Wireless Power Transmitter Feedback for Modulation Depth Noise Control
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in managing modulation depth and reducing audible noise caused by voltage changes in capacitors during in-band communication.
Innovation Solution
A wireless power transmission device that includes a transmission coil, a converter, an inverter, and a controller. The controller identifies a first voltage and its peak-to-peak value, and based on this, provides a first packet to the wireless power reception device to reduce modulation depth, thereby minimizing audible noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If in-band communication is performed using ASK modulation scheme, then information can be transmitted from wireless power reception device to wireless power transmission device, but audible noise is generated due to voltage changes in capacitors
Solution Approach 1:
The wireless power transmission device measures the voltage peak-to-peak value at a specific point in the circuit and uses this feedback information to determine whether to adjust the modulation depth. The controller continuously monitors the voltage changes and dynamically controls the modulation depth to minimize audible noise while maintaining communication functionality
Solution Approach 2:
The system dynamically changes the modulation depth parameter based on the measured voltage peak-to-peak value. When the voltage fluctuation exceeds a threshold, the modulation depth is reduced to minimize capacitor voltage changes and thereby reduce audible noise, while still allowing communication to occur
2Object-affected harmful factors
If modulation depth is reduced to minimize audible noise, then voltage changes in capacitors are minimized, but communication reliability may be affected
Solution Approach 1:
The modulation depth is not fixed but dynamically adjusted based on real-time voltage measurements. The system transitions between different modulation depth levels depending on the operating conditions, allowing it to optimize both noise reduction and communication reliability adaptively
Solution Approach 2:
The system applies partial modulation depth reduction only when necessary (when voltage peak-to-peak value exceeds the threshold), rather than continuously reducing modulation depth. This selective approach maintains communication reliability while achieving noise reduction when needed
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
The solution effectively reduces audible noise and stabilizes in-band communication by adjusting the modulation depth in response to voltage changes, enhancing the overall performance of wireless power transmission systems.
Implementation Method 1
a wireless power transmission device (e.g., a wireless power transmitter) may apply the current to a transmission coil to generate an electromagnetic field for inducing an electromotive force on a reception coil of a wireless power reception device
Data Source
AI summary
An example wireless power transmitter may include a transmission coil, a converter configured to output a driving voltage, an inverter configured to output AC power to the transmission coil using the driving voltage, and a controller. The controller may be configured to identify a first voltage at one point within the wireless power transmitter while power is wirelessly transmitted through the transmission coil. The controller may be configured to perform at least one operation for providing a first packet for reduction in modulation depth of a wireless power receiver to the wireless power receiver based on a peak-to-peak value identified to be larger than a first reference value according to the first voltage.