pe_getEfficiency
Calculate efficiency as a function of dissipated power losses
Syntax
Description
returns the efficiency of a circuit based on the data extracted from a Simscape™ logging node.efficiency
= pe_getEfficiency('loadIdentifier'
,node
)
Before you call this function, generate or load the simulation log variable to your workspace. To generate the variable, simulate the model with simulation data logging enabled. For more information, see About Simscape Data Logging. To load a previously saved variable from a file, right-click on the file and select Load.
Checking efficiency allows you to determine if circuit components are operating within
their requirements. Blocks in the Semiconductor > Fundamental Components library and the
Delta-Connected Load, Wye-Connected Load, and
RLC (Three-Phase) blocks have an internal block variable
called power_dissipated. This variable represents the instantaneous
dissipated power, which includes only the real power (not the reactive or apparent power)
that the block dissipates. When you log simulation data, the time-value series for this
variable represents the power dissipated by the block over time. You can view and plot this
data using the Simscape Results Explorer. The ee_getPowerLossTimeSeries
function also allows you to access this data.
The pe_getEfficiency
function calculates the efficiency of the
circuit based on the losses for blocks that have a power_dissipated
variable and that you identify as a load block. The equation for efficiency is
where:
Eff is the efficiency of the circuit.
Pload is the output power, that is, the power dissipated by load blocks.
Ploss is the power dissipated by nonload blocks.
This equation assumes that all loss mechanisms are captured by blocks containing at least one power_dissipated variable. If the model contains any lossy blocks that do not have this variable, the efficiency calculation gives incorrect results.
Some blocks have more than one power_dissipated variable, depending
on their configuration. For example, for the MOSFET (Ideal, Switching) block,
both the diode
node and the ideal_switch
node have a
power_dissipated
logging node. The function sums the power losses for
both nodes to provide the total power loss for the block, averaged over simulation time. The
function uses the loss data to calculate the efficiency of the circuit.
The nonideal semiconductor blocks also have thermal modeling options. Thermal modeling options have thermal ports that allow you to model the heat that is generated due to switching events and conduction losses. If you use a thermal modeling option, the function calculates power losses and efficiencies based on the thermal parameters that you specify. Essentially, the power dissipated is equal to the heat generated.
If you use a modeling option without a thermal port, the function calculates power losses and efficiencies based on the electrical parameters that you specify, such as on-state resistance and off-state conductance.
efficiency = pe_getEfficiency(
returns the efficiency of a circuit based on the power_dissipated data
extracted from a Simscape logging node within a time interval. 'loadIdentifier'
,node
,...
startTime
,endTime
)startTime
and
endTime
represent the start and end of the time interval for
calculating the efficiency. If you omit these two input arguments, the function calculates
the efficiency over the whole simulation time.
[
returns the efficiency of a circuit and the power loss contributions of the nonload blocks
in a circuit based on the data extracted from a Simscape logging node.efficiency
,lossesTable
]
= pe_getEfficiency('loadIdentifier'
,node
)
Input Arguments
Output Arguments
Assumptions
The output power equals the total power dissipated by blocks that you identify as load blocks.
The input power equals the output power plus the total power dissipated by blocks that you do not identify as load blocks.
The power_dissipated variables capture all loss contributions.