Power Semiconductor Module Shielding for Accurate Current Sensing
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Solution Overview
Problem
As output voltage increases in power conversion devices, radiation noise from power semiconductor elements affects the detection accuracy of sensor elements like shunt resistors due to their weaker detection signals compared to the applied voltage, leading to decreased measurement precision.
Innovation Solution
A power semiconductor module design incorporating a heat dissipation plate with a shield layer and through-holes, where sensor line portions are drawn out to the rear surface, effectively shielding radiation noise and reducing its propagation to sensor elements, thereby maintaining detection signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If output voltage is increased to meet power conversion requirements, then power transmission capability is improved, but radiation noise increases and affects sensor element detection accuracy
Solution Approach 1:
A shield layer is introduced as an intermediary between the power semiconductor element and the sensor element. This shield layer, made of electrically conductive material, acts as a mediator that blocks radiation noise from the high-voltage power lines while allowing the sensor element to function normally. The shield layer is connected to ground potential, creating an electromagnetic barrier that protects the detection circuit.
Solution Approach 2:
The heat dissipation plate is divided into functionally distinct regions: a first region for mounting the power semiconductor element and a second region for mounting the sensor element. This segmentation separates the high-noise power transmission area from the sensitive detection area, reducing electromagnetic interference while maintaining effective heat dissipation across the entire plate structure.
2Adaptability or versatility
If sensor element is provided inside the power semiconductor module for current detection, then detection function is integrated, but the module occupies larger space
Solution Approach 1:
The heat dissipation plate is designed to serve multiple functions simultaneously: it provides thermal management for the power semiconductor element, acts as an electromagnetic shield through its conductive shield layer, and serves as a mounting substrate for both the power element and the sensor element. This multi-functionality integrates the detection function without requiring additional separate components or increasing the overall module footprint.
3Measurement precision
If shield layer is added to the heat dissipation plate to block radiation noise, then detection accuracy is improved, but heat dissipation performance may be affected
Solution Approach 1:
The heat dissipation plate is constructed as a composite structure combining a base material with excellent thermal conductivity (such as aluminum or copper) and a shield layer made of electrically conductive material. This composite construction ensures that the shield layer provides electromagnetic shielding while the base material maintains superior heat dissipation capabilities, preventing any compromise in thermal performance.
Solution Approach 2:
The shield layer is selectively applied to specific regions of the heat dissipation plate where electromagnetic shielding is most needed, particularly in areas between the power semiconductor element and the sensor element. This localized approach provides effective noise blocking while minimizing any potential impact on the overall heat dissipation pathways of the plate.
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 suppresses radiation noise interference, ensuring accurate detection of electric current by sensor elements, such as shunt resistors, even in high-voltage environments by minimizing noise propagation and reducing loop areas and conduction noise generation.
Implementation Method 1
the heat dissipation plate includes a shield layer made of a material having at least one of electrical conductivity and magnetism
Implementation Method 2
the heat dissipation plate includes a shield layer made of a material having at least one of electrical conductivity and magnetism
Implementation Method 3
a heat dissipation plate that has a front surface on which the power semiconductor element is mounted, and a rear surface opposite to the front surface, and is configured to dissipate heat from the power semiconductor element
Data Source
AI summary
A power semiconductor module includes a power semiconductor element, a first power line portion and a second power line portion respectively electrically connected to a first electrode and a second electrode of the power semiconductor element, a heat dissipation plate capable of dissipating heat from the power semiconductor element, a sensor element mounted on a front surface of the heat dissipation plate, and a first sensor line portion and a second sensor line portion electrically connected to the sensor element. The heat dissipation plate has at least one through-hole passing through between the front surface and a rear surface. The first sensor line portion and the second sensor line portion are drawn out to a region on the rear surface of the heat dissipation plate through the through-hole.