# Infineon Power Simulation tool: FAQs - KBA237348

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Community Translation: インフィニオンパワーシミュレーションツール：FAQ- KBA237348

Question 1
: What is the Infineon Power Simulation (IPOSIM) tool?

Answer: IPOSIM is a simulation tool that makes it easy and quick to calculate the maximum junction temperature, conduction loss, switching loss, and temperature ripple in the switching devices. IPOSIM offers topologies for various applications, including the following:

• AC-DC application: Single-phase and three-phase
• AC-AC application: Single-phase and three-phase
• DC-DC application: Buck and boost
• DC-AC application: Single-phase and three-phase

IPOSIM recommends the appropriate switch and gate driver based on the application. IPOSIM's major function is to compare the losses of the selected devices at the same application conditions and help in determining device thermal performance.

It performs the steady state, load cycle simulation, and lifetime estimation and provides the summary report in Excel format.

Question 2: Does IPOSIM provide different heatsink options?

Answer: Yes, IPOSIM provides different heatsink structures like predefined heatsink, user-defined heatsink, and fixed heatsink.

In a predefined heatsink, the cooling method can be selected as forced air cooling or water cooling based on the application.

In a user-defined heatsink, if you know the parameters of the heatsink, you can define the thermal network of the heatsink and the ambient temperature so that the simulated junction temperature is as follows:

Tj=Rthjc * Ploss device + THS (dependent on Rth,hs ) + T ambient

Tj = Junction temperature
Rthjc= Junction to case thermal resistance

Ploss device= Device power loss
THS = Heat sink temperature

Tambient = Ambient temperature
Rth,hs = Heat sink thermal resistance

In a fixed heatsink, the heatsink (as well as the case) has a constant temperature for a specific operating point. Here, the heatsink temperature at a steady state is assumed to be a fixed value specified by the user (independent of Rth(ch)). The simulation then uses the device’s thermal network and simulates power losses to calculate the junction temperature. In other words, the junction temperature that you see is as follows:

Tj=Rthjc * Ploss device + Tcase (fixed HS temperature )
Tj = Junction temperature
Rthjc= Junction to case thermal resistance
Ploss device= Device power loss
Tcase = case temperature
THS = Heat sink temperature

Question 3: How do I select the heatsink values for different modules?

Answer: When entering data for a heatsink, consider the available heatsink values which may be characterized based on the base plate size of the selected module, regardless of the implemented circuit configuration within the module itself (for example, 'FF...' --> two IGBT/Diode switches, 'FS...' --> six IGBT/Diode switches).

Because IPOSIM calculates the loss and temperature per single IGBT and freewheeling diode, the entered Rthhs values must be given per single IGBT/diode switch. Therefore, the available heat sink values must be adapted to the circuit configuration of the selected module by a correction factor according to Table 1.

Table 1 Correction factor

 Configuration Correction factor FZ (single switch) 1 DZ (single diode) 1 FF (half bridge) 2 DD (dual diode) 2 FT (Tripack) 3 F4 (4-pack) 4 FD, DF (chopper) 2 FS (Sixpack) 6 FB, FP (PIM) 7

Multiply the heatsink Rthhs values by x1 for a single switch module, x2 for half-bridge modules, and so on. Do not change the time constants (t values)

Question 4: Can I select the gate resistance? What are the minimum and maximum values?

Answer: Yes, IPOSIM provides an option to select the gate turn ON and gate turn OFF resistances.

The maximum and minimum values of the gate resistances at the turn ON and turn OFF are defined based on the datasheet curves – Eon and Eoff as a function of RG, taking into account the entire tested range.

Question 5: How does IPOSIM calculate the losses for the modules and discretes?

Answer: IPOSIM always calculates the losses for the single switch only. Even for modules, the losses are given for an individual switch. To obtain the total losses, multiply the losses by the total number of switches.

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