About Electric Scooter Mobility. Aspects Regarding the Designing of a Brushless DC Motor for an Electric Scooter

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1 ISSN: , Volume-5, Iue-4, April 06 About Electric Scooter Mobility. Apect Regarding the Deigning of a Bruhle DC Motor for an Electric Scooter Ionuț Daniel Smărăndecu, Petre-Marian Nicolae Abtract: The paper deal with the electric cooter mobility in Europe and with the deigning of a bruhle dc motor for an electric cooter. In the firt part of the paper, the context and the motivation of the theme are preented. In the econd part of the paper, the electric cooter market i decribed. Then, the main part equipping an electric cooter are expoed. The final part of the paper deal with the deigning of a permanent magnet bruhle dc motor for electric cooter propulion. Index Term: deigning, electric cooter, electric cooter mobility, permanent magnet bruhle dc motor. I. INTRODUCTION We will not top till every car in the road i electric. - Elon Muk [], []. Thi peech wa given by the CEO of Tela Motor - one of the mot famou manufacturer of electric vehicle worldwide. Diregarding the trong advertiing content of the preceding quotation, what i true i that, in future, more electric vehicle will hare the road infratructure with traditional vehicle. An electric vehicle, either a car or a cooter, i often preented a an environmentally friendly alternative to the traditional mobility. Thi applie only conidering emiion, but everal factor mut be analyzed to decribe a full frame. Along with electric vehicle, new material are introduced into the product lifecycle, uch a permanent magnet ued in bruhle dc motor, or lithium, ued in batterie. The main interet of Eco Deign i to examine the condition for and to provide help in creating a utainable future by improving recycling, energy aving and product well uited for it purpoe. - Conrad Luttropp [], [3]. With thee word, it i poible to undertand the perpective that were ued to carry out the entire tudy. There i no eay olution or an eay repone to get an efficient deign in term of the environment. Thi tudy wa conducted to gain a clearer view of the electric mobility a an efficient alternative to protect the environment. II. THEME CONTEXT Citie are increaingly populou and cooter are gaining ground a an alternative to car [], [4]. However, traditional cooter, epecially thoe equipped with two-troke engine, Revied Verion Manucript Received on March 09, 06. Ionuț Daniel Smărăndecu, Department of Electrical Engineering, Energetic and Aeronautic, Univerity of Craiova, Faculty of Electrical Engineering, Craiova, Romania. Petre-Marian Nicolae, Department of Electrical Engineering, Energetic and Aeronautic, Univerity of Craiova, Faculty of Electrical Engineering, Craiova, Romania. are due to exhaut gae, one of the main caue of air pollution. According to the Environmental Protection Adminitration, the Government of China, an ordinary cooter with two-troke engine produce from three to even time more pollutant per kilometer than a,000 3 car [], [5]. After an examination of the hitory of electric car and electric cooter, it i intereting to note how they are not a new product. In fact, both were conidered a an alternative to the internal combution engine vehicle before the 0. During the 90, variou reaon (increaed fuel price, environmental iue) led to the redicovery of electric vehicle. In the lat fifteen year, manufacturer have made many effort to produce electric vehicle that are comparable to traditional vehicle, in term of performance. Mot of the major car manufacturer have electric car available through their model. The current electric cooter market ituation can be decribed by the following viciou cycle: high initial price reduced attraction for cutomer reduced requirement for electric cooter lack of interet for the invetor ma production of electric cooter can not be initiated no large-cale ale high initial price. Thi ituation mut be changed by entering the following cycle: high interet for invetor ma production of electric cooter large cale ale low initial cot increaed cutomer atifaction high demand of electric cooter high interet for invetor. The tranport ytem of the t century mut be environmentally friendly, efficient, intelligent and utainable. III. THEME MOTIVATION Two-wheeled vehicle have alway been a practical olution for individual tranport for urban area, where the average peed for a vehicle with four wheel often fall below the peed of walking due to the number of car and tranport infratructure. When thi environmentally friendly pecial mobility i combined with a propulion ytem, reult a vehicle that ubtantially contribute to olving two of the mot ditreing problem of city dweller and local government: tranport and environmental protection. Electric cooter now have a growing popularity, mainly due to the increae in oil price. The battery technologie achieved ignificant progre, making thi mode of tranport increaingly more attractive to potential uer. Benefit: 9 Publihed By:

2 About Electric Scooter Mobility. Apect Regarding the Deigning of a Bruhle DC Motor for an Electric Scooter The cot of fuel i about 5% of the one equivalent to petrol; Quiet far uperior; Lack of noxiou emiion; The batterie can be recharged anywhere there i a public network power upply (even at home); Reduced maintenance cot - whether for labor and conumable (eg. do not require oil change, variou filter, etc.). Diadvantage: Purchae price higher than the one equivalent to the model fitted with internal combution engine; Le autonomy; Recharge time relatively large (matter of hour). IV. ELECTRIC SCOOTERS MARKET DESCRIPTION Firt, it i important to give a definition of the cooter. Oxford Dictionarie define cooter a follow: A light two-wheeled open motor vehicle on which the driver it over an encloed engine with their leg together and their feet reting on a floorboard. - Oxford Dictionarie [], [6]. Electric cooter are plug-in electric vehicle (which are loaded from an electrical outlet) with two or three wheel powered by electricity. Electricity i tored on board in a rechargeable battery, which drive one or more electric motor. Electric cooter (unlike motorcycle) have a tep-through frame type [7]. Two-wheeled vehicle fleet in Europe amounted to over 36 million unit in 0. In the lat decade the number of motorcycle and moped grew by more than 6 million unit. The number of two-wheel vehicle in Europe increaed year by year until 00 when the vehicle market fell due to economic crii. Conidering the lat 0 year, average cooter and motorcycle regitered in Europe every year wa,00,000 [], [8]. The European country that produce mot motorcycle and cooter i Italy, with over 400,000 unit, followed by Germany - 0,000 and 95,000 - Spain. What mut be noted i that ome European brand have the production line in India or China, while ome manufacturer are Japanee, o their production i almot negligible in Europe [], [9], [0]. Conidering the top ten two-wheel vehicle old in 0 [], [8], even out of ten model are from the L or L vehicle categorie. The major manufacturer of two-wheel vehicle with an engine capacity of up to 5 3 are the Italian firm Piaggio and Vepa and Japanee firm Honda Motor and Yamaha Motor. To get an overview of electric cooter market, the report provided by Navigant Reearch Leaderboard [], [] in term of electric cooter, tate that the electric cooter market in Europe i around % of the traditional cooter market. The report tate that the two main market area are Aia Pacific and Wetern Europe. However, the two market have different characteritic. The Aian market hold more than 99% of the global ale. The electric cooter old in Aia Pacific are low cot vehicle, with relatively few option and improvement. The market in Wetern Europe i the econd world market, even if it volume i dramatically lower than in Eatern Europe. In Europe, electric cooter have everal improvement and can compete a a performance with traditional one. However, electric cooter preent on the European market are ignificantly more expenive than the one with internal combution engine. One conducted a brief urvey of the producer of electric cooter preented in the Navigant Reearch Leaderboard report (ee Table I) [], []. The idea i to highlight the difference between a model for the Aian market and one for the European market. It hould be noted that in thi analyi Japan i not part of the Aia market. Japanee market characteritic are imilar to that of Wetern Europe. The main deign difference between the two market are hown in Table II. Alo, there are difference in term of other pecification, uch a the technology of braking, energy recovery technologie, autonomy, etc. Thee requirement differ from model to model [], [] - []. Therefore, without loing generality, it i poible to ay that the main difference remain in battery technology. Lead batterie have a low price, but have low performance. Since the purpoe of the Navigant Reearch Leaderboard report [], [] i making a comparion between a cooter with traditional technology and an electric cooter, the electric cooter model i choen for the European market. After the repreentative technology wa elected, wa made a comparion between the performance and the price of a European electric cooter and thoe of a traditional cooter (ee Table III). Table I. Top Ten Producer of Electric Scooter. Company Targeted market Country where the cooter are manufactured Manufacture and cooter with internal combution engine Jiangu Xinri E-Vehicle Co. Aia China No [] Vmoto [3] Aia + Europe Autralia No SYM [4] Europe Taiwan Ye Vectrix [5] Europe U.S.A. No Terra Motor [6] Europe Japan No Govec [7] Europe Germany No Yamaha [8] Europe Japan Ye Peugeot [9] Europe France Ye io Scooter [0] Aia + Europe Autralia No BV Nimag (Nimoto) [] Europe Holland Ye Table II. Europe / Aia comparion. Apect EU market model Aia market model Battery technology Lithium Lead acid Battery recharging time 3-5 h 6-8 h Weight 00-0 kg 0-40 kg Maximum peed km/h 45 km/h Table III. Performance comparion: electric cooter ordinary cooter. Apect Electric cooter Internal combution engine cooter Recharging point Home outlet / work Ga tation 0 Publihed By:

3 ISSN: , Volume-5, Iue-4, April 06 Recharging time 3-5 h 0 min. Weight 00-0 kg kg Maximum peed km/h 60 km/h Autonomy 65 km 50 km Average fuel conumption 3,3 kwh/00 km 3,3 l/00 km Buying price 5400 $ 700 $ The fuel cot after 50,000 km 345 $ 334 $ V. MAIN SUBASSEMBLIES EQUIPPING AN ELECTRIC SCOOTER Figure depict the electrical chematic of a drive ytem for an electric cooter, in the embodiment with permanent magnet bruhle DC motor. A. Accumulator Batterie Traction motor for electric cooter are, uually, powered from batterie, which - eentially - are formed by grouping of everal electrochemical element in variou connection. Accumulator batterie can be placed either in the pace below the cooter addle or the cooter floor, covered by the element of the bodywork and ecured by mean of pecial upport that allow diaembly eay to replace and enure appropriate retraint, including the ituation where the cooter overturn []. Mot electric cooter from today are powered by rechargeable lithium-ion batterie, but there are model that ue nickel-metal. The manufacturer of cooter Z Electric Vehicle pioneered the ue of ilicate lead / odium batterie (a derivation of the traditional lead acid battery invented in 859) that are comparable a performance with lithium batterie, but at a lower cot [7], [3]. The currently ued traction batterie can be divided into two broad categorie: Lead-acid accumulator which repreent about 95% of current traction batterie; Alkaline batterie and other type, which repreent about 5% of actual traction batterie. The lifepan of a battery i it ability to upport a many charging and dicharging cycle without loing it propertie. Table IV preent a comparion between different battery technologie ued to power electric cooter [], [4]. Table IV. Comparion of Battery Technologie. Battery technology Specific energy Lifepan Energetic efficiency Lead-acid % NiCd % NiMH % Li-ion Na/S B. Electronic Sytem for Battery Charging The electronic ytem for battery charging mut enure a full and correct charging of the traction batterie in a afe way and in a reaonable amount of time (under 0h - to enure the poibility of uing the cooter over the entire range, each day) [34]. Characteritic: Supply voltage: 0 V AC, ingle phae, 50Hz; Circuit type: thruter rectifier controlled by a meaurement and charging control circuit; The maximum current flow: 3 A DC; Limiting the maximum charging voltage. C. Control Sytem of the Bruhle DC Motor For the bruhle DC motor control i neceary to know preciely, at any time, the rotor poition. The neceary information to determine the rotor poition againt the tator, i given by the poition enor (Hall enor). Baed on thi information, we know how to command the inverter tranitor that feed the motor phae [5]. In order to be effective in command and control, the three-phae bruhle DC motor require a three-phae inverter (the half bridge) generating a inuoidal ignal (6-tep control). Alo require that the electronic witching of the motor phae to repect and maintain ynchronim between the rotor flux and the tator flux (magnetic flux). Generally, the control circuit of uch engine ue one or more poition enor which give the information needed to determine the rotor poition and thu preerve the ynchronization between the two flow [6]. D. The Bruhle DC Motor Currently, there are variou technologie available for electric motor. However, mot uitable for electric cooter i the bruhle DC motor with permanent magnet. The main feature of thi engine i the high pecific energy. A high pecific energy mean an engine with low weight [], [7]. The bruhle DC motor replace the motor with with bruhe in many application, due to lower energy conumption, increaed reliability and low maintenance. Bruhle DC motor were required in electric drive with low power, but the control complexity for wide peed range and the high cot of pecialized control circuit have limited their pread worldwide. In the lat decade, the continuou development of technology in variou field and the production of permanent magnet bruhle dc motor led to the emergence of economically effective olution for a wide pread of variable-peed application [8], [9]. Figure. Electrical cheme of the drive ytem for an electric cooter. Publihed By:

4 About Electric Scooter Mobility. Apect Regarding the Deigning of a Bruhle DC Motor for an Electric Scooter VI. ASPECTS REGARDING THE BRUSHLESS DC MOTOR DESIGNING In the following are preented ome apect from the deigning of a permanent magnet bruhle dc motor, ideal for ue in a drive ytem for an electric cooter [6], [30]. Selecting a pecific configuration of a bruhle DC motor depend on the application requirement. In thi cae, a permanent magnet machine with radial flow and inide rotor wa elected. phae, pole, tator notche and winding configuration are determined depending on where the motor run. The number of magnetic pole depend on everal factor uch a inertia, the magnetic material, the effect of ripple and peed of rotation. Stator yoke thickne i reduced by half if the number of magnetic pole double. For a given amount of current and at a certain rotor, the total of the motor can be reduced by increaing the number of pole: Bg Dr π hrr hr. ( ) p B Table V preent the calculated parameter for the bruhle DC motor. With a certain thickne of the radial magnet, the air gap induction can be calculated by: Br Bg, () ge + µ r lm where the effective air gap i defined a: lm ge gc +, (3) µ and g c i the air gap in the the notche area. The inner of the tator i: D D + l g. (4) r ( ) i r m + Stator teeth i: b π D B / Q B. (5) i iron ( ) ( ) i To build a compact motor, a high current denity (S ) i not deirable. The load of the machine mut alway be le than the maximum allowed current (S max ) in order to prevent demagnetization of permanent magnet: 3 T S A/m, (6) π D Bg L k w gc kw ( Bg BD ) S < S p A/m, (7) max D µ 0 inα where B D i the induction demagnetization limit and α i half of the magnet opening in electrical degree. Table V. Calculated parameter of the bruhle DC motor. g iron Torque T 4 Nm Air gap induction Motor active length Notch conductor per notch Speed Current denity Conductor B g L h 4 T 30 0 n 8 ω m J A conductor 7500 RPM 0 A/, Stator outer Tooth Copper urface Magnet thickne Stator yoke Rotor yoke Maximum current load Charging current D o b t A cu l m h r h rr S max S 5,8 3 3,5 4,4 4,4 85, ka/m 47,5 ka/m The active length of the motor i calculated a: 3 T L. (8) π D B S The number of conductor from the notch i: Z n, (9) 3 p q where Z i the total number of conductor and i given by: 3 T Z. (0) D L I B g k w The torque contant derive from the previou formula: T kt ( Z D L Bg kw ) Nm/A () I 3 The induced voltage can be approximated by the equation: E g n D L ω k B () phae Stator teeth urface area baed on the of the notch: π Diz Diz Anotch + h biz h (3) Q The urface of a conductor and the urface of a ingle conductor from the notch: Acu Anotch k fill (4) Acu Aconductor n The outer of the tator reult a: D D + h + h (5) o i g w ( ) The ditribution of the winding i performed differently for each combination of pole / lot. Thu, for the tudied cae, the winding are ditributed a hown in the figure below (Figure ). Table VI how the coil phae ditribution. r g Parameter Symbol Value Parameter Symbol phae pole notche m 3 p 4 Q Air gap g 0,5 Induced voltage Rotor Diameter + air gap Stator inner E ph D r D D i Valu e,9 V 0,5 3 Publihed By:

5 ISSN: , Volume-5, Iue-4, April 06 Figure. Winding ditribution (Phae A - red, Phae B yellow, Phae C - blue). Table VI. Coil Phae Ditribution. Coil Coil Phae A Phae B Phae C Number Angle In Out In Out In Out Vmoto, 4. Sym, 5. Vectrix, 6. Terra Motor, 7. Govec, 8. Yamaha Motor, 9. Peugeot cooter, 0. io cooter, Nimag B.V. (Nimoto), Billing Randy, Z Electric Vehicle Introduce New Model 5000 Scooter, EV World.com, 9 May Sullivan J.L. and Gaine L., Statu of life cycle inventorie for batterie, Energy Convenion and Management, Vol. 58, pp , Bruhle DC motor - three phaed, Electronica AZI, web acce: (in romanian). 7. Larminie J. and Lowry, J., Electric machine and their controller, Electric Vehicle Technology Explained, Chapter 6, Second Edition, *** _f%c4%83r%c4%83_perii e-de-curent-continuu-far7364.php. 30. Franua Al., Măgureanu R., Câmpeanu A., Condruc M., Tocaci M. Machine and electric drive ytem, Ed. Tehnică, Bucharet, 978 (in romanian). VII. CONCLUSIONS The emergence of cooter in urban tranport ha occurred ince the period immediately following the Second World War. Low maintenance cot and agility in handling mattered a lot in a crowded city, making the ue of the cooter a very good olution. Along with the development of power electronic and with the introduction of new legilation regarding pollution, the major vehicle manufacturer have turned their attention toward endowment vehicle with electric motor. The implementation of the olution with the permanent magnet bruhle DC motor in the electric cooter drive ytem, wa taken after it wa found by manufacturer that it meet mot of the requirement, namely: the ize / weight / peed ratio got it to impoe over the other type of engine; implicity of contruction; mooth engine operation under extreme condition; poibility of peed control in a wide range of peed. REFERENCES. Braconi Dario, Green two-wheeled mobility-material Hygiene and life cycle analyi of an electric cooter, Diertation, Stockholm, Sweden, mkomponentdeign/ecodeign. 4. Colella Wh. G., Market propect, deign feature, and performance of a fuel cell powered cooter, Journal of Power Source, Electric motorcycle development action plan, EPA, Environmental protection adminitration, The motorcycle indutry tatitical overview, ACEM, Environmental annual report, Honda, Corporate Social Reponibility report, Piaggio, oard-report-electriccooter.. Jiangu Xinri E-Vehicle Co., 3 Publihed By: