Wireless Power Keep-Out Zone Detection Using Predicted SAR
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Solution Overview
Problem
Conventional wireless charging systems face challenges in accurately distinguishing between valid receivers and foreign objects, often causing damage to sensitive items and requiring complex, costly components for beam-forming control, which complicates the charging process and increases costs.
Innovation Solution
A wireless-power transmission system using a single power amplifier to control a radiation profile, with a power amplifier controller integrated circuit and sensors to detect and classify objects, eliminating the need for beam-forming control and reducing component complexity and cost, while ensuring safe energy delivery within regulatory limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beam-forming control is used to focus energy on receivers, then power transmission efficiency is improved, but device complexity and cost increase due to multiple antennas, beam-forming algorithm control circuitry, and multiple power amplifiers
Solution Approach 1:
The patent extracts and removes the beam-forming control circuitry and algorithm processing from the system. Instead of using complex beam-forming control with multiple antennas and amplifiers, the invention uses a single power amplifier and eliminates the need for beam-forming control circuitry, thereby reducing device complexity while maintaining power transmission capability
Solution Approach 2:
The patent merges the functions of multiple antennas, multiple power amplifiers, and beam-forming control circuitry into a single power amplifier system. The single power amplifier is designed to directly provide power to the receiver without requiring separate beam-forming control components, thus combining multiple complex components into a simpler unified system
2Productivity
If conventional wireless charging systems are used, then power transmission is achieved, but foreign object detection accuracy deteriorates leading to damage of sensitive items
Solution Approach 1:
The patent introduces an intermediary foreign object detection system that operates independently of the power transmission system. This detection system uses separate sensors and processing circuitry to identify foreign objects before power transmission begins, preventing damage to sensitive items while allowing uninterrupted power transmission to valid receivers
Solution Approach 2:
The patent performs foreign object detection as a preliminary action before initiating power transmission. The system scans and identifies objects in the charging area beforehand, classifies them as valid receivers or foreign objects, and only then proceeds with power transmission to authorized devices, thereby preventing damage before it occurs
3Measurement precision
If multiple sensors and processing circuitry are added for foreign object detection, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent designs the single power amplifier to serve multiple functions: it provides power transmission to valid receivers and simultaneously enables foreign object detection through its interaction with objects in the charging area. This multi-functionality eliminates the need for separate dedicated detection hardware, reducing overall device complexity while maintaining detection accuracy
Solution Approach 2:
The system uses the power amplifier's own operational characteristics and its interaction with objects to perform foreign object detection. The detection mechanism leverages the existing power transmission infrastructure and measurements taken during normal operation, allowing the system to detect foreign objects using its own components rather than requiring external dedicated detection devices
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 system effectively differentiates between valid receivers and foreign objects, ensuring safe and efficient energy transfer without beam-forming, reducing costs and complexity, and complying with safety and regulatory standards.
Implementation Method 1
radiate RF energy that is focused within an operating area
Implementation Method 2
detecting a presence of a foreign object... based on the received impedance measurements
Data Source
AI summary
A method includes selecting a power level from among available power levels at which to amplify a radio frequency (RF) signal using a power amplifier. The method includes providing the amplified RF signal to antennas. The antennas are caused to, upon receiving the amplified RF signal, radiate RF energy within a transmission field. The method includes determining predicted specific absorption rate (SAR) values of the transmission field and determining, based on the predicted SAR values, a keep out zone within the transmission field. The keep out zone is an area at which the predicted SAR values are greater than or equal to a predetermined SAR threshold of the transmission field. The method includes receiving, from sensors, an indication that an object is within the keep out zone. The method includes in response to receiving the indication, causing the antennas to cease radiating the RF energy.