Wireless Power Receiver Modulation via Charging Current
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Solution Overview
Problem
The existing wireless power receiving devices using Qi standard face instability in communication due to modulation depth becoming zero at the cross-point of resonance frequencies and efficiency decrease due to power loss through switches and resistors, leading to inefficient data transmission.
Innovation Solution
A wireless power receiving device that modulates the charging current or current flowing into the load to induce a current component in the receiving antenna, allowing for stable AM signal transmission without frequency dependency and minimizing efficiency loss by recovering the charging current to the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If modulation is performed by changing resonance frequency, then data transmission is achieved, but modulation depth becomes zero at resonance frequency cross-point causing communication instability
Solution Approach 1:
The patent changes the modulation parameter from resonance frequency to charging current. By modulating the charging current supplied to the battery, the system avoids the resonance frequency cross-point problem where modulation depth becomes zero, thereby maintaining stable communication across all operating conditions.
2Loss of information
If switches and resistors are used for modulation, then data transmission is achieved, but power loss occurs through these components causing efficiency decrease
Solution Approach 1:
The patent extracts and removes the switches and resistors from the modulation circuit. By eliminating these power-lossy components and using only the charging circuit for modulation, the system achieves data transmission without the associated power losses, significantly improving overall efficiency.
3Productivity
If charging current is increased for faster charging, then charging speed is improved, but efficiency decreases due to power loss through modulation components
Solution Approach 1:
The patent converts the charging current, which was previously lost through switches and resistors during modulation, into a useful signal carrier. By modulating the charging current itself, the system turns what would be wasted energy into the communication medium, improving both charging speed and efficiency simultaneously.
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 achieves stable modulation without frequency dependence and limits efficiency decrease by recovering the charging current, ensuring effective data transmission and maintaining system efficiency.
Implementation Method 1
The receiving coil 302 may receive a power signal S2 from the transmitting coil 202
Implementation Method 2
Both the rectifier circuit 304 and capacitor 306 rectify and smooth a current S4, which is induced in the receiving coil 302 based on the power signal S2, and convert it to a DC voltage
Implementation Method 3
The modulator 308 modulates a coil current and a coil voltage in the transmitting coil 202 by modulating the coil current flowing through the receiving coil 302
Data Source
AI summary
The wireless power receiving device includes a receiving antenna, a rectifier circuit connected to the receiving antenna, that generates a rectified voltage, a charging circuit to receive the rectified voltage and charge a power storage device, and a modulator that modulates a voltage or current of the receiving antenna by changing a charging current of the charging circuit based on data to be transmitted to a wireless power transmitting device.