Explore the Hybrid Electric Vehicle Input Power-Split Reference Application

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

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

  • Nickel-metal hydride (NiMH) battery pack

  • Mapped electric motors

  • Mapped spark-ignition (SI) engine

This diagram shows the powertrain configuration.

This table describes the blocks and subsystems in the reference application, indicating which subsystems contain variants. To implement the model variants, the reference application uses variant subsystems.

Reference Application ElementDescriptionVariants

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.

NA

Drive Cycle Source block — FTP75 (2474 seconds)

Generates a standard or user-specified drive cycle velocity versus time profile. Block output is the selected or specified vehicle longitudinal speed.

 
Environment subsystem

Creates environment variables, including road grade, wind velocity, and atmospheric temperature and pressure.

 
Longitudinal Driver subsystem

Uses the Longitudinal Driver or Open Loop variant to generate normalized acceleration and braking commands.

  • Longitudinal Driver variant implements a driver model that uses vehicle target and reference velocities.

  • Open Loop variant allows you to configure the acceleration, deceleration, gear, and clutch commands with constant or signal-based inputs.

Controllers subsystem

Implements a powertrain control module (PCM) containing an input power-split hybrid control module (HCM) and an engine control module (ECM).

Passenger Car subsystem

Implements a hybrid passenger car that contains drivetrain, electric plant, and engine subsystems.

Visualization subsystem

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.

For more information about the live script, see Analyze Power and Energy.

Drive Cycle Source

The Drive Cycle Source block generates a target vehicle velocity for a selected or specified drive cycle. The reference application has these options.

TimingVariantDescription

Output sample time

Continuous (default)

Continuous operator commands

Discrete

Discrete operator commands

Longitudinal Driver

The Longitudinal Driver subsystem generates normalized acceleration and braking commands. The reference application has these variants.

Block Variants

Description

Longitudinal Driver (default)

Control

Mapped

PI control with tracking windup and feed-forward gains that are a function of vehicle velocity.

Predictive

Optimal single-point preview (look ahead) control.

Scalar

Proportional-integral (PI) control with tracking windup and feed-forward gains.

Low-pass filter (LPF)

LPF

Use an LPF on target velocity error for smoother driving.

pass

Do not use a filter on velocity error.

Shift

Basic

Stateflow® chart models reverse, neutral, and drive gear shift scheduling.

External

Input gear, vehicle state, and velocity feedback generates acceleration and braking commands to track forward and reverse vehicle motion.

None

No transmission.

Scheduled

Stateflow chart models reverse, neutral, park, and N-speed gear shift scheduling.

Open Loop

Open-loop control subsystem. In the subsystem, you can configure the acceleration, deceleration, gear, and clutch commands with constant or signal-based inputs.

To idle the engine at the beginning of a drive cycle and simulate catalyst light-off before moving the vehicle with a pedal command, use the Longitudinal Driver variant. The Longitudinal Driver subsystem includes an ignition switch signal profile, IgSw. The engine controller uses the ignition switch signal to start both the engine and a catalyst light-off timer.

The catalyst light-off timer overrides the engine stop-start (ESS) stop function control while the catalyst light-off timer is counting up. During the simulation, after the IgSw down-edge time reaches the catalyst light-off time CatLightOffTime, normal ESS operation resumes. If there is no torque command before the simulation reaches the EngStopTime, the ESS shuts down the engine.

To control ESS and catalyst light-off:

  • In the Longitudinal Driver Model subsystem, set the ignition switch profile IgSw to 'on'.

  • In the engine controller model workspace, set these calibration parameters:

    • EngStopStartEnable — Enables ESS. To disable ESS, set the value to false.

    • CatLightOffTime — Engine idle time from engine start to catalyst light-off.

    • EngStopTime — ESS engine run time after driver model torque request cut-off.

Controllers

The Controller subsystem has a PCM containing an input power-split HCM and an ECM. The controller has these variants.

ControllerVariantDescription
ECMSiEngineController (default)

SI engine controller

Input power split HCMSeries Regen Brake (default)

Friction braking provides the torque not supplied by regenerative motor braking.

Parallel Regen Braking

Friction braking and regenerative motor braking independently provide the torque.

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

  • 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.

    ModeDescription

    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.

    ControlDescription

    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.

Passenger Car

To implement a passenger car, the Passenger Car subsystem contains drivetrain, electric plant, and engine subsystems. To create your own engine variants for the reference application, use the CI and SI engine project templates. The reference application has these variants.

Drivetrain SubsystemVariantDescription

Differential and Compliance

All Wheel Drive

Configure drivetrain for all wheel, front wheel, or rear wheel drive. For the all wheel drive variant, you can configure the type of coupling torque.

Front Wheel Drive (default)
Rear Wheel Drive

Gearbox

Ideal Fixed Gear Transmission

Configure gearbox efficiency with a constant (default) or 3D lookup table.

Vehicle

Vehicle Body 3 DOF Longitudinal

Configured for 3 degrees of freedom

Wheels and Brakes

Longitudinal Wheel - Front 1

For the wheels, you can configure the type of:

  • Brake

  • Force calculation

  • Resistance calculation

  • Vertical motion

For performance and clarity, to determine the longitudinal force of each wheel, the variants implement the Longitudinal Wheel block. To determine the total longitudinal force of all wheels acting on the axle, the variants use a scale factor to multiply the force of one wheel by the number of wheels on the axle. By using this approach to calculate the total force, the variants assume equal tire slip and loading at the front and rear axles, which is common for longitudinal powertrain studies. If this is not the case, for example when friction or loads differ on the left and right sides of the axles, use unique Longitudinal Wheel blocks to calculate independent forces. However, using unique blocks to model each wheel increases model complexity and computational cost.

Longitudinal Wheel - Rear 1

Electric Plant SubsystemVariantDescription
Battery and DC-DC ConverterBattHevIps

Configured with NiMH battery

GeneratorGenMapped (default)

Mapped generator with implicit controller

GenDynamic

Interior permanent magnet synchronous motor (PMSM) with controller

MotorMotMapped (default)

Mapped motor with implicit controller

MotDynamic

Interior permanent magnet synchronous motor (PMSM) with controller

Engine SubsystemVariantDescription
EngineSiMappedEngine (default)

Mapped SI engine

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.

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