Wireless Inductive Power Transmitter Resonance Alignment
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Solution Overview
Problem
Wireless power transfer systems, particularly those operating in the resonant regime, face challenges with intermodulation distortion and communication performance due to mismatched resonance and drive frequencies, leading to degraded load modulation and power transfer efficiency.
Innovation Solution
A power transmitter with a resonance circuit comprising capacitive and inductive impedances, a driver generating a drive signal, and a resonance modification circuit that aligns the resonance frequency with the drive frequency by slowing state changes for a fractional time interval, allowing the drive frequency to adapt based on load estimates to optimize power transfer and communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resonance frequency of the power transmitter is aligned with the drive frequency by slowing state changes, then intermodulation distortion is reduced and communication performance is improved, but the system complexity increases due to the resonance modification circuit
Solution Approach 1:
The resonance modification circuit dynamically adjusts the resonance frequency of the power transmitter by controlling the switching timing of semiconductor devices. The state changes of capacitive and inductive elements are slowed for a fractional time interval synchronized with the drive signal cycles, allowing the resonance frequency to be dynamically aligned with the drive frequency based on load conditions, thereby reducing intermodulation distortion and improving communication reliability
Solution Approach 2:
The system changes the operational parameters of the resonance circuit by adjusting the switching timing and duration of semiconductor devices. By varying the fractional time interval during which state changes are slowed, the resonance frequency can be tuned to match the drive frequency, transforming a fixed-parameter system into a variable-parameter system that adapts to different load conditions
2Loss of energy
If the drive frequency is adapted based on load estimates to optimize power transfer, then power transfer efficiency is improved, but the device complexity increases due to the drive frequency adapter and load estimator
Solution Approach 1:
The system implements a feedback mechanism where the load estimator continuously monitors the equivalent load resistance at the transmitter, and the drive frequency adapter adjusts the drive frequency based on these load estimates. This closed-loop control allows the system to optimize power transfer efficiency by adapting the drive frequency to match changing load conditions, while the feedback from load modulation communication provides the necessary information for frequency adaptation
3Object-generated harmful factors
If the resonance frequency is aligned with drive frequency by slowing state changes, then intermodulation distortion is reduced, but the processing time and control complexity increase
Solution Approach 1:
The resonance modification is implemented through periodic action by synchronizing the slowing of state changes with the drive signal cycles. The fractional time interval during which state changes are slowed is repeated for each cycle of the drive signal, creating a periodic modulation effect that reduces intermodulation distortion without requiring continuous complex processing, thereby minimizing time loss while achieving the desired distortion reduction
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 improves power transfer efficiency, reduces intermodulation distortion, and maintains reliable communication by dynamically adapting the drive frequency to match changing load conditions, enhancing overall system performance.
Implementation Method 1
a transmitter inductor for generating a power transfer signal for wirelessly transferring power to the power receiver
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 transmitter (101)) comprises a resonance circuit (201) comprises a transmitter inductor (103) for generating a power transfer signal for wirelessly transferring power to the power receiver (105). A driver (203) generates a drive signal for the resonance circuit (201) and a resonance modification circuit (505) aligns the resonance frequency of the resonance circuit (201) with the drive frequency of the drive signal by slowing a state change for resonance circuit (201) for a fractional time interval of cycles of the drive signal. A load estimator (509) generates a load estimate reflecting an equivalent load resistor for the transmitter inductor (103) reflecting the loading of the power transfer signal. A drive frequency adapter (511) then adapts the drive frequency in response to the load estimate. The invention may in particular improve load modulation communication quality.