Design

1
Design Prototyping of Hybrid Electric Vehicle
Electronic Control Unit

• Dinçer Mehmet BAHAR
• Energy Institute
• 2008,Gebze

2
TOPICS

• HEV CONFIGURATIONS OF HEV
• WHY DO WE NEED HECU?
• HARDWARE STRUCTURE OF HECU
• INPUTS OUTPUTS OF HECU
• CASING OF HECU
• SOFTWARE DEVELOPMENT FOR HECU

3
Hybrid Electric Vehicles

• A hybrid electric vehicle (HEV) is the vehicle
  which has both internal combustion engine (ICE)
  and electric motor (EM).

ICE
EM

4
Hybrid Electric Vehicle Configurations

• Series HEV (SHEV)
• SHEV is driven by only EM.
• SHEV contains ICE for generating electrical power
  to keep the batteries charged and propel the
  vehicle by the means of the electrical power
  through the generator when the State of Charge
  (SOC) of batteries is low.

5
Hybrid Electric Vehicle Configurations

• Parallel HEV (PHEV)
• In PHEV, EM and ICE are connected together to the
  transmission line where both of them or one by
  one can propel the vehicle.
• The batteries can be charged by ICE where EM acts
  as a generator or by regenerative braking.

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Hybrid Electric Vehicle Configurations

• Series-Parallel HEV (SPHEV)
• SPHEVs have the properties and the advantages of
  both Series and Parallel HEVs.
• SPHEV can charge the battery packs in the idle
  mode from ICE.

7
Why Do We Need HECU?

• A hybrid vehicle has many subsystems
• ECU of the conventional
• part of the vehicle
• ICE
• EM
• EM Driver
• Battery BMS

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Why Do We Need HECU?

• All this subsystems needs a master controller to
  drive hybrid vehicle properly where HECU steps in
  with the ability of
• Understanding and giving meaning to drivers
  requests.
• Understanding HEVs situation with all subsystems
  conditions.
• Response back and control the HEV according to
  the data collected in the previous steps.

9
Hardware Structure of HECU

• HECU has 2 allocable parts which gives the
  ability of use in different applications
• Power Supply Unit.
• Controller Board.

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Hardware Structure of HECU

• POWER SUPPLY UNIT
• From 12V vehicle battery, gives multiple power
  solution for HECU and sensors that are needed to
  control the HEV.
• Has 4 high efficient DC-DC converters.
• All converters are connected to the 12V vehicle
  battery with LC filters to reduce ripples and
  suppress the noise on the power line.
• Input voltage range 9-18V
• Output voltage levels 5V-12V-15V-24V

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Hardware Structure of HECU

• Controller Board
• Digital Signal Controller
• TI TMS320F2808
• 32-Bit High performance for complex algorithms
  with high efficiency in math task.
• 100 MHZ Fixed-Point signal processor with
  internal flash.
• Peripherals of TMS320F2808
• 16 PWM (6 High resolution PWM)
• 6 32-Bit 6 16-Bit Timers
• 12-Bit ADC, 2x8 channel Analog inputs with fast
  conversion rate.
• Up-to 35 individually programmable GPIO
• JTAG advanced emulation features for analysis,
  real-time debugging and programming.
• 32 Mailbox, 2 Enhanced Controller Area
  Network(eCAN)
• Serial Communication Interface (SCI) to interface
  with computer
• Serial Peripheral Interface (SPI)

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Hardware Structure of HECU

• HECU has 6 Layer PCB to reduce EMI/EMC related
  noises.
• Component layers Top Bottom layers are for
  localization of the active passive circuit
  components.
• Ground Layer Split Analog, Digital and Isolated
  grounds. Where all components and traces are
  placed only over their own ground regions.

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Hardware Structure of HECU

• Signal Layer 1 Signal Layer 2 Differential and
  single-ended signals are routed according to
  crosstalk and reflection consideration. Dif.
  Signals are routed as possible as each other
  where single-ended signal traces are routed at
  least 2 times the trace width apart from each
  other.
• No traces are routed parallel over
• another trace on an other layer.
• If they have to cross over, both
• traces are routed with right angle
• to minimize crosstalk.
• 90º bends are avoided and routed
• with two 45º corners to minimize
• any impedance change.

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Hardware Structure of HECU

• Power layer Split Multiple Power Layer. 24V,
  12V, -12V, Analog 5V, 5V, 3.3V, Analog 3.3V,
  Analog 1.8V, 1.8V, 1.5V power planes.
• Active components are
• connected to their related
• power plane with 1µH
• ferrite coil and 0.1µF
• bypass capacitor for EMI
• consideration.
• With split power planes none
• of the components sourced over another
  component.

15
Inputs Outputs of HECU

• I/O Structure
• HECU has many I O to
• understand the needs of the driver
• know condition of the subsystems of the HEV
• control the subsystems according to this
  information with the processing algorithm.
• Digital Inputs Outputs
• Analog Inputs Outputs

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Inputs Outputs of HECU

• Digital inputs outputs
• CAN BUS HECU has 2 CAN ports and via these ports
  can connect to 2 different CAN BUS with 2
  different speed levels up to 1 megabit/sec.
• HECU communicates with ECU of the conventional
• part of the vehicle to learn the information
  about state of
• the engine, engine speed, vehicle speed, wheel
  speed,
• gear state, brake pedal switch and clutch pedal
  switch
• position
• HECU communicates with BMS to learn the
  information about State Of Charge (SOC) of the
  batteries, pack voltages, pack currents, pack
  temperatures and to send connect and clear error
  commands via CAN BUS.

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Inputs Outputs of HECU

• JTAG HECU interfaces via CCS for programming and
  real-time debugging and analysis.
• SERIAL BUS Via SCI HECU can send software
  parameters to a computer for monitoring.
• PWM digital output for reference signal of ICE
  throttle pedal for ECU

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Inputs Outputs of HECU

• Analog Inputs Outputs
• Analog Inputs From throttle pedal position,
  brake pedal force, clutch pedal position and
  some more sensors HECU reads differential analog
  signals to understand drivers driving request. As
  all sensors have different range of output
  voltages, these signals must be scaled before
  they connect to DSP to be in the meaningful range
  of 0-3V.
• Voltage divider, differential and operational
  amplifiers are used.

19
Inputs Outputs of HECU

• Analog Outputs HECU has 8 Analog outputs which
  are generated by DAC with the drive of Serial
  Peripheral Interface (SPI) in the range of 0-5V.
• SPI sends 16 bit of data to 8 channels DAC. The
  first 4 bits are control bits that select the
  channel of the DAC and the other 12 bits are data
  bits.
• EM torque request, EM brake reference, EM
  direction and EM enable command signals are some
  example of analog outputs that HECU send to
  subsystems (which can be also be send as digital
  signal via CAN BUS to EM if EM is compatible)

20
Casing of HECU

• HECU has aluminum and plexiglas casings which are
  designed to fix the HECU into the HEV and reduce
  EMI/EMC.

21
Software Development of HECU

• HECU can be programmed either using conventional
  programming languages (Assembler, C, C) or
  using Matlab/Simulink automatic code generation
  feature.
• HEV energy management algorithms are very
  complicated and mostly designed using Simulink
• Compatibility of HECU to Simulink allows rapid
  prototyping of algorithms which saves time during
  the RD phase.

22
Software Development of HECU

• While rapid prototyping one should care about
  saturation, rounding and quantization effects
  because HECU has a Fixed-Point processor.
• Simulink helps developing Fixed-Point algorithms
  with Fixed-Point Toolbox where one can easily
  specify range and scaling factor for software
  variables.
• Developing algorithms for Fixed-point processors
  seems challenging at first but they reduces the
  cost of HECUs processor price up 50.

23
Conclusion

• HEVs are getting popular day by day because of
  the environmental point of view also the
  economical reasons of increasing cost of fossil
  fuels.
• Any kind of HEV needs a electronic control unit
  for subsystems added to make hybrid and also to
  communicate with the conventional part of the
  vehicle. HECU was designed to answer these needs
  with
• low cost
• high performance mathematical solutions for
  complex algorithms.
• Rapid prototyping features.

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HECU was designed and developed in accordance
with Designing and Prototype Development of a
Hybrid Electrical Vehicle Control Unit project
supported by FORD OTOSAN AS.
25

• THANK YOU FOR YOUR ATTENTION.