Power-trains for More Electric Road Vehicles

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1 Presentation, Power-trains for More Electric Road Vehicles Dr. Nigel Schofield Professor,

2 Presentation overview : 1 Background to more electric vehicle concepts 2 Vehicle power-train power- and torque-speed requirements 3 Machine and power electronics 4 Vehicle integration considerations 5 Energy sources 6 Summary

3 Early electric road vehicle Brushed dc traction system Lloyd Electric delivery vehicle

4 Electric road vehicle infrastructure Electric vehicle and electrolytic rectifier charging station

5 Hybrid or More-electric road vehicles Tilling-Stevens motor-bus; 6864cc; 28.3kW engine Hybrid-electric racing car, circa 1930 s

Automotive applications of electrical machines and drives Heated windscreen Compartment warm-up Entertainment Engine water pump Electronic engine valve actuation Engine lubricant pump Brake by wire

6 Automotive applications of electrical machines and drives Heated windscreen Compartment warm-up Entertainment Engine water pump Electronic engine valve actuation Engine lubricant pump Brake by wire Electrically heated catalytic converter Electrical air conditioning compressor Automated gearbox Electric power steering Electronically controlled suspension Note: Installed electrical capacity projected to rise to 15kW over next 5 years (simple sum:- 15kW/12V = 1250A)

More electric automotive drive-trains Starter clutch Integrated motor-generator (IMG) IC Engine Robotised gear-box Gear shift control lever High power battery

7 More electric automotive drive-trains Starter clutch Integrated motor-generator (IMG) IC Engine Robotised gear-box Gear shift control lever High power battery Gear-box ECU Sensors Steering rack Example schematic for a minimal hybrid-electric vehicle IMG ECU Inverter Vehicle ECU IC Engine ECU Sensors Accelerator pedal

8 Fleet Conversions 7.5 tonne delivery vehicles 3.5 tonne delivery vehicles Courtesy of Smith EV, Washington, UK

9 7.5 Tonne All-Electric Delivery Vehicle Courtesy of Smith EV, Washington, UK

10 Vehicle kinematics and power-train rating

11 Expressing the wheel and traction machine angular velocities in terms of the vehicle linear velocity yields: w w r v w t m r v n sin cos... v A C mg k n r d dt dv n m r d r n J r J n T f d r t t w f t t w f w t t w w m t m m m T m P From which the machine torque equation can be expressed in terms of the vehicle linear velocity by substituting eqns.(1, 2, 4 and 5) into eqn.(3) : Mechanical power is torque multiplied by mechanical speed : (5) (4) (7) (6)

12 Expressing the wheel and traction machine angular velocities in terms of the vehicle linear velocity yields: w w r v w t m r v n sin cos... v A C mg k n r d dt dv n m r d r n J r J n T f d r t t w f t t w f w t t w w m t m m m T m P From which the machine torque equation can be expressed in terms of the vehicle linear velocity by substituting eqns.(1, 2, 4 and 5) into eqn.(3) : Mechanical power is torque multiplied by mechanical speed : (5) (4) (7) (6)

13 NEDC vehicle reference driving cycle Vehicle speed (km/h) Cycle consists of : 4 x ECE15 standard driving cycles with enhanced acceleration 1 x ECE sub-urban cycle Cycle duration (s)

14 Dynamic power over NEDC driving cycle Mechanical power (W) Peak power at : max. acceleration, low speed. high speed, cruse Machine speed (rpm) 1.5 tonne vehicle on zero road gradient

15 Torque (Nm), velocity (m/s) Traction machine torque vs. time Velocity (m/s) Torque (Nm) Time (s)

16 Torque (Nm) Traction machine torque - speed for a gear ratio of Hill climb Driving cycle Speed (rpm)

17 More electric vehicle machine technologies Brushed dc Brushless - permanent magnet Brushless - induction Brushless - switch reluctance

18 Brushed dc motor 1 Quadrant chopper + S1 + S1 4 Quadrant drive D2 S4 D3 - D1 - S2 D1 S3 D4 V DC S1 D1 S1 D1 Motoring S1,S3 and D1,D3 Braking S2,S4 and D2,D4 Forward duty >50% Reverse duty <50%

19 Induction motor Rotor losses dissipated across airgap by convection + S 1 D2 S3 D4 S 5 D6 - S2 D1 S 4 D3 S6 D5 A B C Phase A Phase B Phase C Narrow airgap for low reactive power Cast aluminium or copper rotor bars Phase A Phase B Phase C

20 Brushless permanent magnet motor + S 1 D2 S3 D4 S 5 D6 - S2 D1 S 4 D3 S6 D5 A B C Phase A Phase B Phase C Concentrated or distributed multi-phase winding topologies Permanent magnet rotor excitation Phase A Phase B Phase C

21 Phase 1 1 Phase 2 Phase 3 Phase 3 Switched reluctance motor Torque produced in pulses from interaction of stator and rotor teeth + S1 D2 S3 D4 S5 D6 S2 D1 S4 D3 S6 D5 - I phase High windage loss and noise Narrow high precision airgap P1 P2 P3 P4

22 Traction motor, gear and differential configurations

23 Prototype traction machine, gear-stage and differential

24 Traction motor, gear and differential integration PM Machine rotor PM Machine stator Gear-stage Differential

25 Toyota Prius drive-train Toyota Prius drive-train

26 Toyota Prius drive-train Starter / generator Traction motor

27 More electric vehicle power electronics and control Toyota Prius : Integrated power electronics Driver display screen

28 Torque generation in an electrical machine D s L Magnetic flux density B (Tesla) Shear stress s = K u B Q Ampere stream Q (A/m)

29 Torque generation in an electrical machine Shear stress s = K u B Q s Output coefficient Torque = p/2 D 2 L K u B Q Torque per unit rotor volume = 2s K u factor which relates to the practical realisation of the magnetic field and current sheet B average airgap flux density - limited by maximum working flux densities of stator/rotor iron and permanent magnets Q electrical loading (total ampere stream per meter of airgap circumference) - limited thermally by ability to dissipate winding I 2 R loss

30 Comparison of motor output coefficients K U B (T) Q (A/m) s kpa) Brushed DC , Induction , Inverter fed IM , Synchronous , Brushless PM , Switched reluctance , Note: Q values assume forced air cooling of windings Reference: J.G. West, IEE Power Division Colloquium on Motors and Drives for Battery Powered Propulsion, London, April 1993, Digest 1993/080

31 Research traction machine examples Machine type Induction Brushless PM Brushless PM Cooling Water jacket Water jacket Direct oil Rated torque (Nm) Max. Speed (rpm) 7,500 10,000 20,000 Rated power (kw) Total mass (kg) Specific output (kw/kg) Specific torque (knm/m 3 ) Materials audit kg kg/kw kg kg/kw Silicon iron Copper NdFeB Magnets

32 Other machine materials, copper : Copper raw material cost 1988 to 2002: US $ / lb Average 1.0 $ / lb, (+1.4 / -0.72) As well as machine mass and volume, material resource and cost impacted by move to lower grade PM s Year TFC Commodity Charts;

33 Typical induction motor traction drive efficiency map Torque (Nm) Speed (rpm) Manufacturer Peak torque Base speed Max. speed Siemens 125 Nm 4000 rpm 9000 rpm

34 Typical brushless PM traction drive efficiency map Torque (Nm) Speed (rpm) Peak torque Base speed Max. speed 180 Nm 4000 rpm rpm

35 Terminal constraints on machine design imposed by the power electronic converter Limited DC supply : limitation of machine phase voltage V dc I phase Converter components and thermal capability of the machine: limitation of phase current during continuous operation (nominal current) limitation of phase current during intermittent operation (peak current)

36 For traction machine design 2 operating points to satisfy: Torque at peak acceleration, and Maximum power. But, within the converter supply constraints, there are only 2 variables that influence Torque and Power: Phase rms emf coefficient ( ) or Phase inductance ( L d ). o

37 Design considerations: Supply constraints yield P e(max), Limit on rms phase voltage, V s Limit on peak phase current, I q T e 3 p o I q P e V s L o sin d Torque consideration Power consideration

38 Minimal hybrid-electric power-train concept

39 Generator winding optimisation for extended speed Power versus speed capability as a function of turns per stator pole Ref.: [1] Schofield et al.

41 Power train connection schemes Series; dc-dc converter interfaces energy source to dc-link

42 Power train connection schemes Series; dc-dc converter interfaces peak power buffer to dc-link

43 Power train connection schemes Parallel; electrical system facilitates power buffer

Average voltage per cell / V Power output per cell / Wcm -2 Battery terminal voltage / V Example electric vehicle: 550-750Vdc traction system Charger Vehicle Management Unit and Data Acquisition 650

44 Average voltage per cell / V Power output per cell / Wcm -2 Battery terminal voltage / V Example electric vehicle: Vdc traction system Charger Vehicle Management Unit and Data Acquisition Traction motor, gear-stage and differential cooling cooling HV DC link to cabin heater Brake vacuum PAS pump Control & isoln. Cabin heater H2 tank Fuel cell Zebra Traction Battery Cooling V Aux Time / s Forced air cooling O 2 /air inlet H 2 inlet Electronic control unit Region A Region B Region C Activation polarisation 0.90 (reaction rate loss) Peak power Ohmic polarisation (resistance loss) Electrical power connections Concentration polarisation (gas transport loss) Voltage Power Current density / Acm Ref.: [2] Schofield et al.

45 Average voltage per cell / V Power output per cell / Wcm -2 Fuel cell performance issues Region A Region B Region C Ohmic polarisation (resistance loss) Activation polarisation (reaction rate loss) Peak power Concentration polarisation (gas transport loss) Voltage Power Current density / Acm

46 Battery terminal voltage / V Battery terminal voltage / V Taxi performance evaluation Battery terminal voltage with time : Max. volts Min. volts Time / s Time / s Zebra Sealed lead-acid

47 Battery capacity / Ah Lead-acid battery performance issues Peukert data for a Hawker 12V, 70Ah sealed lead-acid battery 75 Manufacturer's 20C 70 20C 65 0C -20C Discharge current / A

48 Battery capacity / Ah Lead-acid battery performance issues Peukert data for a Hawker 12V, 70Ah sealed lead-acid battery 75 Manufacturer's 20C 70 20C 65 0C -20C Discharge current / A

49 Battery capacity / Ah Lead-acid battery performance issues Peukert data for a Hawker 12V, 70Ah sealed lead-acid battery 75 Manufacturer's 20C 70 20C 65 0C -20C Discharge current / A

50 Battery terminal voltage / V Battery State-of-Charge Battery terminal voltage with time : Max. volts Min. volts Time / s Sealed lead-acid

51 Traction battery ZEBRA Z5C Traction battery TABLE III ZEBRA Z5C BATTERY DATA Type Zebra Z5C Capacity 66Ah Rated energy 17.8kWh Open circuit voltage 278.6V Max. regen voltage 335V Max. charging voltage 308V Min. voltage 186V Max. discharge current 224A Weight 195kg Specific energy 91.2Wh/kg Specific power 164W/kg Peak power 32kW Thermal Loss <120W Cooling Air Battery internal temperature 270 to 350 C Ambient temperature -40 to +70 C Dimensions (WxLxH) 533 x 833 x 300 mm Number of cells per battery 216 Cell configuration 2 parallel strings of 108 series cells

52 ZEBRA Z5C Traction battery Contactor and fuse unit CAN 2b interface to vehicle management unit (VMU) Forced air ventilation Battery management unit (BMU) TABLE III ZEBRA Z5C BATTERY DATA Type Zebra Z5C Capacity 66Ah Rated energy 17.8kWh Open circuit voltage 278.6V Max. regen voltage 335V Max. charging voltage 308V Min. voltage 186V Max. discharge current 224A Weight 195kg Specific energy 91.2Wh/kg Specific power 164W/kg Peak power 32kW Thermal Loss <120W Cooling Air Battery internal temperature 270 to 350 C Ambient temperature -40 to +70 C Dimensions (WxLxH) 533 x 833 x 300 mm Number of cells per battery 216 Cell configuration 2 parallel strings of 108 series cells

53 ZEBRA battery, Beta-alumina cells Beta alumina ceramic tube with compression bond seal. Circular or slim line cross-section. Cloverleaf or monolith cross-section.

54 Battery capacity / Ah Battery performance issues Peukert data for a Hawker and Zebra batteries Manufacturer's 20C 20C 0C -20C Zebra battery Pb-acid battery Manufacturer's 20C 20C 0C -20C Discharge current / A

55 Battery terminal voltage / V Battery terminal voltage / V Taxi performance evaluation Battery terminal voltage with time : Max. volts Min. volts Time / s Time / s Zebra Sealed lead-acid

56 Battery models C d C w R w R d R p R s C=1/V oc R o E P E s R C O R O R P C c = τ/r P E OC

57 Lead-acid traction battery model R int(d) E oc f n (SOC) E oc V terminal

58 Battery test characterisation Current and voltage waveforms for single-step pulse discharging. V 1 V 2 V 4 Voltage (V) V 3 Time (s) I 1 Current (A) 0A Time (s) t 1 t 3 t 4 time t 0 t 2

59 Battery test characterisation Current and voltage waveforms for single-step pulse charging. V 1 V 2 V 3 V 4 Voltage (V) Time (s) I 1 Current (A) 0A Time (s) t 1 t 3 t 4 time t 0 t 2

60 Discharge internal resistance / m (Log scale) Charge internal resistance / m (Log scale) Voltage / V Lead-acid traction battery model R int(d) E oc f n (SOC) E oc V terminal Test Est Normalised SOC A +20C 014A +20C 028A +20C 042A +20C 084A +20C 133A +20C 140A +20C 175A +20C Discharged capacity / Ah A +20C -014A +20C -042A +20C -084A +20C -133A +20C -175A +20C Discharged capacity / Ah

61 Terminal voltage / V Terminal voltage / V Variation in DC link supply to traction system Simulated and measured battery terminal voltage for repetitive ECE15 driving Sim Exp Sim Exp Time / s Time / s (a) Full data (b) First 1000s of data

62 Eoc/V Zebra traction battery model in Matlab/Simulink E oc f n (SOC) E oc R int V terminal 1 SOC 2 No. of cells Eoc=f (SOC) as Look up Table 1 Eoc 2 Terminal Voltag 3 Current (I) Rint=f(SOC, I) as Look up Table change to ohms 3 Voltage drop SOC

63 7.5 Tonne All-Electric Delivery Vehicle Courtesy of Smith EV, Washington, UK

64 7.5 Tonne All-Electric Delivery Vehicle Courtesy of Smith EV, Washington, UK

g 1 g 1 g 1 g 1 s - 2 2 2 2 i - i - - + + i - + - g 1 g 1 g 1 g 1 2 2 2 2 Multi-battery model in

Conn1 Zebra Battery1 CRNT VT1 SOC1 Conn2 Conn1 Zebra Battery2 CRNT VT1 SOC1 Conn2 Conn1 Zebra Battery3

65 g 1 g 1 g 1 g 1 s i - i i g 1 g 1 g 1 g Multi-battery model in Matlab/Simulink s2 s1 s3 s4 Cotactors states SOC1 SOC2 SOC3 SOC4 Currents i + CRNT VT1 SOC1 Conn2 Conn1 Zebra Battery1 CRNT VT1 SOC1 Conn2 Conn1 Zebra Battery2 CRNT VT1 SOC1 Conn2 Conn1 Zebra Battery3 CRNT VT1 SOC1 Conn2 Conn1 Zebra Battery4 K- + I1 I2 I3 I4 i + SOCs 1 Second Cotractor state Itotal MBS Voltages

66 Voltage (V) Voltage (V) Multi-battery control Simulated Measured Time (s) Simulated Measured Time (s)

67 SOC Current (A) Multi-battery control Ibat.1 Ibat.2 Ibat.3 Ibat Time (s) CONT. 2 ON CONT. 1 OFF CONT. 1 ON SOC1 SOC2 SOC3 SOC CONT. 3 OFF CONT. 1 ON Time (s)

68 Rechargeable Lithium-Ion Traction Battery

69 Rechargeable Lithium-Ion Traction Battery Do not expose to temperatures above 60 o C

70 Rechargeable Lithium-Ion Traction Battery Do not expose to temperatures above 60 o C

Rechargeable Lithium-Ion Traction Battery +12.8 Vdc 150 A max. continuous 300 A max. pulse (30s) 0.5 1.

71 Rechargeable Lithium-Ion Traction Battery Vdc 150 A max. continuous 300 A max. pulse (30s) A shunt current Block balancing A shunt current 99 parallel cells 99 parallel cells 99 parallel cells 99 parallel cells 0 Vdc

72 TSB DESERVE Power-train 3.5 tonne delivery vehicle Courtesy of Smith EV, Washington, UK

73 Supercapacitor peak power buffer Individual unit voltage measurements (red) 3x 48V; 165F Units connected in series Total series current measurement (blue)

74 Supercapacitor model in Matlab/Simulink Demand current Thermal model Non-linear capacitance function Loss calculation for input to thermal model

Supercapacitor load testing (a) PC for Labview control and data acquisition (b) Ward-Leonard for controlled DC supply I SCT I DC V SC1 SC 1 T 1 En 1 V SC2

75 Supercapacitor load testing (a) PC for Labview control and data acquisition (b) Ward-Leonard for controlled DC supply I SCT I DC V SC1 SC 1 T 1 En 1 V SC2 SC 2 T 2 En 2 V SCT V DC DC Field control V SC3 SC 3 T 3 En 3 M 1 Control contactor (c) 3x 48 Volt, 165 F Maxwell supercapacitor units (d) Measurement PCBs

76 Testing at MIRA Dissemination of TSB DESERVE research project activities to UK Govt. Cabinet Minister

77 Electric vehicle energy management Test data over 1xECE15 driving cycle : DC Link voltage (V/3) Velocity (m/s) Traction current (A) Supercapacitor current (A) Battery current (A) Time (s)

-link voltage (V) ink Voltage (V) HPM Generator system components and machine concept ICE PM V DC Primary Energy Source Traction Drive Rotor field excitation via non-contact magnetic coupling ICE/HPM

78 -link voltage (V) ink Voltage (V) HPM Generator system components and machine concept ICE PM V DC Primary Energy Source Traction Drive Rotor field excitation via non-contact magnetic coupling ICE/HPM machine and passive (full-bridge diode) rectification stage (a) ICE/HPM machine and passive (full-bridge diode) rectification stage. ZEBRA Battery TM Gearbox Multi-phase stator windngs ICE HPM Generator DC-link Shaft Wound field part PM field part Fuel 585 ICE Auxiliary Power Source 90 C Phase A Power-train schematic EMF PM + EMF WF I f > 0 EMF PM only I f = 0 EMF PM - EMF WF I f < 0 E Schematic of HPM generator cross-section (b) Schematic of HPM generator cross-section Fig. 2. HPM Generator system components and machine concept D B OR C B 0 Ref.: [3] Schofield et al. t

79 DC-link voltage (V) ge (V) Voltage (V) DC-Link Voltage (V) Voltage (V) Voltage (V) Fuel ICE ICE Auxiliary Power Source Primary Energy Source E 60 ZEBRA Battery HPM Generator C D B OR C Phase A B Phase A Traction Drive DC-link F 55 I G H Time (s) Time (s) Fig. 4.1 Schematic of a series hybrid EV power-train and typical DC-link voltage variation during urban driving. Generator interfacing N issues control philosophy Gearbox EMF PM + EMF WF I f > 0 EMF PM only I f = 0 EMF PM - EMF WF I f < 0 V EMF _ WF Scenario 51 TM Power-train schematic + ΔV + V t V _ + + _ EMF + PM _ EMF WF + EMF WF _ + + _ + _ + _ + _ + _ + + _ EMF PM EMF WF EMF PM Phase (C) Phase (A) EMF WF EMF PM Phase (B) A Scenario 24 EMF PM N A Scenario 42 A Scenario 3 A N N Time (ks) Time (ks) Time (ks) Time (ks) EMF PM EMF PM A EMF PM V DC = 0.96 p.u. V DC-link = 555 V V DC = 0.92 p.u. V DC-link = 535 V Driving cycle V DC-link V DC = 0.89 p.u. V DC-link = 515 V

80 Voltage (V) Voltage (V) Voltage (V) Voltage (V) Voltage (V) Generator interfacing issues control philosophy turn, is substituted in to the phase back-emf calculation. _ + V _ ΔV _ + + _ EMF WF Scenario 15 EMF PM A EMFWF Scenario 24 EMFPM A N N Time (ks) Time (ks) 600 EMF PM EMF PM VV DC-link = V p.u. VV DC-link = V p.u. _ + V _ + _ + V _ + + _ + _ A EMF WF Scenario 42 EMF PM A EMF WF Scenario 3 EMF PM N N Time (ks) Time (ks) EMF PM A EMF PM V DC-link V = V p.u. V DC-link Driving cycle V DC-link V = V p.u. + V _ + _ A EMF WF Scenario 51 EMF PM N Time (ks) Time (ks) EMF PM V DC-link V = V p.u. Fig. 3. Five operating scenarios of the HPM generator with respect to the vehicle system DC-link voltage levels.

81 Excitation power losses (W) Generator interfacing issues control philosophy Impedance/Rectification R DC-link 10 1 HPM EMF Fixed speed ω Current direction Load power function V DC-link Scenario 1 2 λ HPM Flux-linkage calculation I f Field current set point Check for V RDC V RDC Wound field regulator System equation ε k k P DCM P DCD Time (ks) Wound field power loss during driving cycle and over battery SoC variation

Voltages and currents ( WF excitation current (A) WF excitation current (A) Voltages and currents ( Generator design validation 150 DC-link current (A) 100 DC-link voltage (V) 50 0-0.003-0.002-0.

8 7 6 (a) (h) 5 (g) 4 3 (b) (f) DC-link voltage (V) 2 150 Rectified DC-link voltage 1 Phase voltage (V) Phase back-emf 0 (c) (e) 100 DC-link voltage (V) DC-link current (A) -1 0 50 (d) 100 150 200

82 Voltages and currents ( WF excitation current (A) WF excitation current (A) Voltages and currents ( Generator design validation 150 DC-link current (A) 100 DC-link voltage (V) (a) Stators and PM rotor Phase voltage (V) Time (s) Phase current (A) DC-Link voltage = 40V (a) Electrical measurements at a DC-Link voltage of 40V (a) (h) 5 (g) 4 3 (b) (f) DC-link voltage (V) Rectified DC-link voltage 1 Phase voltage (V) Phase back-emf 0 (c) (e) 100 DC-link voltage (V) DC-link current (A) (d) DC-link current (A) Phase current (A) Voltage (V) (V) 50 Fig. 4.4 DC-link voltage and peak phase back-emf with-respect-to the WF ex 0 current for a constant DC-link output power of 3 kw Phase voltage (V) -100 Time (s) Phase current (A) DC-Link voltage = 136V (b) Electrical measurements at an average DC-Link voltage of 136V. (b) Stators and WF rotor Fig. 7. Stages of prototype HPM generator hardware build.

83 Motivating factors for new vehicle concepts

84 Million tonnes carbon dioxide equivalent Motivating factors for new vehicle concepts All of the main vehicle related pollutants have reduced over the past 10 years due to emissions reduction legislation and improved engine technologies this against a background increase in vehicle numbers the exception is carbon (CO and CO 2 ) which is still increasing, hence the various LOW CARBON initiatives CO Year

85 Million tonnes carbon dioxide equivalent Motivating factors for new vehicle concepts All of the main vehicle related pollutants have reduced over the past 10 years due to emissions reduction legislation and improved engine technologies this against a background increase in vehicle numbers the exception is carbon (CO and CO 2 ) which is still increasing, hence the various LOW CARBON initiatives CO Year

86 UK Energy Flow Chart 2007 Source: IET Clerk-Maxwell Lecture, 19 th February 2009, London, UK and BERR

87 2050 CO 2 target means change across all sectors Source: IET Clerk-Maxwell Lecture, 19 th February 2009, London, UK

88 2050 CO 2 target means change across all sectors Source: IET Clerk-Maxwell Lecture, 19 th February 2009, London, UK

89 Presentation review : 1 Background to more electric vehicle concepts 2 Vehicle power-train power- and torque-speed requirements 3 Machine and power electronics 4 Vehicle integration considerations 5 Energy sources

90 I would like to thank the many collaborators who have contributed and invite questions References [1] Schofield, N., Long, S.A., Howe, D. and McClelland, M.: Design of a Switched Reluctance Machine for Extended Speed Operation, IEEE Transactions on Industry Applications, Vol. 45, Issue 1, Jan.- Feb. 2009, pp , DOI /TIA [2] UK Foresight Vehicle LINK Programme: Zero Emission Small vehicle with integrated high Temperature battery and FUel CelL (ZESTFUL), N. Schofield (PI); REE1123/R EPSRC Grant No. GR/S81971/01. [3] Schofield, N., Al-Adsani, A.: Operation of a Hybrid PM Generator in a Series Hybrid EV Power-Train, IEEE Vehicle Power and Propulsion Conference (VPPC '11), Chicago, USA, 6-9 Sept. 2011, pp. 1-6.

4 Wikipedia picture. Brushed DC-Machine. The 4 Quadrants. DC-motor torque characteristics. Brushless DC-Motor. Synchronous AC machines

4 Wikipedia picture. Brushed DC-Machine. The 4 Quadrants. DC-motor torque characteristics. Brushless DC-Motor. Synchronous AC machines Vehicle Propulsion Systems Lecture 5 Hybrid Powertrains Part 2 Component Modeling Lars Eriksson Associate Professor (Docent) Vehicular Systems Linköping University November 5, 21 Energy consumption for