Wireless Charging Frequency Adaptation for FM Interference
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Solution Overview
Problem
Current wireless charging systems experience radio frequency interference (RFI) with FM radio channels due to the harmonics of the magnetic field used for power transfer, which affects system performance and user experience, as existing standards do not address this issue effectively.
Innovation Solution
The system detects the presence and active state of FM radios and communicates this information between the Power Transmitting Unit (PTU) and Power Receiving Unit (PRU) using Bluetooth Low Energy (BLE) or Near Field Communication (NFC), allowing the PTU to adaptively shift the fundamental frequency of the magnetic field to minimize interference, while remaining within regulatory compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless charging uses magnetic field at fixed frequency, then charging efficiency is maintained, but radio frequency interference with FM radio channels occurs
Solution Approach 1:
The patent implements dynamic frequency adjustment of the magnetic field generated by the PTU. The system continuously monitors for FM radio interference and adapts the operating frequency in real-time, transitioning from a static fixed-frequency approach to a dynamic adaptive approach that resolves the contradiction between maintaining charging efficiency and avoiding radio interference.
Solution Approach 2:
The system changes the fundamental parameter of operating frequency based on detected interference conditions. When FM radio interference is detected, the patent modifies the frequency parameter of the magnetic field to move harmonics away from the FM band (88-108 MHz), while maintaining optimal charging performance through coordinated frequency selection.
2Object-affected harmful factors
If magnetic field frequency is shifted to avoid FM interference, then radio frequency interference is reduced, but charging performance may be affected
Solution Approach 1:
The patent implements a feedback mechanism where the PRU communicates detected FM radio interference status back to the PTU. This feedback loop enables the PTU to make informed frequency adjustment decisions, shifting only when necessary and returning to optimal charging frequency when interference is absent, thus maintaining charging performance while reducing interference.
Solution Approach 2:
The system dynamically adjusts frequency based on real-time interference detection rather than operating at a permanently shifted frequency. This dynamic approach ensures charging performance is optimized during non-interference periods while automatically avoiding FM bands when interference is detected.
3Area of stationary object
If wireless charging extends operating area, then charging accessibility is improved, but coupling uniformity and interference control become more difficult
Solution Approach 1:
The patent applies different frequency settings in different spatial zones within the charging area. By detecting interference conditions at various locations and adjusting the magnetic field frequency locally adapted to each zone's characteristics, the system maintains effective charging across extended areas while controlling interference in each specific region.
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 reduces RFI between the wireless charging field and FM radio channels, enhancing user experience and system performance by moving frequency harmonics outside the FM communication channel, thus maintaining regulatory compliance.
Implementation Method 1
Wireless charging or inductive charging uses a magnetic field to transfer energy between two devices. PTUs of A4WP use an induction coil to generate a magnetic field from within a charging base station, and a second induction coil in the PRU takes power from the magnetic field
Implementation Method 2
a second induction coil in the PRU (i.e., portable device) takes power from the magnetic field and converts the power back into electrical current to charge the battery
Implementation Method 3
Magnetic resonance coupling is the near field wireless transmission of electrical energy between two coils that are tuned to resonate at the same frequency
Data Source
AI summary
The disclosure generally relates to methods, system and apparatus to optimize wireless charging while allowing FM radio reception. In an exemplary embodiment, presence of an active FM radio on a wireless platform is detected and the active FM channel is identified. To reduce radio frequency interference between the wireless charging magnetic field and the FM channel, the PTU may adaptively shift the A4WP frequency. The disclosed embodiments improve user experience with FM radios in wireless charging systems.