A quality product by Brainheaters™ LLC Brainheaters Notes EHV Electrical Semester-7 SERIES 313 - 2018 (A.Y 2021-122) © 2016-21 | Proudly Powered by www.brainheaters.inBH.Index (Learn as per the Priority to prepare smartly) sr Chapter Name & Content Priority | Pg No no 1 Introduction to Electric Vehicle 2 2. Induction to Hybrid Electric Vehicle 10 3. Electric Drive Trains 1 15 4. _ | Types of storage Systems 1 28 5. Modelling of Hybrid Electric Vehicle 1 7 Range 6. | Energy Management Strategies 2 45 7. OTHER IMP QUESTIONS = 52 Pageno-1 Hondcrafted by Engineers | P - PriorityMODULE-1 Ql. write a brief note on types of Electric Vehicles in used today OR Explain Electric vehicles with the types (P4 - Appeared 1 Time) (3-7 Marks) ANS: Electric Vehicles: * Anelectric vehicle (EV)is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered ‘autonomously by a battery (sometimes charged by solar panels, or by converting fuel to electricity using fuel cells or a generator).EVs include, but are not limited to, road and rail vehicles, surface and underwater vessels, electric aircraft and electric spacecraft. Types of Electric Vehicles Battery Electric Vehicles (BEVs) * Powered solely by an electric battery, with no gas engine parts. Most BEVs are capable of fast charging and L2 charging. Zero emissions. Examples of BEV © Volkswagen e-Golf * Tesla Model 3 Pageno- 2 Hondcrafted by Engineers | P- PriorityBMW i3, Chevy Bolt Chevy Spark Nissan LEAF Ford Focus Electric Hyundai lonig Karma Revero Kia Soul Mitsubishi i-MiEV Tesla X Toyota Rav4. Plug-in Hybrid Electric Vehicles (PHEVs) Similar to a Hybrid, but with a larger battery and electric motor. Has @ gas tank and a charging port. Can charge by using L2 chargers. Examples of PHEV Porsche Cayenne S E-Hybrid Chevy Volt Chrysler Pacifica Ford C-Max Energi Ford Fusion Energi Mercedes C350e, Mercedes $550e, Mercedes GLESS0e Mini Cooper SE Countryman Page no-3 Hondcrafted by Engineers | P - Prioritye Audi A3 E-Tron © BMW 330e, BMW i8, BMW X5 xdrive40e Hybrid Electric Vehicles (HEVs) * Low-emission vehicles that use an electric motor to assist gas-powered engines. All energy comes from gasoline. Cannot charge with Evgo. Examples of HEV @ Honda Civic Hybrid « Toyota Prius Hybrid © Honda Civic Hybrid « Toyota Camry Hybrid. Q2. Describe Battery Electric Vehicle (P4 - Appeared I Time) (3-7 Marks) ANS: Battery Electric Vehicle (BEV) * ABattery Electric Vehicle (BEV), also called All-Electric Vehicle (AEV), runs entirely on a battery and electric drivetrain. These types of electric cars do not have an ICE. « Electricity is stored in a large battery pack that is charged by plugging into the electricity grid. Page no- 4 Hondcrafted by Engineers | P - PriorityThe battery pack, in turn, provides power to one or more electric motors to run the electric car. Figure: Architecture and Main Components of Types of electric cars - components of BEVComponents of BEV Electric motor Inverter Battery Control Medule Drive train Working Principles of BEV Power is converted from the DC battery to AC for the electric motor The accelerator pedal sends a signal to the controller which adjusts the vehicle's speed by changing the frequency of the AC power from the inverter to the motor Pageno-5 Honderafted by Engineers | P - Priority* The motor connects and turns the wheels through a cog ® When the brakes are pressed or the electric car is decelerating, the motor becomes an alternator and produces power, which is sent back to the battery Examples of BEV © Volkswagen e-Golt « Tesla Model 3 © BMWi3 © Chevy Bolt *® Chevy Spark © Nissan LEAF * Ford Focus Electric © Hyundai loniq * Karma Revero e Kia Soul Mitsubishi i-MiEV Page no - 6 Hondcrafted by Engineers | P - PriorityQ3. What is a Fuel Cell EV? How does it work (P4 - Appeared I Time) (3-7 Marks) ANS; Fuel Cell Electric Vehicle (FCEV) © Fuel Cell Electric Vehicles (FCEVs), also known as fuel cell vehicles (FCVs) or Zero Emission Vehicle, are types of electric cars that employ fuel cell technology to generate the electricity required to run the vehicle. e In this type of vehicle, the chemical energy of the fuel is converted directly into electric energy. Fuel-Cell Motor a + it eae Regenerative Figure: Architecture and Main Components of FCEV Page no - 7 Honderafted by Engineers | P - PriorityTypes of electric cars - FCEVComponents of FCEV * Electric motor « Fuel-cell stack « Hydrogen storage tank « Battery with converter and controller Working Principles of FCEV * The working principle of a ‘fuel cell’ electric car is different compared to that of a ‘plug-in’ electric car. This type of electric car is because the FCEV generates the electricity required to run this vehicle on the vehicle itself. Examples of FCEV © Toyota Mirai * Hyundai Tucson FCEV Riversimple Rasa * Honda Clarity Fuel Cell * Hyundai Nexo. Page no- 8 Hondcrafted by Engineers | P - PriorityQ4. Solar Powered Vehicles. (P4 - Appeared | Time) (3-7 Marks) ANS: Solar Powered Vehicles: e Asolar vehicle or solar electric vehicle is an electric vehicle powered completely or significantly by direct solar energy. Usually, photovoltaic (PV) cells contained in solar panels convert the sun's energy directly into electric energy. The term solar vehicle’ usually implies that solar energy is used to power all or part of a vehicle's propulsion. Solar power may be also used to provide power for communications or controls or other auxiliary functions. * Solar vehicles are not sold as practical day-to-day transportation devices at present but are primarily demonstration vehicles and engineering exercises, often sponsored by government agencies. However, indirectly solar-charged vehicles are widespread and ‘solar boats are available commercially. Page no - 9 Hondcrafted by Engineers | P- PriorityMODULE -2 QI. piscuss the social and environmental importance of hybrid and electric vehicles (P4 - Appeared | Time) (3-7 Marks) ANS: Environmental Impact of Hybrid and Electric Vehicles ¢ Hybrid and electric vehicles play a critical role in reducing global greenhouse gas emissions, with transport estimated to contribute ta 14% of the 49 GtCO2eq produced annually. Analysis of only the conversion efficiency of powertrain technologies can be misleading, with pure battery-electric and hybrid vehicles reporting average efficiencies of 92% and 35% in comparison with 21% for internal combustion engine vehicles. * A fairer comparison would be to consider the well-to-wheel efficiency, which reduces the numbers to 21-67%, 25% and 12%, respectively. The large variation in well-to-wheel efficiency of pure battery electric vehicles highlights the importance of renewable energy generation in order to achieve true environmental benefits. «® When calculating the energy return on investment of the various technologies based on the current energy generation mix, hybrid Page no - 10 Hondcrafted by Engineers | P - Priorityvehicles show the greatest environmental benefits, although this would change if electricity was made with high amounts of renewables. In an extreme scenario with heavy coal generation, the CO2eq return on investment can actually be negative for pure electric vehicles, highlighting the importance of renewable energy generation further. The energy impact of production is generally small (~6% of lifetime energy) and, similarly, recycling is of a comparable magnitude, but it is less well studied. Q2. what is Hybrid traction and Various hybrid OR Explain Hybrid Traction, Motor Alone traction and Engine alone traction(P4 - Appeared | Time) (3-7 Marks) ANS: Hybrid traction: When lock | and lock 2 are released, i.e. the sun gear and the ring gear can rotate both the ICE and EM supply positive speed and torque to the driven wheels. Since, the output shaft is connected to the carrier gear, the output torque and speeds give by Pageno: 11 Handcrafted by Engineers | P - Priority= (1, -1) l=n, Engine alone traction: ® When the lock 2 locks the ring gear, only the ICE delivers the required traction force to the wheels. The output torque and the speed is given by T. = (l-n,)T, 1 = (1/11, os Motor alone traction: When lock I locks the sun gear, only the EM delivers the traction force to the wheels. The output torque and the speed is given by Te = (1-1, Yn,)Tr 1c = (n,/1 — noo, Page no - 12 Hondcrafted by Engineers | P - PriorityQ3. Describe Power flow control in hybrid drive-train topologies (P4 - Appeared 1 Time) (3-7 Marks) ANS: Power Flow Control in Hybrid Drive-Train Topologies: Power Flow Control Due to the variations in HEV configurations, different power control strategies are necessary to regulate the power flow to or fram different components. * Allthe control strategies aim satisfy the following goals: maximum fuel efficiency minimum emissions minimum system costs good driving performance The design of power control strategies for HEVs involves different considerations such as: * Optimal ICE operating point: The optimal operating point on the torque-speed plane of the ICE can be based on the maximization of fuel economy, the minimization of emissions or a compromise between fuel economy and emissions. * Optimal ICE operating line: In case the ICE needs to deliver different power demands, the corresponding optimal operating points constitute an optimal operating line. Safe battery voltage: The battery voltage may be significantly altered during discharging, generator charging or regenerative Page no- 13 Hondcrafted by Engineers | P - Prioritycharging. This battery voltage should not exceed the maximum voltage limit nor should it fall below the minimum voltage limit. Page no - 14 Hondcrofted by Engineers | P- PriorityMODULE-3 Ql. Write a note on Electric traction (P4 - Appeared | Time) (3-7 Marks) ANS: Electric Traction Systems * The system which uses electrical power for traction systems ie. for railways, trams, trolleys, etc. is called electrical traction. Track electrification refers to the type of source supply system that is used while powering the electric locomotive systems. It can be AC or DC or a.composite supply. * Selecting the type of electrification depends on several factors like availability of supply, type of an application area, or on the services like urban, suburban and mainline services, etc. The three main types of electric traction systems that exist are as follows: © Direct Current (DC) electrification system * Alternating Current (AC) electrification system * Composite system. DC Electrification System «The choice of selecting a DC electrification system encompasses many advantages, such as space and weight considerations, rapid Page no - 15 Hondcrafted by Engineers | P - Priorityacceleration and braking of DC electric motors, less cost compared to AC systems, less energy consumption and so on. * In this type of system, three-phase power received from the power grids is de-escalated to low voltage and converted into DC by the rectifiers and power-electronic converters. This type of DC supply is supplied to the vehicle in two different ways: ® 3rdand 4 the rail system operate at low voltages (600-1200v) * Overhead rail systems use high voltages (1500-3000v) The supply systems of DC electrification include; * 300-500V supply for special systems like battery systems. 600-1200V for urban railways like tramways and light metro trains. 1500-3000V for suburban and mainline services like light metros and heavy metro trains. * Due to high starting torque and moderate speed control, the DC series motors are extensively employed in the DC traction systems. They provide high torque at low speeds and low torque at high speeds. Advantages: Inthe case of heavy trains that require frequent and rapid accelerations, DC traction motors are a better choice as compared to AC motors. Page no-16 Hendcrafted by Engineers | P - Priority® DC train consumes less energy compared to AC unit for operating same service conditions. « The equipment in the DC traction system is less costly, lighter and more efficient than the AC traction system. ® Itcauses no electrical interference with nearby communication lines. Disadvantages: Expensive substations are required at frequent intervals. « The overhead wire or third rail must be relatively large and heavy. « Voltage goes on decreasing with an increase in length. AC Electrification System: * An AC traction system has become very popular nowadays, and it is more often used in most traction systems due to several advantages, such as quick availability and generation of AC that can be easily stepped up or down, easy controlling of AC motors, less number of substations requirement, and the presence of light overhead catenaries that transfer low currents at high voltages, and soon. * The supply systems of AC electrification include single, three-phase, and composite systems. The Single phase systems consist of I] to 15 KV supply at 16.7Hz, and 25H; to facilitate variable speed to AC Page no -17 Honderafted by Engineers | P - Prioritycommutation motors. It uses step down transformer and frequency converters to convert from the high voltages and fixed industrial frequency. « The Single phase 25KV at 50Hz is the most commonly used configuration far AC electrification. Itis used far heavy haul systems and main line services since it doesn't require frequency conversion. This is one of the widely used types of composite systems wherein the supply is converted to DC to drive DC traction motors. AC Traction System « Three phase system uses three phase induction motor to drive the locomotive, and it is rated at 3.3.KV, 16.7Hz. The high-voltage distribution system at 50 Hz supply is converted to this electric motor rating by transformers and frequency converters. This system employs two overhead lines, and the track rail forms another phase, but this raises many problems at crossings and junctions. Advantages: «Fewer substations are required. « Lighter overhead current supply wire can be used. © Reduced weight of support structure. @ Reduced capital cost of electrification. Page no - 18 Honderafted by Engineers | P - PriorityDisadvantages: . Significant cost of electrification. Increased maintenance cost of lines. Overhead wires further limit clearance in tunnels. Upgrading needs additional cost especially in case there are brigdes and tunnels. Railway traction needs immune power with no cuts. Composite System . Composite System (or multi-system) trains are used to provide continuous journeys along routes that are electrified using more than one system. One way to accomplish this is by changing locomotives at the switching stations. These stations have overhead wires that can be switched from ane voltage to another. Another way is to use multi-system locomotives that can operate under several different voltages and current types. In Europe, itis common to use four-system locomotives. (1.5 kv DC, 3.kV DC, 15 kV 16% Hz AC, 25 kV 50 Hz AC). Pageno-19 Handcrafted by Engineers| P- PriorityQ2. Enlist and explain Various electric drive-train topologies OR Explain Drive-train topologies in detail (P4 - Appeared 1 Time) (3-7 Marks) ANS: Topology | Positive Qualities Negative Qualities Series ICE working point can be chosen | Many energy conversions freely ICE can be turned off ICE — low-efficiency Electric can be mounted with or machine Il must handle separated from the electric peak power tractive motor + distribute weight and facilitates low floor Parallel | ICE directly connected to the ICE and electric machine wheels — few power must be mounted conversions Due to the electric | together — no low floor machine and the gear boxes the ICE working paint can be chosen freely Strigear | Offers the most efficient solution | The components size etc possible at any time regarding are fixed Demands many Page no - 20 Hondcrafted by Engineers | P - Prioritylosses components Reduce the amount of power Switching modes can't be transformation performed infinitely fast. Power split ICE can be turned off ICE speed | A power vicious circle can can be chosen by adjusting the _| occur -» low efficiency generator speed Q33. expiain Power flow control in electric drive-train topologies (P4 - Ay peared | Time) (3-7 Marks) ANS: Power Flow Control in Electric drive-train topologies: Page no = Two control strategies for power flow control in hybrid electric vehicles (HEVs) with parallel configuration and a planetary gear system as a power coupling device between the internal combustion engine and the electric machine are proposed in this paper. The aim of both strategies is to determine, for a given driving cycle, an appropriate mixture of the power provided by the two engines. Performance is measured not only in terms of fuel consumption; 2 Hondcrofted by Engineers | P - Prioritydriving cycle tracking and preservation of energy in the bank of batteries are also considered. « The first strategy, named the PGS strategy as it is designed around the planetary gear system, is heuristic, inspired by bang—bang optimal control formulations and has low computational load, while the second is an optimal one derived from Pontryagin's minimum principle (PMP). * Itis shown that, under appropriate choice of the weighting parameters in the Hamiltonian of the PMP, both strategies give very similar results and, therefore, that the PGS strategy corresponds to a feasible solution to an optimization problem. Both strategies can be implemented in real time, however, the PGS strategy is easier to tune. Tuning of the strategies’ parameters is independent of the driving cycle. The power flow control laws are continuous and enforce the use of the internal combustion engine with the maximum possible efficiency. « The strategies are tested with simulations of a powertrain of a hybrid diesel-electric bus subjected to the demands of four representative urban area driving cycles. Although optimization solutions are based on simplified dynamic models, simulation results are verified with more detailed dynamic models of the HEV main subsystems. Page no - 22 Hondcrafted by Engineers | P - PriorityThis allows us to evaluate the accuracy of the results and to verify the hypothesis established in the optimization formulation. Simulation results indicate that both strategies attain good fuel consumption reduction levels. QA. explain Configuration and contral OR Explain 1) DC Motor drives, 2) Induction Motor drives, 3) Permanent Magnet Motor drives, 4) Switched Reluctance Motor drives (P4 - Appeared I Time) (3-7 Marks) ANS: DC Motor Drives: The DC motor drive is a type of amplifier or power modulator that integrate between the controller and a DC motor. It takes the low current and then converts it into a high current which is appropriate for the motor. The DC motor drive also provides the high current torque, 400 % more than the rated continuous torque. The important applications of DC motor drives are rolling mills, paper mills, mine winders, hoists, machine tools, traction, printing presses, textile mills, excavators and crane. Page no - 23 Hondcrafted by Engineers | P - PriorityTypes of DC Motor Drives Non-regenerative DC Drive - e This drive rotates only in one direction and hence also called single quadrant drive.The non-regenerative DC motor drive does not have any inherent braking capability. « The motor is terminated only by removing the supply. Such type of drive is used in a placed where high friction load or strong natural brake requires. Regenerative DC Drive — ¢ [tis a four quadrant drive, and it controls the speed, direction and torque of a motor. Under the braking condition, this drive converts mechanical energy and load into electrical energy which is returned to the power source. Induction Motor Drives: * Induction motor drives are the most mature technology among various commutatorless motor drives. There are two types of induction machines (IMs): the wound-rotor and squirrel-cage. This chapter discusses various induction motor drives, including their system configurations, IMs, power inverters, and control strategies. There are three main types of control strategies for induction moter drives: Page no - 24 Hondcrafted by Engineers | P- Priority1. the variable-voltage variable-frequency (VVVF) control 2. field-oriented control (FOC) 3. direct torque control (DTC). The induction motors for electric propulsion is principally similar to that for industrial application. When the electric vehicles (EV) adopt the single-motor configuration, the induction motor is generally designed for high-speed operation while using a planetary gear to step down the motor speed so as to match with the wheel speed. The Ford Siemens EV motor was one of the most well-developed induction motors for EVs. Permanent Magnet Motor Drives: * The magnetic field for a synchronous machine may be provided by using permanent magnets made of neodymium-boron-iron, samarium-cobalt, or ferrite on the rotor. In some motors, these magnets are mounted with adhesive on the surface of the rotor core such that the magnetic field is radially directed across the air gap. In other designs, the magnets are inset into the rotor core surface or inserted in slots just below the surface. Another form of permanent-magnet motor has circumferentially directed magnets placed in radial slots that provide magnetic flux to iron poles, which in turn set up a radial field in the air gap. Page no - 25 Hondcrafted by Engineers | P - PriorityThe main application for permanent-magnet motors is in variable-speed drives where the stator is supplied from a variable-frequency, variable-voltage, electronically controlled source. Such drives are capable of precise speed and position control, Because of the absence of power losses in the rotor, as compared with induction motor drives, they are also highly efficient. Permanent-magnet motors can be designed to operate at synchronous speed from a supply of constant voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding is placed in slots in the rotor surface to provide starting capability. Such a moter does not, however, have means of controlling the stator power factor. Switched Reluctance Motor Drives: . The switched reluctance motor has been gaining interest both at the academic and industrial levels. Its most appreciated characteristics are the nonuse of rare elements and the low construction price. The control of the switched reluctance motor is not as easy as other traditional machines. Page no - 26 Hondcrafted by Engineers | P - Priority* Inthe control, it is necessary to reduce the torque ripple as much as possible, which has been the most studied problem in the field. * This chapter aims to give the reader a concise but focused knowledge on how the switched reluctance motor can be controlled. * Fundamental control methods and their impact on motor performance are described. * Asimulation section is presented, where the simulation files are provided for the reader. * The simulations are based on the theory described and have the advantage of using a non-linear switched reluctance moter model from a real motor. Page no - 27 Hondcrafted by Engineers | P - PriorityMODULE-4 QI. what are the energy Storage Requirements in Hybrid and Electric Vehicles (P4 - Appeared I Time) (3-7 Marks) ANS: Hybrid Storage System: « Ahybrid energy storage system (HESS), which consists of a battery and a supercapacitor, presents good performances on both the power density and the energy density when applied to electric vehicles. In this research, a HESS is designed targeting at a commercialized EV model and a driving condition-adaptive rule-based energy management strategy (EMS) is proposed for the HESS, which takes into account the superiority achievement of each ESS and also the protection to each ESS. The effectiveness of the HESS plus the EMS compared to the single battery case is validated by both the computer simulation and the semi-physical rapid control prototype (RCP) test bench. Electric loading equipment is adopted in the RCP experiment validation for simulating the vehicle driving cycle instead of the traditional combination of a motor and a dynamometer. Page no - 28 Hondcrafted by Engineers | P - PriorityBoth validation results show that compared to the single battery case, the working status of the battery is stabilized by the addition of the supercapacitor in the HESS case during both the propelling and regeneration modes and the battery energy is also saved. A dynamic degradation model for the battery is adopted in order to evaluate the life cycle cost of the HESS. Results show that the HESS. plus the EMS has the effect of prolonging the battery lifetime and the HESS is economically effective compared to the single battery case. Q2. write a note on energy storage and its analysis 1) Battery 2) Super Capacitor 4)Flywheel (P4 - Appeared 1 Time) (3-7 Marks) ANS: Battery storage: Battery storage technologies are essential to speeding up the replacement of fossil fuels with renewable energy. Battery storage systems will play an increasingly pivotal role between green energy supplies and responding to electricity demands. Battery storage, or battery energy storage systems (BESS), are devices that enable energy from renewables, like solar and wind, to be stored and then released when customers need power most. Page no - 29 Hondcrafted by Engineers | P - PriorityLithium-ic n batteries, which are used in mobile phones and electric cars, are currently the dominant storage technology for large scale plants to help electri ity grids ensure a reliable supply of renewable energy. Super Capacitors: Electrochemical capacitors use the double-layer effect to store electric energy; however, this double-layer has no conventional solid dielectric to separate the charges. There are two storage principles in the electric double-layer of the electrodes that contribute to the total capacitance of an electrochemical capacitor Double-layer capacitance, electrostatic storage of the electrical energy achieved by separation of charge in a Helmholtz double layer. Pseudocapacitance, electrochemical storage of the electrical energy achieved by faradaic redox reactions with charge-transfer Both capacitances are only separable by measurement techniques. The amount of charge stored per unit voltage in an electrochemical capacitor is primarily a function of the electrode size, although the amount of capacitance of each storage principle can vary extremely. Page no- 30 Hondcrafted by Engineers | P - PriorityFlywheel: * Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. © When energy is extracted from the system, the flywhee''s rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the flywheel. « Most FES systems use electricity to accelerate and decelerate the flywheel, but devices that directly use mechanical energy are being developed * Advanced FES systems have rotors made of high strength carban-fiber composites, suspended by magnetic bearings, and spinning at speeds from 20,000 to over 50,000 rpm in a vacuum enclosure.Such flywheels can come up to speed in a matter of minutes ~ reaching their energy capacity much more quickly than some other forms of storage Page no = 31 Hondcrafted by Engineers | P - PriorityQ3. Sizing the 1) propulsion motor, 2) power electronics (P4 - Appeared 1 Time) (3-7 Marks) ANS: izing the propulsion motor ¢ Anelectric machine is at the core of hybrid propulsion regardless of whether or not the vehicle is gasoline electric, diesel electric or fuel cell electric. Propulsion is via an ac drive system consisting of an energy storage unit, a power processor, the M/G and vehicle: driveline and wheels. A schematic of the hybrid propulsion system in a multi-converter architecture. The system can be upgraded by the addition of an interface converter (e.g. booster) to the ultra-capacitor bank for maximum performance when non- alkaline electrolyte storage batteries are used. « For example, a lead acid battery system benefits the most from a converter interface to an ultra-capacitor bank. In that case the total energy storage system weight and cost are minimised. With alkaline electrolyte advanced batteries the benefits of adding an ultra-capacitor begin to diminish and with lithium ion the benefits are minimal Page no - 32 Honderafted by Engineers | P - PriorityUltra: cap. OOC oa () Ice a) NS TT & Figure: Hybrid vehicle drivetrain The motor-generator, M/G, is sized as follows: maximum input speed at transmission is restricted to <12 000 rpm from the engine side by the rev-limiter function in the electronic engine controller and on the transmission side by the proper gear selection. Itis possible to over-speed the M/G and engine by improper downshifting of the transmission while at highway speeds. sizing the power electronics All of the electrical power directed to the hybrid propulsion M/G must pass through the power electronics. It has been said that control electronics use power to process information and that power electronics use the information to process power. In this section, we describe how power electronics is sized to match the Page no - 33 Honderafted by Engineers | P - Priorityelectric machine to the vehicle energy storage system, via information processed by the control electronics. « Aschematic for the hybrid propulsion system ac drive system consisting of onboard energy storage, power processing according to control algorithms, and traction actuation via the M/G and vehicle driveline. R, Power electronics — 7 fr. Transmission ren VY Driveline Control clestronies Controller, comm, gate drives, pave supply Figure : Schematic of hybrid ac drive system * The essentials of ac drive system operation are that power from a de source such as a fuel cell, battery or ultra-~capacitor is converted to variable voltage, variable frequency ac power at the M/G terminals. * The M/G then converts this electrical power to mechanical power in the form of torque and speed at the transmission input shaft. Page no - 34 Honderafted by Engineers | P - Priority* The power electronics is an electrical matching element in much the same manner that a gearbox processes mechanical power to match the engine to the raad load requirements. « The power inverter matches the de source to the mechanical system regardless of torque or speed level, provided these quantities are within its capability. Q4. Selecting the energy storage technology (P4 - Appeared | Time) (3-7 Marks) ANS: Selecting Energy Storage Technology: « With the development of energy storage technology, the main Energy storage technology can be divided into the following categories. According to the classification of technology, it is divided into four categories: 1. Physical storage (such as pumped storage, compressed air energy storage, flywheel energy storage, etc.) 2. chemical energy storage (such as sodium sulfur batteries, flow batteries, lead-acid batteries, nickel-cadmium batteries, supercapacitors, etc.) Page no - 35 Henderafted by Engineers | P - Priority3. Energy Storage (superconducting magnetic energy storage, etc.) and the phase change energy storage (ice storage, etc.). According to time division, the energy storage can be divided into 1. short-term energy storage which the discharge time form the second level to the minute level, 2. medium energy storage which the discharge time from afew minutes to several hours 3. long-term energy storage which discharges time from hours to days. According to the functional classification, it can be divided into two types: 1. energy storage Energy-usage (EES) 2. energy storage Power-usage (PES) Energy type energy storage is characterized by high energy, which is mainly used for high energy input and output, and the power type is characterized by high specific power, which is mainly used for instantaneous high power input and output. Energy storage can discharge device relatively slow time and experience over a long period of time (such as 10 minutes to hours) and power energy storage with high discharge rate fast discharge (e.g, several seconds to several minutes), Page no - 36 Henderafted by Engineers | P - PriorityMODULE-5 QI. expiain different types of Driving Cycles (Pa - Appeared 1 Time) (3-7 Marks) ANS: Driving Cycles: ¢ Adriving cycle is a series of data points representing the speed of a vehicle versus time. Driving cycles are produced by different countries and organizations to assess the performance of vehicles in various ways, for instance fuel consumption, electric vehicle autonomy and polluting emissions. There are two types of driving cycles: Model Driving Cycle @ The model driving cycle comprises constant speed and does not represent a real driving pattern of a vehicle. These driving cycles will be used for specific applications such as an emission test. « New European Driving Cycle (NEDC) is an example of a Model Driving Cycle. Page no - 37 Hondcrafted by Engineers | P - Priority200 400 600 Tis} 1000 1200 Total distance : 11.023 km Total time : 1180 s Average speed : 33.6 kmph Transient Driving Cycle * The transient driving cycle represents an actual pattern of a vehicle which contains acceleration, deceleration, constant speed, etc. Federal Test Procedure (FTP 75) is an example of a Transient Driving Cycle. Page na - 38 Handcrafted by Engineers | P - PriorityFTP-75 cycle es Vehicle speed (mph) 8 Time (5), Total distance : 17.77 km Total time 1874 s Average speed : 34.1 kmph Q2. Describe the Range modelling for Battery Electric Vehicle (P4 - Appeared I Time) (3-7 Marks) ANS: Battery Electric Vehicle: * Battery electric vehicles (BEVs) have the outstanding advantages in Zero tailpipe emissions, low noise, convenient maintenance, and high energy conversion efficiency. « The deployment of BEVs helps to reduce oil dependence, improve air quality, and reduce pollutants and greenhouse gas emissions . Page no - 39 Honderafted by Engineers | P - Priority*® Promoting the development of BEVs is considered as one of the promising solutions for the treatment of severe air pollution in metropolises. The incentives, such as subsidies and tax credits, have effectively promoted public acceptance for switching to BEVs. * However, due to the limited battery capacity and charging facilities, inconvenient charging is still an important obstacle to the promotion of BEVs. Compared to conventional internal combustion engine vehicles (ICEV), BEVs have a shorter driving range, generally 150 km-400 km. * Meanwhile, it usually takes hours to charge [5, 6]. Potential customers have repeatedly been found to prefer vehicles with considerably higher available range because of the range anxiety. Although the long driving range design helps to alleviate the user's range anxiety, it results in higher expenditure on purchase and simultaneously, the affordability and cost-effectiveness are lowered. * Optimizing the driving range of BEVs based on users’ daily travel demand is one of the feasible ways to solve this problem The driving range for different types of BEV users is based an the real-world BEV usage data, specifically including the following: Page no - 40 Hondcrafted by Engineers | P - Priority1. constructing the daily trip chain for BEV drivers by combining behavioural variables for a daily trips and each trip 2. applying the copula function to examine the dependence between daily travel variables 3. proposing a simulation framework for the Monte Carlo method to simulate the daily trip chain 4. quantifying the fitness of the driving range to find the optimal driving range for different drivers. Q3. Write a brief note on Fue! Cell EV. (P4 - Appeared 1 Time) (3-7 Marks) ANS: Fuel cell electric vehicles use fuel cell stacks to convert onboard gaseous hydrogen to electricity, which is then stored in a battery to power the vehicle's electric motor. « As with other electric vehicles, fuel cell electric vehicles are equipped with regenerative braking systems to capture the kinetic energy normally lost during braking and store it in the battery. Fuel cell electric vehicles are more efficient than conventional vehicles and produce no tailpipe emissions; they emit only water vapour and warm air. Page no - 41 Handerafted by Engineers | P - Priority* They can travel 300 to 400 miles on a tank of hydrogen and can refuel in three to five minutes. Fuel Cel Stack Electric Traction Motor, \ DC/DC Converter, Fuel Tank (hydrogen) Transmission Power Electronic Controller Battery (auxiliary) Q4. piscuss the features and advantages of Solar Powered Vehicles. OR Explain pros and cons of solar vehicles (P4 - Appeared | Time) (3-7 Marks) ANS: Advantages: * Eco-friendly and Quiet: Solar-powered vehicles have zero-emission levels, as they don't utilize non-renewable resources and burn fuel. The electric motors generate electricity that doesnt emit any greenhouse gases or any other pollutants. These cars are Page no - 42 Hondcrafted by Engineers | P - Priorityquieter than the vehicles powered by conventional fuels, which don't cause noise pollution as well. Energy Availability: Solar cars derive their power from the sun, indirectly, that always shines and provides endless energy. The efficient solar panels can produce and store more horsepower for the vehicle. No Fuel Costs: Unlike the conventionally fueled vehicles, solar vehicles have no fuel costs and a low cost of maintenance. Driving Comfort: Having aluminium and lightweight components, the solar-powered cars run faster and more smoothly than petrol and diesel engine vehicles. Disadvantages: Design Challenge: The solar vehicles require a large surface area on the roof for mounted solar panels, have low wind resistance and space only for two passengers. Poor Practicality: These green cars don't have any driver safety features and other equipment such as wiper blades, headlights and rearview mirrors. Aspects like suspension, chassis strength, steering, brakes, secured solar panels and batteries arrangement also need ta be taken seriously. Page no - 43 Hondcrafted by Engineers | P - Priority© Expensive Batteries: The efficient solar panels and batteries and their replacement are way too expensive that need to be changed so often. This is what makes the solar vehicles a costly affair. e Energy Storage Capacity: The photovoltaic cells or solar panels can convert 15-30% of sunlight into electricity, depends on the material used, which is quite limited. Page no - 44 Hondcrafted by Engineers | P - PriorityMODULE-6 Ql. Energy management strategies used in hybrid electric vehicles (P4 - Appeared 1 Time) (3-7 Marks) ANS: Energy Management Strategies: The existing energy management and control strategies of hybrid vehicles can be mainly classified into three categories. The first type employs heuristic control techniques, such as rules/fuzzy logic for the control algorithm development [1, 2]. The principle is commonly based on the concept of “load leveling,” which attempts to operate the internal combustion engine in an efficient area and the battery as a load-leveling device used to provide the remaining power demand. The second type of approach is based on static optimization methods that instantaneously determine the efficient power split between different energy sources by minimizing a cost function. To calculate the cost of energy, the electric energy is translated into an equivalent amount of fuel [3, 4]. Due to its relatively simple point-wise optimization nature, itis possible to extend the Pageno- 45 Handcrafted by Engineers | P - Priorityoptimization scheme to solve the simultaneous fuel economy and emission optimization problem. The fundamental mechanism of the third type of HEV control algorithm considers the dynamic nature of the vehicle system when performing an optimization [6-8]. * Atime horizon is involved in this type of dynamic optimization, instead of a time instant in the static one mentioned above. ® Power split algorithms obtained from dynamic optimization are thus more accurate under transient conditions but are computationally more intensive. Despite that dynamic optimization cannot be realized on board due to its preview nature and heavy computation requirement, it has been recognized as a good benchmark to the first two types of algorithms. Q2. Classification, Comparison OR Implementation issues of energy management strategies. (P4 - Appeared | Time) (3-7 Marks) ANS: Classification of energy management strategies: Rule-based strategies: * Fuzzy Control Strategy Page ne - 46 Honderafted by Engineers | P - Priority® State Machine Control Strategy © Classical PI Control Strategy © Frequency decoupling and fuzzy logic strategy (FDFL) © Power Prediction Optimisation-based strategies: 1. Global Optimisation e Linear programming e Dynamic Programming e Global Extremum seeking * Genetic algorithms 2. Real-time Optimisation ® Quadratic programming ® Multi-agent system ® Convex programming « Soft-run strategy Learning based strategies ¢ Reinforcement learning *® Supervised learning ® Neural network « Unsupervised learning Page no - 47 Honderafted by Engineers | P - PriorityEnergy management strategies comparison for electric vehicles with hybrid energy storage system The real-time energy management strategies for a hybrid energy storage system (HESS), including a battery and a supercapacitor (sc), for an electric city bus. The most attractive advantage deriving from HESSs is the possibility of reducing the battery current stress to extend its lifetime. ¢ To quantitatively compare the effects of different control strategies on reducing battery degradation, a dynamic degradation model for the LiFePO4 battery is proposed and validated in this paper. The battery size is optimized according to the requested minimal mileage, while the size of SC is optimized based on the power demand profile of the typical China Bus Driving Cycle (CBDC). * Based on the optimized HESS, a novel fuzzy logic controller (FLC) and a novel model predictive controller (MPC) are proposed and compared with the existing rule-based controller (RBC) and filtration based controller (FBC), after all the controllers are tuned to their best performance along the CBDC. ¢ It turns out that FLC and RBC achieve the best performance among the four controllers, which is validated by the DP-based result. Furthermore, about 50% of the HESS life cycle cost is reduced in comparison with the battery-only configuration. In addition, the Page no - 48 Honderafted by Engineers | P - Prioritycontrollers are also compared along the New European Driving Cycle (NEDC), which represents another normalized driving cycle. The results show that the RBC, MPC, and FLC achieve a similar performance, and they reduce about 23% of the HESS life cycle cost when compared to the battery-only configuration. The RBC and FLC are regarded as the best choices in practical applications due to their remarkable performance and easy implementation. Q3. Various charging techniques and schematic of charging stations. OR Explain choosing a charging station and location(P4 - Appeared 1 Time) (3-7 Marks) ANS: Choosing a Charging Station: Public and private charging stations This section describes the different types of charging station installations to aid in selecting the most appropriate for your needs. Since this Guide frequently mentions private and public stations, it is important to define these concepts. 1. Aprivate station is a station purchased by an individual for personal use Page no - 49 Henderafted by Engineers | P - Priority2. A public station is a shared station; it may be installed on public or private property by a public organization or a company. Charging station selection criteria: A variety of models designed for different uses are available on the market. When selecting a charging station, consider these factors: 1 2. 3, The power required (charging time, vehicle capacity, pricing) The communication requirements (access control, payment system, help system) The number of cables and plugs (for shared-access stations) Public stations may offer telecommunications features, which will vary by manufacturer. Some models have transmitters compatible with cellular telephone networks and require no additional infrastructure, while others will require a local wireless network,7 such as a ZigBee protocol network,* which involves careful siting of stations and transmitters. Other stations communicate over a wired link such as a twisted-pair or fibre-optic Ethernet network, which would have to be included in the design of the electrical installation. Some stations have multiple connectors and can charge several vehicles at a time, thus sharing the charging station’s maximum output among the connected vehicles. A power management Page no - 50 Honderafted by Engineers | P - Prioritysystem that manages several stations can be used to modulate the power they supply. Page ne - St Honderafted by Engineers | P - Priority mOTHER IMP QUESTIONS: MODULE-1 Ql. What are the various forces acting on the Vehicle in static and dynamic conditions? (P4 - Appeared 1 Time) (3-7 Marks) MODULE-2 QI. what is the significant impact of modern drive trains on energy supplies? (P4 - Appeared I Time) (3-7 Marks) MODULE-4 QI. state and expiain the Hybridization of different energy storage devices. (P4 - Appeared 1 Time) (3-7 Marks) Q2. Explain matching the electric machine and the internal combustion engine (ICE) (P4 - Appeared | Time) (3-7 Marks) Page no - 52 Handcrafted by Engineers | P - Priority