ee_getNodeDvDtSummary
Calculate maximum absolute values of terminal voltage time derivatives (dv/dt) based on logged simulation data
Syntax
Description
summaryTable = ee_getNodeDvDtSummary(node,tau)foundation.electrical.electrical domain, based on
logged simulation data. The function returns the data for each terminal in a table. The data
in the table appears in descending order according to the maximum magnitude of the
rate-of-change of voltage variables with respect to the ground, over the whole simulation
time. The table does not contain data for terminals that are held fixed.
Before you call this function, you must have the simulation log variable in your current
workspace. Create the simulation log variable by simulating the model with data logging
turned on, or load a previously saved variable from a file. If node is
the name of the simulation log variable, then the table contains the data for all the blocks
in the model that have nodes based on the
foundation.electrical.electrical domain. If node
is the name of a node in the simulation data tree, then the table contains the data only for
the children of that node.
Examining rates-of-change of voltage variables in power electronics circuits is useful
for determining the potential for unwanted conducted or radiated emissions. The
rate-of-change data also helps you to identify switching devices that might be susceptible
to parasitic turn-on. All nodes that are based on the
foundation.electrical.electrical domain store the potential with
respect to electrical ground as the variable v. When you log simulation
data, the time-value series for this variable represents the trend of the potential over
time. You can view and plot this data using the Simscape™ Results Explorer.
To evaluate the rates-of-change of voltage variables, the
ee_getNodeDvDtSummary function employs finite difference
approximation of the first derivative with respect to time. It performs 1-D data linear
interpolation of voltage variables using a uniform grid with the time step,
tau. The function then applies the central differencing scheme to the
interpolated data.
Tip
For small time steps, finite differencing may lead to inaccurate results. The time
step tau should be small enough to capture waveforms, but not so
small that the finite differencing error becomes large. For example, for power
transistors with an expected limit of 50 V/ns for their voltage rate-of-change, a
reasonable guess for tau is 1e-9 s.
summaryTable = ee_getNodeDvDtSummary(node,tau,startTime,endTime)startTime and endTime represent the
start and end of the time interval for evaluating the maximum values. If you omit these two
input arguments, the function evaluates the maximum absolute values of rates-of-change of
voltage variables over the whole simulation time.
Examples
Open the Class E DC-DC Converter example model.
open_system('ClassEDCDCConverter')
This example model has data logging enabled. Run the simulation to create the simulation log variable simlog_ee_converter_dcdc_class_e in your current workspace.
sim('ClassEDCDCConverter');
Calculate the maximum absolute values of rates-of-change of voltage variables for the whole model with a time step of 1e-9 seconds, and display the results in a table.
summaryTable = ee_getNodeDvDtSummary(simlog_ClassEDCDCConverter,1e-9)
summaryTable =
19×3 table
LoggingNode Terminal max_abs_dvdt
______________________________________________________________________ ________ ____________
"ClassEDCDCConverter.R_Trans" "n" 3.9387e+10
"ClassEDCDCConverter.Transformer" "p1" 3.9387e+10
"ClassEDCDCConverter.Cs" "n" 3.9371e+10
"ClassEDCDCConverter.R_Trans" "p" 3.9371e+10
"ClassEDCDCConverter.Cs" "p" 3.3428e+10
"ClassEDCDCConverter.LDMOS" "D" 3.3428e+10
"ClassEDCDCConverter.Ls" "n" 3.3428e+10
"ClassEDCDCConverter.Sense_Vds.Voltage_Stress_Sensor" "p" 3.3428e+10
"ClassEDCDCConverter.D2" "p" 6.5415e+09
"ClassEDCDCConverter.Transformer" "n3" 6.5415e+09
"ClassEDCDCConverter.D1" "p" 6.4406e+09
"ClassEDCDCConverter.Transformer" "p2" 6.4406e+09
"ClassEDCDCConverter.Behavioral_Gate_Driver.Controlled_Voltage_Source" "p" 1e+09
"ClassEDCDCConverter.LDMOS" "G" 1e+09
"ClassEDCDCConverter.Cout" "p" 3.0551e+06
"ClassEDCDCConverter.D1" "n" 3.0551e+06
"ClassEDCDCConverter.D2" "n" 3.0551e+06
"ClassEDCDCConverter.R_Load" "p" 3.0551e+06
"ClassEDCDCConverter.Sense_Vout.Voltage_Sensor" "p" 3.0551e+06
The table shows the maximum absolute values over the whole simulation time of voltage rates-of-change for all the blocks in the model that have nodes based on the foundation.electrical.electrical domain.
Open the Class E DC-DC Converter example model.
open_system('ClassEDCDCConverter')
This example model has data logging enabled. Run the simulation to create the simulation log variable simlog_ClassEDCDCConverter in your current workspace.
sim('ClassEDCDCConverter');
Calculate the maximum absolute values of rates-of-change of voltage variables for the LDMOS block with a time step of 1e-9 seconds, and display the results in a table.
mosfetTable = ee_getNodeDvDtSummary(simlog_ClassEDCDCConverter.LDMOS,1e-9)
mosfetTable =
2×3 table
LoggingNode Terminal max_abs_dvdt
___________ ________ ____________
"LDMOS" "D" 3.3428e+10
"LDMOS" "G" 1e+09
The table shows the maximum absolute values over the whole simulation time of voltage rates-of-change for the LDMOS block. The table does not list the S terminal because it is held fixed to the ground.
To explore the voltage data for the LDMOS block further, use the sscexplore function.
sscexplore(simlog_ClassEDCDCConverter.LDMOS,'D.v')
The block has a variable, v, for each of the D, G, and S terminals.
Open the Class E DC-DC Converter example model.
open_system('ClassEDCDCConverter')
This example model has data logging enabled. Run the simulation to create the simulation log variable simlog_ClassEDCDCConverter in your current workspace.
sim('ClassEDCDCConverter');
The model simulation time is 1.25e-4 seconds. Calculate and display the maximum absolute values of rates-of-change of voltage variables for the LDMOS block during the second half of the simulation. Use a time step of 1e-9 seconds.
mosfetTable1 = ee_getNodeDvDtSummary(simlog_ClassEDCDCConverter.LDMOS,1e-9,0.5*1.25e-4)
mosfetTable1 =
2×3 table
LoggingNode Terminal max_abs_dvdt
___________ ________ ____________
"LDMOS" "D" 2.8487e+10
"LDMOS" "G" 1e+09
The table shows the maximum absolute values of voltage rates-of-change for the LDMOS block during the second half of the simulation. The table does not list the S terminal because it is held fixed to the ground. The magnitude of the D terminal is lower than the magnitude for the whole simulation time because the initial high-magnitude spikes of the stress voltage are disregarded.
To see the voltage time derivative for the D terminal of the LDMOS block over the whole simulation time, use the ee_getNodeDvDtTimeSeries function.
Input Arguments
Output Arguments
Version History
Introduced in R2018b
