S-Notched Conductor Structure for Accurate Heat-Sink Current Sensing
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Solution Overview
Problem
Existing current sensors in electric vehicles experience inaccurate measurements due to eddy currents, particularly when high-frequency currents are present, which are exacerbated by the use of heat sinks in conductor structures.
Innovation Solution
The integration of a power module with a high-current conductor structure featuring an S-notch portion to mitigate eddy currents, a low-current conductor structure connected to a heat sink, and a differential current sensor aligned to minimize the impact of eddy currents on measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat sink is connected to the conductor structure, then thermal management is improved, but eddy currents increase and measurement accuracy deteriorates
Solution Approach 1:
The patent introduces a non-conductive layer as an intermediary between the heat sink and the conductor structure. This layer allows thermal energy to be transferred while blocking the path for eddy currents, thus maintaining effective thermal management while preventing the generation of harmful eddy currents that would interfere with current measurements.
Solution Approach 2:
The conductor structure is segmented by introducing slots or breaks in the conductive path near the heat sink connection point. This segmentation interrupts the continuous conductive loop that would otherwise allow eddy currents to flow, thereby reducing measurement errors while preserving the heat dissipation function through the non-conductive coupling layer.
2Productivity
If high-frequency current is used, then power conversion efficiency is improved, but eddy currents increase and measurement accuracy deteriorates
Solution Approach 1:
The non-conductive coupling layer acts as an intermediary that permits high-frequency current operation by blocking eddy current paths. This allows the system to operate at high frequencies for improved power conversion efficiency without suffering from the eddy current-induced measurement errors that would otherwise increase with frequency.
Solution Approach 2:
The patent converts the potentially harmful effect of high-frequency operation (increased eddy currents) into a benefit by using the non-conductive layer to selectively block eddy currents while allowing the desired high-frequency power conversion to proceed efficiently. The structure that would normally be harmful becomes advantageous for high-frequency operation.
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 provides robust current measurement by reducing eddy currents, especially at higher frequencies, ensuring accurate and reliable current sensing in electric vehicle power modules.
Implementation Method 1
Such conductors, however, typically develop eddy currents which degrade accurate current measurements. These eddy currents typically increase in magnitude—and negative impact on current measurement—with increasing frequency of current in the conductor.
Implementation Method 2
a current sensor having magnetic field sensing elements is typically used. The current sensors typically measure current flowing in a high-side conductor such as a bus bar.
Data Source
AI summary
Systems, circuits, and methods provide heat-sink-coupled conductive structures having eddy current mitigation structures, formed as S-notches, and integrated current sensors. An example conductive structure includes a high-current conductor structure having a main current path including an S-notch portion configured to mitigate eddy currents. The structure includes a low-current conductor structure connected to a first heat sink and having a main current path configured to conduct a second current. A differential current sensor is connected to the low-current conductor structure and configured to detect current flowing in the high-current conductor structure. A power module includes the conductive structure and a power converter that is configured to convert power between the first current in the high-current conductor structure and the second current in the low-current conductor structure. The conductive structures and power modules can be used for EV applications.