Power Semiconductor Module Current Sensor Potting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-phase current sensors in high power drive applications face challenges with air gaps between the sensor and busbar, leading to reliability issues and mechanical stress during assembly, which affect isolation and accuracy.
Innovation Solution
A power semiconductor module design that integrates a current sensor module with a potting material to eliminate air gaps between the sensor and busbar, using a gauge for precise placement and standard equipment for manufacturing, ensuring tight signal-to-sensor pin tolerances and minimizing tooling efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sensor module is placed in proximity to a busbar for magnetic field sensing, then measurement accuracy is improved, but air gaps between the sensor and busbar cause reliability issues and mechanical stress
Solution Approach 1:
A potting material is introduced as an intermediary substance between the current sensor module and the busbar. This potting material fills the air gap while providing electrical isolation, thus maintaining measurement accuracy through close proximity while eliminating reliability issues associated with air gaps. The potting material acts as a mediator that allows the sensor to be positioned optimally for sensing without creating harmful electrical paths.
2Measurement precision
If the current sensor module is positioned close to the busbar for accurate measurement, then measurement precision is improved, but mechanical stress during assembly increases
Solution Approach 1:
The potting material serves as a cushioning medium that is applied before final assembly is completed. It provides mechanical support and stress distribution between the sensor module and busbar, preventing excessive mechanical stress during assembly while maintaining the close proximity needed for accurate magnetic field sensing. The cushioning effect protects the sensor module from mechanical loads.
3Reliability
If air gaps are eliminated between the sensor and busbar, then isolation is improved, but manufacturing complexity increases
Solution Approach 1:
The invention changes the physical state and properties of the gap-filling material by using a potting material that can be applied in a liquid or semi-liquid state and then cured or hardened. This parameter change allows the material to flow into and fill all air gaps completely, ensuring thorough electrical isolation. After curing, it becomes a solid structural element that maintains the gap-free interface, thus improving isolation without significantly increasing manufacturing complexity.
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
This design enhances reliability and accuracy by eliminating air gaps, improving isolation, and reducing mechanical stress, while allowing for efficient production with reusable manufacturing processes.
Implementation Method 1
a core-based principle of magnetic current sensing... implements a field concentrator (e.g., an iron core wrapped around a current rail) to concentrate a magnetic field produced by a current flowing through the current rail onto a magnetic sensing element
Data Source
AI summary
Described is a power semiconductor module that includes: a frame made of an electrically insulative material; a first substrate seated in the frame; a plurality of power semiconductor dies attached to the first substrate; a plurality of signal pins attached to the first substrate and electrically connected to the power semiconductor dies; a busbar extending from the first substrate through a side face of the frame; a current sensor module seated in a receptacle of the frame in sensing proximity of the busbar, the current sensor module including a current sensor attached to a circuit board; and a potting material fixing the current sensor module to the frame such that no air gap is present between the current sensor and the busbar. The potting material contacts the frame and the current sensor. Methods of producing the power semiconductor module are also described.