isEnrgyBalanced

Logical flag for energy conservation

Syntax

flag=isEnrgyBalanced(PlantInfoObj)

Description

flag=isEnrgyBalanced(PlantInfoObj) returns logical 1 (true) if the system conserves energy. Otherwise, it returns logical 0 (false).

Input Arguments

PlantInfoObj — Instance of PlantInfo object

autoblks.pwr.PlantInfo object

autoblks.pwr.PlantInfo object for the system that you want to analyze.

Output Arguments

flag — Indicator of energy conservation

1 (true) | 0 (false)

Indicator of energy conservation, returned as a logical 1 (true) or 0 (false).

Data Types: logical

Algorithms

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

Version History

Introduced in R2019a