Wireless Power Transmitter Frequency Tuning for 15 Mm Coil Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless power transfer systems are limited to small separation gaps (3-5 mm) due to near-field operation, restricting their use in applications with thicker materials or devices with obstructions, and lack granular power control, which is necessary for commercial adoption.
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 granular power control through dynamic frequency adjustment, enabling compatibility with off-the-shelf power supplies and reducing costs.
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 work with thicker materials and obstructions, but the power transfer efficiency and operability deteriorate due to near-field limitations
Solution Approach 1:
The patent applies parameter changes by operating at extended frequency ranges (87 kHz to 205 kHz) rather than fixed frequencies, and by dynamically adjusting operating parameters based on gap distance and load conditions. This allows the system to maintain efficient power transfer across varying separation gaps from 3 mm to 15 mm or more, resolving the contradiction between increased gap distance and maintained power transfer efficiency
Solution Approach 2:
The system implements dynamics through real-time adjustment of operating frequency and power levels based on feedback from the power receiver and detection of gap distance. The transmitter dynamically adapts its operating characteristics to maintain optimal efficiency across varying separation gaps, transforming a static near-field system into a dynamic extended-range system
2Measurement precision
If granular power control is implemented to meet commercial application requirements, then power level precision improves, but system complexity and control mechanism requirements increase
Solution Approach 1:
The patent implements feedback mechanisms where the power receiver communicates power requests and status to the transmitter, enabling granular power control. The transmitter uses this feedback to precisely adjust power levels in small increments, achieving high power level precision without requiring overly complex control hardware, as the control intelligence is distributed through the communication protocol
Solution Approach 2:
The system achieves granular power control using existing communication and control infrastructure designed for other purposes. The same communication channel used for device identification and basic power negotiation is extended to provide fine-grained power requests and adjustments, avoiding the need for separate dedicated control mechanisms and reducing overall system 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 and provides granular power control, expanding the range of commercial applications and reducing the need for internal voltage regulation, thus enhancing compatibility and cost-effectiveness.
Implementation Method 1
a ferrite core shielding around the coil except at the top
Implementation Method 2
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 3
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
Implementation Method 4
operates at frequencies between 87 kHz and 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.