Wireless Power Transmitter Control for Extended Coil Gaps
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Solution Overview
Problem
Current wireless power transfer systems are limited to small separation gaps (3-5 mm) between transmitter and receiver coils, restricting their commercial applications due to inefficiencies in power transfer over larger distances and the need for precise power control.
Innovation Solution
A wireless power transmitter design that operates at frequencies between 87 kHz and 205 kHz, using a ferrite core shielding around the coil except at the top, allowing for extended separation gaps up to 15 mm, and utilizing external power supplies with control schemes for precise power management, reducing costs and enhancing compatibility with various power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the separation gap between transmitter and receiver coils is increased beyond 3-5 mm, then the range of commercial applications is improved, but power transfer efficiency deteriorates
Solution Approach 1:
The patent changes the operating frequency parameter from the standard 6.78 MHz to an extended range of 87 kHz to 205 kHz. This frequency parameter change enables the system to maintain effective power transfer at larger separation gaps (up to 15 mm or more) while preserving power transfer efficiency, thus resolving the contradiction between increased separation gap and maintained efficiency
Solution Approach 2:
The patent implements dynamic power level control that adjusts transmission power based on the detected separation gap distance. The control circuit continuously monitors the gap and modulates the power output accordingly, allowing the system to maintain optimal efficiency across varying separation distances from 3-5 mm up to 15 mm or greater
2Measurement precision
If precision power control is implemented for extended range transmission, then power level management is improved, but device complexity increases
Solution Approach 1:
The patent incorporates a feedback control circuit that continuously monitors the separation gap distance and uses this information to adjust the power transmission level. The control circuit receives feedback about the gap distance and dynamically modifies the operating parameters to maintain precise power control, achieving high measurement precision without excessive complexity through intelligent feedback mechanisms
Solution Approach 2:
The control circuit is designed to perform multiple functions: it detects the separation gap distance, determines the appropriate power level based on the detected distance, and adjusts the transmission power accordingly. This multi-functional approach consolidates what could be separate complex subsystems into a single integrated control unit, improving power level control precision while managing device complexity
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 larger distances, increasing the range of commercial applications and reducing the need for internal voltage regulation, while maintaining thermal and charging efficiency.
Implementation Method 1
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
inductive wireless power transfer, which occurs when magnetic fields created by a transmitting element induce an electric field, and hence, an electric current, in a receiving element
Data Source
AI summary
A power transmitter for wireless power transfer includes a control and communications unit configured to provide power control signals to a power supply external to the power transmitter for controlling a power level of a power signal configured for transmission to a power receiver, the power supply configured to configure a direct current (DC) power based on the power control signals. The power transmitter further includes an inverter circuit configured to receive the DC power from the power supply external to the power transmitter and convert the input power to a power signal. The power transmitter further includes a coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face and 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.