Wireless Power Receiver Load Detachment Control
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Solution Overview
Problem
Wireless power transmission systems face issues with overvoltage and potential malfunctions due to counter electromotive force generated when a load, such as a battery, is disconnected during power reception, leading to electrical disconnection and excessive voltage applied to the power receiving coil.
Innovation Solution
A power reception apparatus with a detection unit that identifies when a load is being detached and sends a request to the power transmission apparatus to stop power transmission, preventing overvoltage by managing the state transition and communication to ensure safe disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the load unit is electrically disconnected during power reception, then the power reception apparatus can operate flexibly with removable loads, but an overvoltage caused by counter electromotive force is applied to the power receiving coil causing potential malfunctions
Solution Approach 1:
The detection unit detects the detachment state of the load unit before the electrical disconnection occurs. When detachment is detected, the reception control unit proactively transmits a power transmission stop request to the transmission apparatus, stopping power transmission before the load is fully disconnected. This preliminary action prevents the generation of counter electromotive force and overvoltage that would occur if power transmission continued after disconnection.
Solution Approach 2:
The system implements a feedback mechanism where the detection unit continuously monitors the attachment state of the load unit, and this detection information is fed back to the reception control unit. Based on this feedback, the reception control unit dynamically controls the power transmission stop request transmission, ensuring power transmission is stopped at the appropriate moment to prevent overvoltage while allowing flexible load removal.
2Reliability
If the power transmission is stopped proactively when load detachment is detected, then overvoltage is prevented, but additional detection and control mechanisms are required
Solution Approach 1:
The detection unit serves as an intermediary component that bridges the physical state of load attachment and the control system. It detects the detachment state and converts it into a signal that the reception control unit can process. This intermediary simplifies the overall control mechanism by providing clear, discrete detection information rather than requiring complex monitoring of electrical parameters to infer detachment state.
Solution Approach 2:
The reception control unit automatically transmits the power transmission stop request based on the detection unit's output without requiring external intervention or complex decision-making logic. The system serves itself by using the detection information directly to control the power transmission stop, minimizing the need for additional complex control mechanisms while ensuring reliable overvoltage prevention.
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
Prevents overvoltage application and potential malfunctions by proactively stopping power transmission when there is a risk of load disconnection, ensuring the safety of the power receiving coil and connected circuits.
Implementation Method 1
a power transmission apparatus and a power reception apparatus that perform the wireless power transmission via a power transmitting coil and a power receiving coil
Implementation Method 2
A relatively large counter electromotive force can be generated at the end of the power receiving coil when the load is electrically disconnected
Data Source
AI summary
A power reception apparatus including a power receiving unit receiving electric power wirelessly supplied from a power transmission apparatus, a member capable of being in at least a first state for attachment and detachment of a load unit and a second state restricting the attachment and detachment, wherein the load unit can consume the electric power received by the power receiving unit in a state where the load unit is attached to the power reception apparatus, a detection unit detecting that the member will be turned into the first state, and a transmission unit transmitting information for requesting the power transmission apparatus to stop power transmission when the detection unit detects that the member will be turned into the first state while the power receiving unit is receiving the power from the power transmission apparatus and the load unit is consuming the power received by the power receiving unit.