Build Hybrid Electric Vehicle Input Power-Split Model

The hybrid electric vehicle (HEV) input power-split reference application represents a full HEV model with an internal combustion engine, transmission, battery, motor, generator, and associated powertrain control algorithms. Use the HEV input power-split reference application for HIL testing, tradeoff analysis, and control parameter optimization of a power-split hybrid like the Toyota^® Prius^®. To create and open a working copy of the HEV input power-split reference application project, enter

autoblkHevIpsStart 

By default, the HEV input power-split reference application is configured with:

• Lithium-ion battery pack

• Mapped motor and generator

• Mapped spark-ignition (SI) engine

This diagram shows the powertrain configuration.

Note

The Virtual Vehicle Composer configures the reference application. If you want to the change the configuration, use the Virtual Vehicle Composer to specify a different powertrain and vehicle.

This table describes the blocks and subsystems in the reference application.

Reference Application Element	Description
Analyze Power and Energy	Double-click Analyze Power and Energy to open a live script. Run the script to evaluate and report power and energy consumption at the component- and system-level. For more information about the live script, see Analyze Power and Energy.
Scenarios	Implements the Drive Cycle Source block to generate a FTP75 (2474 seconds) drive cycle.
Environment	Creates environment variables, including road grade, wind velocity, and ambient temperature and pressure.
Driver Commands	Implements the Longitudinal Driver to generate normalized acceleration and braking commands.
Controllers	Implements a powertrain control unit containing a hybrid vehicle control unit (VCU) and an engine control unit (ECU).
Vehicle	Implements a hybrid passenger car that contains drivetrain, electric plant, and engine subsystems.
Visualization	Displays vehicle-level performance, battery state of charge (SOC), fuel economy, and emission results that are useful for powertrain matching and component selection analysis.

Evaluate and Report Power and Energy

Double-click Analyze Power and Energy to open a live script. Run the script to evaluate and report power and energy consumption at the component- and system-level. For more information about the live script, see Analyze Power and Energy.

The script provides:

• An overall energy summary that you can export to an Excel^® spreadsheet.

• Engine plant, electric plant, and drivetrain plant efficiencies, including an engine histogram of time spent at the different engine plant efficiencies.

• Data logging so that you can use the Simulation Data Inspector to analyze the powertrain efficiency and energy transfer signals.

Controllers

The Controller subsystem implements the hybrid vehicle control unit (VCU), engine control unit (ECU), and open loop braking control.

The input-power split VCU implements a dynamic supervisory controller that determines the engine torque, generator torque, motor torque, and brake pressure commands. Specifically, the input power-split VCU:

• Converts the driver accelerator pedal signal to a wheel torque request. The algorithm uses the optimal engine torque and maximum motor torque curves to calculate the total powertrain torque at the wheels.

• Converts the driver brake pedal signal to a brake pressure request. The algorithm multiplies the brake pedal signal by a maximum brake pressure.

• Implements a regenerative braking algorithm for the traction motor to recover the maximum amount of kinetic energy from the vehicle.

• Implements a virtual battery management system. The algorithm outputs the dynamic discharge and charge power limits as functions of battery SOC.

• Determines the vehicle operating mode through a set of rules and decision logic implemented in Stateflow^®. The operating modes are functions of wheel speed and requested wheel torque. The algorithm uses the wheel power request, accelerator pedal, battery SOC, and vehicle speed rules to transition between electric vehicle (EV) and HEV modes.

  

  Mode	Description
  EV	Traction motor provides the wheel torque request.
  HEV – Charge Sustaining (Low Power)	Engine provides the wheel torque request. Torque blending algorithm transitions the torque production from the EV motor to the HEV engine. The algorithm allows the motor to ramp down the torque while the engine torque ramps up. Once the blending is complete, the motor can start sustaining the charge (negative torque), if needed. Based on the target battery SOC and available kinetic energy, the HEV mode determines a charge sustain power level. The mode includes the additional charge power in the engine power command. To provide the desired charge power, the traction motor acts as a generator. Depending on the instantaneous speeds of the engine and motor, the generator may consume energy while regulating the engine speed. In this case, the motor provides the additional charge sustaining power.
  HEV – Charge Depleting (High Power)	Engine provides the wheel power request up to its maximum output. If the wheel torque request is greater than the engine torque output at the wheels, the traction motor provides the remainder of the wheel torque request.
  Stationary	While the vehicle is at rest, the engine and generator can provide optional charging if battery SOC is below a minimum SOC value.

• Controls the motor, generator, and engine through a set of rules and decision logic implemented in Stateflow.

  Control	Description
  Engine	Decision logic determines the engine operation modes (off, start, run). In engine run mode, lookup tables determine the engine torque and engine speed that optimizes the break-specific fuel consumption (BSFC) for a given engine power request. The ECM uses the optimal engine torque command. The generator control uses the optimal engine speed command.
  Generator	As determined by the HCM, the generator either starts the engine or regulates the engine speed. To regulate the engine speed, the generator uses a PI controller. A rule-based power management algorithm calculates a generator torque that does not exceed the dynamic power limits.
  Motor	A rule-based power management algorithm calculates a motor torque that does not exceed the dynamic power limits.

Vehicle

The Virtual Vehicle Composer configures the reference application vehicle subsystem. If you want to the change the configuration, use the Virtual Vehicle Composer to specify a different powertrain and vehicle.

The hybrid vehicle has the characteristics provided in this table.

Element	Description
Dual clutch transmission (DCT)	Implements the Ideal Fixed Gear Transmission block to configure an ideal fixed gear transmission without clutch or synchronization.
Wheels and Brakes	Implements the Longitudinal Wheel block with disc brakes to configure drivetrain for front wheel drive.
Vehicle Body	Implements the Vehicle Body 3DOF Longitudinal block to configure vehicle for 3 degrees-of-freedom.
Engine	Implements the Mapped SI Engine block.
Battery and DC-DC Converter	Implements the Datasheet Battery block to configure a lithium-ion battery pack.
Motors	Implements the Mapped Motor blocks with implicit controllers.

References

[1] Balazs, A., Morra, E., and Pischinger, S., Optimization of Electrified Powertrains for City Cars. SAE Technical Paper 2011-01-2451. Warrendale, PA: SAE International Journal of Alternative Powertrains, 2012.

[2] Burress, T. A. et al, Evaluation of the 2010 Toyota Prius Hybrid Synergy Drive System. Technical Report ORNL/TM-2010/253. U.S. Department of Energy, Oak Ridge National Laboratory, March 2011.

[3] Rask, E., Duoba, M., Loshse-Busch, H., and Bocci, D., Model Year 2010 (Gen 3) Toyota Prius Level-1 Testing Report. Technical Report ANL/ES/RP-67317. U.S. Department of Energy, Argonne National Laboratory, September 2010.