Wireless Power Transmitter Dither Control for Demodulation Dead Spots
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Solution Overview
Problem
Wireless power transfer systems experience stalling due to misalignment of the receiver and transmitter coils, leading to communication timeouts and failure to demodulate control error values, resulting in a repeating cycle of power transfer failure.
Innovation Solution
The transmitter perturbs its operating point by adding a dither signal, such as changes in frequency, duty-cycle, or phase, to ensure effective power level control and prevent communication failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitter operates at a fixed operating point, then the system is simple to control, but communication failures occur at certain coil alignments causing power transfer stalling
Solution Approach 1:
The transmitter dynamically adjusts its operating point by adding a dither signal to the primary current, transforming the fixed operating point into a dynamically varying one. This allows the system to escape from dead spots where communication fails, improving reliability without requiring complex additional hardware
Solution Approach 2:
The system changes the operating parameters by superimposing a dither signal on the primary current, which modulates the magnetic coupling between coils. This parameter change enables the transmitter to overcome alignment-specific communication failures while maintaining simple control architecture
2Measurement precision
If the transmitter uses a fixed frequency and duty cycle, then the control loop is stable, but demodulation fails at specific receiver alignments causing timeouts
Solution Approach 1:
The dither signal introduces a periodic modulation to the primary current at a specific frequency. This periodic action creates a time-varying magnetic field that improves demodulation accuracy by ensuring the receiver can be detected at different phases, preventing continuous power transfer interruptions
Solution Approach 2:
The system uses feedback from the receiver's response to the dither-modulated signal to adjust the operating point. This feedback mechanism ensures accurate demodulation of control error values while maintaining continuous power transfer by adapting to receiver alignment conditions
3Reliability
If the transmitter maintains a constant operating point, then the system is easy to implement, but communication timeouts occur leading to repeated power transfer stalling
Solution Approach 1:
The system transitions from a static operating point to a dynamic one by superimposing a dither signal on the primary current. This dynamic adjustment is achieved through simple signal addition in the control circuit, improving power transfer reliability without significantly increasing system complexity
Solution Approach 2:
The operating parameters (current magnitude, frequency) are changed by adding a dither component. This parameter modification enables the system to overcome communication timeouts and stalling issues while maintaining relatively simple implementation through existing control circuitry
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 stabilizes the control loop, ensuring continuous wireless power transfer by overcoming dead spots and preventing power stalling, even with varying load conditions and receiver types.
Implementation Method 1
transmitter circuitry including a transmit coil to generate a wireless power signal
Implementation Method 2
receive coil of the wireless power receiver
Data Source
AI summary
In one or more examples, an apparatus may comprise a wireless power transmitter. The apparatus may include transmitter circuitry including a transmit coil to inductively couple with a receive coil of a wireless power receiver. The apparatus may further include a controller to control the transmitter circuitry to generate a wireless power signal in the transmit coil; perform demodulation on a communication signal, modulated over the wireless power signal, in attempt to decode one or more packets from the wireless power receiver; and perturb an operating point of the transmitter circuitry responsive to identifying a failure in decoding the one or more packets.