Main Content

Calculate dissipated power losses and switching losses

calculates dissipated power losses and switching losses for semiconductor blocks in
a model, based on logged simulation data, and returns the data for each block in a
table. `lossesTable`

= ee_getPowerLossSummary(`node`

)

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 semiconductor blocks in the model. If
`node`

is the name of a node in the simulation data tree,
then the table contains the data only for the blocks within that node.

Checking dissipated power is useful for verifying that circuit components are
operating within their working envelopes. All blocks in the Semiconductor Devices
library, as well as some other blocks, have an internal variable called
`power_dissipated`

, which represents the instantaneous power
dissipated by the block. 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.

**Note**

The `power_dissipated`

internal variable does not report
dynamic losses incurred from semiconductor switching or magnetic
hysteresis.

Two different variables, `lastTurnOnLoss`

and
`lastTurnOffLoss`

report the switching losses.

Switching losses are losses associated with the transition of the semiconductor
switch from its on-state to its off-state and viceversa. They are frequency
dependent. The `ee_getPowerLossSummary`

function averages the
switching losses over time and expresses them in watts.

The `ee_getPowerLossSummary`

function calculates average losses
for each block that has a `power_dissipated`

variable. Some blocks
have more than one `power_dissipated`

variable, depending on their
configuration. For example, the N-Channel MOSFET block has separate
`power_dissipated`

logging nodes for the MOSFET, the gate
resistor, and for the source and drain resistors if they have nonzero resistance
values. The function sums all these losses and provides the power loss value for the
whole block, averaged over simulation time.

calculates dissipated power losses within a time interval.
`lossesTable`

= ee_getPowerLossSummary(`node`

,`startTime`

,`endTime`

)`startTime`

and `endTime`

represent the
start and end of the time interval for averaging the power losses. If you omit these
two input arguments, the function averages the power losses over the whole
simulation time.