Types of Electric Motors Used in SeveralElectric Vehicles Lizeth Castillo, EPN Student; Jennifer P. Taipe, EPN Student. Abstract— The following paper contains information about different electric motors and how electric motors make work a big electric vehicles (EV) like trolleys, trains, underground or small vehicles as cars, just like a combustion motor does. There are five main electric motor types, DC, induction, permanent magnet synchronous, switched reluctance and brushless DC motors are studied. Studying these motors develop a concept in the reader about how it works, and the characteristics on them to finally understand why electric motors it is used in Ecuadorian public transport as we see on Metrobus, Trolley-Bus, and other electric vehicles arrived. Information will be collected for do a summary show it below, this information is taken from thesis, essays or papers in order to encourage the reader on finding a clear idea of whether the electric motor is an option to replace combustion motors in cars or is better stay with the old ones. Index Terms— Electric Motors, Electric Vehicles, Subways, Trolleys. I. INTRODUCTION T 1960s and 1970s saw a need for alternative fueled vehicles to reduce the problems of exhaust emissions from internal combustion engines and to reduce the dependency on imported foreign crude oil. During the years from 1960 to the present, many attempts to produce practical electric vehicles occurred and continue to occur. HE The purpose of this paper is to describe the technology used to produce an electric vehicle and explain why the electric motor is better than the internal combustion engine. It includes reasons why the electric vehicle grew rapidly and the reason it is a necessity to better the world today. The paper describes the most important parts in an electric vehicle and hybrid electric vehicle. The overall impact of the electric vehicle ultimately benefits the people. Compared to gasoline powered vehicles, electric vehicles are considered to be ninety-seven percent cleaner, producing no tailpipe emissions that can place particulate matter into the air. [1] The first electric vehicle (EV) was built between 1832 and 1839, the exact year is not known, in Scotland by Robert Anderson, who created the first crude electric carriage. It was not until 1895, after A.L. Ryker built an electric tricycle and William Morrison built a six passenger wagon, that America paid attention to the electric vehicle. In 1902 Wood created the Electric Phaeton, which was more than an electrified horseless carriage and surrey. “The Phaeton had a range of 18 miles, a top speed of 14 mph and cost $2,000” The decline in use and production of the electric vehicle occurred in the 1920s. Causes of the decline in production include: a better road system, reduced price of gasoline by the discovery of the Texas crude oil, invention of the electric starter, and the mass production of the internal combustion engine vehicles. According to the History of Electric Vehicles, “In 1912, an electric roadster sold for $1,750, while a gasoline car sold for $650”. By 1935, electric vehicles completely disappeared. The 1960s and 1970s electric vehicles reappeared because internal combustion vehicles were creating an unhealthy environment for the people in America at that time. One of the earliest gasoline-electric hybrid vehicles was developed by an important IEEE member, named Victor Wouk. He and his partners converted a Buick Skylark into a hybrid automobile that was shown in 1974. His primary motivation for pursuing hybrid technology was to reduce greenhouse gas emissions, and the automobile was capable of obtaining 85 miles per gallon of gas. [2] In that time frame, gas was inexpensive and emission controls weren’t a concern, and his funding eventually ran out. Wouk continued to promote hybrid vehicles throughout his illustrious career as an electrical engineer and entrepreneur, including the submission of many articles in IEEE conferences and IEEE Spectrum magazine. Victor Wouk is often referred to as “the Godfather of the hybrid car.” Dr. Wouk’s vehicle is known as a forerunner to today’s hybrid plug-in electric vehicles, and he, along with many This work has been done on February 02, 2016 in Quito Ecuador for the class Electric Machines (IEE584) of the National Polytechnic School dictated by engineer Dr. Franklin Quilumba. other IEEE members, have been involved from the beginning of electric vehicle development. The earliest related document in the IEEE Electronic Library (IEL) entitled “Petro-Electric Motor Vehicles” by JBG Damoiseau was written in 1913. The IEL itself holds an excess of 4000 articles related to Electric Vehicles and more than 1,800 articles on batteries for EVs. [2] II. ELECTRIC VEHICLES The electric vehicle (EV) is propelled by an electric motor, powered by rechargeable battery packs, rather than a gasoline engine. From the outside, the vehicle does not appear to be electric. In most cases, electric cars are created by converting a gasoline-powered car. Often, the only thing that clues the vehicle is electric is the fact that it is nearly silent. [3] Under the hood, the electric car has: An electric motor. A controller. A rechargeable battery The electric motor gets its power from a controller and the controller gets its power from a rechargeable battery. The electric vehicle operates on an electric/current principle. It uses a battery pack (batteries) to provide power for the electric motor. The motor then uses the power (voltage) received from the batteries to rotate a transmission and the transmission turns the wheels.[1] Four main parts make up the electric vehicle (Figure 2.1): Potentiometer: It is circular in shape and it is hooked to the accelerator pedal. The potentiometer, also called the variable resistor, provides the signal that tells the controller how much power is it supposed to deliver. Fig. 2-1. Parts of an electric Vehicle. [3] A. Theory of Operation for EV When the driver steps on the pedal the potentiometer activates and provides the signal that tells the controller how much power it is supposed to deliver. There are two potentiometers for safety. The controller reads the setting of the accelerator pedal from the potentiometers, regulates the power accordingly, takes the power from the batteries and delivers it to the motor. The motor receives the power (voltage) from the controller and uses this power to rotate the transmission. The transmission then turns the wheels and causes the car to move forward or backward. If the driver floors the accelerator pedal, the controller delivers the full battery voltage to the motor. If the driver takes his/her foot off the accelerator, the controller delivers zero volts to the motor. For any setting in between, the controller chops the battery voltage, thousands of times per second to create an average voltage somewhere between 0 and full battery pack voltage. B. Description of a Hybrid Vehicle Batteries: The batteries provide power for the controller. Three types of batteries: leadacid, lithium ion, and nickel-metal hydride batteries. Batteries range in voltage (power). DC Controller: The controller takes power from the batteries and delivers it to the motor. The controller can deliver zero power (when the car is stopped), full power (when the driver floors the accelerator pedal), or any power level in between. If the battery pack contains twelve 12-volt batteries, wired in series to create 144 volts, the controller takes in 144 volts direct current, and delivers it to the motor in a controlled way [3]. The controller reads the setting of the accelerator pedal from the two potentiometers and regulates the power accordingly. If the accelerator pedal is 25 percent of the way down, the controller pulses the power so it is on 25 percent of the time and off 75 percent of the time. If the signals of both potentiometers are not equal, the controller will not operate. [3] Motor: The motor receives power from the controller and turns a transmission. The transmission then turns the wheels, causing the vehicle to run. The hybrid vehicle (HV) is powered by both a gasoline engine and electric motor. Argueta - 4 The HV runs using power from an internal combustion engine and electric motor. The engine provides most of the vehicle’s power, and the electric motor provides additional power when needed, such as accelerating and passing.[4] The hybrid vehicle operates on a gasoline and electric energy principle. A hybrid car features a small fuel-efficient gas engine combined with an electric motor that assists the engine when accelerating. The electric motor is powered by batteries that recharge automatically while you drive. [4] Four main parts make up the electric vehicle (Figure 2-2.): Battery: The batteries in a hybrid car are the energy storage device for the electric motor. Unlike the gasoline in the fuel tank, which can only power the gasoline engine, the electric motor on a hybrid car can put energy into the batteries as well as draw energy from them. Internal Combustion Engine (ICE): The hybrid car has an ICE, also known as a gasoline engine, much like the ones found on most cars. However, the engine on a hybrid is smaller and uses advanced technologies to reduce emissions and increase efficiency. Receives its energy from the fuel tank where the gasoline is stored. Generator: The generator is similar to an electric motor, but it acts only to produce electrical power for the battery. Power Split Device: The power-split-device resides between the two motors and together with the two motors creates a type of continuously variable transmission. Electric Motor: The electric motor on a hybrid car acts as a motor as well as a generator. For example, when needed, it takes energy from the batteries to accelerate the car. But acting as a generator, it slows the car down and returns energy to the batteries. A. DC Motors Although DC motors have been the subject of interest since old time because of simple control and decoupling of flux and torque, their construction (having brushes and rings) poses maintenance problems. Therefore, after the growth of vector control for AC motors (synchronous and induction), the DC motors' attraction in traction applications diminished. Of course, DC motors are still good candidates for low power applications. The commutator actually acts as a robust inverter; therefore, power electronics devices can be mush simple and inexpensive. The Peugeot factory of France has introduced a HEV named "Dynavolt" in which, DC motor has been used as traction motor Fig. 3-1. DC Motor. (Courtesy of Drive-electric, org.) Fig. 2-2. Parts of a hybrid Vehicle. [4] C. Theory of Operation for Hybrid When the driver steps on the pedal the generator converts energy from the engine into electricity and stores it in the battery. The battery then provides power to the electric motor. The internal combustion engine and electric motor work simultaneously and each provide power to the power split device. The power split device combines both powers and uses it to turn the transmission. The transmission then turns the wheels and propels the vehicle. [1] The energy used when braking is converted into electricity and stored in the battery. When braking, the electric motor is reversed so that, instead of using electricity to turn the wheels, the rotating wheels turn the motor and create electricity. Using energy from the wheels to turn the motor slows the vehicle down. When the vehicle is stopped, the gasoline engine and electric motor shut off automatically so that energy is not wasted in idling. The battery continues to power auxiliary systems, such as the air conditioning and dashboard displays. [1] III. CARS In this section, the advantages and disadvantages of different electric motors are discussed. B. Induction Motors (IM) Squirrel cage induction motors have already been the most important candidate because of their reliability, robustness, less maintenance and the ability to work in hostile environments. The induction motors have the most mature technology among all other AC competitors. In Fig. 2, the main characteristics of an induction motor have been shown. Torque and field control can be decoupled using vector control methods. Speed range may be extended using flux weakening in the constant power region. [5] Fig. 3-2. A typical squirrel cage rotor. (Courtesy of General Electric Company.) C. Permanent Magnet Synchronous (PMS) motor (or brushless AC- BLAC) PMS motors are the most serious competitor to the induction motors in traction applications. Actually, many car manufacturers (such as Toyota, Honda and Nissan) have already used these motors in their vehicles. These motors have several advantages: higher power density, higher efficiency and the more effective distribution of heat into the environment. However, these motors have intrinsically a narrow constant power region. To widen the speed range and increase the efficiency of PMS motors, conduction angle of the power converter can be controlled at speeds higher than the base speed. Speed range can be extended to three of four times the base speed. A shortcoming of these motors is that they can be demagnetized due to the heat or armature reaction. [5] However, in the following section the DC and SRM motors are not taken into consideration due to their disadvantages [5]. Fig. 3-3. Differences between IM and PMS. D. Switched reluctance motors (SRM) Switched reluctance motors are receiving much attraction in HEV (Hybrid Electric Vehicle) systems every day. Among the advantages of these motors are: simple and rigid construction, fault tolerance, simple control and excellent torque-speed characteristic. A switched reluctance motor can intrinsically operate under a wide constant power region. Several disadvantages such as high noise, high torque ripple, special convertor topology and electromagnetic interference have been mentioned for this motor [5] Fig. 3-5. Common EVs and their propulsion systems IV. TROLLEYBUS Trolleybus, also known as trolley or trolley, is an electric bus powered by a catenary wires from two Superior where it takes the electricity through two poles. The trolley does not use special lanes or tracks in the driveway, which it by a more flexible system. It has rubber tires on steel wheels Time on rails, as the trams. [6] Fig. 3-4. Conventional Characteristic of a SRM. E. Brushless IX motors (BLOC) These motors are conceptually the outcome of reversing the stator and rotor of permanent magnet DC motors. They are fed by rectangular waves in contrast to BLAC motors which are fed by sinusoidal waves. Their main advantages are the deletion of the brushes, their compactness, high efficiency and high energy density. In, the traction systems commonly used in EVs are evaluated based on six factors. As shown in table. II, a score out of 5 is given for each point to each motor. It is concluded that based on these factors, the 1M and PM motors are more suitable. The electric trolleybus system has multiple electrical connections making it very complex. To conduct a review of the motor cable should review their respective cable connection. To distinguish them, the cables generally have different colors, thereby to be a kind of electric coding language to operate the entire system. To repair some of the connections that make electricians detect electrical short first required and then repair damaged and insulated with a special ribbon cable. A. Trolleybus (Trolebús) in Ecuador Trolleybus is a medium of electromechanical public transport, using electrical power is carried by a catenary two upper cables, specifically in the city of Quito trolleybus has built an internal combustion engine that allows greater versatility, however the biggest advantage provided by this type of vehicle is to be a means of friendly transportation environmentally avoiding the emission of gases into the atmosphere. Use a three-phase 4-pole asynchronous electric motor with standard output of 230 kW and the cooling system is with forced ventilation, these features are presented in all fleets, Figure 3.1 shows the main electrical parts.[7] through pilot service tests with the customers. [8] Fig. 4-1. Trolleybus diagram. [7] Fig. 5-1. Driven by Toshiba’s PMSM. [8] DISADVANTAGES Trolleybus share benefits with tram and bus but also some disadvantages. If the trolleybus is accidentally separated from the catenary stops. For the same reason, the possible routes are limited to the sections with catenary installed. However, one may incorporate a battery a conventional combustion engine to enable greater versatility ADVANTAGES Trolleybuses are of particular importance to rugged and mountainous cities, where electricity is more effective than diesel when climbing hills; also they have more grip than tranvías. Trolleybuses, like all electric vehicles, often seen as a means of transport more compatible with the environment than burning buses that consume hydrocarbons and emit gases. The use of energy produced in power plants has advantages over internal combustion engines : it is more efficient , you can use wider range of fuels and is more convenient for pollution control and can reuse the heat generated by supplying hot water for all uses ( industries , hospitals , sports facilities ) , or cold generation with absorption equipment . In any case, you can also use renewable electricity. V. SUBWAY Toshiba is one of the suppliers to be used a PMSM (Permanent Magnet Synchronous Motor) for a different types of subways. The goals have been the following two: developing an environment-friendly new system and reducing signicantly the running costs for the operator. Using data accumulated through research, development and led tests during the development phase, we established the PMSM traction system technologies for railway cars. The PMSM's advantages such as energy savings, noise reduction and easier maintenance were veried Since then, PMSM systems have been deployed in mass produced commuter/subway trains and have been operated since 2007. Using this technological breakthrough as a starting point, Toshiba continues to innovate and improve this environment-friendly PMSM system to allow its use by more customers. Some characteristics mentioned: A. Efficient Global activities are underway to reduce CO2 emission, and railway companies also face considerable expectations to reduce electric consumption of train cars. The Toshiba Permanent Magnet Synchronous Motor (PMSM) achieved higher efficiency than traditional Induction Motor (IM) due to the elimination of secondary loss. Toshiba's technology appropriately exploits the advantages of this PMSM system, and boasts a high efficiency of 97%. [8] B. Smarter Railway systems are constantly striving to make periodic maintenance simple and cost effective, which is essential for stable operation. The maintenance of conventional open selfventilating type IM systems is time consuming, mostly due to the nature of its construction. For conventional motors, the case has to be opened with a dedicated jig to remove the rotor, the inside cleaned, and the bearing regreased. Toshiba has developed a totally-enclosed structure to make maintenance operations smarter compared to our conventional Induction Motor (IM) in terms of cost and time. We have successfully eliminated potential internal contamination, which makes cleaning no longer required through the PMSM's service life. We have also engineered a structure allowing the bearing unit to be replaced without disassembly of the entire motor. Consequently, while improving the maintenance of bearing crucial for stable operation, Toshiba successfully eliminated the conventional maintenance 3D (Dirty, Demanding, and Dangerous) C. Quieter Demands to ensure low noise operation have been intensifying year by year, especially for the traction of subway trains. Toshiba has succeeded in reducing ventilation noise by about 12dB throughout all speed ranges compared to our conventional open self-ventilating type. Additionally, since exhaust air and heat are also reduced as well as noise, this limits the temperature increase in subway tunnels, helping conserve electricity used to power air conditioning in the tunnels. [8] D. Reliable o o Simple and Lightweight: Toshiba's PMSM has a lighter weight than that of conventional open selfventilating type IM as well as a simple, totallyenclosed and natural cooling structure without radiation ns and ventilating fans. Despite the totallyenclosed natural cooling structure, its appearance is equivalent to that of the conventional open selfventilating type IM, and its size and mass are generally equivalent to less than an IM. Therefore, in most cases the PMSM can be installed in existing bodies as-is. When under the same cooling condition as an IM, reduced weight or increased output of approximately 20% is also achieved. Implannter permanent magnet: Toshiba's PMSM rotors are the IPM (Interior Permanent Magner) type. Toshiba interior magnets have an improved shape to accomplish a structure that is easy to manufacture, simple, and reliable in terms of strength, and are arranged to efectively exploit the reluctance torque. o High.-performance permanent magnets: Since permanent magnets are implanted in the rotor core of PMSM, the magnetic force is not leaked from inside the motor even if an Nd-Fe-Bo magnet is used. The magnetic force is selected to achieve necessary performance even at the end of the design life. Toshiba's totally-enclosed structure requires no disassembly through its service life, hence no strong magnetism is perceptible during normal handling.[8] The simple totally- enclosed structure enchances product reliability: Reduced failure rate due to insulation deterioration because cleaning through the service life was formerly required to prevent internal contamination and the ingress of water has been eliminated. Reduced concern about overheating of the motor insides caused by reduced air intake due to dust clogging. Because dust does not attach to the inside of the rotor in this structure, it is expected to decrease unbalanced vibration due to use over time.[8] VI. CONCLUSION The induction motors have been known as the best candidate for the EV applications because they are robust, less costly, and mature in technology and need less maintenance. However, in this paper it is demonstrated that in terms of pollution and fuel consumption, the permanent magnet and the brushless DC motors have more priorities such as less pollution, less fuel consumption and more power to volume ratio which makes them attractive in the EV applications. The disadvantages in pollution caused by combustion engines and even though its advantages in cost, now you can see as the progress to use the EV will increase, it is now more by caring for the planet that many engineers working to make these new profitable vehicles and cleaner, so in Ecuador should push for more projects to create these vehicles REFERENCES Fig. 5-2. Rotor of IM, Rotor of PMSM [8] [1] Rony Argueta and Ann Holms, “A Technical Research report: The Electric Vehicle,” University of California Santa Barbara College of Engeneering, California, Research Report, Mar. 2010. [2] “Electric Vehicle Technology in the IEEE -Dr. Russell Lefevre - IEEE Transportation Electrification Community Web Portal.” . [3] “Electric Vehicle (EVs).” 31-Jan-2010. [4] “How Hybrids Work, (2009).” 20-Feb-2010. [5] B. A. Nasser Hashemnia, “Comparative study of using different electric motors in the electric vehicles,.” 2008. [6] “Trolleybus.” . [7] Edisson Fernando Calderon Freire, “ELABORACION DE UN RPOCEDIMIENTO DE FANRICACION DE LOS PATINES DE CONDUCCION ELECTRICA DE CABLES DE ALTA TENSION EN TROLES (transportes de servicio público ),” Escuela Politécnica Nacional, Quito-Ecuador, 2012. [8] Toshiba, “Permanent Magnet Synchronous Motor for Traction Systems.” . CASTILLO RIVERA LIZETH WAS BORN IN QUITO CITY IN ECUADOR, ON 5 DECEMBER 1993. She graduated from Giovanni Antonio Farina high school, on 2011. She is currently on the fifth level of the career of Electronic and Control Engineering at the National Polytechnic School, in Quito. Her dreams are become to be a good Engineer, and help people, whit her work, maybe, do things that help special people, like make some robots that, could do all things for everybody who’s needed. Taipe CH. Jennifer estudio FísicoMatemático en la Unidad Educativa “Julio María Matovelle”. Actualmente se encuentra cursando el quinto semestre de la carrera de Ingeniería Eléctrica en la Escuela Politécnica Nacional. Entre sus aspiraciones se encuentra trabajar en algún proyecto o plan de investigación fuera del país, sin importar su idioma porque le son de interés varias lenguas, para luego poder aprender todo lo relacionado con energías alternativas y sus avances para luego poner en práctica en su país.