Variable Resonance Circuit for Wireless Inductive Power Transfer
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Solution Overview
Problem
Current wireless power transfer systems face challenges in efficiently managing high power levels and reducing complexity and losses, particularly in amplitude modulation for communication and power transfer, especially in high power applications like kitchen appliances, where accurate control of amplitude variations is critical for performance and efficiency.
Innovation Solution
A power transmitter with a variable resonance circuit that adjusts its resonance frequency in response to data values, using a modulator to control the duration of fractional time intervals and impedance changes, allowing for efficient amplitude modulation and reduced complexity, enabling high power transfer with low standby power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If amplitude modulation is used for communication and power transfer in wireless inductive systems, then data transmission capability is improved, but power losses increase and efficiency decreases
Solution Approach 1:
The patent applies dynamics by making the resonance frequency variable rather than fixed. The system dynamically adjusts the resonance frequency of the transmitter circuit to match the receiver's needs, enabling efficient power transfer at different operating points while supporting communication through controlled frequency variations. This dynamic adaptation allows the system to optimize between power transfer efficiency and communication capability.
Solution Approach 2:
The patent changes the resonance frequency parameter to achieve both power transfer and communication functions. By varying the resonance frequency within a controlled range, the system can modulate power transfer levels for communication purposes without requiring separate communication coils, thereby reducing overall system losses while maintaining bidirectional communication capability.
2Reliability
If separate communication coils are used for bidirectional communication, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the transmitter resonance circuit serve multiple functions: power transfer, communication from transmitter to receiver, and communication from receiver to transmitter. By using the same resonant circuit for all these purposes through frequency modulation and demodulation techniques, the system eliminates the need for separate communication coils, reducing complexity while maintaining reliable bidirectional communication.
Solution Approach 2:
The patent merges the power transfer function and communication function into a single integrated system. The same inductive coupling path is used for both purposes, with communication achieved through modulation of the power transfer signal itself. This consolidation reduces the number of components needed while ensuring communication reliability through the established power transfer pathway.
3Power
If high power levels are transmitted wirelessly, then power transfer capability is improved, but control precision over amplitude variations deteriorates
Solution Approach 1:
The patent implements feedback by having the receiver detect the transmitter's resonance frequency and send this information back to the transmitter. The transmitter then uses this feedback to automatically adjust its resonance frequency to achieve optimal power transfer. This closed-loop control system maintains precise amplitude control even at high power levels by continuously adapting to changing conditions and ensuring accurate power delivery.
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 enhances communication and power transfer efficiency, reduces power losses, and allows for flexible operation with improved control over amplitude variations, supporting high power applications while maintaining low complexity and cost.
Implementation Method 1
a power transmitter for wirelessly providing power to a power receiver via an inductive signal... the inductive impedance comprising a transmitter coil arranged to generate the inductive signal
Implementation Method 2
power is inductively transferred from a transmitter inductor in a power transmitter device to a receiver coil in the individual devices
Data Source
AI summary
A wireless power transfer system comprises a power transmitter (101) arranged to wirelessly power a power receiver (103) via an inductive signal. The power transmitter (101) comprises a variable resonance circuit for generating the inductive signal in response to a drive signal. The resonance circuit has a variable resonance frequency and comprises a transmitter coil (121) arranged to generate the inductive signal. A driver (707) generates the drive signal for the variable resonance circuit and a modulator (711) amplitude modulates the inductive signal by varying the variable resonance frequency in response to data values for transmission to the power receiver (105). The power receiver (105) comprises a demodulator (1105) for demodulating amplitude modulation of the inductive signal and a first power extractor (1113) for extracting power from the inductive signal and for powering at least part of the power receiver. The inductive signal may be provided in addition to a higher power main power transfer signal.