Encrypted Resonant Inductive Power Transfer
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Solution Overview
Problem
Resonant inductive power transfer systems face challenges in preventing unauthorized receivers from receiving power while ensuring efficient transmission to authorized receivers, as unauthorized devices can detect and tune into the resonant frequency, leading to power theft and reduced efficiency.
Innovation Solution
Implementing an encrypted resonant inductive power transfer method where the frequency of the power transfer signal changes according to a schedule known only to the transmitter and receiver, using capacitive or inductive elements switched at moments of zero-crossing to maintain phase alignment, and synchronizing switching states between the transmitter and receiver to prevent unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resonant inductive power transfer is used for wireless power transmission, then power can be transmitted efficiently over a range of a few times the coil diameters, but unauthorized receivers can detect the resonant frequency and steal power
Solution Approach 1:
The patent applies dynamics by making the resonant frequency time-varying rather than static. The transmitter and receiver both switch between two resonant frequencies (f1 and f2) according to a predetermined sequence, creating a dynamic frequency hopping pattern that prevents unauthorized receivers from stealing power while maintaining efficient power transfer between authorized devices.
Solution Approach 2:
The patent implements periodic action through the use of a frequency hopping sequence that alternates between two resonant frequencies. Both transmitter and receiver switch frequencies periodically according to the same predetermined pattern, creating a periodic encryption scheme that allows authorized receivers to track the frequency changes while blocking unauthorized access.
2Object-affected harmful factors
If physical security measures are imposed to prevent unauthorized receivers from getting close to the transmitter, then power theft is prevented, but this adds inconvenience, delay, and cost to authorized receivers
Solution Approach 1:
The patent replaces physical security measures (mechanical barriers, access control systems, proximity restrictions) with an electronic/cryptographic security mechanism based on frequency hopping. This substitution eliminates the need for physical security infrastructure while providing equivalent protection against unauthorized power reception, thereby improving ease of operation for authorized users.
Solution Approach 2:
The patent introduces frequency hopping as an intermediary security mechanism between the transmitter and receiver. Instead of direct physical security measures, the system uses a frequency switching pattern as a mediator that authorized receivers can track through synchronization, allowing convenient access while preventing unauthorized access without physical barriers.
3Object-affected harmful factors
If the frequency of the power transfer signal changes according to an encrypted schedule, then unauthorized receivers cannot track the frequency to receive power, but this requires synchronous switching between transmitter and receiver
Solution Approach 1:
The patent applies preliminary action by establishing a predetermined frequency hopping sequence before power transfer begins. Both transmitter and receiver are pre-configured with the same frequency switching pattern, allowing them to synchronize automatically without complex real-time communication protocols, thus reducing device complexity while maintaining security.
Solution Approach 2:
The patent implements self-service through automatic frequency synchronization between transmitter and receiver. The receiver autonomously tracks the frequency hopping pattern by detecting the transmitter's frequency switches and adjusting its own resonant frequency accordingly, eliminating the need for complex external synchronization mechanisms or continuous communication overhead.
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 effectively prevents unauthorized power reception while maintaining efficient power transfer to authorized devices, reducing costs and inconvenience compared to physical security measures, and enhancing the economic effectiveness of resonant energy transfer.
Implementation Method 1
Resonant inductive coupling is the near-field wireless transmission of electrical energy between two coils that are tuned to resonate at the same frequency
Implementation Method 2
If the primary and secondary coils are resonant at a common frequency, significant power can be transmitted from the primary coil to the secondary coil
Implementation Method 3
a capacitive or inductive element is switched in or out of each circuit at moments of zero-crossing: zero charge on a capacitor or zero current in an inductor
Data Source
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AI summary
Systems and methods for ensuring that resonant inductive power transfer goes only to authorized users using encryption. Resonant inductive power transfer requires near-identical resonant frequencies in the transmitter and the receiver. The frequency of the power transfer signal changes on a schedule known only to the transmitter (1) and receiver (3) so a "power eavesdropper" cannot track the frequency well enough to efficiently receive power. To make the frequency transitions energetically efficient, a capacitive or inductive element is switched in or out of each circuit at moments of zero-crossing: zero charge on a capacitor or zero current in an inductor. To maintain phase alignment, either switching an inductor (2b) on the transmit side is nearly simultaneous with switching a capacitor (8b) on the receive side, or switching a capacitor (6b) on the transmit side is nearly simultaneous with switching an inductor (4b) on the receive side.