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1. MODULE – 5 Modelling of Hybrid Electric Vehicle Range

2. Power Train and Drive Cycles The power train of EVs and HEVs consists of Electric Motor (EM) and the Internal Combustion Engine (ICE ). The first step towards the design of the power train is to determine the power ratings of the motor used in the EV and HEV drive train is to ascertain the motor specifications . These specifications are determined making use of the drive cycle the vehicle operates on and the vehicle dynamic equation for tractive force calculation. The design constraints set on the drivetrain like the initial acceleration time, the value of the cruising at rated vehicle speed, and the value of the cruising at maximum vehicle speed affects the specification of the induction motor. Finally , the tractive force required to propel the vehicle to the drive cycle chosen gives the necessary motor specifications used in the drivetrain .

3. Operating regions of a Vehicle Hence, in order to size the components of the vehicle properly, it is necessary to understand the drive cycle properly.

4. Concept of Drive cycle How much energy will a vehicle take per km? Concept of Energy-efficiency of a vehicle: Wh /km Depends upon how the vehicle travels and how much energy it takes Energy required will depend upon Speed, Acceleration, idling, Deceleration Definition of a Drive-cycle A definition of how the vehicle is typically driven Vehicles tested as per a Standard Drive-cycle, against which its performance is measured and compared for similar vehicles How long it travels at what speed and how long and when it is accelerated decelerated?

5. Standard Drive Cycle

6. Driving Cycle A  driving 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, as for instance fuel consumption, electric vehicle autonomy and polluting emissions . Fuel consumption and emission tests are performed on chassis dynamometers. Tailpipe emissions are collected and measured to indicate the performance of the vehicle. Another use for driving cycles is in vehicle simulations. More specifically, they are used in propulsion system simulations to predict performance of internal combustion engines, transmissions, electric drive systems, batteries, fuel cell systems, and similar components.

7. Driving Cycle There are two types of driving cycles: Transient  driving cycles involve many changes, representing the constant speed changes typical of on-road driving. Modal  driving cycles involve protracted periods at constant speeds. The American FTP-75 ,  and the unofficial European Hyzem driving cycles are transient, whereas the Japanese 10-15 mode  and JC08 cycles are modal cycles.

8. The various drive cycles used are:

9. New York City Cycle (NYCC) The New York City Cycle (NYCC) is a standard test drive cycle for the city traffic.

10. New York City Cycle (NYCC)

11. New York City Cycle (NYCC) Moreover, from both figure of NYCC it can be seen that the vehicle is subjected to frequent start-stop . Since the ICEs tend to be very fuel inefficient for such frequent start-stop operation, it is wise to use only EM as the prime mover.

12. Japanese(JP-10-15 )

13. Japanese(JP-10-15)

14. Japanese(JP-10-15)

15. Extra Urban Driving Cycle (EUDC)

16. Federal Test Procedure (FTP-75)

17. New European Driving Cycle (NEDC)

18. Range Modelling of Battery Electric Vehicles To predict the range, the energy required to move the vehicle for each second of the driving cycle is calculated, and the effects of this energy drain are calculated. The process is repeated until the battery is flat. It is important to remember that if we use time intervals of 1 second, then the power and the energy consumed are equal.

19. The starting point in these calculations is to find the tractive effort( Fte ). The power is equal to the tractive effort multiplied by the velocity. Using the various efficiencies in the energy flow diagram, the energy required to move the vehicle for 1 second is calculated.

20. Tractive Effort The first step in vehicle performance modelling is to produce an equation for the required ‘ tractive effort’. This is the force propelling the vehicle forward, transmitted to the ground through the drive wheels. Consider a vehicle of mass m, proceeding at a velocity v, up a slope of angle ψ. The force propelling the vehicle forward, the tractive effort, has to accomplish the following: overcome the rolling resistance; overcome the aerodynamic drag; provide the force needed to overcome the component of the vehicle’s weight acting down the slope; accelerate the vehicle, if the velocity is not constant.

21. The forces acting on a vehicle moving up a slope

22. Rolling Resistance Force

23. Aerodynamic Drag

24. Hill Climbing Force

25. Acceleration Force

26. A simple arrangement for connecting a motor to a drive wheel

27. Total Tractive Effort

28. Modelling Equations The efficiency of the gear system η g is normally assumed to be constant, as in electric vehicles there is usually only one gear. The efficiency is normally high, as the gear system will be very simple. The efficiencies of the motor and its controller are usually considered together, as it is more convenient to measure the efficiency of the whole system. Motor efficiency varies considerably with power, torque and also motor size.

29. Efficiency The efficiency of motor is Output Copper loss = Losses : C= those losses that occur even if the motor is totally stationary, and that vary neither with speed nor torque

30. Efficiency

31. An average power will need to be found or estimated for these, and added to the motor power, to give the total power required from the battery. Note that when braking, the motor power will be negative, and so this will reduce the magnitude of the power:

32. Modeling of Hybrid Electric Vehic les The term hybrid vehicle refers to a vehicle with at least two sources of power. A hybrid - electric vehicle indicates that one source of power is provided by an electric motor. The other source of motive power can come from a number of different technologies, but is typically provided by an internal combustion engine designed to run on either gasoline or diesel fuel. As proposed by Technical Committee (Electric Road Vehicles) of the International Electrotechnical Commission, an HEV is a vehicle in which propulsion energy is available from two or more types of energy sources and at least one of them can deliver electrical energy

33. Types of HEV the gasoline ICE and battery diesel ICE and battery battery and FC battery and capacitor battery and flywheel battery and battery hybrids. Most commonly, the propulsion force in HEV is provided by a combination of electric motor and an ICE. The electric motor is used to improve the energy efficiency (improves fuel consumption) and vehicular emissions while the ICE provides extended range capability.

34. HEV Configurations i . powertrain 1 alone delivers power ii . powertrain 2 alone delivers power iii . both powertrain 1 and 2 deliver power to load at the same time iv . powertrain 2 obtains power from load (regenerative braking) v . powertrain 2 obtains power from powertrain 1 vi . powertrain 2 obtains power from powertrain 1 and load at the same time vii . powertrain 1 delivers power simultaneously to load and to powertrain 2 viii . powertra in 1 delivers power to powertrain 2 and powertrain 2 delivers power ton load ix . powertrain 1 delivers power to load and load delivers power to powertrain 2. The various possible ways of combining the power flow to meet the driving requirements are:

35. The load power of a vehicle varies randomly in actual operation due to frequent acceleration, deceleration and climbing up and down the grades. The load power can be decomposed into two parts: i.steady power, i.e. the power with a constant value Ii.dynamic power, i.e. the power whose average value is zero Generally, electric motors are used to meet the dynamic power demand Load power decomposition

36. Hybrid configuration Hybrid drivetrain concept can be implemented by different configurations as follows: Series configuration Parallel configuration Series - parallel configuration Complex configuration series hybrid is to couple the ICE with the generator to produce electricity for pure electric propulsion. parallel hybrid is to couple both the ICE and electric motor with the transmission via the same drive shaft to propel the vehicle

37. Hybrid configuration

38. Series hybrid electric drive trai n Series hybrid system the mechanical output is first converted into electricity using a generator. The converted electricity either charges the battery or can bypass the battery to propel the wheels via the motor and mechanical transmission. Conceptually, it is an ICE assisted Electric Vehicle (EV). The advantages of series hybrid drive trains are: Mechanical decoupling between the ICE and driven wheels allows the IC engine operating at its very narrow optimal Region . Nearly ideal torque speed characteristics of electric motor make multigear transmission unnecessary. Series hybrid drive train has the following disadvantages: The energy is converted twice (mechanical to electrical and then to mechanical) and this reduces the overall efficiency. Two electric machines are needed and a big traction motor is required because it is the only torque source of the driven wheels.

39. Series hybrid electric drive train The series hybrid drive train is used in heavy commercial vehicles, military vehicles and buses. The reason is that large vehicles have enough space for the bulky engine/generator system

40. Series hybrid electric drive train The term “peak power source” will replace “battery pack,” because, in HEVs, the major function of batteries is to supply peaking power. They can be replaced with other kinds of sources such as ultracapacitors and flywheels.

41. Series hybrid electric drive train Hybrid traction mode Peak Power Source-Alone Traction Mode Engine/Generator-Alone Traction Mode PPS Charging from the Engine/Generator Regenerative Braking Mode

42. Illustration of the Max. SOC-of-PPS control strategy

43. Control flowchart of the Max. SOC-of-PPS control strategy

44. Parallel Hybrid System

45. Parallel Hybrid System

46. Parallel Hybrid System The parallel HEV allows both ICE and electric motor (EM) to deliver power to drive the wheels. Since both the ICE and EM are coupled to the drive shaft of the wheels via two clutches, the propulsion power may be supplied by ICE alone, by EM only or by both ICE and EM. The EM can be used as a generator to charge the battery by regenerative braking or absorbing power from the ICE when its output is greater than that required to drive the wheels.

47. Parallel Hybrid System The advantages of the parallel hybrid drivetrain are : Both engine and electric motor directly supply torques to the driven wheels and no energy form conversion occurs, hence energy loss is less compactness due to no need of the generator and smaller traction motor. The drawbacks of parallel hybrid drivetrains are: Mechanical coupling between the engines and the driven wheels, thus the engine operating points cannot be fixed in a narrow speed region. The mechanical configuration and the control strategy are complex compared to series hybrid drive train. Due to its compact characteristics, small vehicles use parallel configuration. Most passenger cars employ this configuration.

48. Illustration of engine-on–off control strategy

49. The operation modes Motor-alone propelling mode: The vehicle speed is less than a preset value

50. The operation modes Hybrid propelling mode The load power demand, is greater than what the engine can produce, both the engine and electric motor must deliver their power to the driven wheels at the same time. This is called hybrid propelling mode.

51. The operation modes Engine-alone propelling mode:

52. The operation modes Regenerative-alone brake mode

53. The operation modes Hybrid braking mode:

54. Flowchart of Max. SOC-of-PPS control strategy

55. Series-Parallel System

56. Series-Parallel System The configuration incorporates the features of both the series and parallel HEVs. However, this configuration needs an additional electric machine and a planetary gear unit making the control complex.

57. Complex Hybrid System

58. Complex Hybrid System The complex hybrid system involves a complex configuration which cannot be classified into the above three kinds. The complex hybrid is similar to the series-parallel hybrid since the generator and electric motor is both electric machines. However, the key difference is due to the bi-directional power flow of the electric motor in complex hybrid and the unidirectional power flow of the generator in the series-parallel hybrid. The major disadvantage of complex hybrid is higher complexity.

59. Fuel Cell In recent decades, the application of fuel cells in vehicles has been the focus of increased attention. In contrast to a chemical battery, the fuel cell generates electric energy rather than storing it and continues to do so as long as a fuel supply is maintained. Compared with the battery-powered electric vehicles (EVs), the fuel cell-powered vehicle has the advantages of a longer driving range without a long battery charging time. Compared with the internal combustion engine (ICE) vehicles, it has the advantages of high energy efficiency and much lower emissions due to the direct conversion of free energy in the fuel into electric energy, without undergoing combustion.

60. Operating Principles of Fuel Cells A fuel cell is a galvanic cell in which the chemical energy of a fuel is converted directly into electrical energy by means of electrochemical processes. The fuel and oxidizing agents are continuously and separately supplied to the two electrodes of the cell, where they undergo a reaction. An electrolyte is necessary to conduct the ions from one electrode to the other. The fuel is supplied to the anode or positive electrode, where electrons are released from the fuel under catalyst. The electrons, under the potential difference between these two electrodes, flow through the external circuit to the cathode electrode or negative electrode, where, in combination with positive ions and oxygen, reaction products, or exhaust, are produced

61. Fuel Cell Car

62. Fuel cell

63. Fuel cell characteristic

64. Typical operating characteristics of a fuel cell system

65. Configuration of a typical fuel cell hybrid drive train

66. It mainly consists of a fuel cell system as the primary power source, peaking power source (PPS), electric motor drive (motor and its controller), vehicle controller, and an electronic interface between the fuel cell system and the PPS. According to the power or torque command received from the accelerator or the brake pedal and other operating signals, the vehicle controller controls the motor power or torque output and the energy flows between the fuel cell system, PPS, and the drive train. For peak power demand, for instance, in a sharp acceleration, both the fuel cell system and the PPS supply propulsion power to the electric motor drive. In braking, the electric motor, working as a generator, converts part of the braking energy into electric energy and stores it in the PPS. The PPS can also restore its energy from the fuel cell system, when the load power is less than the rated power of the fuel cell system.

67. Control Strategy

68. Solar Powered Electric Vehicles Solar Electric Powered Hybrid Vehicle (SEPHV) system which solves the major problems of fuel and pollution. An electric vehicle usually uses a battery which has been charged by external electrical power supply. All recent electric vehicles present a drive on AC power supplied motor. An inverter set is required to be connected with the battery through which AC power is converted to DC power. During this conversion many losses take place and also the maintenance cost of the AC System is very high. This topology has the most feasible solar/electric power generation system mounted on the vehicle to charge the battery during all durations. With a view of providing ignited us to develop this “Solar/Electric Powered Hybrid Vehicle” [SEPHV].

69. Solar Powered Electric Vehicles When there is no presence of sun, electric power supply act as an auxiliary energy source. The performance of the SEPHV was found to be satisfactory for the load of four people with the average speed of 45km/hr. The integrated system consisting of Solar module, Charge Controller, Batteries, Boost Converter, Step-down Transformer, Diode Rectifier and PMDC motor which are required for the vehicle. Diode Rectifier can be used to charge the batteries in normal AC supply during sunless conditions

70. Solar Powered Electric Vehicles

71. The Fig. represents an overall view of the Solar/Electric Powered Hybrid Vehicle (SEPHV) sun is the main source of energy for the vehicle and electric power supply is the auxiliary source of energy for the vehicle Solar/Electric Powered Hybrid Vehicle (SEPHV) system are composed by solar panels, charge controller, battery bank, PMDC motor, step down transformer, battery charging unit and altered ‘ Maruti Omni’ vehicle. Hybrid vehicle carries the energy from the both the solar and normal ac supply. The output power from the solar panel is varied depending up on the light irradiation on the atmosphere conditions. Discrete power from the solar panel is connected to the charge controller circuit and fed to the battery bank circuit. At the same time the continuous power from the ac supply is connected to the stepdown transformer (230V/48V) and battery charging unit to battery bank. The electric energy thus formed is being fed to the battery bank. The Vehicle combines the use of electric energy from the three different sources a) Photovoltaic solar energy b) Rectified power supply c) Batteries

72. The Solar cell collects a portion of Sun’s energy and stores it in the batteries. Before that the charge controller convert the energy collected from the solar array to the proper system voltage. So, that the batteries and the motor can use it. Once the energy is utilized by the motor and the battery, an additional charging unit is implemented on the SEPHV to drive.

73. Solar Powered Electric Vehicles The additional charging unit is a rectifying unit of which will step down the 230V of normal electric AC Supply to 48V using a step-down Transformer and rectify it to DC supply to charge the batteries. The rotor shaft of the motor is directly coupled through the solenoid control a gear system. Solenoid control acts as a speed control switch. A Switch is designed with a 4 tapping, giving different values of resistance at each tapping, hence limiting the current that flows in the motor. The performance of the vehicle was found satisfactory for the load of four people with an average speed of 45km/hr.

74. The block diagram represents the overall representation of SEPHV. We altered a Maruti Omni Vehicle into Solar/Electric Powered Hybrid Vehicle (SEPHV) by first replacing its engine with a Permanent Magnet DC Motor [PMDC]. The Motor is made to run from a battery set which is charged from two methods. In the first method a series of Solar Panels are kept at the top of the SEPHV which produces a DC Voltage from the availability of solar radiation. The amount of DC Voltage developed is controlled using a charge controller. In the second method the normal AC Supply is stepped down and rectified to produce a DC Voltage. These two methods are combined to charge the batteries. The charge controller controls the depth of discharge (DOD) of the battery in order to maintain the life of the battery. The motor controller can be used to control both the speed and its electrical braking. Solar charging controllers are designed to prevent solar/electric hybrid vehicle (SEPHV) from overcharging and excessive discharging, therefore to protect our investment and extend the battery life. The electrical energy thus formed is being fed to the batteries that get charged and is used to run 24V PMDC motor. The shaft of the motor is connected to the gear box of the vehicle. The batteries are initially fully charged and thereafter they are charged by PV panels and electric supply.

75. The batteries are directly connected to the motor through a Solenoid control circuit. The Solenoids are acting as the speed control switch. Initially, First accelerator contact is pressed where the solenoid-I activates and the single battery is connected to the motor. When the second accelerator contact is pressed, solenoid-II activates and the two set of batteries are connected to the motor. When the third accelerator contact is pressed , solenoid-III activates and the three set of batteries are connected to the motor. When the fourth accelerator contact is pressed solenoid-IV activates aand the four set of batteries are connected to the motor. In this method it acts as a voltage control method.

76. Solar Powered Electric Vehicles SPECIFICATIONS: This multi charging vehicle can charge itself from both solar and electric power. The vehicle is altered out of a Maruti Omni vehicle by replacing its engine with a 1.2HP, 24V Permanent Magnet DC [PMDC] Motor. The Supply to the motor is obtained from a battery set of 12V, 150AH. The household electric supply of 230V is reduced with a step-down transformer to 48V and then it is converted to the DC with a rectifying unit to charge the battery. Two solar panels each with a rating of 230watts are attached to the top of the Vehicle to grab the solar energy and is controlled with a help of charge controller. The SEPHV can be driven by 1.2 HP PMDC motor consisting of two 230 watts PV panel in the voltage rating of 24 V. The power which is absorbed by the PV panel is stored into the four 150 AH 12 V batteries.

77. Solar Powered Electric Vehicles The PV array has a particular operating point that can supply the maximum power to the load which is generally called Maximum Power Point (MPP). The maximum power point has a non linear locus where it varies according to the solar irradiance and the cell temperature. To boost the efficiency of the PV system, the MPP has to be tracked and followed by regulating the PV panel to operate at MPP operating voltage point, thus optimizing the production of the electricity.

78. Solar Powered Electric Vehicles Solar Energy is being used to produce electricity with the help of these technology our aim to make solar energy powered Vehicle. Main disadvantages of solar energy is such that it is not a constant source of power and the amount of solar energy available keeps on varying throughout the day and at night time it is completely unavailable. So to power our vehicle during the absence of solar energy we designed as alternative method of obtaining power to run the vehicle from the Electric supply.

79. This multi charging vehicle can charge itself from both solar and electric power. The vehicle is altered out of a Maruti Omni vehicle by replacing its engine with a 1.2HP, 24V Permanent Magnet DC [PMDC] Motor. The Supply to the motor is obtained from a battery set of 12V, 150AH. The household electric supply of 230V is reduced with a step-down transformer to 48V and then it is converted to the DC with a rectifying unit to charge the battery. Two solar panels each with a rating of 230watts are attached to the top of the Vehicle to grab the solar energy and is controlled with a help of charge controller. The SEPHV can be driven by 1.2 HP PMDC motor consisting of two 230 watts PV panel in the voltage rating of 24 V. The power which is absorbed by the PV panel is stored into the four 150 AH 12 V batteries.