Transmit Coil Selection Using Peak-to-Peak Voltage Detection
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Solution Overview
Problem
Existing wireless power transfer systems face high power consumption and unreliable detection of receivers and foreign objects, particularly in multi-coil designs, leading to inefficient power transfer and potential overheating.
Innovation Solution
A low-power method using average peak-to-peak amplitude measurements of tank circuit voltage potentials to identify the strongest coupling between transmit coils and detect the presence of receivers and foreign objects, utilizing a controller to select the transmit coil, which includes a controller to determine the presence of receivers and foreign objects by computing the average peak-to-peak amplitudes of the transmit coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high power is used for receiver detection in wireless charging systems, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent changes the voltage amplitude parameter from high to low by exciting the resonant tank circuit with a low voltage amplitude signal. This allows reliable detection of receivers and foreign objects through measurement of average peak-to-peak voltage amplitudes while significantly reducing power consumption compared to conventional high-power detection methods
Solution Approach 2:
The patent replaces additional dedicated detection systems with the existing resonant tank circuit by using it in a detection mode. The same circuit used for power transfer is repurposed for detection by measuring voltage amplitudes at different frequencies, eliminating the need for separate high-power detection hardware
2Measurement precision
If additional detection systems are added to distinguish receivers from foreign objects, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The resonant tank circuit is designed to perform multiple functions: it serves as both the power transfer circuit and the detection circuit. By measuring average peak-to-peak voltage amplitudes at different excitation frequencies, the same circuit identifies both receivers and foreign objects, eliminating the need for additional dedicated detection systems
Solution Approach 2:
The system uses its own existing resonant tank circuit to perform detection functions without requiring external or additional detection equipment. The circuit detects objects by measuring its own voltage response characteristics when excited at different frequencies, making the detection capability inherent to the power transfer system itself
3Duration of action of stationary object
If power is transferred to foreign objects undetected, then power transfer continuity is maintained, but harmful effects increase
Solution Approach 1:
The system performs detection before initiating power transfer by measuring average peak-to-peak voltage amplitudes of the resonant tank circuit at different excitation frequencies. This preliminary detection identifies foreign objects in advance, allowing the system to prevent power transfer to foreign objects and avoid harmful heating effects before they occur
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 method reduces power consumption by up to 90% compared to existing Qi systems while accurately detecting receivers and foreign objects, ensuring efficient power transfer and preventing power wastage.
Implementation Method 1
A low-power method using a resonant tank circuit excited with a low voltage amplitude to compute average peak-to-peak voltage amplitudes
Implementation Method 2
a transmitter of a transmitting device may generate an electromagnetic field, and a receiver of a receiving device may extract power from the electromagnetic field
Data Source
AI summary
Object detection in wireless power systems and related system, methods, and devices are disclosed. A controller for a wireless power transmitter includes a measurement voltage potential input terminal and a processing core. The processing core is to determine an average of peak to peak amplitude differences present in sampled measurement voltage potentials for each of the plurality of transmit coils, determine a lowest average of the peak to peak amplitude differences, and select a transmit coil corresponding to the lowest average of the peak to peak amplitude differences to transmit wireless power to a receive coil of a wireless power receiver. A wireless power system includes a tank circuit selectively including any one of a plurality of transmit coils.