Power Module Temperature Sensor Thermal Coupling

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Solution Overview

Problem

Existing temperature measurement methods for power semiconductors in power modules are thermally decoupled, leading to inaccurate temperature readings and reduced maximum current capacity due to spatial spacing and thermal tolerances, resulting in incorrect conclusions about the thermal preload and behavior of the power semiconductor.

Innovation Solution

A contact arrangement where a temperature sensor is directly or indirectly connected to the power semiconductor via a high thermal conductivity connecting layer, ensuring close thermal coupling and accurate temperature monitoring, allowing the power semiconductor to operate at maximum currents before reaching critical temperature values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a temperature sensor is spatially spaced from the power semiconductor (e.g., SMD resistor soldered onto circuit carrier), then the temperature sensor can be electrically decoupled and safely measure temperature, but the temperature measurement becomes inaccurate due to thermal decoupling and spatial spacing

Engineering Contradiction:
Improveelectrical decoupling safetyVSAvoidtemperature measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The temperature sensor is merged with the power semiconductor by direct mounting on the semiconductor chip surface, combining the measurement function with the monitored object to eliminate thermal decoupling while maintaining electrical isolation through appropriate sensor design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A thermally conductive but electrically insulating interface layer serves as an intermediary between the temperature sensor and power semiconductor, enabling efficient heat transfer while preventing electrical short circuits between the sensor and high-voltage semiconductor components

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If thermal tolerances are introduced to account for thermal decoupling, then the power semiconductor can be protected from overheating, but the maximum current carrying capacity cannot be fully utilized

Engineering Contradiction:
Improveoverheating protectionVSAvoidmaximum current carrying capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The mechanical/spatial separation approach is replaced with direct thermal contact through surface mounting, substituting the need for thermal tolerance compensation with accurate real-time temperature measurement that enables full current capacity utilization

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The temperature sensor mounted directly on the power semiconductor provides self-service temperature monitoring that accurately reflects the actual semiconductor temperature, enabling the system to operate at maximum current capacity without requiring external thermal tolerance margins

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If a temperature sensor is mounted on the circuit carrier rather than directly on the power semiconductor, then the circuit layout is simpler, but the temperature sensor cannot clearly indicate the thermal preload on the power semiconductor

Engineering Contradiction:
Improvecircuit layout simplicityVSAvoidthermal preload information
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The temperature measurement is moved from the circuit board plane to the semiconductor chip surface, adding a vertical dimension to the mounting approach that enables direct thermal contact while maintaining electrical isolation through the sensor's inherent design

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables real-time, accurate temperature monitoring of power semiconductors, allowing them to be operated at maximum current capacity while preventing critical temperature conditions, thereby improving operational reliability and efficiency.

Implementation Method 1

The temperature sensor is arranged directly or indirectly on the top side of the power semiconductor via a connecting layer, the connecting layer in particular having a high thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3245672B1Contact arrangement and power module
Publication Date: 2023.06.28 ROBERT BOSCH GMBH
  • EP3245672B1 patent drawingFigure 1~2

AI summary

The invention relates to a contact arrangement of at least one power semiconductor, comprising a circuit carrier (10) of a circuit. The at least one power semiconductor (20) has an upper face and a lower face, and the lower face of the power semiconductor is connected to the circuit carrier (10). Furthermore, an electric and/or electronic component (40) is arranged directly or indirectly on the upper face of the at least one power semiconductor (20). The electric and/or electronic component (40) is a temperature sensor which is designed to ascertain the temperature of the power semiconductor (20) and provide a temperature signal that is used as a control variable for a maximum current in the at least one power semiconductor.