Wireless Power Receiver Voltage Control via Series Inductor
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Solution Overview
Problem
Resonant or inductive wireless power receivers lack control over the magnetic flux applied to the receiver coil, leading to induced voltages exceeding the voltage limits of hardware and circuitry, resulting in reduced power transfer and usability.
Innovation Solution
A wireless power receiver is configured to control the induced voltage hysteretically using a comparator that compares the generated voltage to a threshold voltage, limiting it to a safe value and communicating overvoltage conditions to the transmitter, while allowing digital communications to continue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiver coil dimensions are reduced to limit induced voltage, then voltage limits are protected, but power transfer capability and positional freedom are reduced
Solution Approach 1:
The patent changes the electrical parameters of the receiver coil by introducing a series inductor that modifies the impedance characteristics. This allows the coil dimensions to remain large for optimal power transfer while the inductor limits the induced voltage to safe levels, resolving the contradiction between voltage protection and power transfer capability
Solution Approach 2:
The series inductor acts as an intermediary element between the receiver coil and the rectifier circuit. It mediates the induced voltage by limiting its magnitude while allowing the coil to maintain its full dimensions for maximum power transfer, thus protecting downstream components without sacrificing power transfer capability
2Reliability
If the receiver coil dimensions are reduced to limit induced voltage, then voltage limits are protected, but positional freedom is reduced
Solution Approach 1:
By changing the electrical parameters through the series inductor rather than physical dimensions, the system maintains the receiver coil's full size and spatial extent, preserving positional freedom while achieving voltage limit protection through electrical parameter modification
3Reliability
If voltage limiting is implemented in overvoltage state, then hardware protection is achieved, but digital communications are interrupted
Solution Approach 1:
The rectifier switches operate in periodic pulse-width modulation (PWM) cycles, switching on during portions of the AC cycle when voltage is limited and off during portions when communication occurs. This periodic switching allows both voltage protection and communication to function simultaneously without mutual interference
Solution Approach 2:
The rectifier switches dynamically adjust their on/off states based on the instantaneous voltage conditions and communication requirements. This dynamic control allows the system to provide voltage limiting when needed while maintaining communication channels open, achieving both hardware protection and information continuity
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 enables safe operation within voltage limits, maintaining maximum power transfer and positional freedom without reducing receiver coil dimensions, and allows for simultaneous overvoltage protection and digital communication.
Implementation Method 1
a transmitter can include a transmitter coil which generates a magnetic flux to be applied across a receiver coil in a receiver, wirelessly inducing current in the receiver
Data Source
AI summary
A wireless power receiver includes circuitry configured to receive a wirelessly induced voltage from a wireless power transmitter via a magnetically induced connection with the wireless power transmitter. It is determined that an overvoltage condition exists when the wirelessly induced voltage exceeds a threshold voltage, and the wirelessly induced voltage is reduced in response to determining that the overvoltage condition exists. The circuitry communicates the overvoltage condition to the wireless power transmitter via the magnetically induced connection while over-voltage protection is enabled.