Wireless Power Coil Unit for Foreign Metal Detection
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Solution Overview
Problem
Existing contactless power transmission systems face accuracy issues in detecting foreign matter due to multiple resonance frequencies and decreased Q values when using multiple detecting coils without gaps, leading to reduced accuracy in metal detection.
Innovation Solution
A coil unit with resonators arranged in rows and columns, where an excitation coil generates alternating magnetic fields with different resonance frequencies, preventing interference between resonators and maintaining high Q values, thus improving metal detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple detecting coils are disposed without gaps to eliminate dead areas, then the coverage area for foreign matter detection is improved, but multiple resonance frequencies are generated and Q values are significantly lowered, deteriorating detection accuracy
Solution Approach 1:
The detection area is divided into multiple independent detection regions, each corresponding to one detecting coil. The coils are arranged with gaps between them, creating separate detection zones that avoid mutual interference. This segmentation allows each coil to operate at its own resonance frequency without being affected by adjacent coils, thereby maintaining high Q values and detection accuracy while still providing comprehensive coverage through the array of separated detection regions.
2Measurement precision
If multiple detecting coils are connected to capacitor for resonance, then the sensitivity of foreign matter detection is improved, but multiple resonance frequencies are present making measurement difficult and Q values are lowered
Solution Approach 1:
Each detecting coil is assigned a distinct resonance frequency and operates independently within its own detection region. The system uses local quality differentiation by giving each coil unique resonant characteristics rather than having all coils resonate at the same frequency. This approach simplifies measurement by allowing selective excitation and detection of individual coils, avoiding the complexity of managing multiple simultaneous resonance frequencies while maintaining high detection sensitivity through resonant enhancement in each local detection zone.
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 enhances the accuracy of foreign matter detection by preventing multiple resonance frequencies and maintaining high Q values, even when resonators are disposed without gaps, effectively improving the detection of metals during contactless power transmission.
Implementation Method 1
an excitation coil which excites the plurality of resonators
Implementation Method 2
a plurality of resonators having a resonance coil and a resonance capacitor... generate an alternating magnetic field with resonance frequencies different from each other
Implementation Method 3
each resonator can be prevented from influencing each other... generate an alternating magnetic field with resonance frequencies different from each other
Implementation Method 4
resonators adjacent with each other in a row direction and a column direction among a plurality of resonators to generate an alternating magnetic field with resonance frequencies different from each other
Implementation Method 5
when the foreign matter is a metal, an eddy current will generate due to the magnetic flux passing through the foreign metal, and when the foreign matter is a magnetic body, there will be a hysteresis loss due to the magnetic flux passing through the foreign magnetic body, so that the foreign matter may be heated
Implementation Method 6
an eddy current will generate due to the magnetic flux passing through the foreign metal
Implementation Method 7
when the foreign matter is a metal, an eddy current will generate due to the magnetic flux passing through the foreign metal, and when the foreign matter is a magnetic body, there will be a hysteresis loss due to the magnetic flux passing through the foreign magnetic body, so that the foreign matter may be heated
Data Source
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AI summary
The present invention aims to provide a coil unit with an improved accuracy in detecting foreign matter and an apparatus for detecting foreign matter with a better accuracy in detecting foreign matter when power is transmitted in a contactless manner. A power feeding coil unit L100 (a coil unit) is provided with a power feeding coil L1 (a coil for power transmission) and an apparatus D100 for detecting foreign matter. The apparatus D100 for detecting foreign matter is provided with a plurality of resonators R1 having a resonator coil M1 and a resonator capacitor C1 and also an excitation coil E1 for exciting the plurality of resonators R1. The plurality of resonators R1 are disposed in rows and columns to cover at least an area interlinking with a magnetic flux generated by the power feeding coil L1. The excitation coil E1 makes resonators adjacent in a row direction and a column direction among the plurality of resonators R1 to generate an alternating magnetic field with resonance frequencies different from each other within a frequency band in which the power feeding coil L1 is not excited.