Electric Power Steering Power Module Thermal Layout
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Solution Overview
Problem
Existing electric power steering drive control apparatuses face challenges in achieving size reduction, cost reduction, and heat generation balance, with inhomogeneous heat generation leading to performance deterioration and increased size and cost due to inadequate heat-releasing structures.
Innovation Solution
A power module with balanced heat generation and release, incorporating shunt resistors and snubber capacitors, and a heat sink design that ensures even heat distribution across components, using mold resin encapsulation to integrate power circuit components and heat sinks, and optimizing the layout to reduce temperature rises and enhance thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If power circuit components are integrated in a compact power module, then device size is reduced, but heat generation becomes inhomogeneous and heat release efficiency deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct thermal zones within the power module. Different components (IGBTs, diodes, capacitors) are positioned in locations with optimized thermal characteristics. The housing includes strategically placed heat dissipation portions and heat generation portions, where local thermal properties are tailored to match the heat generation characteristics of specific components, ensuring uniform heat release despite compact integration.
2Adaptability or versatility
If motor relay switching element is added to control motor power, then motor control capability is improved, but temperature rise of the relay element increases due to high current flow
Solution Approach 1:
The patent introduces thermal management structures as intermediaries between the motor relay switching element and the external environment. Heat dissipation portions and heat generation portions are designed to act as thermal mediators, facilitating efficient heat transfer from the high-current relay element to the housing and ultimately to the external cooling system, preventing excessive temperature rise while maintaining motor control functionality.
3Temperature
If heat generating components are laminated on the back surface of the motor, then heat radiation performance is improved, but device size and cost increase
Solution Approach 1:
The patent merges the heat dissipation function with the structural housing of the power module. Instead of adding separate heat sinks or cooling structures, the housing itself is designed with integrated heat dissipation portions and heat generation portions. This consolidation achieves effective heat radiation while avoiding the size and cost penalties of laminated heat generating components on the motor back surface.
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
The solution achieves balanced heat release, suppressing performance deterioration, enabling size and cost reduction while enhancing the drive ability of electric power steering systems by exploiting heat resistance capabilities effectively.
Implementation Method 1
heat-releasing efficiency... heat sink design that ensures even heat distribution across components
Implementation Method 2
heat-releasing efficiency... efficiently release heat to heat resistance abilities of individual components
Data Source
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AI summary
An object is to release heat efficiently to heat-resistance abilities of individual components by enhancing a heat-radiation performance of power circuit components forming a power module (100) and by enhancing a heat generation balance. The power circuit components formed of power switching elements (107 and 108) forming a bridge circuit and a motor relay switching element (109) are mounted on conductive members (102) while a heat generation balance is maintained. Then, the conductive members (102) are disposed on a heat-releasing heat sink (30) by abutment, and the power circuit components and the heat sink (30) are integrally molded using mold resin (101).