Dynamic Model Input (Basic and Advanced Dynamic IGBT and Basic Dynamic Power MOSFET)

In the Dynamic Model Input page, you can enter the data for the calculation of the energy correction coefficients and switching delay times for the Basic and Advanced Dynamic IGBT and the Basic Dynamic Power MOSFET models. The switching energy data under at least six different working conditions are required to calculate the complete set of energy correction coefficients.

These six data sets must be entered following a predefined format:

The first row is the set of data under the nominal working conditions.
Each subsequent row may have only one change in the working condition; for example, temperature T is different from the value in the nominal values row. The required variation for each row is listed in the Note column.

If any of these data sets are not available, clear the Enable check box for the row and the corresponding coefficients will remain at their default values (see the IGBT Basic Dynamic model reference in the component help for more information on the algorithm of the switching energy calculation). Additional information provided will be used to fine tune these coefficients.

Dynamic model parameters of the Basic Dynamic IGBT model

Eon	Turn-On Switching Loss
Eoff	Turn-Off Switching Loss
Ton	Turn-On Time (vendor-specific)
Toff	Turn-Off Time (vendor-specific)
Residue	The target error in the parameter fitting for the specified case. In general, lowering the residue results in higher accuracy at the expense of extraction time; however, lower residues are not always achievable. Increasing the residue values increases the probability of successful convergence. The default provides good model accuracy with reasonable extraction time. Fitting of the nominal working point must converge before the extraction process can proceed to other working points. Failure to converge on any other working point will warn you of the failure and provide you with the option to continue the extraction process with other working points. Change the residue to place more or less emphasis on fitting to a set of parameters.

In addition to those dynamic parameters, the following table lists the parameters whose values can be determined without the need of a measuring template. These values result from either integration or direct measurement of the simulated wave form.

Qrr	Reverse recovery charge
Irr	Reverse recovery absolute current peak

You can adjust weights for the switching energies, Eon and Eoff, the delay times, Ton and Toff, and for the reverse recovery characteristics, Qrr and Irr. A higher Weight gives a higher importance to fit more precisely to that particular value. A default weight of 1 is set for these parameters. By default, the reverse recovery characteristics are not used. They can be turned on the Model & Goal Settings page in the Advanced Settings dialog box.

It is possible to define the Switching Energy and Delay Time Measurement criteria; click Measurementto open the Measurement Data dialog box in which you can set the start and stop times for Eon, t(on), Eoff, and t(off) for the device being characterized.

Note:

The Measurement Data dialog box contains the same settings as those in the Manufacturer Data dialog box (see Component Information).

When finished, click Next to continue characterizing the device (see Dynamic Parameter Validation).

Dynamic Parameters of the Advanced Dynamic IGBT Model

The first group of parameters is the same as those used for the Basic Dynamic IGBT model.

Eon	Turn-On Switching Loss
Eoff	Turn-Off Switching Loss
Ton	Turn-On Time (vendor-specific)
Toff	Turn-Off Time (vendor-specific)

In addition to the basic dynamic parameters, the following table lists the advanced dynamic parameters whose values can be determined without the need of a template function fitting. These values result from either integration or interpolation of the simulated wave form.

Qrr	Reverse recovery charge
Flux	Off switch voltage overshoot area
Cos	Relative current overshoot at on switch
Vos	Relative voltage overshoot at off switch
TdG	Input voltage delay time before current rise
TrG	Input voltage rise time
TsG	Input voltage storage time before current fall
TfG	Input voltage fall time
TdI	Load current delay time before current rise
TrI	Load current rise time
TsI	Load current storage time before current fall
TfI	Load current fall time
TdV	Voltage wave form delay time before voltage rise (off switch)
TrV	Voltage wave form rise time (off switch)
TsV	Voltage wave form delay time before voltage fall (on switch)
TfV	Voltage wave form fall time (on switch)

Detailed descriptions of each of these are given below.

Q_RR

Q_RR is an integral value. The integration starts above 100% of the collector current which is equal to the DC like load current at this moment and goes until the current overshoot has settled down to 100% collector current again, or until the next off switch trigger occurs. The equation or the measurement instruction is:

if the current overshoot,

is positive.

The value Q_RR includes the charge of the capacitive components of the upper half bridge transistor and the excess charge storage of the free wheeling diode parallel to the upper transistor at the moment of I_RR zero crossing. It represents the remaining excess charge at the crossing time.

Flux

Another integral value is the area under the voltage overshoot. Define the voltage overshoot as , then if the voltage overshoot is positive or maximum until the next on switch trigger occurs. This overshoot is caused by stray inductances of the circuit from the power source to the half bridge, throughout the half bridge back to the power source ground. From FLUX it is possible to calculate the effective stray inductance. Using FLUX module stray inductances can be adapted to the best fit.

Cos

To adopt the parasitic capacitances and the charge controlling life time parameters TAUFD and TAUBE according to given values of this relative collector current overshoot goal value is useful.

COS strongly depends on the reverse recovery current slope at the moment of zero crossing and thus on the total inductance of the current commutation path. Both values, COS and the overshoot duration, fit to preserve the excess charge Q_RR.

Vos

The voltage overshoot is sensitive to the stray inductances and values. It can be used to fit for the most appropriate circuit stray inductance.

Its definition is .

T_xG, T_xI, T_xV

These advanced parameters provide full flexibility for device parameter optimization. Every switched signal is characterized by typical trigger levels and the corresponding time values. Usually a signal rise time is defined from 10% of rise beginning to 90% of signal maximum. This is only one example for more possible definitions.

Here four trigger points and their times used. Starting from Low come delay, rise, storage and fall time. This simple definition is applied to the input wave form , the output current and the output voltage .

As constraints the device characterization must be provided the level definition. Each trigger level can accept values in the range of 0.0 to 1.0. The resulting time values are all related to the on switch or the off switch trigger. By combination of these twelve time durations, it is possible to generate very different measurement conditions which are used as fitting targets or for comparison between measurement and simulation. The following images give an overview of the existing definitions: