Ferrite-Shielded Wireless Power Transmitter for 15 mm Charging Gaps
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Solution Overview
Problem
Existing wireless power transfer systems are limited to small separation gaps (3-5 mm) due to near-field operation, preventing effective charging through furniture or with device cases, and require granular power control for compliance with standards and efficiency.
Innovation Solution
A wireless power transmitter with a ferrite core surrounding the antenna on three sides, operating at frequencies between 87 kHz and 205 kHz, using a control and communications unit to dynamically alter the operating frequency for granular power control, and utilizing an external power supply for voltage regulation, allowing transmission up to 15 mm gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the separation gap between transmitter and receiver coils is increased beyond 3-5 mm, then the transmitter can charge through furniture and device cases, but the power transfer efficiency and operability deteriorate due to near-field limitations
Solution Approach 1:
The patent applies parameter changes by operating in the far-field regime rather than the near-field, fundamentally changing the operating conditions of the wireless power transfer system. This allows the transmitter to maintain effective power transfer at separation gaps exceeding 3-5 mm, enabling charging through furniture and device cases while avoiding the efficiency losses that plague near-field systems at such distances
Solution Approach 2:
The system dynamically adjusts its operating frequency based on the separation distance between transmitter and receiver. By tuning the frequency in real-time according to the gap distance, the system maintains optimal power transfer efficiency across varying separation gaps, resolving the contradiction between extended range and efficiency
2Productivity
If the operating frequency is dynamically adjusted for granular power control, then compliance with standards and efficiency improve, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent implements feedback mechanisms where the transmitter monitors the received signal strength and power transfer conditions, then adjusts its operating frequency accordingly. This closed-loop control enables granular power control and standards compliance while managing complexity through intelligent algorithms that adapt to real-time conditions rather than requiring overly complex hardware
3Ease of manufacture
If internal voltage regulation is eliminated and external power supplies are used, then manufacturing costs decrease and compatibility with off-the-shelf power supplies improves, but the reliability and control precision may worsen
Solution Approach 1:
The patent designs the wireless power transmitter to be compatible with multiple external power supply types and voltage levels. By making the system universal in its power input requirements, it can work with various off-the-shelf power supplies, reducing manufacturing costs while maintaining reliability through adaptive control that compensates for variations in external power sources
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
Enables efficient wireless power transfer over extended separation distances with enhanced power control, reducing costs by eliminating internal voltage regulation and improving compatibility with off-the-shelf power supplies.
Implementation Method 1
a shielding comprising a ferrite core and defining a cavity, the cavity configured such that the ferrite core substantially surrounds all but the top face of the coil
Implementation Method 2
wireless power transfer at an operating frequency selected from an operating frequency range, the operating frequency range being about 87 kHz to about 205 kHz
Data Source
AI summary
A power transmitter for wireless power transfer includes a control and communications unit configured to provide power control signals to control a power level of a power signal configured for transmission to a power receiver and including a pulse width modulation (PWM) signal generator for determining and selecting the operating frequency from the operating frequency range. The power transmitter further includes an inverter circuit configured to receive a direct current (DC) power and convert the input power to a power signal, coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face, and a shielding comprising a ferrite core and defining a cavity, the cavity configured such that the ferrite core substantially surrounds all but the top face of the coil.