 16 supplies power to primary convener 20. If the power supplied by source 16 is AC power, 15 illustrated as three-phase AC power in Fig. 4, the convener 20 includes a primary power electronic input stage 60. The primary input stage 60 may be a conventional thyristor rectifier bridge using Ih~ f~ , gate turnoff thyli~ (GTO's), and the like to conven the received AC power into DC power.
At power levels of cc,~.- ial interest, such as greater than one ll,Co.... (1 20 MW), for large vehicles or shon recharge times, or at levels of 1-10 kW for 1 g_r vehicles, one cost effective 1, r~ involves using a power elr~ll~,l,ics convener with a thyristor rectifier as the primary input stage. For the lower charging levels, a voltage source convener with ~ I devices may be a preferred f ...l~-f;.., ..t The rectifier provides DC power to a choke coil 62 which together serve as a DC current source for a high frequency convener 64.
25 The high frequency convener 64 may be any type of invenor capable of providing a high frequency output, such as a current source invertor. The convener 64 has a plurality of ng devices arranged and controlled as known in the an to provide a desired high L~u~ output to link 25. If the power source 16 supplies DC power to primary convener 20, the prirnary input stage 60 may adv~tAO2~u~1y be omitted.
The primary input stage 60 and the high frequency c~).. ie,t~,, 64 each may receive respective control signals 66 and 68 from a control logic unit 70, which may be a ~ luccssor based device. The control logic unit 70 receives various operator inputs 72, such as a ~begin cc~nflllc~ing~l or ~on~ switch signal.
Control power 74 is provided to the control logic unit 70, such as DC power 35 required for a digital control system. The control logic unit 70 may also receive feedback signals 76, ~ fing signals from current ~ ' ~ (not shown) ~r ll~ lg charging at the battery load 12 and the output of the high L~_.u~ convenor 64 as applied to link 25; a signal ~094/09544 2i~7,~59 PCr/US93/0997~

from a .ll~ us~ilch sensor (not shown) inAi~ ' v that the link 25 is coupled to the conductor coil 30, ir.A; g a ~ready to charge" signal; and the like.
The control logic unit 70 may generate a cc..------~ on or control signal 78.
The control signal 78 may be sent to the s.xond&, ~ converter 32, or converter 32 may provide S a feedback signal to control logic 70 via the c- on signal 78. The ~ n or control signal 78 is typically sent at a much higher f.~u~.u~ than the power provided by high f _Iwn~ converter 64. For e~ample, the control signal 78 may be on the order of a g ~ f ~u~ signal. Such l. of control signals is routinely accomplich~A by utilities ~ ,............. ;lI;ny control signals over power 1.~ Iines.
The s~on~ converter 32 has a sxonda.y power cl.~l.u.. c input stage 80 which receives power from con.luulor loop 30. The secondary input stage 80 converts the high fi~u~ l power I r ~cid through link 25 into AC and/or DC power, or a cO~ n ofAC an DC power, as dictated by the needs of the battery 12. The required output power provided by the primary input stage 80 is filtered by filter 82 then supplied as charging power 15 to the battery 12. Of course, if the energy storage device requires AC charging power, or a cc,.-l.:A~ n of AC and DC charging power, the power electronics of the s~cou~l~ input stage 80 may be modified as known in the art to provide the required charging power.
The ~u ~.y converter 32 may include an optional power cnnAilion~r 84 which receives power from the output side of the secon~.~ input stage 80 via conductors 86.
20 However, it may be ad~ g~uc in some applications to tap tne high f.~..~ ;y power received by conA~c~or 30 before rectification at the input side of the secun~ y input stage 80.
The power cu.~A;li~ 84 provides power as required by other loads 88 which are typically mounted on-board the vehicle 14. To serve the needs of the other loads 88, the power cn~ r)nPr 84 may be a bridge rectifier for a DC output, an AC/DC controlled convertor for 25 variable DC output, or an AC/AC ~ ~_loco..~-"ler for variable AC output. The other loads 88 powered by c~ nAilir~n~r 84 may be AC or DC loads, or some cc,--~ ;rn thereof.
For e~cample, if the vehicle 14 is a motor home, the o~p- ~ may wish ~o watch television, cook on an electric stove, and/or use other electrical e,rl ~~~ in the motor home while the motor home battery 12 is being charged. Other loads 88 may also include:
30 auxiliary relays for the battery ~hal2~il-g system 10; an electronic latching ---~ ", insuring that link 25 remains closed around c~ c-r 30 during ch~u~ , a battery ~u..itu~h~g system to monitor the charging level of battery 12, such as a state-of-charge indicator; and a venril (~n fan for a battery 12 enclosed within a small confined space.
In ._h~.-.g system 10, control of the power delivered to the battery 12 may 35 be achieved from the primary convertor 20 without feedback if there are no other loads 88.
For e~ l 'e, the ~un~.~ co..~ llul 32 and battery 12 may be monitored and controlled by the co...--~ -';on signal 78. Signal 78 is injected into the core-mounted c~onA~ct( r 45 and induced into the secondary con~nctor loop 30 of link 25, which serves as a carrier. This W O 94/09544 21 4 ~ 2 ~ ~ -8- PC~r/US93/09975 alternate embodiment of l~cha~gLug system 10 has the least cost for the mobile e~lul~Lu~Llt of the embodiments dicc~lccp~A~ herein. AAAitionqlly~ the primary convertor 20 may deliver power in an open loop mode, that is without feedback, by controlling current flowing in the primary core-mounted c~ nAurtQr 45. Monitoring, control and protection signals may be achieved 5 without the need for a separate control wire coupling between the primary convertor and vehicle 14.
The ,~LB.~ Ig system 10 may also handle multiple loads, which appear to the primary convertor 20 as series j'~ r~-~ The COL~ UI 20 regulates the current, and voltages change to &cco -~ ~ any changes in the bsttery load 12 and other loads 88. Such 10 a system may have some on-board control of the current delivered to battery 12 using the sGcond...y converter 32. Even for a singular energy storage device, on-board control, in addition to the main control logic unit 70, is preferred. This is a preferred .1 ' on because it provides greater fle~cibilityand the ability to qrrc -' diverse battery types, G ~,~ 'onc, and e~ ~eçifi~ on variations.
The advantages of the Ic,l~l~Lllg system 10 include having a very simple structure illCOlr~l ' 1 into vehicle 14, that is, a power pickup loop 30 and the converter 32.
Thus, system 10 can be , ' ~ with mini~l cost and complexity, either as a retrofit or in new vehicles. Further, this structure may be standardized for various vehicle models, and may be adapted with a ~ ---- investment by the vehicle rnqnl~fqrhlrer and owner.20 AAAi~ionqlly~ the control and protection features are provided by the stationary e~;p~ that is, by the primary converter 20. The owner of the stationary converter 20 provides -- and updates for the control e4u,pL~.-t. Furthermore, this system may be readily accepted by the public, due to its close analogy to the conventional gas pump station.
One possible d,..~.l,~ to system 10 over the other PmkYiimpn~c diccl~ccp~
25 further below is that each stationary power supply location may require revised control logic and updates as technology evolves. With the system 10, the supplier of the energy has a -.. investment in the converter and control logic. ~AAi~ qlly, system 10 is less fl~r~ible re~5~dLug the vehicle owner's choice of recharge lr ~ fmc, unless the industry and cuLuL~-- ,al infi~tlu~ lUIG cc . '-~ ly standardize on this system. Furthermore, the operator of the electric 30 vehicle 14 is more depPnAPn~ upon the owner and operator of the converter station to provide a proper recharge strategy than in the system of Fig. 5 described below. Thus, a conflict may evolve if vehicle e~l ~p- - ..1 is damaged or if battery life was found to be shorter than P~t~Pd Second Fmhod Referring to Fig. 5, an alternative Pm~imPn~ of a con~PrtlPcc l~hhr~;Lllg 35 system 100 of the present invention is shown. In the alternate charging system 100, an alternate prirnary ~ ~,tu, 102receives power from the power source 16via co~lu~lu,~ 18.
While the c~nA~ctQrs 18 are illustrated for a three-phase AC power source, it is apparent that DC or other polypbase AC power may also serve as a suitable power sourcG 16. The primary ~9~ 21 ~ 725g convertor 102 receives and converts power from source 16 into high frequency AC power as described further below, and provides a high frequency output power to a conductor loop 104.
The op~" t;nn of the various c~ of the ~~Lu~;iug system 100, such as primary cc,u~_,t~, 102, is .1;~ ~ further below after an overview of the o~, ~n~l interrelationship S be~ween the various ~~, ' Vehicle 106 has an energy storage device as described above for vehicle 14, and referred to for simplicity herein as battery 12. However, vehicle 106 differs from vehicle 104 in the manner of control and coupling with the primary converter. Rather than having only a conductor loop 30 mounted on the vehicle (see Fig. 1), vehicle 106 has a tethering 10 cc,uJu 1~, or tether 108 which couples coupling means, such as a coupling sheath or link 110 to the vehicle 106. The tether 108 may be as described above for tether 22 of Fig. 1, and the link 110 may be cou~llu~led as described above with respect to Fig. 1, with the following differences.
The link 110 has a ~ le core 112 with separable core portions or 15 ~ 114 and 114'which may be pivoted or otherwise joined together as described above with respect to core ~tu~nl~ 42 and 42' of Fig. 2. Here, the core ~ 114 and 114' are shown pivoted together by a hinge 116.
The link 110 has a core-mounted cnn~luctor 120 split into two core portions or 122and 122'.Each ofthe conJu;l~- sc~ 122and 122'are carried bycore 20 sc~ 114 and 114', respectively. With link 110 closed, as skown in Fig. 6~ there are two minimal air gaps where core sc~.~t~ 114 and 114' abut. Also with link 110 closed, c~ n~h~c~r 120defines an interwinding region 124withinlink 110. With the c-~ -. Ioop 1041Ocated in the ' wuuJIug region 124, an ~h,~ulding space S' may be defined as between the co---loop 104 and the corc u~ ~ c~..du lor 120.
Referring to Fig. 6~ the method of ~ ' g link 110 differs from that of link 25 and 25',in that the coaxial winding l. r (CWT) formed by the coupling of link 110 with couJu.ilu. Ioop 104 has power flows different from that of the links 25 and 25' showL in Figs. 1-3. Spe~cifi~ slly~ the co ~ ., loop 104 serves as the primary con~ r in the power flow system. The core-mounted . ~uct~)r 120 serves as a s~ondd-~ cf~ nr, receiving 30 power through i~l--cti-n from the conJu.,lor loop 104. While link 110 is shown for the purposes of illu~ as being similar in c~ ~l~u- Iion to link 25, it is apparent that link 110 may also take on a configuration as shown for Fig. 25'. Fu-lLe,u o-c, other g~u._l-ic forms are also possible for the coaxial winding tl~U~lUU~ to transfer power between a core-mounted c~ or and a loop CJ~ t-, An illustrated ~ for the cnn~srtl~-cc I~L&gillg system 100 of Fig. S
is shown cc~.. .. ~i- Llly in Fig. 7. Power is received by primary co ~..lur 102 from power source 16 which may be as described above with respect to the system of Fig. 1. Power source 16 supplies a primary power electronic input stage 130, which may be as described above for WO 94/09~44 2 ~ ~7 ~5 9 -lo- PCI/US93/09~7~

the primary input stage 60 of Fig. 4. If DC power is supplied by source 16, primary input stage 130 may be omitted.
In the ill ^d e~ample, primary input stage 130 converts power from source 16 into DC power which is supplied to a high L~u~ y converter, such as a series 5 resonant high L~u~uc.y converter 132. A ml ,r 134 is used to provide a constant DC
voltage to inverter 132. In the ill ~ ~ .,...1~1;,._..-, the high L~u~ y series re,onant inverter 132 is shown as having four switched legs 136a, 136b, 136c and 136d. Each inverter leg, such as leg 136d, has a diode 138 coupled across the collector and emitter of a 1l2u~i~lv 140. Other power electronic devices may also be used in place of switch 140, such as lh~ u~
10 or gate turnoff IhyliDlv~ (GTO's). The high L~u~ output of inverter 132 is supplied to a resonant ca~)dcilor 142.
Resonant converter topology is known in the art, for example, as described in an article by F.C. Schwarz and J.B. KlssccPnc entitled ~Controllable 45 kW Current Source for DC Ms^hinPc. ~ IEEE Tr~-^s^~innc IA, Vol. IA--I5, No. 4, July/August, 1979, pp. 437 444.
15 The use of resonant inverter topology advantageously allows the c ,--r ratings for the primary and sccond~y converters to be .~ rd at an ecnA -;r level. The resonant capacitor 142 serves to supply the volt-amperes-reactive (VAR) ~uL~ u~,nt~ of the cnn.lllctor loop 104, so the inverter 132 need only supply real power (watts) as needed by the system.
The second concern governing the choice of cvuie.t~, topology is that inverter switching at 20 high L~ - -es are normally limited by the ~ Ling losses within the devices. The use of resonant topologies allows device switching at near zero voltage or near zero current crossing points, which results in cignifi~ ~y lower ~ Lug losses and the ability to obtain higher fresluPnriPc Thus, the output of pri ry converter 102 is supplied to cC~n~ ctor loop 104 25 and by ' : nn to the corc ~ d ~--^tnr 120 of link 110 (each of which are shown E~ lly in Fig. 7). Referring also to Fig. 5, power received by link 110 is delivered via a conductorwithintether 108toasecondarycvu~c,lel 150mounted on-board vehiclelO6. ~he cvu~c,t~,r 150 has a ~vudal ~ power clc~;tlunic input stage 152 which receives power from the core-mounted C~ J~Or 120and rectifies it into charging power supplied to filter 154. The 30 sccond~l ~ input stage 152 and filter 154 may be as de-sc~ibPd above for ~cvu~u,~ input stage 80 and filter 82"~,~lrully, as di-^r~CC~d with respect to Fig. 4. The filtered rectified charging power is then supplied by S'XVU~I,~ converter 150 to battery 12 for ._I. u~uug.
The S3Cvu~l~ cvu~,,t.,, 150 may be modified as known in the art to provide other types of charging power to the energy storage device. If desired, the &~ ' .~ charging 35 current can be cn~ innPd with a fi ~^~u~;r change, voltage change, or phase change. For , the s~cond~.. y power el~ v~ùc input stage 152 may be a bridge rectifier for DC
output, and AC/DC controlled cvu~ ,. for variable DC output, or an AC/AC ~ ~.lvcvu~erter WO 94/09544 21 ~ 72~ 9 Pcr/US93/0997~

for variable AC output. Such an , ~ on, with at least some control on both sides of link 110 is a preferred embodiment, as well ac for a DC charging current PmhoAimPn~
The secondary cc,~-,.t~. 150 may also include an optional power cnn~litionPr 156, tapping a portion of the DC power rectified by the s3~d&ly input stage 152 via S conductors 158. In some ~Irl nnc, it may be adv g~ for power cnnAitionPr 156 to receive high fil I .r power directly from cnnAuctnr 120, prior to ploce~illg by the secondary input stage 152. The power cnnAitinnPr 156 provides power to other loads 160, which may be as d~l.l,cd above for the other loads 88 of Fig. 4.
The ~..~.~ ,t~,. 150 includes a control logic unit 162, which may be 10 of the same type ac deccribed for control logic unit 70 of Fig. 4. The control logic unit 162 receives operator inputs 164,control power 166, and a plurality of feedback signals 168, each of which may be as describe_ above for operator input 72, the control power 74, and feedback signals 76, respectively, of Fig. 4.
The control logic unit 162 may cc 1' with the primary converter 102 15 via a c~ or control signal 170. The c - ~nn control signal 170 rnay operate as described above for control signal 78, with ultra-high fi~..~n~y c~.---~ n and control signals, on the order of ~c ' 1~. The illustrated kilohertz power t. ~ through link 110 serves as the carrier for the c4-- ~ ;on signal 170.
For e~ample, the primary c~ ,.t~,. 102 and the power source 16 may be 20 Il.~mlolcd and controlled with the co ~ on signal 170. The C~u~ u~ on signal 170 can be an analog m~~ -tit n signal or a series of discrete digital pulses induced into the loop conductor 104. Momlululg, control and protection signals between the primary converter 102 and vehicle 106 are adv~thg~u~ly achieved without the need for a separate control wire coupling between the primary c~..~e.t~,. 102 and vehicle 106.
The l~h&l5h~g system 100 having the s~n~- ~ converter 150, control logic unit 162, and link 110 all mounted on-board vehicle 106 has several advantages.
For e~cample, in a method of o,~, nn, the operator of vehicle 106 parks the vehicle adj~ent the primary co..~, t~.. 102 and manually clamps link l lO around the stationary off-board cnn~ rtor IQOP 104. The on-board s~..~.~ converter 150 provides power conditioning, 30 recharge strategy logic, circuit protection and safety permissives.
The P 1~ ges of system 110 are that re of the control system is mounted on-board the vehicle, and thus the vehicle cQuld have c~? bilitj~P5 to adapt to non-standard primary converter power sources at various lc- nnc Fu-lh~.~Qle, less initial investment would be required by a power provider to CIJ..stlu~l a recharge location, that is the primary 35 . ~_.k;l 102 has a more simple topology without the control strategy of the Fig. 1 charging system 10.
AAAitinn~ y~ recharge system 100 would be higb~y suitable for r~llal~illg vehicles during metered parking. The owner of vehicle 106 is in charge of ~e, and WO 94/09544 2 1 ~ 2 ~ PCI /US93/0997 protection of link 110 and tether 108, and they are thus likely to receive better care.
Fu~lh_,~-c, the recharge system 100 requires only minimal stan~Lud nn of iuf ~tlu- lu--;, and gives the operator of vehicle 106 a choice of energy sources.
However, the recharge system 100 will provide a higher initial cost to the 5 owner of vehicle 106, and provide a more complex on-board system l~u~iUg Fu IL~, uo~c~ the energy supplier in charge of the primary converter 102 is more A..~.,~Af.,n proper operation of the vehicle owner's e~ to prevent damage to the primary converter 102. The vehicle 106 must carry the -~Ai~innol weight and provide the r~Ai~jnnol space for the control logic, tether 108 and link 110. ~AAi~jnnolly~ the expensive control and converter 10 ~1";1"~ works under a lower load factor than the r~Lu~ulg system 10 of Fig. 1, that is, the expensive hardware of system 100 is used less per day than the converter cyui~Juh~lt of Fig. 1.
Third Fmho~
Fig. 8 illustrates an automatic cnntartl~-cc rc~,La-~ g system 200 which may operate as illustrated s~hf mo~ically in Fig. 4, and may have a link 25 or 25' as shown in Figs. 2 15 or 3. The recharge system 200 has a primary converter 202 receiving power from the power source 16 via conlu~ 18, as described above for Fig. 1. The electric vehicle 14 of Fig. 8 may be identical to vehicle 14 in Fig. 1, having a power pickup cnnA~ct~r loop 30 coupled with a s~xoJld,.,~ co,.ve,t~, 32. The ~UU~I,~ cou~e,t~,r 32 provides the required charging power to the energy storage device as desc,ibf~d above for the Fig. I embodiment, and is shown as a 20 banery 12 only for simplicity herein.
The primary cou~ . 202 may be as described above for converter 20, but preferably also includes several a~lAitil -l control features. Rather than the tether 22 and rnanually coupled link 25 of Fig. 1, the ~ l~hàr2~ing system 200 has a robotic-type pnci~ir- ' !c arm 204, which may be actuator cF .c' The arm 204 extends outwardly from 25 primary convener 202 to support r coupling means, such as a coupling sheath or link 205. If the link 205 has a ~Ja~alJ~ core, such as core 40 of Fig. 2, the robotic arm 204 may be a reach and grasp type arm which opens the link 205 to receive conductor loop 30 and ~en closes the link around the vehicle-mounted cn~lllctor 30. If link 205 is similar to link 25' shown in Fig. 3, the robotic arm .- ;..~,.;..c position of core segment 52 and cnnA--rtnr 55 with 30 respect to core segment 54 to provide a minimal air gap between the core ~U~,Il~ 52,54.
The method f ~sF "n~ of the c Iink 205 is similar to that of the manual coupling link 25, in that it is also configured to grasp and surround the pickup loop cn~A~tor 30 mounted on vehicle 14. Flux and position sensors, such as Hall effect and optical position sensors, respectively, (not shown) may be mounted on the arm 204 or link 205, or on 35 the housing for converter 202. The position sensors are used in controlling the e~fnFion of arm 204 and link 205 into a grasping engagement with the pickup loop 30. The converter 202 may include control logic to receive signals from the position sensors and use these position ~O 94/09544 -13- 21 ~ 72~g Pcr/us93/0997 sensor signals in moving arm 204 and link 205 into a charging position, and aher charging, to retract to a neutral, starting or "at rest~ position.
A~ 'nn-~lly, flw~ and position sensorD can be mounted to the link and/or to the vehicle 16 to allow feedback of the arm position relative to co~ mrtor loop 30 for ~ . pOcitjoninvp of 5 the arm. Such use of sensors and po~itinnirlg of the arrn 204 in response thereto are well known in the robotic arm art.
In a method of operating the ~ ' ''c re~_L~r~ ing system 200 of Fig. 8, an operator of vehicle 14 parking the vehicle within a bounded area 208 adjacent primary co ~e.lef 202. The vehicle may be reirinnfd by a variety of means, such as with light ' ''~ '.CID, limit switches, or simple r~ce6ses 210 in the psvement 212 adjacent converter 202.
Upon s~tl-otinn, the L _ system 100 ~ om~tirslly rnakes a cn~ts~tl~-cc clamp-on coupling of link 205 with the vehicle-mounted conductor loop 30. The o ~om~ ~ic system 200 allows for erh~~ invP of recharge time and strategy, _nd provides autornatic recharge, monitors and records results, then .l;~rn.~ .; and provides an inrlir~-~ion of comrle~inn to a driver of vehicle 15 14.
The advantages of the ~ ' ' c l~l~l~ing system 200 include the use of an reitinri.lg controller, as is well known in the art of robotic arms, in which ' safety rnay be p~u~ The a ~ 'c system 200 is al_o well suited to fleet u~v. nne where the vehicle parking pattern and operator use are cnnci~ That is, fleet vehicles are typically 20 in the care of a single driver, and are required to be parked in dP-C;V i areas, I-~..de~iug 'c recharge a very attractive option for fleet use.
Fu-lh~..~olc, the 'r system 200 provides a ' ability, cc , vd to the other systerns .I~ ~d herein, to provide high usage rates, to minin~i7P on-going labor, and the ability to provide load leveling or Q '', ~r~ --1jn~ of power delivery as a part of 25 an energy ~ . system to rcduce pe_k power demand, that is, to recharge during the F ' lo_d hours of the utility. FullL~..~IG, the system 200is well suited to ' 'crlig,gnncticc~ trend l,~mlolmg, and a t '- record keeping systems.
Finally, there is minirnal user involvement required with the - 'c system 200, other than parking the vehicle in the d~civ ~ location adjacent the prirnary cuu~r~,.t~.
30 202. However, the ~ '- system 200 is the most comple~c of the three p~u~oxed here. The '- system 200 has a higher initial cost and rnay be sGnsitive to user abuse. At~ i system 200 is highly ~F ~ ~ upon ' lized vehicle ~lin~n~ nc and standardization of the ~ll~e.t~. circuit 32 on-board the vehicle. ~ lly, system 200 is less likely to be , ' ~ for l~ ing at variouc distributive sites.
35 Fourth Fnnb~' Referring to Fig. 9, another ~- ~hO~ t of a . ' I~l~v ug system 300~ Dllu~;~Gd in acco,~ with the present ill~ nn is shown for supplying charging power for l~hal~5lug an energy storage device, such as battery 12 onboard an electric vehicle WO 94/09544 PCI`/US93/0997~
2 1 4~ 2 ~ ~ 14 302. The ~I~Oiug system 300 has a primary converter 304 for receiving power from power source 16 via conductors 18. The battery 12 onboard vehicle 302 is coupled to a ~condaly converter 306. The primary and ~c.ud~.~ converters 304 and 306 may be as described above for primary c~,u~e.t4. 20 and 5 ~ .~ c4,~-,-t,- 32"~,~lively, as shown in Fig. 4.
S Alternatively, the c4u~,.t .~ 304 and 306 may be as described as above for the primary converter 102 and ~ e. ' .~ converter 150, respectively, as shown in Fig. 7.
Preferably, the primary converter 304 includes a recessed portion 308 for receiving a coupling link, such as an alternate e~k~Aim-P-n~ of a coupling sheath or link 310 cor~l.u~;tt,d in ~cco.d e with the present iu~_ - as shown in Figs. 10-12. The coupling link 310 may be instslled for protection within the recessed portion 308 of primary couie,t~., 304. The link 310 is illustrated as a dual coupling link having two link UU~lUbel~ 312 and 314.
The link 310 is preferably surrounded by a protective jacket or shell 316 of a durable, insulative material, such as a plastic, rubber or other r ' The core ~O~ 318,320,322 and 324 may be of a ferrite core material, such as a PC~0 type ferrite cores. Preferably, the gap at the core separation is ,.~ - A
For eAample, design studies and CiA~ F nn show an effective gsp of 0.1 mm (millin is acLe~ , and gaps of more than about two m~ mptprs lead to an I r I _,~ deO
~. rO. - e The dual link 310 also has a core-mounted primary c~ndu- ~u. Colu~J..s..lg two portions, one located in each link member 312and 314. The link member 312has a ~ t J primary c --d~u~ur portion illustrated as being split into two core-mounted cn~ or s~O.~ 326and328. Thelinkmember 314hasa~Gu~t~d primarycondu~
portion illustrated as being split into two corc ~ ^~ cn---l~ " ~O~ 330 and 332. The primary cn-~ u. ;~O"~ .,t~ 326,328,330and 332 are electrically coupled together, as ' r~lly illustrated by cn~ tQr 334 in Fig. 10. As illu~l. ' . the ~g-- ~ ~ link 310 has an upper first portion 336 mating with a lower second portion 338. The upper link portion 336 comprises core G ' 318,322and primary C~w1uctnr scOUU~nLi 326,330,whereas the lower link portion 338 cuu~.ix~ core a.,O.- -t` 320,324 and primary c~ r Cfo 328,332.Alternatively, the upper and lower link portions 336 snd 338 may be formed into c~- ~;.----~- ~ U-shaped portions (not shown), rather than the dual link confiGu~ nc shown in Figs. 10-11. For eAample, the cn~ r S~G ' 326 and 330 may be leg portions of a single U-shaped upper con~luc~or segment (not shown), with conductor ~G.,.~nt~ 328 and 332 similarly joined together as a single U-shaped lower c~ lu- segment (not shown). Using a U-shaped primary conductor reduces end winding leakage losses and f~ ' the need for the separate conductor 334. Further leakage .~ e reduction may be schieved by forming U-shaped upper snd lower core ~ (not shown) to su' -lly surround such respectiveU-shaped upper and lower primary Cf~ lU~lur ~ ' - For link r,~ ;Oc in the 20 kHzrange, press sintered core material is ~,..,f~,,.ed and may ad~ g~u~ be formed into various WO 94/09544 -15- 21 ~ ~25~ Pcr/US93/0997 shapes, such as a U-shaped core, which rnay require s~lhs~ I finishing to form a channel therein to receive the prirnary conductor.
As shown in Fig. 11, the link member 312 has a s~gr- d core illustrated as being split into two core sc~ 318 and 320. Similarly, link member 314 has ~O d S core illustrated as being split into two core ~ O 322 and 324. While the cores of linlc ' b 312and 314are ill 1' d asbeing-~lmd,.câlinshape, itisapparent tothose skilled in the art that core ~ .o,-~ ..t~ 318,320,322 and 324 rnay have cross sectional configurations other than the illustrated semi-circular configurations, such as rectangular or square shapes as illustrated in Fig. 3 above.
Referring also to Fig. 12, optionally, the primary converter 304 may include a fluid cooling system 340 for circulating a cooling fluid, such a a gas or a liquid, for instance, water 342, through the link 310. The link 310 has a cooling fluid chamber defining a ~ ..a~ which may be divided into a plurality of ~- g~ ....yb inAi. d by the tubular c4nA~itC~ such as conduits 344 in Fig. 11. Preferably, the plural fluid carrying conduits are of a 15 non-Tr~agrPtiG electrically insulative material`, such as a plastic, located between the core and the core-mounted c~ nAl-rt~r, such as between core segment 318 and primary conductor segment 326, as ill ~ in Fig. 11. Alternatively, the fluid chamber may be located within the core-mounted con.lu,lu" for instance with each of the conduits 344 being of a copper material which also serves as the core-mounted primary condu~tur.
As shown in Fig. 12, the illustrated fluid cooling system 340 has a reservoir 346 in Co~ n with a pump or co~l~bur unit 348 which supplies the fluid from reservoir 346 to a heat d - ~ir nn device, such as an air-cooled heat exchanger 350. The cooled fluid flows from the heat e~changer 350 to a supply manifold 352. The supply manifold 352 is illustrated as splitting into four inlet conduits 354,356,358 and 360 to feed the fluid 342 25 to conduits 344 located adjacent primary c~ Ic-r ~ 330,326, 332 and 328, ,~Dt~lively. The fluid flows through conduits 344 of link 310 to a dis. h&O_ manifold 362.
The disch&ige r 1-1 362 is illl~etra~^A as joining four outlet conduits 364. 366, 368 and 370 receiving the fluid 342 from conduits 344 located adjacent primary conlu ;lo, ~0~ 330, 326,332 and 328, respectively. The cooling system 340 has a return conduit 372 which returns 30 fluid 342 from the lisch~Oe manifold 362 to the reservoir 346. It is apparent that the fluid cooling system 340 may be co~tlu;l~d in a variety of different structurally equivalent forms as known to those skilled in the art.
I2PfP~ring again to Figs. 9-11, preferably, a fle~ible tethering c~nA v~t~ r 374couples a i'- s~xo~ cn ~lct~r loop 380to the s3;~.,d~ - ;e,t~r 306. The loop 35 380 is ill ~ Fig. 11 as a high-capacity or e~pPAitP~d rate charging loop having four parallel cnr~' 1"~ 382, 384, 386 and 388, as shown Fig. 13.
Referring to Figs. 13-l5,three altemate c-.-l~~ t~ for ~ g and joining together the link s~ o.-, ,.t~ are ill ' ~ The link portions 336 and 338 are s~,dble WO 94/09544 , PCI /US93/09975 2 1 4~ ~ ~ 9 -16-to open and receive loop 380 Ihc.~. The link portions 336,338 are then closed together for charging battery 12, and opened when charging is c~ . l t Fig. 13 shows the link 310 has a cl&,.. bhcll-type opening, where the two link portions 336 and 338 are pivotally joined together by a hinge 390. Preferably, the upper S portion 336 is pivotally opened away from the lower portion 338 as ' ~ by arrow 392, allowing the loop 380 to be inserted lh~ .~t~.~n, as ~ by arrow 393, then pivotally closed to transfer power Ih~,.~t~.~
Referring to Fig. 14, an alternate link 310' is shown eq~ippe_ for a radial opening by radially , ~ portions 336 and 338 in the direction ' ~ by arrow 394.
The radial opening of link 310' allows loop 380 to be inserted between the open link portions 336 and 338, as inAi~ PA by arrow 395.
Fig. 16 illustrates another alternate link 310"eq~lippe_ for a t ~- n~ql opening by sliding segment 336 ap_rt from segment 338, as illustrated by arrow 396. The onql opening of link 310~ allows loop 380 to inserted therein, as inAirs~PA by arrow 397.
The link 310" is closed by moving link portion 336 in a direction opposite arrow 382, as long as adequate cl~ -~ exists so portion 336 clears loop 380. Such cle_rance may be provided by c-~ uuliug n~ u~t~ link portions (not shown) having the st_tionary portion formed with a deeper loop receiving contour 398, or by moving link portion 336 in an upward direction perpPnAir~ls- to horizontal arrow 396 as illustrated in Fig. 15. Alternatively, the link portion 336 may be moved l. ' 'nn-~lly in an axial direction ~.~t Dlly parallel with a l~ngih-~
axis 399 of the link 310~,illustrated in end view as a point 399 in Fig. 15. Other struchurally equivalent v - --nc and c ' onc of the radial and l, ~ onql link opening ~
of Figs. 14 and 15, as well as the pivotal opening of Fig. 13, may be , ' ~ by cams, links, levers, and ser~ r~ (not shown) as known by those skilled in the art.
Referring again to FiB. 9, the çnn~ -cc cch~giug system 300 preferably has a c on system 400,which in the illl ~ en~loAin~pn~ includes the primary c~ ~n~. station 304havingc~....~ n (~COMM.")control <l";l~ 402. The n ~1--;~ 402 interacts with the control logic of the primary converter 304, such as logic unit 70 of Fig. 4, or alternatively with logic unit 162 of the s~on~l y converter 30 150 of Fig. 7 via signal 170.
The control ~l";l~ 402 may receive an input from a charging rate indicator for inAi ' Ig~ a selected charging rate for battery 12. The converter 304 responds to the charging rate indicator by c~,u~e.luug power from source 16 into AC power supplied to link 310 at the selected charging rate. The charging rate indicator may be l...l~ vd in a variety 35 of different manners. In one .o~i~oAim~n~ the selected charging rate may be an operator input, supplied to the primary converter 304 by an operator, for instance, from a keypad (not shown) located at, or remote from, the converter 304. Alternatively, as l~,n~inn~A, above, a charging rate indicator signal may be :~ulr.~ ~d in ultra-high r~u~,n~y uh~ signals WO 94/09~44 -17- 2~72~ Pcr/US93/09975 over the high fi~cy kilohenz power delivered via conductors 382, 384,386 and 388 of loop 380.
In the e~ of Fig. 9, an interactive c~ --;rqtinn system 400 is ill~l.lt I The electric vehicle 302 may have 8 control sensor array 404 for g~ lg a S charging rate indicator signal. The on-board control sensor array 404 rnay cu~.,se a pOnion of the 9' . ' ~ convener 306 (not shown), or be coupled thereto as jnAi~ ' by the dashed line in Fig. 9. The sensor array 404 may monitor the battery for charging status, rate, failed cells, and the like, as ~' lly inAirsted by sensor signal 405.
The charging rate indicator signal is carried by a ~ nn conductor 10 406 from sensor array 404. In the illustrated e~ of Fig. 9, the .__ conductor 406 e~tends through, or adjacent to, the tether 374 and is coupled to an indicator interface device 408 mounted on a handle 410 of the loop 380. The inAi ' ~r device 408 may be aligned to CG.. -~ r~'P with a co.. -~ cq~ion interface device 412 when the loop 380 is coupled with link 310. The co~ -.;rqtion interface device 412 is supponed by the convener 15 340 adjacent recess 308,and is coupled to the primary convener c~.. ---.----irq~ion e4ui~ t 402 by conductor 414.
In the optional embodiment of Figs. 10 and 11, the loop 380 may carry an inAi~ ~l interface device 415 mounted an e~terior surf. ce 416 of loop 380 for inAi g the selected charging rate for battery 12. In this ill.-ctr.s~ embodiment, the co __ - -nn 20 conductor 406 e~tends through the tether 374 and the loop 380 ~o couple with the indicator 415. With the indicator 415 located on loop 380, the c~----------: I~;on interface device is pogi~ n~d at an alternate location, i~ 9t~A as device 412',inside recess 308 to co with indicator 415 when loop 380 is coupled with link 310.
One pl.,f~,.lcd embodiment uses a fiber optic tl for the indicator 25 interface devices 408, 415, and a fiber optic receiver for the co!-.----~-~;rq~inn interface devices 412, 412',as illustrated in Figs. 9 and 10. Other structurally equivalent convener c~ on and indicator interface devices may be substit~te~ as known by those skill~d in the an for the illustrated fiber optic devices, such as metal-to-metal cnn~P~ing interface devices, optical readers, and clc~ t;c or inductive interface devices (not shown). The 30 indicator signal generated by the on-board sensor array 404 may ~ ---- - ;r9~e other inf "nn from the vehicle 302 to the primary convener 304, such as charge status; battery cnn~1itinnC for instance, a shoned battery cell; vehicle identification; charge account nn and the like.
The contqrtlecs l~cL~l~;hlg system 300 is readily r~l, 'le for charging a 35 variety of el~ctricsl vehicles having different charging rates, or for charging a single vehicle at two or more different charging rates, such as a normal rate and an c~l~l;t~l rate. For e~arnple, the loop 380 may be sized for ~ ' fast charging of battery 12, with a rating, for e~ample, on the order of 120 kilowatts. Fig. 16 illustrates an alternate coupling loop 420 WO 94/09544 ~ PCI /US93/0997 coupled to the onboard Ee~ ' y converter 306 by the fle~ible conJu~ e tether 374. The loop 420 has a smaller capacity than loop 380 ir~Air ~ by the smaller cross sectional area of loop 420 co~uGd to loop 380. The loop 420 may also be con~l,u;led of one or rnore parallel loops or turns, as illustrated for the sxondu.~ Ioop 380, but for simplicity has been illustrated as having a single power - ' ~ 422. The loop 420 is ill - d as carrying a C ~ ~ n loop c~nA ~t~ r 406 as d~ribcd above. The ~ iing space S~ in Fig. 11 for the high capacity loop 380 is far less than the interwinding space S"'shown for conductor loop 420 in Fig. 16.
Referring to Fig. 17, an alternate thin-walled tubular c~nAuctor loop 430 is shown as a ~ for the single-turn loop 420 illustrated in Fig. 16. The tubular loop 430 fills a greater volume within link 310 than loop 420, and places the c~-nAllctc-r material of loop 430 closer to the core-mounted primary conduclor. For instance, the outer cross sectional diameter of the loop 430 may be sized to yield an h,tc. ~i- dillg space S ~ of the same dimension as shown for loop 380 in Fig. I l.
The smaller v~i.,dh,g space S~ achieved with loop 430 adv g~u~ly lowers the leakage: h. e compared with that e~ ,d using a loop 420 having a single turn. The leakage ~ per a~ial meter of core length (parallel with l(~ngit-~A ~l axis 399) may be A ~ in a fashion similar to that used for a coaxial ~ n line.
For instance, when the outer primary c~- ' is ~p,~ ~ by an infinitely thin current 20 sheet:

L = [(N 2~lo) . (8 ~)] [l + 4 In (K)] Hlm (1) (2) K = (R1 . R2) 2 1 where:
N = turns ratio of the number of ~n~ turns to the number of primary turns;
R1 = distributed primary current sheet radius;
R2 = the E~ond~uy cc ' : outer radius; and 30 ~ = pe. '"lity of free space (4 ~r x 1~7 H/m).

It is apparent that by making the ratio K close to one, for example, by il,~l~hlg the R2 ~o"d~.,y c~ l-J~r outer radius, adv g~usly de~l~ the leakage inA~c-q-re L.
As illustrated in Fig. 17, the interior of the loop 430 may be packed with a 35 filler 432 of an insulative, nu.. ula~;u~,lic material. Alternatively, the interior of the loop 430 may be hollow and air-filled or evacuated. In another alternative embodiment, the interior of loop 430 may be filled with an insulative, non-magnetic cooling medium (not shown). While ~10 94/09~44 -19- 21 ~ PCr/US93/0997 not shown, if used, the optional cn -~ nn COndU~OI 406 may travel in parallel along the exterior or interior of the tubular loop 430.
The vehicle 302 rnay be C~ e.d with both types of conductor loops, with loop 420 or 430 for normal charging and loop 380 for ~ A charging. The loops 380 and 420 (or 430) rnay both be ~. ~/ coupled to the sxond6,~ converter 306. Preferably, the loops are iut~ ,,f ~ SO only a single loop 380 or 420 (or 430) is coupled to converter 306 at a given tirne. For exarnple, for extended road trips, the ~ . A charging loop 380 is installed for fast charges during driving breaks along interstate highways and the like. For daily cc --~ g, the normal loop 420 or 430 is used, allowing the heavier fast charging loop 380 to be stored in the vehicle owner's garage, for instance, to reduce on-board weight for ",~ ,~d ~rG~
Alternatively, the vehicle 302 may be equipped only with the higher capacity r~l~A;t~A rate loop 380, with the charging rate indicator 408, 415, or an operator input (not shown) ~;o_ g a selected charging rate, normal or çYpPAitPA to the primary converter 304. The current state of battery technology favors normally charging at a lower rate to extend battery life, and the e~r of c~ - - . usage favors charging at a lower rate at home wh~ . possible.
As a practical e~ample, a typical cnnt~tlP~cc charging system 300 in the United States may be configured to receive AC power from power source 16 at 230 VAC~ single phase, with a 30 Amp capacity. Assuming standard losses in the primary and secondary C~L.~.,.t,.~
304 and 306 indicates that an overall efficiency of 95% is feasible. For a typical electric vehicle 302 with 20 kilowatt-hours of energy storage capacity, a charging time of three to six hours is P-p~tPA d~ l;.,g upon any trickle charge ,c-~ui,,u~u~ and the specific type of battery 12 selected. For remote or e..A..gen~ appli~ ~nC, a lower rated cu~.geùuy charger for operation from a single phase 115 VAC power source 16 has a 1.3 kW (kilowatt) rating.
To efficiently replace today's fleet of internal cnmh~c~ion engine vehicles, theelectric vehicles 302 are capable of ~vc~pl~g a fast, high power charge at a road side ser~ice station during a long distance trip. For example, a 15 minute charging period may require charging rates of 50 kW to 370 kW"lPrPn~ling upon the size of vehicle 302. These illustrated ratings are expected to grow as battery energy storage capacity increases with improvements in battery technology. Preferably, electric vehicles 302 having high power charge capacity are also able to connect to a home based 230 VAC and euu~ u~ 115 VAC primary converting stations 302 without requiring ~ litjnn~l hardware. The system 300 operates over such a wide power range, while .... ........-;~ g the weight and cost of on-board and re~ Pn~ charger COLU~
The use of the coaxial winding ~ ru,Lu~,~ comprising link 310 and loop 380, for instance, allows an unprecPAPn~Pd degree of scalability by allowing design over a wide power range, as well as control over otherwise ~ parasitics, such as l1~5~1LI~. ~
leakage flux. By placing all the 11 CUILU~. core material off-board in the charging station 304, WO 94/09544 4~-Z 5 ~ PCl /US93/0997 the on-board tl ~1~, c~ .o..~ is limited to a simple wire loop 380 sized for the highest current level. The loop 380 has no rnagnetic material, and hence minirnal sensitivity to op~ ~ frequency or to flw~ density, allowing the system 300 to operate over a wide L~ rsnge, with a variety of converter ~op~logi~Ps and core -Ic Since the on-board S sacond~ ~ conduu~or . i~s a sirnple wire loop 380, the loop 380 may be over-sized with a very small cost or weight penalty for the vehicle user.
For lower power a~ r l "~)nC, a srnaller, lower rated loop 420 may be used, and may be rnade to fit within the geometrical c~ lln;~ of the larger loop 380 without -I cost penalty. By . ing Figs. I 1 and 16, it is apparent that the inner diarneter 10 of the primary c~,u.lu-,lo~ of link members 312 and 314 may be the same, as well as the center-to-center span between link members 312 and 314, to advantageously provide charging scalability using a single link 310. These din~Pnci--nc may be used to describe a universal loop geu~ interface, as illustrated by loops 320 and 420. Thus, the system 300 efficiently handles this wide power range without significant penalties on the co...ln nf..t~
15 designed for lower power levels.
Table 1 below shows c~ ulP~P~l data for a 6.6 kW system, such as for loop 420 of Fig. 16, optimized for o~, "on at 77 kHz, as well as cc.~ul~r c~lc~l ~ data for a 6.6 kW
(Fig. 16) and a 120 kW . ' -)n (Figs. 10-11). Any overall penalty in terms of size and efficiency (and possibly cost) of system 300 is minirnal for the 6.6 kW design, especially as 20 viewed by a user of the electric vehicle 302. One 6.6 kW systerr. has been built without the optional water cooling system 400, and tested in the labol~tol y with c ~icfPr-ory WO 94/09544 2 1 4 7 ~ 5 9 Pcr/us93/0997~

Coaxial Windin~ T- _ "u- -.e. Desi~n Data Optimized for 6.6 kW only Universal Desi~n Ratings:
S Power 6.61cW 6.6 kW120 kW
Primary Voltage 200 V 200 V 200 V
Primary Current57 Amp 58 Amp 600 Amp Secondary Voltage400 V 400 V 400 V
SPcr~ ' .y Current25 Amp25 Amp 300 Amp 10 Fl~ 77 kHz 77 kHz 20 kHz Bm (PC-40 Ferrite)210 mT 210 mT 210 mT

Transformer D-Core Length total 260.0mm 260.0mm 260.0mm 15 Inner C-n~luctor OD ~4 3.4mm 3.4mm 15.0mm Outer Conductor ID 11.2mm 46.4mm 46.4mm Outer C-n~ r~or OD 11.6mm 46.9mm 47.4mm Core ID 12.2mm 47.4mm 58.0mm Core OD 23.8mm 59.2mm 102.8mm 20 Total Effective Air Gap 0.5mm 0.5mm 0.5mm Transfor ner Weight:
Core Weight (PC-40) 0.414kg 1.225kg 7.07kg Primary Copper Weight 0.055kg 0.389kg 0.77kg 25 So~lld ly Copper Weight 0.038kF 0.066kF 0.67k~
Total Weight 0.507kg 1.680kg 8.51kg PowerDensity (kW/kg)19.98 6.0 14.1 30 F.ff.-- ~ 99.58% 99.01% 99.70%

C~
As .1;~ ~1 above, each system has its features and d-~.l~ks. System 10 of Fig. 1 - ' t.c~lly l~.~ s a gasoline service station configuration. The lechaJ~illg system 35 100 of Fig. S .~i ' '^ . a conventional c~r.-.~.. r electric ~ e having a cord plugging into a power recep~ o. Thus, c~ lly, I~~ g systems 10 and 100 would likely be well received by the cn~ .g public, d ~ g upon whether they consider an electric vehicle to be similar to a gasoline powered car, or an electric appliance. The n~tom~ic system 200 of WO 94/09544 2 ~ 4rl ~ ~ 9 -22- PCT`/US93/o997~

Fig. 8 has appeal in that no user contact with the coupling is required to initiate charging, other than proper parking of the vehicle 14 adjacent the primary converter 42. However, the robotic arm is more comple~ and costly to . ' than the systems of Figs. I and 5. The system 300 is p.ef4..~ for its scalability, allowing charging of vehicles having different charging , ~ ~ from a single charging station 304, as well as allowing for selecting different charging rates for a single vehicle 302, such as normal and e~pedited charging rates. For e~ample, the loop 380 of Fig. 11 may be rated for charging at 120 kW, whereas the loop 420 may be rated for charging at 6.6 kW. The .~h~...g system 300 also illustrates a fluid cooling system 400 which may be used for the coupling links 25, 25' and 110 by adding cooling conduits (not shown) as described for conduits 344 of link 310. Fluid cooling of the link adva. tag~lr diCCip ~s heat g~..e._ ~ by 12R losses, allowing for faster charging with lower initial core-mounted conductor costs.
Thus, the cnn~ ~tle-cc battery t;chd~g system described herein is suitable for high frequency ope._ nn, on the order of 2-50 kHz, with a very high power density of the 15 CWT link conductors and converters o~, ` g with a very fast response time. Arl~ nn 11y, the power cnnn~tion between the primary converter and vehicle requires no exposed conductors at any time. ~Arliti~nolly, the r~h~g.ng circuit is insensitive of the position of the core relative to the inner c~ ut.~. in all directions, that is a~cially and radially. This insensitivity to the position of the inner conductor with respect to the outer conductor allows 20 for a large i~lt4.V~g c'~ -e while still g output pe,rv -~ The coupling link is also force neutral, e~hihi~ing no a~ial or radial forces between the core-mounted co..du.tor and the cnn~ rtor loop. These vanious features render the .~La.~ g system described herein to be in a practical sense both physically simple and rugged to c~l--r e for user and envi.. ~ physical abuse to the various . ~ of the system.
Roch~2~.l.g systems 10, 100 and 200 supply power to their respective links at a high r.~ , such as on the order of 20 kHz for loads of 1-100 kW, and 2 kHz for loads greater than 1 ulc~5a~.a~l (I MW). The primary current provided by the shtionary conv~.er induces an equal and opposite amount of ampere-turns in the on-board ~o.,~.r winding, without any physical contact between the cn~ in the CWT. Fu.lL~.,.,,~..~, the ~vindi~g space in the CWT may be filled with - gr~tic material for electrical and envi.~ I jnC 1~ nn Both the primary and se~ circuits of the CWT adv g~u~lr have no e~posed cn~ and no e~posed magnetic core material when I ~ g power.
Thus, .- ~;..-- -.. safety may be achieved in these systems with .~ Pm~arClll f.n of both sides of the CWT, that is, ~ ic.n of the cnnf~llrtt~r and core portions mounted to the 35 primary c ~"t~,r and the vehicle-mounted c~ . and core portions.
The l~hal~;i..g systems 10, 100, 200 and 300 with the inductively coupled links and loops provide inherent electrical isolation of the source 16 and the battery load 12, so cost WO 94/09544 -23- 1 ~ 7~59 Pcr/US93/0997~

penalties over and above providing galvanic isolation are minimal. Other advantages of system 10, 100, 200 and 300 include:
- unity power factor and low h~nic currents;
- interface suitable for range of vehicles sizes;
- interface suitable for range of power levels;
weight loops for , to handle;
- inherent safety and benign fault modes; and - low cost.
The technology illustrated for the .~I~...g systems described herein is in its 10 infancy. ConcP~luPntly, any decision made in terms of standardization preferably lends itself well to change occurring due to technology growth. Thus, the ~..~un~ nt~ illustrated herein may be ~.~h ~ tr_ by their structural equivalents as known to those skilled in the art as such structural equivalents evolve.
Having illustrated and described the p~ of our invention with respect to 15 several preferred emhoAirnpnt~A~ it should be apparent to those skilled in the art that our invention may be modified in ~u.~ge~u~..l and detail without d~,"~..li- g from such p.i :. '^ .
For e~cample, other core confi~;u. onc rnay be used for the links APc~^rihpd herein, as well as other confi~ nc for the core-mounted c~n.l~J~o" and the c~hstih~ion of other devices and configurations known to be ,~ IA by those skilled in the art. Also, the location of 20 the core may be opposite to the control logic, for instance, the CWT configuration of Figs. 1-3 may be used with the primary and ~"d..- ~ converters 102 and 150 of Fig. 7. Also, the operator inputs 72 and 174 may be received by either the primary or the secondary converters in Figs. 4 and 7. AAAifi~--'ly~ suitable material cllhs~ ionc and .I;..~ n~l variations may be made for the co--.~ -t~ of the link as described herein. Additionally, the configuration of 25 the primary and ~cvnd~.r converters may vary ~ -lly, de~ --I;"g upon the state of the art of power electronics and other ..it~;l~g deviceAs. We claim all such nu~Aifi~ "on~ falling within the scope and spirit of the following claims.

Claims

1. A contactless charging station for charging batteries on board plural electrical loads each having a conductor loop and a secondary converter coupled thereto for converting AC power into DC power to charge the battery at a selected charging rate, the station comprising:
a coupling link having a magnetic core and a core-mounted conductor at least partially surrounded by the magnetic core, the core-mounted conductor countoured for selectively at least partially surrounding each load loop; and a primary converter coupled to the core-mounted conductor for converting power from a power source into the AC power at the selected charging rate corresponding to a load when coupled thereto by the link.
2. A contactless charging station according to claim 1 wherein the primary converter converts power at the selected charging rate in response to a charging rate indicator for indicating the selected charging rate.
3. A contactless charging station according to claim 2 for charging a load whichgenerates a charging rate indicator signal, wherein the primary converter is responsive to the charging rate indicator signal.
4. A contactless charging station according to claim 2 for charging a load having a fiber optic transmitter carrying a charging rate indicator signal, wherein the primary converter includes a fiber optic receiver responsive to the fiber optic transmitter for receiving the charging rate indicator signal.
5. A contactless charging station according to claim 1 wherein:
the link includes a chamber defining a passageway for receiving a cooling fluid to cool the core-mounted conductor; and the station further includes a cooling fluid circulation system coupled to the chamber for circulating a cooling fluid through the coupling link passageway.
6. A contactless charging station according to claim 1 wherein the link is openable to receive, and closable to substantially surround, each load loop.
7. A contactless charging station according to claim 1 wherein the link is separable into at least two link segments pivotally connected for opening to receive and disengage each load loop, and for pivotally closing to engage each load loop.
8. A contactless charging station according to claim 1 for coupling with plural load loops each having a longitudinal axis, wherein the link is separable into at least two link segments which are radially openable for disengaging each load loop and radially closable for engaging each load loop in radial directions respectively away from and toward the longitudinal axis of the surrounded portion of each load loop.

9. A contactless charging station according to claim 1 wherein the link is separable into at least two link segments which are translationally openable for disengaging, and translationally closable for engaging, each load loop.
10. A contactless charging station for charging batteries on board first and second electrical loads each having a secondary converter for converting AC power into DC power to charge the battery at a selected charging rate, with the first load having a first load loop sized for charging at a first charging rate, and the second load having a second load loop sized for charging at a second charging rate greater than the first charging rate, the station comprising:
a coupling link having a magnetic core and a core-mounted conductor at least partially surrounded by the magnetic core, the core-mounted conductor countoured for selectively at least partially surrounding each load loop, with the link sized for interchangeably at least partially surrounding each of the first and second loops; and a primary converter coupled to the core-mounted conductor for converting power from a power source into the AC power at the selected charging rate corresponding to a load when coupled thereto by the link.
11. A contactless charging station according to claim 10 wherein the primary converter converts power at the selected charging rate in response to a charging rate indicator for indicating the selected charging rate.
12. A contactless charging station according to claim 10 for charging a load which generates a charging rate indicator signal, wherein the primary converter is responsive to the charging rate indicator signal.
13. A contactless charging station according to claim 10 wherein:
the link includes a chamber defining a passageway for receiving a cooling fluid to cool the core-mounted conductor; and the station further includes a cooling fluid circulation system coupled to the chamber for circulating a cooling fluid through the coupling link passageway.
14. A contactless charging station according to claim 10 wherein the link is openable to receive, and closable to substantially surround, each load loop.
15. A contactless charging station according to claim 10 wherein the link is separable into at least two link segments pivotally connected for opening to receive and disengage each load loop, and for pivotally closing to engage each load loop.
16. A contactless charging station according to claim 10 wherein the link is separable into at least two link segments which are radially openable for disengaging each load loop and radially closable for engaging each load loop in radial directions respectively away from and toward a longitudinal axis of the surrounded portion of each load loop.

17. A contactless charging station according to claim 10 wherein the link is separable into at least two link segments which are translationally openable for disengaging, translationally closable for engaging, each load loop.
18. A coupling link, comprising:
a core-mounted conductor for surrounding a portion of a conductor loop coupled to a power source or a load, the core-mounted conductor for coupling to the other of the power source or the load;
a magnetic core at least partially surrounding the core-mounted conductor; and a cooling fluid chamber defining a passageway for circulating a cooling fluid through the link.
19. A coupling link according to claim 18 wherein the cooling fluid chamber is located within the core-mounted conductor.
20. A coupling link, comprising:
a core-mounted conductor for surrounding a portion of a conductor loop coupled to a power source or a load, the core-mounted conductor for coupling to the other of the power source or the load;
a magnetic core at least partially surrounding the core-mounted conductor;
a cooling fluid chamber located within the core-mounted conductor and defining a passageway for circulating a cooling fluid through the link; and a shell of an insulative material encasing the core and the core-mounted conductor, the shell defining a loop receiving portion for receiving the loop therein.

21. A coupling link according to claim 18 wherein the cooling fluid chamber comprises plural fluid carrying conduits located between the core and the core-mounted conductor.
22. A coupling link according to claim 18 wherein the link is openable to receive the loop and closable to substantially surround the loop.
23. A coupling link according to claim 18 wherein the link is separable into at least two link segments pivotally connected for opening to receive and disengage the loop, and for pivotally closing to engage the loop.
24. A coupling link according to claim 18 wherein the link is separable into at least two link segments which are radially openable for disengaging the loop and radially closable for engaging the loop in radial directions respectively away from and toward a longitudinal axis of the surrounded portion of the loop.
25. A coupling link according to claim 18 wherein the link is separable into at least two link segments which are translationally openable for disengaging the loop and translationally closable for engaging the loop.

26. An electric vehicle adapted for receiving AC power from a primary converter outside the vehicle, the primary converter including a coupling link having a magnetic core and a core-mounted conductor at least partially surrounded by the magnetic core, the vehicle comprising:
a battery on board the vehicle; and an on-board charging system comprising:
a secondary converter for converting AC power into DC
power for charging the battery; and a conductor loop coupled to the secondary converter for transferring AC power from the primary converter to the secondary converter, the loop shaped for being selectively surrounded by at least a portion of the coupling link's magnetic core and core-mounted conductor.
27. An electric vehicle according to claim 26 for charging the battery from a stationary primary converter which converts power at the selected charging rate in response to a charging rate indicator for indicating the selected charging rate, wherein the electric vehicle generates a charging rate indicator comprising a charging rate indicator signal.28. An electric vehicle according to claim 27 wherein the secondary converter generates the charging rate indicator signal.
29. An electric vehicle according to claim 27 for charging by a primary converter having a fiber optic receiver, wherein the charging rate indicator signal comprises a fiber optic signal transmitted by a fiber optic transmitter supported by the loop for reading by the primary converter fiber optic receiver.
30. An electric vehicle according to claim 26 wherein the loop is connected to the secondary converter by a flexible tether.
31. An electric vehicle according to claim 26 wherein:
the loop comprises a normal loop sized for charging the battery at a normal rate;
the vehicle further includes an expedited charge conductor loop for coupling to the secondary converter for charging the battery at an expedited rate faster than the normal rate; and wherein the secondary converter interchangeably is coupled to one of the normal loop or the expedited charge conductor loop.
32. An electric vehicle according to claim 26 wherein:
the loop is sized for charging the battery at a normal rate;
the charging rate indicator indicates to the primary converter that the battery is to be charged at the normal rate;

the vehicle further includes an expedited charge conductor loop coupled to the secondary converter for charging the battery at an expedited rate faster than the normal rate;
and the vehicle also includes an expedited charging rate indicator carried by the expedited charge conductor loop for indicating to the primary converter that the battery is to be charged at the expedited rate.
33. A contactless charging system for charging plural energy storage devices each having at least one selected charging rate, comprising:
plural secondary converters for converting AC power into DC power, with each secondary converter charging a single respective one of the plural energy storage devices;
plural conductor loops each coupled to a single respective one of the plural secondary converters;
a coupling link having a magnetic core and a core-mounted conductor at least partially surrounded by the magnetic core, the core-mounted conductor for selectively at least partially surrounding a single one of the plural loops to transfer power therebetween; and a primary converter coupled to the core-mounted conductor for converting power from a power source into the AC power at the selected charging rate.
34. A contactless charging system according to claim 33 wherein the primary converter converts power at the selected charging rate in response to a charging rate indicator.
35. A contactless charging system according to claim 34 wherein the charging rate indicator comprises a charging rate indicator signal generated by the secondary converter.
36. A contactless charging system according to claim 33 wherein:
the link includes a chamber defining a passageway for receiving a cooling fluid to cool the core-mounted conductor; and the charging system further includes a cooling fluid circulation system coupled to the chamber for circulating a cooling fluid through the coupling link passageway.