Non-contact Power Supply Foreign Object Detection via Coil Position Sensing
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Solution Overview
Problem
Existing contactless electricity supply systems cannot detect foreign objects between the power feeding coil and the power receiving coil based on transmission efficiency changes, as positional deviations between the coils also affect efficiency.
Innovation Solution
The system employs sensors to detect the positional relationship between the coils, using the output values from these sensors to differentiate between coil misalignment and the presence of a foreign object, allowing for accurate foreign object detection without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmission efficiency sensing is used to detect foreign objects, then power supply safety is improved, but detection accuracy deteriorates because coil positional deviations also reduce transmission efficiency
Solution Approach 1:
The patent divides the detection function into two independent parts: transmission efficiency sensing and positional relationship sensing. By segmenting the detection mechanisms, the system can independently evaluate each parameter and distinguish between efficiency changes caused by misalignment versus those caused by foreign objects, thereby resolving the detection accuracy problem while maintaining safety.
Solution Approach 2:
The patent introduces sensors as intermediary devices that directly measure the positional relationship between coils, independent of the power transmission efficiency measurement. These intermediary sensors provide additional information that mediates between the efficiency data and the final foreign object detection conclusion, enabling accurate differentiation between misalignment and foreign object presence.
2Measurement precision
If separate foreign object sensors are added, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the sensors serve multiple functions: they detect both the positional relationship between coils and the presence of foreign objects. By designing sensors with multi-functionality, the system achieves accurate foreign object detection without adding separate dedicated sensors, thereby avoiding increased device complexity while maintaining high detection accuracy.
Solution Approach 2:
The patent combines the foreign object detection function with the existing positional sensing system. Instead of adding separate foreign object sensors, the system merges these detection capabilities into the unified sensor framework, allowing a single sensor system to perform both positional measurement and foreign object detection, thus avoiding additional hardware 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 approach enables the detection of foreign objects between the coils, preventing potential issues such as heat generation and ensuring reliable contactless power transfer by distinguishing between positional deviations and foreign object presence.
Implementation Method 1
a power feeding coil (12) and a power receiving coil (22), wherein the power feeding coil (12) and the power receiving coil (22) perform contactless electricity supply to each other
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
Provided is a non-contact power supply device which detects foreign objects interposed between a power transmission coil and a power receiving coil. This non-contact power supply device is provided with a second coil which contactlessly transmits power to or receives power from a first coil at least by means of magnetic coupling, multiple sensors for detecting position shifts between the first coil and the second coil, a position detection means which, on the basis of the output values of the sensors, detects the relative positions of the first coil and the second coil, and a foreign object detection means which compares the output values of the sensors and from these comparison results detects foreign objects between first coil and the second coil.