Wireless Power Transmit Coil Current Distribution Control
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Solution Overview
Problem
Current wireless power transfer systems face inefficiencies in energy transfer due to uniform current distribution in transmit coils, which can be affected by the presence of power receiving units with varying characteristics, such as metal backings, leading to suboptimal charging times and energy transfer.
Innovation Solution
The implementation of a wireless power transmitter unit with a transmit coil and reactive elements, where a controller dynamically adjusts the reactance value of these elements in response to detected characteristics of power receiving units, modifying the current distribution to enhance energy transfer efficiency and reduce charging time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform current distribution is used in transmit coil, then system complexity is reduced, but energy transfer efficiency deteriorates
Solution Approach 1:
The patent applies local quality by dividing the transmit coil into multiple sections with independent reactive elements (capacitors or inductors) that can be individually adjusted. This allows different portions of the coil to have different reactance values, creating a non-uniform current distribution that optimizes energy transfer to the receive coil while maintaining manageable system complexity through modular adjustment.
2Loss of energy
If reactive elements are added to adjust current distribution, then energy transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements parameter changes by introducing reactive elements (capacitors or inductors) connected to different sections of the transmit coil. These elements allow independent adjustment of reactance values at various coil locations, enabling optimization of current distribution and energy transfer efficiency without requiring complete redesign of the coil structure.
3Loss of time
If current distribution is modified dynamically, then charging time is reduced, but control complexity increases
Solution Approach 1:
The patent applies dynamics by making the reactance values of the reactive elements adjustable during operation. The controller can modify the current distribution in real-time based on detected characteristics of the receive coil or charging conditions, enabling optimized charging times while managing control complexity through responsive adjustment rather than static configuration.
Solution Approach 2:
The patent implements feedback by using the controller to detect characteristics of the power receiving unit and adjust the reactance values of reactive elements accordingly. This closed-loop control allows the system to optimize energy transfer and reduce charging time by continuously adapting the current distribution based on actual charging conditions.
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 increases the amount of energy transferred to power receiving units and decreases charging time by dynamically adjusting the current distribution in the transmit coil, compensating for mutual coupling changes and optimizing energy delivery.
Implementation Method 1
the transmit coil creates an alternating electromagnetic field and the receive coil takes power from the electromagnetic field
Implementation Method 2
A reactive element, as referred to herein, can include a fixed capacitor, a tunable capacitor, an inductor, such as a tunable inductor
Implementation Method 3
compensating for mutual coupling changes and optimizing energy delivery
Data Source
AI summary
Techniques for modifying the electrical current distribution of transmit coil of a wireless power transmitting unit are described. An example power transmitting unit includes a transmit coil configured to generate a magnetic field to wirelessly power a device within an active wireless charging area. The power transmitting unit can also include a power source to transmit an alternating electrical current to an input terminal of the transmit coil and a plurality of reactive elements placed in series with the transmit coil. In some examples, the plurality of reactive elements attach to the transmit coil at least a quarter of a turn from the input terminal. The power transmitting unit can also include a controller to modify a reactance value of the reactive elements to adjust a current distribution of the transmit coil in response to detecting a characteristic of a power receiving unit.