autoblks.pwr.PlantInfo

Analyze powertrain power and energy

Description

To assess powertrain efficiencies, use the autoblks.pwr.PlantInfo object to evaluate and report power and energy for component-level blocks and system-level reference applications.

Creation

Syntax

VehPwrAnalysis = autoblks.pwr.PlantInfo(SysName)

Description

MATLAB creates an autoblks.pwr.PlantInfo object for the system that you specify. VehPwrAnalysis = autoblks.pwr.PlantInfo(SysName) where SysName is the name of the model or subsystem that you want to analyze.

Input Arguments

SysName — Model name

character vector

Model that you want to analyze.

Example: 'ConfiguredConventionalVirtualVehicle'

Data Types: char

Properties

AvgEff — Average efficiency

double

This property is read-only.

Average efficiency, η_avg, dimensionless. The AvgEff property derives the average efficiency from the total change in stored, input, and output energy using this equation.

$${\eta }_{avg}=\{\begin{array}{l}\frac{\Delta E_{store}-\Delta E_{output}}{\Delta E_{input}}\Delta E_{store}\ge 0\\ \frac{\Delta E_{output}}{\Delta E_{store}-\Delta E_{input}}\Delta E_{store}<0\end{array}$$

After a simulation, the autoblks.pwr.PlantInfo class calculates changes in stored, input, and output energy for each signal using these equations.

$$\Delta E_{store}={\displaystyle \underset{0}{\overset{t_{final}}{\int }}{P}_{store}dt}\Delta E_{input}={\displaystyle \underset{0}{\overset{t_{final}}{\int }}{P}_{input}dt}\Delta E_{output}={\displaystyle \underset{0}{\overset{t_{final}}{\int }}{P}_{output}dt}$$

The equation uses these variables.

Pstore	Stored power
Pinput, Poutput	Input and output power logged by Power Accounting Bus Creator block
ΔEstore, ΔEinput, ΔEoutput	Change in stored, input and output energy

Eff — Instantaneous efficiency

time series

This property is read-only.

Instantaneous efficiency, η, dimensionless. The Eff property derives the instantaneous efficiency from power using this equation.

$$\eta =\left|\frac{{\displaystyle \sum P_{output}-{{\displaystyle \sum }}^{\text{}}{P}_{store}\left(P_{store}>0\right)}}{{{\displaystyle \sum }}^{\text{}}{P}_{input}-{{\displaystyle \sum }}^{\text{}}{P}_{store}\left(P_{store}<0\right)}\right|$$

The equation uses these variables.

Pstore	Stored power
Pinput, Poutput	Input and output power logged by Power Accounting Bus Creator block

EnrgyBalanceAbsTol — Energy balance absolute tolerance

0.0100 (default)

Energy balance absolute tolerance, EnrgyBal_AbsTol.

To determine if the system conserves energy, the isEnrgyBalanced method checks the energy conservation at each time step.

$E_{Err}={{\displaystyle \sum }}^{\text{}}{E}_{trans}+{{\displaystyle \sum }}^{\text{}}{E}_{nottrans}-{{\displaystyle \sum }}^{\text{}}{E}_{store}$

Blocks change the input energy plus released stored energy to output energy plus stored energy. For example, a mapped engine block uses fuel (not transferred energy) to produce torque (transferred energy) and heat loss (not transferred energy). The total modified energy represents the average between the input fuel energy and the energy exiting the system (torque and heat loss). To calculate the total energy modified by the block, the method uses the integral of the average transferred, not transferred, and stored power.

$E_{total}=\frac{1}{2}{\left(\underset{0}{\overset{t_{end}}{{\displaystyle \int }}}\left({{\displaystyle \sum }}^{\text{}}\left|P_{trans}\right|+{{\displaystyle \sum }}^{\text{}}\left|P_{nottrans}\right|+{{\displaystyle \sum }}^{\text{}}\left|P_{store}\right|\right)dt\right)|}_{t=t_{end}}$

If the energy conservation error is within an error tolerance, the method returns true. Specifically, if either condition is met, the method returns true.

Condition
$\frac{\left|E_{Err}\right|}{E_{total}}<EnrgyBa{l}_{RelTol}$	or	$E_{total}<EnrgyBa{l}_{AbsTol}$

The equations use these variables.

EErr	Energy conservation error
Etotal	Total energy modified by block
EnrgyBalRelTol, EnrgyBalAbsTol	Energy balance relative and absolute tolerance, respectively
Ptrans, Etrans	Transferred power and energy, respectively
Pnottrans, Enottrans	Not transferred power and energy, respectively
Pstore, Estore	Stored power and energy, respectively
Pinput, Poutput	Input and output power logged by Power Accounting Bus Creator block

Data Types: double

EnrgyBalanceRelTol — Energy balance relative tolerance

0.0100 (default)

Energy balance relative tolerance, EnrgyBal_RelTol.

To determine if the system conserves energy, the isEnrgyBalanced method checks the energy conservation at each time step.

$E_{Err}={{\displaystyle \sum }}^{\text{}}{E}_{trans}+{{\displaystyle \sum }}^{\text{}}{E}_{nottrans}-{{\displaystyle \sum }}^{\text{}}{E}_{store}$

Blocks change the input energy plus released stored energy to output energy plus stored energy. For example, a mapped engine block uses fuel (not transferred energy) to produce torque (transferred energy) and heat loss (not transferred energy). The total modified energy represents the average between the input fuel energy and the energy exiting the system (torque and heat loss). To calculate the total energy modified by the block, the method uses the integral of the average transferred, not transferred, and stored power.

$E_{total}=\frac{1}{2}{\left(\underset{0}{\overset{t_{end}}{{\displaystyle \int }}}\left({{\displaystyle \sum }}^{\text{}}\left|P_{trans}\right|+{{\displaystyle \sum }}^{\text{}}\left|P_{nottrans}\right|+{{\displaystyle \sum }}^{\text{}}\left|P_{store}\right|\right)dt\right)|}_{t=t_{end}}$

If the energy conservation error is within an error tolerance, the method returns true. Specifically, if either condition is met, the method returns true.

Condition
$\frac{\left|E_{Err}\right|}{E_{total}}<EnrgyBa{l}_{RelTol}$	or	$E_{total}<EnrgyBa{l}_{AbsTol}$

The equations use these variables.

EErr	Energy conservation error
Etotal	Total energy modified by block
EnrgyBalRelTol, EnrgyBalAbsTol	Energy balance relative and absolute tolerance, respectively
Ptrans, Etrans	Transferred power and energy, respectively
Pnottrans, Enottrans	Not transferred power and energy, respectively
Pstore, Estore	Stored power and energy, respectively
Pinput, Poutput	Input and output power logged by Power Accounting Bus Creator block

Data Types: double

EnrgyUnits — Energy units

MJ (default) | J

Energy units.

Example: VehPwrAnalysis.EnrgyUnits = 'MJ';

Data Types: char

PwrUnits — Power units

kW (default) | W

Power units.

Example: VehPwrAnalysis.PwrUnits = 'kW';

Data Types: char

Object Functions

addLoggedData	Add logged data
dispSignalSummary	Display powertrain subsystem energy analysis
dispSysSummary	Display powertrain system efficiency
findChildSys	Powertrain subsystem energy analysis
histogramEff	Display powertrain subsystem efficiency histogram
isEnrgyBalanced	Logical flag for energy conservation
loggingOff	Turn signal logging off
loggingOn	Turn signal logging on
run	Run powertrain energy and power analysis
sdiSummary	Display Simulation Data Inspector plots of powertrain energy and power
xlsSysSummary	Write powertrain energy analysis to spreadsheet

Examples

Create PlantInfo Object for Powertrain Energy Analysis

Analyze the power and energy in the conventional vehicle reference application. To create a PlantInfo object, see step 2.

Open the conventional vehicle reference application. By default, the application has a mapped 1.5 L spark-ignition (SI) engine and a dual clutch transmission. Project files open in a writable location.

autoblkConVehStart 

Set the system name to ConfiguredConventionalVirtualVehicle.

Create the autoblks.pwr.PlantInfo object.

Use the PwrUnits and EnrgyUnits properties to specify the units.

SysName = 'ConfiguredConventionalVirtualVehicle';
VehPwrAnalysis = autoblks.pwr.PlantInfo(SysName);
VehPwrAnalysis.PwrUnits = 'kW';
VehPwrAnalysis.EnrgyUnits = 'MJ';

Use the run method to turn on logging, run simulation, and add logged data to the object.

run(VehPwrAnalysis);

Use the dispSysSummary method to display the results.

dispSysSummary(VehPwrAnalysis);

Use the xlsSysSummary method to write the results to a spreadsheet.

xlsSysSummary(VehPwrAnalysis,'EnergySummary.xlsx');

Use the findChildSys method to retrieve the autoblks.pwr.PlantInfo object for the Engine subsystem.

To display the results, use the dispSignalSummary method.

Use the histogramEff method to display a histogram of the time spent at each engine plant efficiency.

EngSysName = SysName+"/Vehicle/ConfiguredSimulinkPlantModel/Engine";
EngPwrAnalysis = VehPwrAnalysis.findChildSys(EngSysName);
dispSignalSummary(EngPwrAnalysis,EngSysName);
histogramEff(EngPwrAnalysis);

Use the findChildSys method to retrieve the autoblks.pwr.PlantInfo object for the Transmission subsystem.

To display the results, use the dispSignalSummary method.

TransSysName = SysName+"/Vehicle/ConfiguredSimulinkPlantModel/Transmission";
TransPwrAnalysis = findChildSys(VehPwrAnalysis,TransSysName);
dispSignalSummary(TransPwrAnalysis,TransSysName);

To plot the results, use the sdiSummary method.

sdiSummary(VehPwrAnalysis,{EngSysName,TransSysName})

Version History

Introduced in R2019a