Wireless Power Receiver Antenna Frequency Shift
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Solution Overview
Problem
Existing wireless power transmission systems face issues with electromagnetic interference and heat generation due to overlapping frequencies between power transmission and contactless IC communication, which can reduce communication distances and cause unintended heating effects, even when a contactless IC card is not intentionally mounted on a power receiving apparatus.
Innovation Solution
A power receiving apparatus with a control unit that alternately switches between power reception and communication processing, setting the resonance frequency of the power reception antenna to a lower frequency than the communication antenna to avoid resonance with the power transmission carrier frequency, thereby preventing electromagnetic interference and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power receiving apparatus uses a contactless IC function with a carrier frequency of 13.56 MHz, then wireless communication capability is achieved, but electromagnetic waves from power transmission at 6.78 MHz cause overlapping at the secondary harmonic frequency, leading to heat generation and overloading of the contactless IC
Solution Approach 1:
The patent implements time-division multiplexing where the power receiving coil alternates between power reception mode and communication mode. During communication processing, the resonance frequency of the power receiving coil is shifted away from the power transmission carrier frequency (6.78 MHz) and its harmonics (13.56 MHz), preventing resonance and heat generation while maintaining communication capability
Solution Approach 2:
The patent dynamically changes the resonance frequency parameter of the power receiving coil based on operating mode. When switching from power reception to communication, the resonance frequency is adjusted to avoid overlap with the power transmission frequency and its harmonics, thereby eliminating the harmful heating effect while preserving communication functionality
2Productivity
If the resonance frequency of the power receiving coil is set to match the power transmission carrier frequency for efficient power reception, then power reception efficiency is improved, but the communication antenna cannot detect unintentionally located contactless IC cards due to frequency overlap
Solution Approach 1:
The patent employs periodic switching between power reception and communication modes. During communication intervals, the power receiving coil's resonance frequency is shifted to allow the communication antenna to detect contactless IC cards without interference from power transmission frequencies, while maintaining high power reception efficiency during power reception intervals
Solution Approach 2:
The patent performs communication processing and detection of contactless IC cards during predetermined time intervals before or between power reception operations. This preliminary action allows the system to identify and avoid unintentional contactless IC cards before power transmission begins, preventing harmful effects while maintaining efficient power transfer
3Device complexity
If power transmission and communication are conducted simultaneously at overlapping frequencies, then system complexity is reduced, but electromagnetic interference occurs and communication distance is reduced
Solution Approach 1:
The patent implements time-division multiplexing that alternates between power reception and communication modes. This periodic switching eliminates electromagnetic interference between power transmission and communication functions while using a single shared coil structure, thus maintaining low device complexity without suffering from frequency overlap issues
Solution Approach 2:
The patent dynamically adjusts the resonance frequency of the power receiving coil based on the current operating mode. During communication mode, the resonance frequency is shifted to prevent interference with communication signals, while during power reception mode, it is tuned to the power transmission frequency for maximum efficiency, thereby resolving the contradiction between simultaneous operation and interference avoidance
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 effectively reduces electromagnetic interference and heat generation, maintaining communication distances and ensuring safe operation by isolating the power transmission and communication processes through frequency switching, even when a contactless IC card is unintentionally present.
Implementation Method 1
electromagnetic waves radiated from an antenna of a power transmission apparatus (power transmission antenna) are received by an antenna of a power receiving apparatus (power receiving antenna) to drive the power receiving apparatus
Implementation Method 2
A power receiving apparatus can be mounted with a contactless IC function or a contactless IC reader/writer function
Implementation Method 3
control to set a resonance frequency of the first antenna to be a frequency lower than a carrier frequency band of the second antenna for the execution of the communication processing
Data Source
AI summary
A power receiving apparatus includes a first antenna, a second antenna, and a control unit that executes control to exclusively and alternately execute power reception processing of wirelessly obtaining power from a power transmission apparatus via the first antenna and communication processing of wirelessly communicating with the power transmission apparatus via the second antenna, where, during execution of the communication processing, the control unit executes control to set a resonance frequency of the first antenna to be a frequency lower than a carrier frequency band of the second antenna for the execution of the communication processing.