Wireless Power Receiver Frequency Control for Overvoltage Protection
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Solution Overview
Problem
Current wireless power charging systems face challenges in effectively protecting power receivers from overvoltage and overpower conditions, particularly due to varying power transmitter standards and limitations in existing protection techniques such as resistive loads and power termination methods, which can lead to inefficiencies and potential device damage.
Innovation Solution
A controller is used to compare the frequency of the electric current induced in the power receiving circuit against a threshold, and in response, communicates a control command to the power transmitting apparatus to modify the power charge signal, ensuring protection by adjusting the frequency or voltage to prevent overvoltage and overpower conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistive load is added directly on the charging voltage for overvoltage protection, then the power receiver can be protected from overvoltage and overpower, but the layout area increases and the solution cannot cover all power transmitter cases
Solution Approach 1:
The patent changes the protection approach from using a fixed resistive load to dynamically adjusting the switching frequency of the power receiver circuit. By varying the frequency parameter, the system can adapt to different power transmitter cases and provide protection without requiring additional physical space for resistive load components.
2Reliability
If power termination is used by sending an EPT packet to the power transmitter, then the power receiver can be protected from overvoltage and overpower, but the response time is in the order of tens of milliseconds which is too slow for dynamic protection
Solution Approach 1:
The patent implements a feedback mechanism where the power receiver continuously monitors the rectified voltage and compares it against a threshold. When overvoltage is detected, the system immediately adjusts the switching frequency in real-time, creating a fast closed-loop protection system that responds in microseconds rather than tens of milliseconds.
Solution Approach 2:
The system performs preliminary protection by proactively adjusting the switching frequency before excessive power can damage the receiver. The frequency adjustment is made in advance based on voltage threshold comparisons, preventing overvoltage conditions rather than responding after they occur.
3Reliability
If power termination is used by waiting for a timeout, then the power receiver can be protected from overvoltage and overpower, but the response time is delayed and communication errors may occur
Solution Approach 1:
The patent replaces timeout-based passive protection with active feedback monitoring. The system continuously monitors voltage levels and immediately responds to overvoltage conditions through real-time frequency adjustment, eliminating the delays inherent in timeout-based approaches.
4Reliability
If a fixed resistive load is used for overvoltage protection, then the power receiver can be protected, but the solution cannot cover all cases especially when minimizing layout area is crucial
Solution Approach 1:
The patent transitions from a static resistive load solution to a dynamic frequency adjustment mechanism. The switching frequency is continuously adapted based on real-time voltage conditions, enabling the system to handle diverse power transmitter cases and varying power levels without requiring additional physical components.
Solution Approach 2:
By changing the operating frequency parameter dynamically, the system achieves versatility across different power transmitter cases. This parameter-based adaptation allows the same circuit to effectively protect against overvoltage from various power sources without requiring multiple fixed resistive loads.
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 solution dynamically adjusts the power transfer to prevent overvoltage and overpower, enhancing the safety and efficiency of wireless charging across different power transmitter standards, thereby protecting the power receiver and maintaining optimal charging performance.
Implementation Method 1
an alternating current (AC) is applied to a power transmitting coil in a state where the power transmitting coil provided in the power transmitter is disposed proximate to a power receiving coil provided to the power receiver, and an alternating electromotive force (voltage) is induced in the power receiving coil of the power receiver to generate an alternating current in the power receiver
Data Source
AI summary
An apparatus, a method and a non-transitory computer-readable storage medium storing a program for controlling power receiving operation. The apparatus includes a controller configured to compare a frequency of an electric current generated by a voltage induced in a power receiving circuit by a magnetic field generated by a power transmitting apparatus, against a frequency threshold to determine whether the frequency is equal to or below the frequency threshold, and in response to determining that the frequency is equal to or below the frequency threshold, control a communications circuit to communicate a control command message instructing the power transmitting apparatus to modify a power charge signal used to provide the magnetic field in a manner for protecting the apparatus.