Wireless Power Transmitter Beacon Control After Charge Completion
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Solution Overview
Problem
The A4WP standard's wireless power transfer system requires a charging completion signal from the receiver to stop charging, leading to unnecessary resource and power waste as the transmitter may reinitiate charging procedures with the same receiver.
Innovation Solution
A wireless power transmitter and receiver configuration that prevents reinitiation of charging after completion, using a control method where the transmitter enters a power save mode and only resumes operations based on specific authentication and impedance changes, thereby disabling unnecessary charging procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitter continuously monitors and reinitiates charging procedures after charging completion, then charging reliability is improved, but energy waste and operational overhead increase
Solution Approach 1:
The transmitter performs preliminary actions by entering power save mode immediately after charging completion is detected, and pre-configures authentication mechanisms to be triggered only by specific impedance changes. This prevents continuous monitoring and reinitiation of charging procedures, thereby reducing energy waste while maintaining charging reliability through event-driven resumption.
2Loss of energy
If the transmitter enters power save mode and requires authentication for resumption, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The system implements self-service by automatically detecting impedance changes that indicate the presence of a valid receiver, and autonomously triggering the authentication and charging resumption processes without requiring continuous external control or complex manual intervention. This reduces the operational complexity while maintaining energy efficiency through automated event-driven operations.
3Reliability
If the transmitter uses impedance change detection for authentication, then security is improved, but measurement precision requirements increase
Solution Approach 1:
The system utilizes changes in electrical impedance parameters as the receiver is placed on or removed from the charging surface. By monitoring these parameter changes over time and comparing them against predefined thresholds, the system achieves reliable authentication without requiring extremely high measurement precision, as the impedance changes during valid placement are typically significant and distinct from noise.
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 configuration prevents unnecessary resource and power waste by ensuring that charging is only resumed when necessary, optimizing energy efficiency and reducing operational overhead.
Implementation Method 1
A power transmission method based on the electromagnetic induction corresponds to a scheme of transmitting power between a first coil and a second coil. When a magnet is moved in a coil, an induction current occurs. By using the induction current, a magnetic field is generated at a transmitting end, and an electric current is induced according to the change in the magnetic field so as to generate energy at the receiving end.
Implementation Method 2
With respect to the resonance scheme, Prof. Soljacic of MIT announced a system in which electricity is wirelessly transferred using a power transmission principle of the resonance scheme based on a coupled mode theory even if a device to be charged is separated from a charging device by several meters. The wireless charging system of the MIT team employs the concept of resonance in physics, which describes the phenomenon in which when a tuning fork oscillates at a particular frequency, a wine glass, for example, next to the tuning fork oscillates at the same frequency.
Data Source
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AI summary
A method for controlling a wireless power transmitter for charging a wireless power receiver may comprise the operations of: transmitting power for charging; receiving a first PRU dynamic signal indicating completion of charging, from the wireless power receiver, applying a beacon for detecting the wireless power receiver through a load change to a resonance circuit of the wireless power transmitter; receiving, from the wireless power receiver, a first advertisement signal including information indicating that charging is not requested; and ignoring the advertisement signal and maintaining application of the beacon.