Wireless Power Receiver Foreign Matter Detection via Sensor Spacing
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Solution Overview
Problem
Existing wireless power transfer devices face challenges in precisely sensing foreign matter heated to high temperatures without increasing costs, as they require a large number of temperature sensors to achieve sufficient precision.
Innovation Solution
The implementation of a power receiving and transmitting device design that incorporates a casing with a lid member allowing a magnetic field to pass through, featuring temperature sensors spaced closer together in regions of strong electromagnetic field strength, utilizing PTC thermistors connected in series, and a sensor circuit that outputs a signal when a temperature exceeds a prescribed level, allowing for efficient detection of foreign matter without excessive cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of temperature sensors are provided on the lid member to sense foreign matter with sufficient precision, then the measurement precision of foreign matter temperature is improved, but the cost of the wireless power transfer device increases
Solution Approach 1:
The patent applies local quality by providing temperature sensors at specific locations on the lid member where foreign matter is most likely to be heated. Instead of uniformly distributing sensors across the entire lid, the invention places sensors strategically at positions corresponding to regions where electromagnetic field strength is highest, thereby achieving effective foreign matter detection with fewer sensors and reduced cost.
2Measurement precision
If temperature sensors are spaced closer together at locations of strong electromagnetic field strength, then the measurement precision of foreign matter temperature is improved, but the quantity of temperature sensors increases
Solution Approach 1:
The patent implements local quality by varying the spacing of temperature sensors according to the local electromagnetic field characteristics. Sensors are spaced closer together at locations where electromagnetic field strength is strong (where foreign matter is more likely to be heated) and spaced farther apart where field strength is weak, thereby optimizing detection precision while minimizing the total number of sensors required.
Solution Approach 2:
The patent applies parameter changes by adjusting the spatial distribution parameter of temperature sensors based on the electromagnetic field strength parameter. The sensor spacing is dynamically optimized according to the field characteristics, creating a non-uniform distribution that adapts to the physical conditions of the power transfer environment.
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 enables precise sensing of foreign matter heated to high temperatures while maintaining cost-effectiveness by optimizing sensor placement and configuration within the power transfer system.
Implementation Method 1
a lid member (64) located on the power receiving unit's side and allowing a magnetic field to pass therethrough
Implementation Method 2
a plurality of temperature sensors provided at the lid member (64) and sensing in temperature a foreign matter present between the power transmitting unit (56) and the power receiving unit (20), the temperature sensors being spaced closer together at the location of a strong portion of an electromagnetic field strength generated from the power receiving unit (20) than the location of a weak portion of the electromagnetic field strength generated from the power receiving unit (20)
Implementation Method 3
the temperature sensors are PTC thermistors, respectively
Data Source
AI summary
A power receiving device includes: a power receiving unit that receives electric power from an externally provided power transmitting unit contactlessly; and a casing having the power receiving unit accommodated therein, the casing including: a lid member located on the power transmitting unit's side and allowing a magnetic field to pass therethrough, and a plurality of temperature sensors provided at the lid member and sensing in temperature a foreign matter present between the power transmitting unit and the power receiving unit, the temperature sensors being spaced closer together at the location of a strong portion of an electromagnetic field strength generated from the power receiving unit than the location of a weak portion of the electromagnetic field strength generated from the power receiving unit.