Conductive Loop Array for Wireless Charging Field Mapping
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Solution Overview
Problem
Current methods for testing wireless power systems face challenges in accurately measuring magnetic field density and evenness, particularly in placing and moving sensing loops over multiple locations on a wireless charging pad without disturbing the device or coil.
Innovation Solution
An apparatus comprising a plurality of conductive loops configured to sense magnetic field strength, providing a voltage signal proportional to the field strength, and a method to determine the field strength based on these signals, allowing for precise measurement of magnetic field strength across predefined spatial areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a loop is moved around the transmitter pad to measure magnetic field density, then measurement coverage is improved, but measurement precision deteriorates due to difficulty in accurate placement and movement
Solution Approach 1:
The measurement system is segmented into multiple fixed conductive loops arranged in a grid pattern across the transmitter pad surface. Each loop is positioned at a predetermined location and connected to separate measurement circuitry, allowing independent measurement at each point. This segmentation enables comprehensive coverage while maintaining precise measurements at each fixed location, resolving the contradiction between coverage and precision.
2Measurement precision
If a coil is inserted under an operating device to measure magnetic flux density, then measurement accuracy is improved, but device stability deteriorates due to disturbance caused by insertion
Solution Approach 1:
The measurement approach transitions from inserting coils vertically under the device (z-dimension) to placing conductive loops on the top surface of the transmitter pad (x-y plane). This dimensional change allows measurement of magnetic field effects without physical intrusion beneath the device, maintaining device stability while achieving accurate measurements through top-surface loop arrays that detect magnetic flux density indirectly.
3Quantity of substance
If multiple measurement locations are tested by moving a loop, then measurement completeness is improved, but measurement time increases due to manual movement and placement
Solution Approach 1:
Multiple conductive loops are pre-positioned at all desired measurement locations across the transmitter pad surface before measurements begin. Each loop is permanently or semi-permanently installed and connected to its measurement circuitry in advance. This preliminary arrangement eliminates the need for manual movement during the measurement process, allowing simultaneous or rapid sequential measurements at all locations, thus reducing total measurement time while maintaining comprehensive coverage.
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
Enables accurate and efficient testing of wireless power systems by providing a means to measure and map magnetic field strength and evenness, facilitating the design and optimization of wireless charging pads.
Implementation Method 1
a plurality of conductive loops configured to sense a strength of a magnetic field passing through a respective one of the plurality of conductive loops
Data Source
AI summary
This disclosure provides methods and apparatus for wireless power field testing. An apparatus for sensing magnetic field strength of a wireless charging pad is provided. The apparatus includes a plurality of conductive loops each configured to sense a strength of a magnetic field passing through a respective one of the plurality of conductive loops. The apparatus includes at least one pair of terminals configured to be electrically connected to one or more of the plurality of conductive loops and configured to provide a voltage signal having a magnitude proportional to the strength of the magnetic field passing through the one or more of the plurality of conductive loops. In some implementations, the apparatus further includes a multiplexer circuit configured to individually electrically connect each of at least a subset of the plurality of conductive loops to the at least one pair of terminals.