Motor Compressor Common Mode Choke Coil Heat Dissipation
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Solution Overview
Problem
Motor-driven compressors face challenges in effectively transferring heat from the conductor of the common mode choke coil, which is essential for damping effects, leading to potential overheating due to trapped heat and the need for improved heat radiation performance.
Innovation Solution
A motor-driven compressor design featuring a common mode choke coil with a loop-shaped core, windings, and a loop-shaped conductor that covers the core and windings, where the conductor has increased electric resistance for efficient heat radiation, thermally coupled to a metal housing, and includes a slit to enhance heat transfer via thermal grease, improving heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common mode choke coil is covered with a conductor to achieve damping effect, then normal mode current generates induced current that converts to thermal energy, but heat is trapped inside requiring additional heat radiation structures
Solution Approach 1:
The conductor is designed with locally varied electric resistance: high resistance portions are positioned at specific locations to generate heat, while low resistance portions facilitate heat conduction to the housing. This local differentiation allows the conductor to simultaneously achieve damping effect through induced currents and efficient heat radiation to the housing.
Solution Approach 2:
The conductor acts as an intermediary element between the windings and the housing. It receives induced currents from the windings, converts them to thermal energy, and efficiently transfers this heat to the housing which serves as a heat radiating member. This intermediary function resolves the contradiction by providing a dedicated heat transfer path.
2Reliability
If the conductor has high electric resistance to generate damping effect, then induced current converts to thermal energy, but heat transfer to housing becomes inefficient
Solution Approach 1:
The conductor features spatially varying electric resistance properties. High resistance regions are positioned where induced currents are generated to maximize thermal energy conversion, while low resistance regions are positioned to facilitate efficient heat conduction to the housing. This local quality differentiation resolves the contradiction between heat generation and heat transfer efficiency.
3Temperature
If a structure against heating is added to the choke coil, then heat radiation performance improves, but device complexity increases
Solution Approach 1:
The conductor serves multiple functions simultaneously: it provides damping effect through induced currents, acts as a heat generation element through resistive heating, and functions as a heat transfer medium to the housing. This multi-functionality eliminates the need for separate heat radiation structures, maintaining device simplicity while improving heat radiation performance.
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 design effectively reduces common and normal mode noise while enhancing heat radiation performance by converting induced currents into thermal energy, efficiently transferring heat to the housing and maintaining the structural integrity of the conductor.
Implementation Method 1
a normal mode current through the conductor generates an induced current in the conductor, which is converted into thermal energy
Implementation Method 2
the conductor needs to have some electric resistance to have the damping effect
Implementation Method 3
the conductor includes a heat radiation portion that is thermally coupled to the housing
Implementation Method 4
the noise reducer reduces a common mode noise and a normal mode noise included in the direct-current power
Data Source
AI summary
A metal film includes portions that are opposed to each other and located away from each other between the first winding and the second winding. The metal film includes the first linear part that is thermally coupled to a housing. The average value of electric resistance per unit length in the peripheral direction of the first linear part of the metal film is greater than an average value of electric resistance per unit length of locations other than the first linear part.