Wireless Inductive Power Transfer Standby Mode Control
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Solution Overview
Problem
Current Qi wireless power transfer standards lack the ability to efficiently manage power transfer for devices that do not require immediate power, leading to potential waste and heating issues, and struggle with detecting and adapting to various usage scenarios, especially in applications like kitchen appliances.
Innovation Solution
A wireless power transfer system that includes a standby mode where the power transmitter detects the presence of a power receiver but does not initiate power transfer until explicitly requested by the receiver, using a separate communication inductor for bidirectional communication and impedance changes to manage the transition from standby to power transfer mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power transmitter continuously provides power to the power receiver upon detecting its presence, then the power receiver can immediately receive power, but energy is wasted and heating occurs when the receiver does not need power
Solution Approach 1:
The patent implements dynamic power transfer by transitioning from a static continuous power provision model to a dynamic on-demand model. The system continuously monitors receiver power needs and adjusts power transfer accordingly, switching between standby and active power transfer states based on real-time conditions.
Solution Approach 2:
The patent employs feedback mechanisms where the power receiver communicates its power needs back to the power transmitter. The transmitter detects impedance changes in the communication inductor that indicate receiver presence and power requirements, then adjusts power transfer levels accordingly, creating a closed-loop control system.
2Device complexity
If the power transmitter uses a single inductor for both power transfer and communication, then the device complexity is reduced, but the ability to detect impedance changes for communication purposes is compromised
Solution Approach 1:
The patent segments the electromagnetic coupling function into two separate inductors: a power transfer inductor for high-power energy transmission and a communication inductor for low-power bidirectional communication. This segmentation allows each inductor to be optimized for its specific function, with the communication inductor having lower inductance suitable for detection purposes.
Solution Approach 2:
The communication inductor serves as an intermediary element that enables the power transmitter to detect receiver presence and power needs without relying on the power transfer inductor. By monitoring impedance changes in this separate communication pathway, the system can distinguish between receiver presence and actual power requirements.
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 approach allows for efficient power management, reducing waste and heating, and enables quick power delivery when needed, while maintaining low complexity and reliability, supporting a wide range of scenarios and applications, including kitchen appliances.
Implementation Method 1
a wireless inductive power transfer signal generated by the power transmitter
Implementation Method 2
a separate communication inductor for bidirectional communication
Implementation Method 3
a detector for detecting an impedance change of the communication inductor
Data Source
AI summary
A wireless power transfer system includes a power transmitter (201) arranged to provide a power transfer to a power receiver (205) via a power transfer signal. The power receiver (205) comprises a first mode controller (709) for transmitting a standby mode exit request to the power transmitter (201) by changing a loading of a communication inductor (209) of the power transmitter (201). The power transmitter (201) comprises a mode controller (405) which controls the power transmitter (201) to operate in a standby mode wherein a presence of the power receiver (205) is detected but no power transfer signal is generated. It furthermore comprises a detector (403) for detecting an impedance change of the communication inductor (209). The mode controller (405) is arranged to initiate a transition from the standby mode to a power transfer mode in response to the detector (403) detecting the impedance change.