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APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 FOR OFFICIAL USE ONLY J6'RS L/ 10276 ~ 25 January 1982 West E t~ ro e Re ort p ~ SCIENCE AND TECHNOLO~Y CFOUO 1 /.8?) FBIS FQREIGN BROADCAST INFORMATION SERVICE FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 NOTE JPRS publications contain information primarily from foreign newspapers, periodicals and books, but also from news agency transmissions and broadcasts. Materials from foreign-language sources are translated; those from English-language sources are transcribed or reprinte3, with the original phrasing and other characteristics retained. - Headlines, editorial reports, and material enclosed in brackets are supplied by JPRS. Processing indicators such as [TextJ or [Excexpt] in the first line of each item, or following the last line of a brief, indicate how the original information was processed. Where no processing indicator is given, the infor- - mation was summarized or extracted. Unfamiliar names rendered phonetically or transliterated are enclosed in parenthe~es. Words or names preceded by a ques- tion mark and enclosed in parentheses were not clear in the original but have been supplied as appropriate in context. Other unattributed parenthetical notes within the body of an item originate with the source. Times within iterns are as given by source. The contents of this publication in no way represent the poli- cies, views or attitudes of the U.S. Government. COPYRIGHT LAWS AND REGULA.TIONS GOVERNING OWNERSHIP OF MATERIALS REPRODUCED HEREIN REQUIRE THaT DISSEMINATION UF THIS PUBLICATION BE RESTRICTED FOR OFFICIAL USE O~ILY. APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 FOR OFFICIAL USE ONLY - JPRS L/10276 25 January 1982 WEST EURO�E REPO~T S~IENCE AND TE~HNOLOGY (~ouo 1/8 2 ) CONTENTS TRANSPORTATION Current Research Efforts in Magnetic Levitatioi7 Teckinology (Herbert Weh; ZEI~SCHRIFT FI1ER EISENBAHN~JESEN UND � VFRKEHR.STECHNIK, 6ct 81) 1 ~ ~ I i I ~ I i , - a- [zII - WE - 151 S&T FOUO] ~no ~c~r* . ~ r rc~ nuT v APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 FOR OF F[CIAL t1SE ONI,1' T~ANSPORTATION CURRENT RESEARCH EFFORTS IN MAGNETIC LEVITATION TECHNOLOGY [~est Berlin ZEITSCHT:IFT FUER EISENBAFINWESEN UND VERKIIiRSTECHNIK in German Oct 81 pp ~11-319 [Article by Prof Dr-Eng Herbert Weh, Technical University c~f Braunschweig: "Re- ssarch Efforts in the Areas of Magnetic Suspension Technology and Linear Drives"] [Text] 1. Introduction Contactless transpo~t technology is still today at the beginning of its develop- - ment. In the FR~ the direction taken by magnetic suspension technology is char- acterized by a developmental trend in which components are employed for combined propulsive and support functions. ~ The area of application of various designs always enlarges whenever it is possi- ~ ble to improve the characteristice of the functional elements. This continues ~ to be true when it is a matter of applying contactless trar~sport technology to small vehicles and to goods transport. Both of theae latter call for a subetan- i tial simplification and cheapening of the primary structural components. i The research studies described in the following paper relate in each case to ! aubdomains of contactless support and propulsion technology. They are segments i of the research pro~ects carried out at the Inst~tute for Electrical Machines, Propulsion Systems and Roadways of the Technical Un~versity of Braunschweig for ! the German F~deral Ministry of Research and Technology (BMFT). These pro~ects aimed at developing further improvemente for the future application of magnetic suspension technology. ; 2. The Deaign of an Energy Supply for Long-Stator Drives The long-stator drive preaenta us ~�~ith the task of ~utlining and developing while maintaining the desired high efficiency a cost favorable procedure for procesaing energy and conducting it to the winding. Here one must take into ac- count the need for keeping thrust variat�ions low. There are also a number of technoloc~ical prerequisites which must be taken into account here. For reasons of economy pref2rence is given to the use of conventional switches to serve as switching elemenrR connecting the winding sections with the power lines. The transmission voltage must be set at about 5 kilovoltg in order to limit losses at the given conductor cross section. 1 FOR OFFIC[AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00854R004500020045-5 F'OR OFFICI~~~. ust~: otvt.~~ The power feed design and winding arrangement for the Emsland Transrapid Test Facility (TVE) are ahown schematically and in single phase in Figures la to lc [1]. The winding section~ are fed alternately by the inverted converters (WR) I and II. This synchror.ous procedure [2] permits a shc~ckless motion of the vehi- c].e from one winding sectlon to another but on the other hand gives rise to only about 50-percent utilizati~n of the inverted Gonverters. The latter involve a pulse rectifier with automatic commutation which accounts for a substantial fraction of the cost of the substructure equipment. 'i'he engineering design which is still satisfactory for the test series of the Emsland pro3ect appe~rs to be too expensive for the commercial use of magnetic suspension technology. . U _ L~� ~ , ~ _ , , ~ / / ~X,y ~i~ Uo J~ _ ~ s ~ ~a , ~ ~ ~ . ' ,NaIl ic Figure 1. Single-strand winding, syncr~ronous circuit (one sloi, per pole and phase). The basic ~dea of a new design which is being investigated with the support of the BMFT is: i. full utilization of the inverted converters and ii. reduction of the apparent power of the winding sections. By subdividing the winding stranda of the three-phase winding into two parallel aubetrands and by feeding them separately through the inverted converters 1 and ' 2 it is poasible to sharply reduce the inverted converM:,r power by using the ` power feed echeme aketched in Figure 2a and 2b. The c3rcuiting ia so selected that in providing vehicle power both winding s~rands carry current. Thus normally both inverted convertera are in uae. It is not neceasary to hold an additional inverted converter in reserve. In addi- tion there is the fact that as a result of the dieplaced 1.ongitudinal arrange- ment of the winding sections their total idling power demand is reduced in com- parieon with the aingle-strand arrangement. Thie situation is also shown in the voltage diagram 2c and there in particular corresponds to rh~a length of the in- ductive voltage Xd/g~. For the same toCal length of the wirdding sections, the full magnitude of the surface magctetic enArgy ia generated only by the section within whose two strands current ia being carried. However, in comparison with the single-strand winding it has only half the length. On the remaining half of the corresponding section the magnetic energy is lower. He~e ~he current in the 2 FOR OFFICIAL USF. ONLI' APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 ~ _ e . ~ FOR OFF[C1A,L USE ONLY ' - winding ia reduced t,y at Ieaet half eo that the eurface energy amounta to at the most one-quarter. ~ / . ~XaJo, _ Uvi i , U.i ~ ~ Z � `�a ao~ WR1 WA2 1c i Io ! Figu~e 2. Double-etrand arxangement, one inside the other. If the "short-circuit syatem" is designed in accordance wit'~ Figc~re 2a then one ~ muat also take into account that in the unfed wiading as a consequence af the ~ magnetic field in the fed winding a current ie induced wllich further weakens the primary field. The effec*_ of thie process becomee all the greater the ~nore cloeely the t~vo etrc*~ds lie together (Figure 2b). In the case when ~:he arrange- men~ ie in aeparate equidietaat slote the coupling ie about 20 p~rcent. The re- sulting voltage drop then corresponds.roughly to Chat of the diagram in Figure ~ 2c. It eeen thgt in comparison with the eingle-etrand winding design one obtaina ~ sharp xeduction in the phase angle betweea curr~at and voltage. The appaxent power of the two clearly l~es than the apparent,power of an ~ uneu~divided winding. _1, ~ t ; It is evident that the proe�dure cf double-strand dieplaced winding sectiona is not exclusively confined to ~he use of "sh~rt~-circuit fePd lines" but can alsc be used ~ointly with t:~e tap line deaigxi (ia anal,ogy to Figure la). The two subconductors can here aleo without disadvantage be placed in a common elot. Examinati.on of the problems'of awitching over ehowa that here, too, there are _i~; clear adva~ntages on the eide of the double-strand winding. In the case when the 'j ewitching procese compels a curr~nt ir~terruption for one wiading strand the xe- ; aidual thxu~t etill amounte under th~ most peesi~nietic ae~umptioas to 50 percent of the initial value. Through dynamic proc~se0s in the current circuit, through ~ the tendency of the winding to keep the magnetic flux conetant, the thrust-qen- erating winding will~ hower~er~ carry a eomewhat higher current and wi11 Chue ! partially compeneate the interruption of force. i ~ ~ In order to obtain a full amoothi,~g out of the thrust va~iariona the ewitching ~ on of ~he new winding section can be carried out already prior to entrance of the vehicle. If one simultaneously employees in the oth~r strand a somewhat in- ' cxeaeed current then the two common-fed eections can be operated at a reduced ~ .current with very elightly increased voltage. Since the startup processes take 1 place very rapidly and can be very rapidly stabilized by means of the regulating syatem it ie poesible to avoid oecillations in the thrust if the inverted con- - verters are elightly overdimensioned, The rated output of the inverted convert- ~ ers 1 and 2 taken tAgether ia also im this case no higher than that associated , 3 ~ FUR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 FOR OFFICIAI. USE ONLY with about 50 ~.~rcent of the~power of the inverted converters I and II in the case of a single-strand winding. 3. Inverter Design for Short- and Long-Stator Drives The magnitude of the drive power, requires for the transport of energy transmis- sion voltagea in the range of 5 kilovolts. Low-loss linear drives are at the presen.t time fed via automatically commutated inverted converters. This places a restriction on the conditians which must be met in order to obtain 1{mi.ted costs for the subatructure ec~uipment in the case of a long stator and to obtain - low structural yolumes and weights for a short-stator drive atta~hed to the ve- hicle. In addition.there ie the fact that while it is possible for additionaY - transformers to be used on the load side of the inverted converters in the case _ of the long-stator design nevertheless this gi�ves rise to difficulties in - achieving simple and cheap awitching arrangemente. Also in the case of short- = stator drives a transformer on the vehicle implies an undesirable increase in waight which in turn must be paid for with greater driv~ power. Thus there arises a demand for frequenc~ converters of eufficiently high voltage and havtng a design which is as simple ae posaible. Converter circuits which get along _ with natural commutation are moat Zikely to meet this demand: Another argument in favor of such converters is the fact that aemiconductor componenta are avail- , able which permit a higher blocking voltage and greater currents. Admittedly, the use of naturally commutating c~nvertera should not be inaisted upon at the coat of having to operate the linear motor in a state of hyperexcitatian. Thi.s ~ could result in too great disadvantages for the overall proceas of energy con- versions; with traditional inverted converter circuits it also impliea limita- ~ tion of the inverted con~~erter function to frequencies which are not too low. A compromise solutiom may be found if one employeea adjustable idle current in- puts on the load aide, such as swl.tchable coz?denaere. They permit, e.g., natu- ral commutation above 50 percent of the higheet frequency.while in the lower range they serve as energy reaervoirs for the quenchin.g circuits of the auto- matic commutation. An inverted converter design operates throughout the entire frequency range without change in circuitry; its intermediate circuit ie designed (Figure 3) in the form of a resonance circuit [3]. The connection to the primary power supply as well as to the load is through an invarting rcectifier for single-phase con- nection to the oacillating circuit. This inverter ia thus fully controllable with regard to frequency and power--in both directions, so far as the power is concerned. It requires for the primary power supply no id~e current in reaerve and imposes no requirementa on the load resistance. Its control deaign is sim- ple; its frequancy range is large and not tied to the frequency of the primary _ power supply. A series arrangeffi~nt of the rectifiers for adaptation to high op- erating voltage~ appears here to be far freer of problems than in the case of automatically commuting inverters. The described inverter design obviously eliminates the frequency variationa so familiar with direct inverters but in- volvea only two-thirds of the rectifiers required by the latter. Within the framework of the research pro~ect funded by the BMFT investigations are being ' carried out of the propertiea and dimensioning conditions of this type of in- verter. 4 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 FOR OFFICIA[. USE ONLY _ } - -----T--T---------- , r----- i,~ ~ , , ~ ~ - ~ 3 S ~ ~ I 1~ I _ ~ z� 6~ ~ ~ ~ I R' ~ - I S' j uZ ~ - I T ~ I ~ ~ ~ - I 2 L G 1, 3, 5, I I' i i 3 i ~ 1S1rom-~ ~ I ~(1) U. Sir. I (2 Zw.Kr.l U. Sir. ll ~ Lost (3) ~ L---------~---~--------�---~ ----J Y) f I 1 I 1 q i u~ ~ u~ ~ ~ I 1 ' WI f i2 Y i _ ~ f o~~____ WI tJl Figure 3. Ci.rcuit and current profiles o� a new inverter design. Key: 1. Inverting rectifier 3. Load 2. Current intermediate circuit The ob�viously favarable structural volume makes this inverter appear to be very - well suited to application to vehicles. Figure 4 shows a circuit in which two inverters of this type, each of which feeds a line~r motor, are electrically connected in aeries. Here the power is fed from the DC power supply, or in other worda, via DC current cErrying electric rails having a voltage of, e.g., 4 kilovolta. The voltage division is symmetrized by a current control which op- eratea on the two motor curreat circuita. In the design of the motors the se- ries c~rcuitry has the advanta~e that the windinge need be insulated only for the haif-voltage and thia is important for heat dissipation and in the construc- tion of lighCweight motors. Through the saving in transformers and the favor- able deaign of the motora it is poesible to obtain a clear improvement in the uehicle deaign. 4. The Uae of New Magnetic Materials The technologies of magnetic su~pension and electrical linear drivea are of par- - ticular interest to the engineer specializing in magnetic technology because it is apparent that often very slight improvements in individual parts (magnets) can lead to considerable savings in other vehicle or roadway components. Thus, - FOR UF~'ICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 FUR OFFICIAL USE ONLI' _ e.g., merely an increased flux density in the magnets--even when this involvea a certain added expense--can lead to a quite eignificant cheapening of other vehi- cle or roadway components. Simultar~eo~sly it is possible with new and more ef- ficient magnets to achieve an improvement in the levitation characteristic~. More favorab2e dynamic properties in the levitation magnets yield a more rapid return to a new position of equilibrium after a perturbation. In turn one can also derive from this savings in the control elements of the ma.gnets. In the chain of elements, mutually interdependent in their dimensio!ning, the supporting _ and propulsion magnets assume a"strategically" important place; improvements in these specially criticaZ locations have a particularly marked effect upon the characteristics of the entire system. R I , ~ -T WR1 ' _ ~ ~ I ; ~ ~ ~ ~ , i u ' ' 9 ~ ~ ~ ~ I~2 WR 2 . i Figure 4. Series circuitry of the inverted converters for feeding power to lin- ear motors. . The use of new magnetic materials makes possible, as has .:ecently been learned, ' a new design of linear motors which are in fact of a tqpe previouelv written off _ because of their too unfavorable operating characteristics fcr use in the trans- port sector. It now seems to be becomtng poseible to achieve high efficiencies and power factors simultaneously with acceptable weights for the drive. In con- sequence the installation of power-carrying motor parts into the vehicle (short- atator technology) io again bec~ming more attractive. Specially favorabl~ de- sign solutions evidently arise whenever the motor can also take over the func- tion of the supporCing element. As a further example of the use of high-energy permanent magnets (REC magnets) some etatements should be made regarding poesible improvementa in the repulaive aupport procesa on the baeie of permanent magnete. This aupport technology had _ already been suggested more than 10 yesrs ago; however, ita characterietica for use in transport technology had not yet become eufficiently favorable. Then the course was adopted of ueing superconductive coils ae vehicle magnets and of in- troducing cLrrent-carrying rails or coils in place of magnets (normally conduct- ing) along the side of the roadway. T'nis procedure which has been atill further developed by the JNR in Japan requires a relatively high energy consumption for the aupport technology and leads to a rather complex overall system. 6 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 ~ . FOR OFFICIAL USE ONLY ~ ~ ~ 5. High-Energy Permanent Magn~ta in Long-Stator Technology : Synchronous long-atator drive is either de~igned with auperconducting exciter coile in the vehicle--in which case it then uses an ironless etator--or elae the iron-containing atator variant ic employed eo that electromagneta and/or perma- ' nent magnete can be used for the exciter field. In the case of 3ron-containing technology it ie also possible to uae the normal forces of the motor to compen- ~ sate the weight of the vehicle. When a controlled magnetic field is used one i can dispenae with further support~ng elempnts such as wheels [4]. i ~ For velocitiea the dynamic effects produced by perturbing forces and inac- ' curaciee in the roadway acquire inereaeing sigaificance. In the case of inechan- ; ical guidance they give ri~e to increased wear of the (mechanical) guiding ele- menta. For this reason contact-free auspension is an attractive transport vari- ~ ant; not least of all it ~lso has the advantage of reduced maintenance coet. But in addition it ie also poseible to allow greater tolerances in the accuracy of the roadway and thie in turn can yield a cheapening of the roadway conatruc- ~ tion. ~ The disadvantage of the electromagnete lies in the fact that particularly in th~ case of low-lose design they poesees a large time conetant. In order to achieve adequately rapid interventions in stabilizing the eupporting function there are therefore required high values of maximwn voltage and high power amplificatione. The result is an increase in the quantity of power.-~iectronica devices in the vehicle. If one dispenaes with a high reaponse epeed in the magnets then this implies greater deviationa between the roadway contour and the magnet pathway. Z'his requires a gre~ter average dietance from the rail and a higher magnet power. The simultaneously,increased magnet mass has an ~dditional negative affect upon ;j the levitation behavior and the attainable riding comfort. ; ~ Especially from the dyaamic point of view a relatively narrow range of options. is available in the ues:~~ of supporting magnete and propulaion magnets. . Low magnet weight, low loseea and high f.orce gradients are the desired goals. An average gap of about 1 cm is eought. The maximum gap deviations resulting from flexure of the carriere ahould not exce~ed 3~n. In thio way it is possible ' to meet conventional comf~rt criteria. which easentially restrict the vartical acceleratione of the paesQnger cabin. up to velocitiee of more thar~ 400 km/hr. Here it ie assumed that ower carrier epane of abaut 25 meters the maximum flex- i ure amounte to about 0.8 cm. The use of high-energy permanent magnete (REC magnets) for carrying and propul- ~ aion substantially increases the range of design optione in achieving a high riding comfort for given roadway tolerancee. A placement of the permanent mag- nets directly at the air gap permite, with remanence inductions of about A.9 T, ' flux deneities from 0.4 to 0,5 T and is characterized by small leakage flux. ~ However, ths use of additional control coils turns out with this form of magnet ~ to be very unsuitable. The additional electrical excitation of the magnet required for gap control re- quires, it is true, a modif~ed magnet deaign. The average magnetic flux, which 7 = FOR OFFICIAL USF. ONL.Y APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R400540020045-5 FOR OFE'ICIAL USE ONLY corresponds to the etationarq state, generated by the permanent magnet has au- perimpoaed upon it a~n ad~ustable flux generated by a. coi1. ~ith relatively = small additional flux componenta it ia posaible becauae of the quadratic rela- tion between flux and force to produce proportionately great control forces. It is certainly important for the magnetic circuit to be so configured that the ad- ditionally required flux componenta can be generated with limited circulation of magnetic potential through th~e coils [5]. The latter should also continue to be small for the maximum value of force ae compared with the value required for electromagneta. In this connection experl.~ental investigationa have been car- ~ ried out with the aupport af the Federal Ministry of Research and Technology in - the Institute for Electrical Machines, Drives and Roadways (see Figure 5) which confirm ~he superiority of controlled permanent magneta in comparison with elec- trc~nagnets. As the f~rce current characteri~tic curves show when compared as in Figure 5 it is possible to carry out the control of the permanent magnets with relatively small circulations~. Figure 6 shows an arrangement of magnets in which the flux-conducting magnet eurface ie ~reater than the pole surface (flux focusing) and in which soft iron poles serve to deflec* the flux in the region of the air gap. In this way the magnetic resista.nce of the permanent magnet , segment is diminiahed. As a consequence of the relatively small circulation of magnetic potential the winding crose sectione can be reduced in comparison with the electromagnets. The magnetic time constant which is proportional to the winding croas aection is also raduced. In th~s way the dynamic behavior of the magnet is made more favorable; the force gradient rises with constant voltage elevation. With the aim of obtaining the same dyaamic behavior it is possible to diminiah the power amplification (eize of the current xegulatora) [5-7]. -'.s 'PM EM I -'.o ~ 0.5 Circulation of~magne~ic po`tentia~ ei~~ J ~'igure 5. Suppor~ing force comparioon between permanent magnet and electromag- net. A consideration important for applicationa in the case of long-atator drive ie the reduction in levitaticm power. This power, apart from some other amaller elemente. deci~ively determir~ee the on-board energy require~ent and is thue of easential importance for t.he provieion ef energy on board ~he vehicle. If it ia deaired to accomplish the :Latter without resorting to turbine.power euppliea or to a apecial power transmiE~eion syetem then one csn ti?ak~ use of an induction ef- fect. Through the slot openings of the staCor there arises in opposition to the - fundamental wave of the exciter field a harmonic wave which ~aries relative to the exciter polea ae a function of travel velocity. Its en~rgy can be decoupled ~ ~ 8 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 FOR OFFICIAL USE UNI.ti' by means of an alternating current winding in the poles of the vehicle. The use of the permanent maf,~nets contributes significantly to limiting the power of this linear generator. _ arrying rail - n.: _~~r r 1':/~~. ~:I~ ' . ~"y~.~~~ ~ ~U,n'.~~ . ,;a~ , ~ ~ ~r , .u~�~ rp. sY~; ~�.~r{~lW~l:j,~~.~j ~y~'~i,~ i i ~ ' 1~ I ~ Control coil r ~ t Soft iron ~ 4 ~ ~ IJ ~ ~ , ; i~ ~r~ ~ ' Permanent ~ M?d ~ magnet Figure 6. Permanent magnet arrangement. I Rail 50 , I ' So perturbation b5~, 3mm/Rnsttr ~ ~g 5e~ ~~e bN Magn. , COIIt~01 I _!i CUY'~ei1t5A/R ~ i St Q K ~ Power loss _ ~ of control coil ' PVSt 6DW/A ~ ~ 2 4 sec 6- ~ 2 4 Sec 6 Controlled permanent magnet UB�15V Electromagne : UB� SSV Figure 7. Oscillograms of controlled permanent magnets. Figure 7 shows oscillograms which displa,~ the favorable behavior of control].ed permanent magnets. The measurements show that in the case of electromagnets of the same weight perturbations of. the same size are responded to with about the same gap deviations ss in the case of the permanent magnet only if the battery - voltage is approximately tripled. A perturbation was produced by exciting the carrying rail with a pulse generator. It is also apparent that for the control- led permanent magnet the power peaks are very much lower than for the electro- magnet . 9 FOR OFFICIAL USE UNLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-04850R000500020045-5 - FOR OFFI('IAI. Util~: ONI,~' If. one attempte to simulate the effects of carrier fiexure at high velocitq _ (400 km/hr) on power requirement one can make a conputational estimate of the - requisite carrying power. To thia end the selected simple two-mass model sup- plies a comparatively cor.servative estim~te (with a proportionately high value). Converted to a vehicle which is about 50 meters long the simulat~on shown in Figure 8 yields a power peak of about 20 kilowatte; the average power is very much lower. These power values are to be compared with a carrier power of more than 300 kilowatts in the case of a~vehicle using electromagnets. ~ 1~C~ = J,5 + y~ i~~ r"~ V i`~ Z ml e s ~ ~ ~ r 1 ~ 1 I 1 ~ s ~ ; ~ ; ; ; ~ ~ ~ m ' , , ~ ~ ~ ? a ' ' ~ ~ ~ ~ ' 1 ; ; c~ k1 , ~ , . ~ ~ Z ~;2 ~ ~ m2 ~ i-- 0,2 S --I Time 1 ( S ~ Figure 8. Power requirement in the case of sinusoidal perturbation (~s = 8 mm); nominal force of the magnets: Fo ~ 15,000 N. _ The qualitatively favorable levitation behavior can be made useful for high- I velocity vehicles in various ways. Besides the positive effects upon the design and size of the control elements as well as upon the nec~.3sary on-board power i the greater force gradients also permit more favorable conditions for allowing ; _ greater roadbed tolerances [7]. In order to test the adequacy of th3.s magnet design on the scale of actual ap- plication there was developed in cooperation with Thyssen Henschel and Thyssen = Stainless Steel Works a combined carrying and propulsion ma.gnet having the di- _ mensione appropriate to the IVA vehicle TR 05. Figure 9 shows the magnet on the test stand in the institute. Lifting devic2e were used in constructing the large-volume magnet unita; also used were epecial aasembling devices for in- atalling the magneta. With an 8-mm gap to the etator the carrying force in the currentleae state amounts to 16,000 N; this ia about 30 times the weight of the SmCoS maCerial and about 6 times the magnet weight. 6. A New Short-Stator Linear Mator With High Efficiency The linear motor designs known up until recently could be adapted to a number of conditions of use; but without ex.ception they all displayed a low efficiency which did not correapond to their power level--this efficiency being clearly - less than 90 percent. In the case of a linear induction motor because of the - so-called end effects one is limited to eff3ciencies below 80 percenY,. In con- sequence of the large gap and of a relatively high leakage the power factor is - generally far lo~er so that it was hardly possible to exceed products r1 � cos - 0.4. This in turn implies very great deaign power for the frequency inverter 10 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00854R000540020045-5 FOR OFFICI~.1_ U~N: ONLY required on the vehicley thus giving rise to a considerable additional space and weight requ~rement. If it is to be possible to solve the problem of energy sup- ply at high velocities then there exists moreover the problem of designing a linear motor having an apparent power which is not substantially greater than - the yielded mechanical power. ~ . . , . , , , ~ ~ . . i ~t s~ ~s ~s~ � ~ Y~~: r ~ � 1. : ~ . 'wiidfi! ~ ~y i ~ t' ~ . ~ � ~I (0 yj n f,: ` 1 ~ , ~ ~ - - ~ ~ CD . c;~~s'` I t ~ ~ ~ ` : ~ a -i ~ . . 7'` ~ _ ~ ~L+r`'~,~ _ . . /r~ ~ . :,ey,., ~:t- . Figure 9. Test stand for investigating Figure 10. DELSYM model motor. controlled permanent magnets - Within the framework of a research program for developing vehicles having short- stator drives investigations are being carried out at the Technical University , of Braunschweig of a new synchronous motor with permanent magnet excitation. In ; contrast to previously known types this motor has no electrical excitation but ; an excitation through REC magnets, thus reducing in this way the losses and the ! motor weight. By doubling the exciter arrangement it is possible to achieve an additional amplification of the interaction between the magnetic field and the armature currents. The effects of a homopolar and of a heteropolar interaction are superposed and lead to an increase in the induced voltage. The armature ' winding is designed with toroidal coils [9]. - Figure i0 shows the model motor as used for the first tests for force measure- ment. The rail amployed here is of massive design. Measured force values are plotted in Figure 11 as a function of the surface current of the armature wind- ing; the ma.gnet height amounts to 2 cm. It is apparent that the force densities required for propulsion can be generated with relatively small surface currents. This in turn implies that the motor can be operated with low wlnding losses so that an eff iciency of about 95 percent appears to be obtainable. Of special in- terest with regard to achievement of a light vehicle is a motor configuration which provides not only the propulsive forces but also the carrying force and when necessary the lateral force. The cross section of such an arrangement is sketched in Figure 12. In addition to the REC magnets there is an arrangement - of guide coils which via a control element excite the additional flux components _ required for dynamic stabilization. A control coil inserted in the toothed re- gion outside the winding produces by means of inward or outward field displace- ments controllable lateral forces for guiding the vehicle. These flux compo- nents generated by the control coils can also generate lateral forces when the vehicle is in the middle position. 11 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00854R000540020045-5 FOR OFFICIAL I~SE ONLY ~,'i;i - - _ . E i ~ I- 30~ - - ~ DElSYN ~ L- Madel ~ ~ U I W 2~~ - - - - - - ~r-I V a ~ DELSYM E- h'ud?I 100 - D ' 0 50 100 150 Surface current A ~A/cm1 - Figu~e 11. DELSYM: thrust as ~ function of the surface current (hpM = 2.0 cm - and 1.0 cm). i Secondary part: cross section ~ Guiding ~ i~;~~ ~ I, winding ~;I Carrying Primary part: 2': windin I I g cross section ~~;i; 4~~; _ , ' - Primary part: elevation view Armature winding Figure 12. Integrated DELSYM carrying and guiding motor. Computatione show that, when thus d~saigned, combined carrying, guidance and pro- _ pulsion elements in approximately uniform distribution over the length o� Che vehicle lead to interesting characteriatics of a magnetic suspension system. In 12 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 FOR OFF[CIAL L!SE ON1..1' auch a case the weight of the motor elemente ie probably not more than 20 per- cent of the vehicle weight. In consequence of the very high magnitude of the product of efficiency and power factor there is a considerable reduction in the design power o� the inverted converter as compared with previously known design solutions. i. The Use of REC Magnets in Repulaive Magnetic Support Technology With the emergence of the ferrite magnets with their straight magnetization characteriatic B(H) in the second qua~rant it was possible to consider invest~- gating the possible applicability of ~ contactlees supporting technology which - in addition operates without power [eicJ [10]. This was also especially attrac- tive because the repulsive magnet arrangement leads to a magnetic vehicle which is fundamentally very simple in its structure, permits a gmall vehicle cross section and allows a simple attachment of th~ magrcet to the vehicle. Quantita- tive investigationa of ferrites yielded, however, several problem areas. As Figure 13 indicates the attainable force densities in repulsive carrier technol- - ogy under the same conditions (surprisingly enough) are of the same size as in the case of the pulling magnet arrangement. If ferritie magnets are used then even in the case of lateral ratios of the magnets h:b = 1 only force densities of less than 2.5 N/cm2 are attainable and this gives rise to very broad magnet rails or magnet coverings and a large magnet mase in the vehicle. Despite low apecific magnet costs the result is very expensive vehicle equipment. The pro- portionately large share contributed by the magnets to the vehicle weight and the limited stiffness of the support characteristic curve imply natural �re- quencies of from 1 to 2 Hz when the gap ie small. Sin~e this type flf magnet _ support is lossless and accordingly takes place without damping it is easy to prove that the procedure is not suitable for which are intended to reach speede greater than 50 km/hr. Also the bilateral use of REC magnets in the roadway and on the vehicle does not come within the sphere of discuseion. While thia magnet arrangement does yield the deaired reduction in magnet weight neverthelese the atill absolutely large magnet weighta for the given road~�ay structuxe are subatantially too expensive. The basically obvious idea of uaing ferrite magnets on the roadway and REC mag- nets in the vehicle is to be sure fascinating, but it is not without ita prob- - lems. For it must first be made aure that the ferrite magnets are either not at all or very little demagnetized in the curved portion of their B{H) characterie- tic. Tt~is must also be the case when taking into account temperature variations. 7Chie is all the more readily achieved the thinner the REC magnets and the higher the ferrite magneta and the more favorable their B(H) characteriatic profiles (Figure 14). Such magnet combinations lea3 to force denaitiea cloae to 5 N/cm2 and lie approximately in the middle between the two characteristfc curves for - magnets of the same type according to Figure 13. To thia value of Che force density there corresponds a reduction in the magnet weight to less than 40 per- cent of the usual ~alue for ferrite [11]. ' For the magnet configuration (Figure 15a) the field lines show that in the fer- rite magnet there is practically no reversal of the field direction. In Figure 15b there is plotted the carrying force characteristic for various magnet spac- ings. In order to avoid stronger demagnetizations, approximations of the magnets - 1,, FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 F'OR OFFI('IAl. l~S}~; ONL1' in the range below 4 mm are "blocked" by suitable coverings. In this way there is produced at the noml.nal point of the force a gap of 8 mm. Here the carrying - force per side amounts to 10 kN/m. In con~equence o� the low weight of the REC carrying magnets it is possible, when the latter are coupled opposite to the ve- _ hicle in individual suspension, to attain a resonant frequency up to about 13 Hz. - This yields with regard to the dynamic properties not only gradual changes but also predictions which are fundamentally different from those in the case of a pure ferrite combination. If the magnets are connected via springs and dampers _ to the susp~ension structure and if this latter is then connected via the "sec- ondar.y" springs and dampers at low frequency with the vehicle body then one ob- tains an oscillatory syst~m (Figure 16) which is well damped over a large e~ci- tation range. Also withoufi damping in the range of magnetfc support it is pos- - sible at all velocitiea of interest to limit the accelerations of the passenger cabin to values which meet comfort epecifications (Figure 17). 15 - - ~ ~ F T - - t,o m E i ~ (Pr5m1Co ~ G ~ o Z -hM - o,e ; ~~1 bM . - 06 ~ ~ SmCo5 v H ~ FT Repulsive 0 0.4 w ~ ~ Fer ite 01 ~ 5 Sm o5 0 ro Ferrit 4 3 1 t U -0.2 Ferrit ~4 Field atrength H IkA/cm1 ~ ~ ~,5 Figure 14. Demagnetization charac- Ratio hM/bM teristics. Figure 13. Carrying force as a func- tion of magnet geom~try. The use of REC magnets with a remanence induction of about 1 T has the effect of causing a highly interesting solution to arise out of a practically unusable de- - sign. The computational results shown here were experimentally confirmed with regard to the support characteristic curve (force as a function of magnet spac- - ing) for an appropriate material combination. _ I'urther improvements in the B(H) characteristic curve with REC magnets and fer- rites will have an additional favorable effect upon reductian of the magnet vol- ume. 14 FOR OFF[CIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00854R004500020045-5 - , FOR OFFI('IAI. USN: ONLY a) I SmLoS- Ferrite- ~ _ i I - b) E 150 ~ _ Y IJ.. ~ ~ 1~0 O w ~ ! U-+ rl i u ~ 50 a~ ~ a cd , cn u ; 0 ~'4 1'2 o to zo Air gap d [cm1 ~ Figure 15. a) Field pattern, b) carrying force as a function of the air gap. ~ F r ~ ~ r@. . f~a,� ~s ~ ~c a'y~ � v i M ~ ~ a3 ' ' y,:. ,~iitS,,~v''~C ; ~ ~ . P ~~+c~�>'~ '~}~y~ ~ - + . ~~'~~y~~.r.~.~~`~ ~ ~ s~ ~ 2 t ~'1l7{( ~ : ,~`td 9 , t f , bl ~ ' > . � ~5 r~h _ �s. h _i r y t:~'K}~. ~ ~p'."9`A~ ~i~ ~y :~Y > n~~'~"~~~ � r ~y.s"rR t"~, z s - 4~ R.` � . V.. ~ , E'~ t m fK, OK ; -fj , DZ , fM. ~M . . .u M..~ ;t ~ . . , t.: Figure 16. Multimass model for aimulating the vehicle dynamics: m= mass, f= resonant frequency, D= damping, index K= cabin, Z= intermediate plan~. M ~ magnet. l~or citmensioning the aupport aetup the attainable force densities for a particu- lar gap and also the attainable etiffness represent properties which are of equal importance. A low vehicle magnet weight is of great interest with regard to goud dynamic properties. In order to be able to extract the energy of oscil- lation from the oscillatory magnets when there is excitation coming from the track, the intermediate plane (suspension structure) inserted between magnet and 15 POR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00854R004500020045-5 FOR OFF'I('IA1. ll~l~: ONI.Y . vehicle body must possess a definite minimum mass. This is practically realiz~- able, e.g., by connecting the propulsive motor to the suspension structure. , --1- 6 - - - E E 4 - - ~ N 1 a~ aN c~ ~ 0 0 20 40 60 BO 100 120 ~ Velocity ~ Im/s1 0 6 - - - - N ~E04 _ - - O IN c~d A~1 - _ v A ~ u p - - - _ 1 - - ~ 0 10 40 60 80 100 17U d o Velocity v (m/sl Figure 17. Dynamic operating behavior. . The shock absorptive connection between the magnet and the intermediate plane is in this latter case accomplished with a resonant frequency lying between that of the magnet support and the secondary spring system (see Figure 16). For mag- netic suspension technology there would ~robably be great advantage in being able to secure contactless support without resorting to control-theoretic sta- bilization. The number of required electronic devices and components can be s~sbstantially restricted and in this way a far greater measure of protection against perturbations can be achieved than was the case with the previously con- sidered engineering solutions. But the fact remains that the lateral guidance of the vehicle, if this is to be contactless, is impossible withaut resorting to an active control system. The mere use of an uncontrolled permanent magnet guidance system orthogonal to the stably operating carrying forces would produce destabilization for the latter. The multidimensional suspension of bodies in a magnetic field by permanent mag- nets is known to contradict the Earnshaw theorem. But this is not to say that the described supporting proced~lre cannot be translated into an entirely favor- able system design involving a sharply reduced expense of control electronics. BIBLIOGRAPHY 1. Eitlhuber, E., "The Transrapid Test Facility in Emsland," ETR, Vol 29, No 6, 1980, pp 202-204. 16 FOR OFFIC[AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5 APPROVED FOR RELEASE: 2047/02/09: CIA-RDP82-00850R000504020045-5 FOR ON'FI(7,11, l!tiN: ON1.S' 2. Parsch, C. P., and Raschbichler, H.-G., "The Ferrous Synchronous Long- Stator Motor for the Transrapid Test Facility in Emsland (TVE)," ZEV-GLAS. ANN., Vol 105, No 7/8, 1981, pp 225-232. 3. Schwarz, F. C., "An Improved Method of Resonant Current Pulse :fodulation _ for Power Converters," IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS AND CC1N- TROL INSTRUMENTATION, Vol II C1-22, No 2, May 1976. 4. Weh, H., Vollsted, W., and Meins, J., "Model of an Integrated Support and Propulsion System of Electromagnetic Type," ELEKTROTECHNISCHE ZEITSCHRIFT-A, 1974, p 684. 5. Weh, H., "Linear Synchronous Motor Development for Urban and Rapid Transit Systems," IEEE TRANS. ON MAGN., Vol MAG-15, No 5, 1979, p 1422. 6. May, H., "Controlled Permanent Magnet (CPM) Configurations Generating Forces for Lift, Guidance and Thrust," IEEE PROCEEDINGS Or THE INTERNA- , TIONAL CONFERENCr OF CYBERNETICS AND SOCIETY, 1980, p 793. 7. Kaupert, G., Huebner, K. D., and [Jeh, H., "Dynamic Behavior of Controlled ~'ermanent-Excited Carrying Magnets for High-Speed Railways," ELIICTROTECH- PIISCHE ZEITUNG--archive (to appear shortly). 8. Weh, H., "Linear Synchronous Propulsion With Permanent Magnet Excitation," IEEE PROCEEDINGS OF THE INTERNATIONAL CONFERENCE OF CYBERNETICS AND SOCI- ETY, 1980, p 1042. 9. Weh, H., and May, H., "Investigation of Synchronous Linear Motor With Double Permanent Magnet Excitation," PROCEEDINGS OF THE INTERNATIONAL CON- FERENCE ON ELECTRICAL MACHIIIES, 1980, p I92. 10. Polgreen, G. R., "New Applications of Modern Magnets," MacDonald, London, 1966. 11. Weh, H., "Uses of. Rare-~arth Permanent Magnets in Tracked Vehicles," paper No II-3 at the Fifth International Workshop on Rare Earth-Cobalt Permanent Magnets and Their Applications, Roanoke, VA, June 1981 (book by University oE Dayton, KL-365, Dayton, Ohio, 45469, USA). COPYRIGHT: Georg Siemens Verlagsbuchhandlung 1981 8008 CSO: 3102/80 END . FOR OFF[CIAL USE ONLI' APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500020045-5