# ee_getNodeDvDtSummary

Calculate maximum absolute values of terminal voltage time derivatives (dv/dt) based on logged simulation data

*Since R2018b*

## Syntax

## Description

calculates the maximum absolute values of rates-of-change of voltage variables for nodes
that are based on the `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.

calculates the maximum absolute values of rates-of-change of voltage variables within a time
interval. `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

## Input Arguments

## Output Arguments

## Version History

**Introduced in R2018b**