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5xx - Thermal Simulation¶

Power loss calculation and thermal analysis for reliable converter design.

Tutorial	Title	Difficulty	Materials
501	Loss Calculation	⅔	circuit
502	Junction Temperature	3/3	circuits
503	Heatsink Design	3/3	README

Learning Objectives¶

Calculate conduction and switching losses in semiconductors
Model thermal impedance networks (Foster/Cauer)
Estimate junction temperatures during operation
Design cooling systems for target reliability
Analyze transient thermal behavior

Contents¶

501 - Loss Calculation¶

BuckBoost_thermal.ipes - Thermal model of buck-boost converter
Conduction loss: I²R, Vce×Ic
Switching loss: Eon + Eoff at fsw

502 - Junction Temperature¶

BuckBoost_thermal_with_java.ipes - Advanced thermal with Java blocks
ThreePhase-VSR_10kW_thermal.ipes - 10kW VSR thermal analysis
ThreePhase-VSR_10kW_thermal_with_java.ipes - Enhanced thermal model

503 - Heatsink Design¶

Comprehensive README with design methodology
Thermal resistance calculations
Heatsink selection guidelines
Transient thermal analysis

Quick Reference¶

Thermal Resistance Chain¶

Junction → [Rth,jc] → Case → [Rth,ch] → Heatsink → [Rth,ha] → Ambient

Tj = Ta + Ploss × (Rth,jc + Rth,ch + Rth,ha)

Typical Thermal Resistances¶

Component	Rth (K/W)	Notes
IGBT module	0.1-0.5	Junction to case
Thermal grease	0.05-0.2	Case to heatsink
Small heatsink	2-5	Natural convection
Large heatsink	0.2-1	Forced air

Loss Equations¶

Conduction:

IGBT: Pcond = Vce0×Ic + Ron×Ic²
Diode: Pcond = Vf×Id + Rd×Id²

Switching:

Psw = (Eon + Eoff) × fsw × (Vdc/Vref) × (Ic/Iref)

Prerequisites¶

Complete 2xx DC-DC Converters (base circuits)
Understanding of power semiconductor operation
Basic heat transfer concepts