Wireless Charging Receiver Detection via Resonant Voltage Sensing
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Solution Overview
Problem
Conventional power transfer systems experience inefficiency and power loss due to continuous power transmission without detecting the presence of a receiver device, leading to increased maintenance costs and potential damage from interconnecting wires in contact-based systems.
Innovation Solution
A wireless charging device with a control unit that detects receiver devices based on changes in capacitive and inductive voltages across a resonant capacitor and coil, allowing power transmission only when the device is present and aligned, using a low-power AC signal for detection and a high-power AC signal for charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If continuous power transmission is used in conventional charging devices, then power is always available for transfer, but power loss increases and efficiency decreases
Solution Approach 1:
The system performs preliminary detection of the receiver device using a low-power first AC voltage signal before initiating high-power charging. This preliminary action allows the transmitter to verify receiver presence and alignment, preventing unnecessary power transmission and reducing energy loss while maintaining charging efficiency when the receiver is present
Solution Approach 2:
The system uses periodic transmission of low-power detection signals to continuously monitor receiver presence without continuous high-power transmission. This periodic detection approach reduces average power consumption and energy loss while ensuring charging efficiency is maintained when the receiver is detected
2Loss of energy
If wireless power transfer is implemented, then power transmission efficiency improves, but detection of receiver device becomes necessary to prevent power loss
Solution Approach 1:
The transmitting unit serves multiple functions: it transmits both low-power detection signals and high-power charging signals using the same resonant capacitor and resonant coil. The control unit performs both detection and charging control functions. This multi-functionality reduces device complexity by eliminating separate detection hardware while still preventing power loss through intelligent signal transmission
3Loss of energy
If receiver device detection is implemented using voltage changes, then power loss is reduced, but measurement precision requirements increase
Solution Approach 1:
The system changes the power level parameter of transmitted signals - using low-power first AC voltage signals for detection and high-power second AC voltage signals for charging. This parameter change creates distinct voltage change magnitudes that are easier to detect and distinguish, reducing the measurement precision requirements while still effectively preventing power loss through accurate receiver detection
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 reduces power loss and improves efficiency by ensuring power is transmitted only when a receiver device is detected, enhancing the reliability and longevity of the charging system while minimizing electromagnetic interference.
Implementation Method 1
a transmitting unit including a resonant capacitor and a resonant coil, coupled to the driver unit
Implementation Method 2
detect a receiver device based on a change in at least one of a capacitive voltage across the resonant capacitor and an inductive voltage across the resonant coil
Implementation Method 3
detect a receiver device based on a change in at least one of a capacitive voltage across the resonant capacitor and an inductive voltage across the resonant coil
Data Source
AI summary
A wireless charging device includes a power source configured to generate a direct current (DC) voltage signal. Also, the wireless charging device includes a driver unit configured to receive the DC voltage signal and convert the DC voltage signal to a first alternating current (AC) voltage signal. Further, the wireless charging device includes a transmitting unit including a resonant capacitor and a resonant coil, coupled to the driver unit, wherein the transmitting unit is configured to receive and transmit the first AC voltage signal. Additionally, the wireless charging device includes a control unit configured to detect a receiver device based on a change in at least one of a capacitive voltage across the resonant capacitor and an inductive voltage across the resonant coil if the receiver device is positioned within a predetermined distance from the transmitting unit.