Contactless Power Transmission Coil Selection for Foreign Substance Detection
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Solution Overview
Problem
The position of a power reception coil in a vehicle varies, leading to reduced or failed power transfer efficiency due to foreign substances on the selected power transmission coil in contactless charging systems.
Innovation Solution
A contactless power transmission device with multiple power transmission coil units, a detection unit to identify foreign substances, and a control unit that selects a different coil based on the vehicle's mounting position information and guides the vehicle to a foreign-substance-free coil before charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power transmission coil is used for contactless charging, then the device structure is simple, but power transfer efficiency is reduced or charging fails when a foreign substance is present on the coil
Solution Approach 1:
The power transmission device is divided into multiple independent power transmission coils (first coil, second coil, etc.), each capable of performing contactless power transfer separately. This segmentation allows the system to switch between coils when foreign substances are detected, preventing complete charging failure and maintaining reliability while keeping each individual coil structure simple.
2Reliability
If multiple power transmission coils are used to handle varying vehicle positions, then power transfer reliability is improved, but the device complexity increases
Solution Approach 1:
Different power transmission coils are positioned at different locations to match varying vehicle mounting positions. Each coil is optimized for specific spatial zones, allowing the system to handle position variations reliably. The control unit selects the appropriate coil based on vehicle position and foreign substance detection results, managing complexity through intelligent coordination rather than simultaneous activation of all coils.
Solution Approach 2:
The system dynamically selects which power transmission coil to use based on real-time conditions including vehicle position and foreign substance detection results. This dynamic adaptation allows the system to maintain reliability across varying conditions without requiring all coils to operate simultaneously, effectively managing device complexity through selective activation.
3Reliability
If a detection unit is added to detect foreign substances, then power transfer efficiency is protected, but device complexity and cost increase
Solution Approach 1:
The detection unit performs foreign substance detection before contactless power transfer begins. By detecting foreign substances in advance, the system can prevent power transfer efficiency reduction or charging failure before they occur, rather than attempting to correct problems after they arise. This preliminary action protects power transfer efficiency while keeping the detection system relatively simple.
Solution Approach 2:
The detection unit provides feedback information about foreign substance presence to the control unit, which then adjusts power transmission coil selection accordingly. This feedback mechanism enables the system to adapt to detected conditions and maintain optimal power transfer efficiency without requiring complex real-time control during the actual power transfer process.
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
Prevents reduction in power transfer efficiency by ensuring contactless power transfer using a different power transmission coil unit when a foreign substance is detected, maintaining efficient charging.
Implementation Method 1
a power transmission device is configured to include a plurality of power transmission coils, an appropriate power transmission coil is selected from the plurality of power transmission coils in accordance with a vehicle having a power reception coil mounted therein, and power transfer is performed using the selected power transmission coil
Data Source
AI summary
A contactless power transmission device includes: a plurality of power transmission coil units; a plurality of detection units configured to detect a foreign substance on and around each power transmission coil unit; a communication unit configured to communicate with a vehicle; and a control unit configured to select one of the plurality of power transmission coil units based on information about a mounting position of a power reception device from the vehicle obtained by the communication unit, and to guide, when a detection unit detects a foreign substance at the selected power transmission coil unit, the vehicle toward a power transmission coil unit different from the selected power transmission coil unit, before the vehicle stops. This can prevent a reduction in power transfer efficiency due to a foreign substance or the like in a power transmission device including a plurality of power transmission coils.