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Hello and welcome to the Power Loss calculationlesson.
This lesson will cover different approacheswithin the Typhoon HIL software to calculate
power losses in your models.
Including power loss calculations is one wayyou can increase simulation fidelity.
First, let s discuss the advantages of simulatingpower losses in real time in comparison to
offline simulations.
Knowing losses in real time allows you toemulate thermal behavior in real time which
is useful to test thermal management systems.
Additionally, including forward voltage dropin your converters can affect the power stage
behavior allowing you to better assess therobustness of your converter controller under
test.
In comparison to other HIL applications, C-HILapplications benefit the most from power loss
calculation since it provides a clearer overviewof the control algorithm s impact on power
losses.
There are several requirements that have tobe fulfilled before you can simulate power
losses.
First, the Power Loss Calculation toolboxmust be active.
For more information about the Power LossCalculation Toolbox, please refer to the link
in the materials tab.
There you will also learn which converterssupport power loss calculation.
The next requirement is that your HIL deviceis set to an appropriate firmware configuration.
This is best demonstrated with an example.
On the screen, you can see a drive model whichhas been used previously in this course.
We ll use this model to demonstrate the powerloss calculation feature.
By checking the device configuration table,you can see which firmware configurations
support Power Loss calculation.
As you can see in the Converter Power losscalculation row, the HIL404 supports Power
Loss Calculation in all configurations exceptconfiguration 4.
Since we are not using configuration 4, ourconfiguration supports power loss calculation.
Now, let s go to the converter and reviewthe properties related to power loss calculation.
These properties can be found in the Lossestab of the properties window for every converter
that supports power loss calculation.
In this window you can see two checkboxesone for forward voltage drop and another for
losses calculation.
Here we will be focusing on power loss calculation.
Forward voltage drop will be reviewed in greaterdetail in the next lesson.
Enabling the losses calculation checkbox revealsa number of properties related to power losses.
These power loss properties can be importedin two ways automatically from xml files,
sometimes referred to as PLECS format, ormanually by referencing datasheet information.
If you are interested in automatic importationof power loss data, more information about
this is provided in the tutorial called TutorialMOSFET power loss calculation linked in the
materials tab.
Automatic importation of power loss data isfurther demonstrated in the High Fidelity
EV Drive HIL Simulation webinar also linkedin the materials tab.
The second method of importing power lossdata is manual importation, meaning that you
will populate all the properties in the windowmanually.
The first three properties in the window arecurrent, voltage, and temperature values.
These values define the points on the axesin the 3D space or 2D plane, based on which
you later define the voltage drop or energylosses.
It is common to define these axis points byinspecting graphs in the datasheet being referenced.
Let s open the datasheet we ll use for thisdemonstration and start by inspecting the
conduction characteristics.
In Figure 1 you can see the values of voltagedrop, shown on the x axis, in relation to
conduction current, shown on the y axis.
In this figure, current values range from0 to 300 amperes.
You can select values in this range to populatethe Current values list in the losses calculation
properties.
For this example, we ll take 7 values 0, 50,100, 150, 200, 250, and 300 amperes.
Remember that these values don t have to beequidistant.
It is recommended that you include more pointswhere graphs are more curved and fewer points
in the parts where they are less curved.
You can also see that there are multiple curveson the graphs which correspond to different
temperatures.
You can enter these temperature values asan array in the Temp values property for loss
calculation.
For simplicity, this example will only usetwo temperatures: 125 C and 175 C.
Moving to Figure 5, you will see curves forswitching losses.
You can see in the legend that this data wasgathered at a voltage of 900 V. You can enter
this voltage value in the Voltage values entryfor loss calculation.
These current, voltage, and temperature valueswill define the axes for energy loss and voltage
drop data which you will enter into the model.
Since only one voltage value is specified,all loss data must be approximated assuming
a constant 900 V voltage.
In cases like this, there is a simple wayto introduce voltage dependence and increase
the fidelity of the power loss calculationfor different voltage values.
This is done by adding an additional datapointfor 0 V at the beginning of the voltage array.
Let s do that.
With the additional voltage value, the powerloss calculation algorithm will take into
consideration different voltage values onthe switch.
With axes points defined, it is now time toenter loss and voltage drop data.
Let s start with the voltage drop for theswitch.
As mentioned earlier, we ll include data forthe 125 C and 175 C curves.
For the collector current value of 0 amperes,the forward voltage drop is approximately
0.6 V for 125 C and 0.5 V for 175 C. At 50amperes, the voltage drop is around 1.55 V
for 125 C and 1.6 V for 175 C.
This process should be repeated, recordingvoltage values for all previously defined
current and temperature values.
You can see the appropriate format for enteringvoltage drop data on this slide.
If only one temperature value is entered,you should enter voltage drop values as a
1D array.
If there are multiple temperatures, you canenter voltage drop data as a 2D list.
Using this format, the forward voltage dropdata for this device should be entered as
the 2D list shown here.
You can enter these data into the Vt tableproperty on the losses tab of the converter.
Next, let s inspect the forward characteristicsof the diode.
On this datasheet, Figure 14 presents theforward voltage drop behavior for the diode.
As before, let s collect information for forwardvoltage drop at 125 C and 175 C. The procedure
is the same as for the forward voltage dropfor the switch.
The diode forward voltage data are shown onthis slide using the same 2D list format that
was used for the device forward voltage dropcharacteristics.
You can enter these data into the Vd tableproperty on the losses tab of the converter.
The next three properties Et on table, Etoff table and Ed on table describe switching
losses for the device.
You can also extract these switching lossvalues from the datasheet.
Let s start with switching energy losses inthe switch.
Switching energy curves are presented in Figure5 on this datasheet.
In the figure, there are four curves in total.
Two of them are for the energy loss when theswitch turns on, marked Eon, while the second
two are for the energy loss when the switchturns off, marked Eoff.
For both turn-on and turn-off losses, thereis one curve for 125 C and another for 175
C.Switching loss data should be formatted in
a 2D or 3D list, depending on the number ofvoltages you ve defined.
If there is only one voltage, you would usea 2D look up table.
For the 2D look up table approach, each entryof the list contains loss information defined
for one predefined current value.
Each entry comprises a list which itself hasone entry for each temperature you have previously
defined.
If there are multiple voltages, you woulduse a 3D look up table.
In this approach, each list entry containsinformation for one predefined current value.
Each entry comprises a list with one elementfor each defined voltage.
Each element in the nested list itself comprisesa list which has one entry for each temperature
you have previously defined.
These nested list structures are depictedvisually on this slide.
Now that we have covered the format for describingswitching loss data, let s extract some values
from the datasheet.
Here you can see Figure 5 from the datasheet.
Next to the figure, you can see the data thatis extracted.
On top, you can see the 3D list for switchinglosses during turn-on of the switch.
Below that, you can see the 3D list for switchinglosses during turn-off of the switch.
Notice that the structure is made up of nestedlists as described previously.
Each element of the outer list is itself alist.
These nested lists contains two lists, whereeach one is dedicated to one fixed voltage
value.
In this case, these voltages are 0 V and 900V.
You can see that the first list in each paircontains the same entry, [0, 0].
This is because there are no losses in thecase of switching at 0 V. Including these
zero values enables the power loss calculationalgorithm to calculate losses when switching
at voltages between 0 V and 900 V.You can enter these data into the Et on table
and Et off table properties on the lossestab of the converter.
The last property to add is the switchingpower losses for the diode.
For the diode, you only need energy loss valuesduring turn-off.
These values are presented in the reverserecovery characteristics shown in Figure 12.
The property of interest in this figure isenergy loss during diode recovery, referred
to here as Erec.
The procedure for extracting data is the sameas before.
Here you can see the extracted energy lossdata for the diode.
Diode energy loss data should follow the sameformat as the energy losses for switches switching
on and off.
You can enter the extracted values into theEd off table property on the losses tab of
the converter.
Now that you have entered all the data inthe power loss properties, you can click OK
to save the data and exit the properties window.
You can see that the converter now has anadditional input port to accept an input for
the junction temperature.
It is possible to model thermal behavior ofthe switches, but for this example we will
control the temperature from a SCADA input.
The next lesson will cover thermal behaviormodeling in more depth.
You can also see that the converter has twoadditional output ports one for switching
losses and one for conduction losses.
Let s add a probe to each of the outputs andthen compile the model.
In SCADA, you can add widgets to control thejunction temperature and monitor losses.
When you start the simulation, you can seethat the converter is now computing and reporting
energy loss information.
By varying the temperature set point, youcan observe the effect that temperature has
on device losses.
In the properties window of the converter,you can also see that there is a property
for Switch type.
If you want to perform power loss calculationfor a MOSFET instead of an IGBT, you can change
the switch type to MOSFET.
Configuring power loss calculations for MOSFETsfollows a very similar process to that for
IGBTs.
Since MOSFETs are bidirectional switchingelements, the Current values vector must consist
of both positive and negative currents.
This means that you should specify forwardvoltage drop for both the first and third
quadrant of operation.
Power loss calculation for MOSFETs supportsinternal current sharing, which means that
when current flows from Source to Drain, thepower loss calculation algorithm will consider
power loss created by current passing throughthe MOSFET channel as well as through the
antiparallel diode.
During this lesson, data was collected fromdatasheet figures by inspection.
This method may not provide sufficiently precisedata values, therefore it is recommended to
use a data extraction tool for data extractionfrom figures.
The LUT Extraction tool within the TyphoonHIL software has been developed for this purpose.
If you are interested in using this tool,please refer to the video tutorial linked
in the materials tab.
This concludes the lesson on power loss calculation.
The next lesson will cover more informationabout thermal modeling.
Thank you for your attention.
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