Power Circuit Shielding Against Heat Sink Interference
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Solution Overview
Problem
In power circuit mount units, detection errors occur due to electromagnetic waves generated by the heat sink during switching operations, which interfere with detection signals in nearby detection circuits.
Innovation Solution
An electromagnetic shielding member is placed between the heat sink and the detection circuit, held at ground or control potential, to shield against electromagnetic waves, thereby reducing noise interference and ensuring accurate signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat sink is attached to the power module for heat dissipation, then heat dissipation performance is improved, but electromagnetic waves are generated that interfere with detection circuits
Solution Approach 1:
An electromagnetic shielding member is introduced as an intermediary component between the heat sink and the detection circuit. This shielding member blocks electromagnetic waves generated by the heat sink during switching operations, preventing interference with the detection circuit while allowing the heat sink to continue its heat dissipation function.
Solution Approach 2:
The space between the heat sink and detection circuit is segmented by introducing the electromagnetic shielding member. This segmentation separates the high-electromagnetic-interference zone (near the heat sink) from the low-interference zone (detection circuit area), allowing both components to coexist without mutual interference.
2Volume of moving object
If the detection circuit is mounted near the power module for compact design, then device compactness is improved, but detection accuracy deteriorates due to noise from electromagnetic waves
Solution Approach 1:
The electromagnetic shielding member acts as a protective intermediary that enables the detection circuit to be positioned close to the power module without sacrificing detection accuracy. It blocks electromagnetic noise from reaching the detection circuit, allowing compact mounting while maintaining measurement precision.
3Device complexity
If no electromagnetic shielding is provided, then device complexity is reduced, but detection errors occur due to electromagnetic wave interference
Solution Approach 1:
A relatively simple electromagnetic shielding member is introduced as a mediator to protect the detection circuit. This component adds minimal structural complexity while significantly improving detection reliability by blocking electromagnetic wave interference from the heat sink.
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 shielding effectively reduces noise irradiation into the detection circuit, preventing detection errors and enhancing the reliability of the power circuit mount unit by isolating electromagnetic waves from the heat sink.
Implementation Method 1
an electromagnetic shielding member (70) for shielding against electromagnetic waves generated from the heat sink (53) to the detection circuit (60) side
Implementation Method 2
a heat sink (53) for dissipating heat from the power modules (51, 52), which is attached to surfaces of the power modules (51, 52)
Implementation Method 3
Heat generated in a switching element is conducted to the heat sink, and then is dissipated to air through a heat dissipating fin
Data Source
Figure 1
Figure 2
AI summary
A first power module, a second power module, and a detection circuit are mounted on a printed circuit board. A heat sink is attached to surfaces of the power modules. An electromagnetic shielding member for shielding against electromagnetic waves from the heat sink side to the detection circuit side is provided between an attachment section of the detection circuit of the printed circuit board and a base of the heat sink.